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1
Goater, C. P., J. D. Goss-Custard, and C. R. Kennedy. "Population dynamics of two species of intestinal helminth in oystercatchers (Haematopus ostralegus)." Canadian Journal of Zoology 73, no. 2 (February 1, 1995): 296–308. http://dx.doi.org/10.1139/z95-034.
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The cestode Micrasomacanthus rectacantha and the trematode Psilostomum brevicolle are the two most common intestinal helminths of oystercatchers, Haematopus ostralegus, on the Exe estuary, England. Each was present in 57 of 60 birds, in numbers ranging from 1 to 9833 and from 1 to 182, respectively. Cockles (Cerastoderma edule) were used as paratenic host by M. rectacantha and as second intermediate host by P. brevicolle. Over 90% of the transmission of M. rectacantha from intermediate hosts occurred in winter, between cockles and juvenile birds. Exposure to M. rectacantha was highest in cockles from muddy sites, where up to 80% of older cockles were infected with 1–14 larvae. Exposure to P. brevicolle was similarly high at one sandy site. Juveniles also made up > 90% of the birds present on the estuary in summer, when significantly more worms were gravid. Estimates based on the numbers of uterine eggs per individual P. brevicolle showed that 8 % of the total Exe population of oystercatchers (ca. 200) contributed 51% of the eggs to the estuary. The results implicate host age, host feeding preference, and host population structure as important factors determining variation in helminth abundance in birds.
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Macke, Emilie, Sara Magalhães, Hong Do-Thi Khan, Anthony Luciano, Adrien Frantz, Benoît Facon, and Isabelle Olivieri. "Sex allocation in haplodiploids is mediated by egg size: evidence in the spider mite Tetranychus urticae Koch." Proceedings of the Royal Society B: Biological Sciences 278, no. 1708 (October 6, 2010): 1054–63. http://dx.doi.org/10.1098/rspb.2010.1706.
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Haplodiploid species display extraordinary sex ratios. However, a differential investment in male and female offspring might also be achieved by a differential provisioning of eggs, as observed in birds and lizards. We investigated this hypothesis in the haplodiploid spider mite Tetranychus urticae , which displays highly female-biased sex ratios. We show that egg size significantly determines not only larval size, juvenile survival and adult size, but also fertilization probability, as in marine invertebrates with external fertilization, so that female (fertilized) eggs are significantly larger than male (unfertilized) eggs. Moreover, females with on average larger eggs before fertilization produce a more female-biased sex ratio afterwards. Egg size thus mediates sex-specific egg provisioning, sex and offspring sex ratio. Finally, sex-specific egg provisioning has another major consequence: male eggs produced by mated mothers are smaller than male eggs produced by virgins, and this size difference persists in adults. Virgin females might thus have a (male) fitness advantage over mated females.
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Colabuono, Fernanda I., Satie Taniguchi, Maria V. Petry, and Rosalinda C. Montone. "Organochlorine contaminants and polybrominated diphenyl ethers in eggs and embryos of Antarctic birds." Antarctic Science 27, no. 4 (December 15, 2014): 355–61. http://dx.doi.org/10.1017/s0954102014000807.
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AbstractOrganochlorine contaminants (OCs) and polybrominated diphenyl ethers (PBDEs) were investigated in the eggs of five bird species from the South Shetland Islands. Additionally, OCs and PBDEs were also analysed in embryos of two species. The concentration ranges in eggs were (ng g-1wet weight) 2.11 to 541 for polychlorinated biphenyls (PCBs), <0.25 to 0.88 for PBDEs, 2.45 to 405 forp,p’-DDE and 1.50 to 603 for mirex. The PCBs were predominant in the eggs ofMacronectes giganteus,Catharacta antarcticaandLarus dominicanus, whereas hexachlorobenzene (HCB) was the major compound found in the eggs ofPygoscelis antarcticusandSterna vittata. The PBDE congeners were detected only in the eggs ofC. antarctica(PBDE 47 and 153) andS. vittata(PBDE 47). There were differences in OC concentrations of up to two orders of magnitude betweenM. giganteusembryos which were related to the development stage and OC concentrations in the respective eggs. Trophic ecology and post-breeding dispersal exerted an influence on contaminant patterns. Comparisons with data from the literature indicate an increase in the concentrations of some OCs over recent years.
4
Koppenheffer, Thomas L. "“Natural” antibodies against bacterial lipopolysaccharide and lipoteichoic acid in juvenile chickens (44.36)." Journal of Immunology 178, no. 1_Supplement (April 1, 2007): S55. http://dx.doi.org/10.4049/jimmunol.178.supp.44.36.
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Abstract Naturally occurring Abs are thought to provide protection from microbial pathogens. Chickens are susceptible to, and are potential carriers of, a number of pathogenic bacteria, yet sera of adult birds contain Abs against bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA). This apparent anomaly led to undertaking a study of the production of these Abs during post-hatching development, the pattern of which may provide insight into understanding the factors that are involved in resistance to infection. Using Salmonella minnesota LPS and Staphylococcus aureus LTA as sentinel antigens in ELISA tests, relatively large amounts of LPS- and LTA-specific IgY were found in yolk of embryonated eggs and in serum of hatchlings. Thereafter, serum IgY levels declined rapidly over several weeks, but by 5–6 weeks of age some birds began to produce specific IgM and IgA Abs. Subsequently, the levels of LPS- and LTA-specific Abs of all isotypes gradually increased, approaching adult levels by 12 weeks of age. Thus, if resistance to infection is related to the levels of these Abs, chicks of about one month of age would be most susceptible to bacterial pathogens. Further, the concomitant appearance of specific Abs of all isotypes during the later phase of post-hatching development suggests that the birds in this study were sensitized through environmental exposure to bacterial cell wall antigens. Supported in part by the Ralph and Louise Bricker Memorial Endowed Fund
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Denis, D., and U. Olavarrieta. "¿Existe isomorfía en los huevos de las especies de la familia Ardeidae (Aves, Ciconiiformes)?" Animal Biodiversity and Conservation 34, no. 1 (2011): 35–45. http://dx.doi.org/10.32800/abc.2011.34.0035.
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Egg shapes in birds reflect many anatomical, biophysical and ecological aspects. In previous literature it has been assumed that a similarity in volumetric indexes from external dimensions is an indicator of constancy in shape of egret eggs (Birds, Ardeidae), but results are not consistent. Previous researchers have used lineal dimension rates to estimate shape, but these can distort the results because both aspects are orthogonal by definition. In the current research we analyze differences in egg shape between eight species of egrets and herons using elliptic Fourier descriptors and landmarks over 203 digital pictures of eggs kept in oological collections. Comparison between species and a discriminate function analysis show that shape is insufficient to distinguish species. The elongation index and breadth of eggs were significantly correlated. Our results suggest that egg shape can discriminate ecological groups but not species, indicating there is no general isomorphy in Ardeidae.
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Whitehead, PJ, WJ Freeland, and K. Tschirner. "Early Growth of Magpie Geese, Anseranas-Semipalmata - Sex-Differences and Influence of Egg Size." Australian Journal of Zoology 38, no. 3 (1990): 249. http://dx.doi.org/10.1071/zo9900249.
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The magpie goose, Anseranas semipalmata, is the most conspicuous and among the most numerous of waterfowl inhabiting the seasonal wetlands of tropical northern Australia. Modelling of juvenile growth rates of captive birds with the logistic equation showed that magpie geese grow at rates similar to the fast-growing anserine geese. High juvenile growth rates permit exploitation of seasonally favourable environments that, although highly productive, may deteriorate rapidly and unpredictably. Sex differences in juvenile growth patterns are consistent with pronounced sexual dimorphism in adult body size (larger males), which is associated with an unusual polygynous mating system. Although smaller, females grow relatively faster than males, so that at a given age they have completed a greater proportion of the pre-fledging growth phase; wing growth is particularly advanced and females fly earlier. Slower development may increase mortality among juvenile males when family groups are forced to abandon drying swamps, and contribute to skewing of the sex ratio towards females. Larger hatchlings from large eggs tend to maintain a size advantage, at least until fledging.
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Mamedova, Y. P., and A. B. Chaplygina. "Breeding of black-winged stilt Himantopus himantopus in muddy sites of a wastewater treatment plant." Biosystems Diversity 29, no. 3 (September 4, 2021): 286–93. http://dx.doi.org/10.15421/012136.
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A stable group of birds has been formed at water treatment facilities. Sewage treatment sites are a well-known nesting place for long-legged waders. Black-winged stilts are included in the Bonn (Appendix II) and Berne (Appendix II) conventions, the AEWA agreement. Listed in the Red Book of Ukraine (1994, 2009) (status – vulnerable). In Ukraine, it is under protection on the territory of the natural reserve fund. The arrival of black-winged stilts waders at the nesting sites was recorded in the second-third decade of April (April 23, 2020; April 17, 2021). Immediately after returning to the nesting areas, the birds begin to build nests and lay eggs. The first eggs in this population were seen on 01.05.2020, 07.05.2021. The process of laying eggs lasted until the end of the first decade of July (08.07.2020). The average clutch size in the nests of Himantopus himantopus decreased from 3.8 ± 0.1 (2020) to 3.5 ± 0.1 (2021). The average egg sizes and their limits have been determined for long-legged waders. The chicks hatched from late May (30.05.2020), throughout June to the first decade of July (02.07.2020). The chicks were able to fly in a month – 29.06.2020. The muddy site of the wastewater treatment ponds of Kharkiv supported Black-winged Stilts until early August. Later, the birds started post-breeding movements. The last adults with juvenile birds were observed on 13.08.2020. Stilts in some years may stay until early October. The reproductive success of the black-winged stilt increased from 35.6% (2020) to 38.8% (2021). On average, 1.3 ± 0.2 (2020) and 1.4 ± 0.3 (2021) chicks fledged from the nests. In 2021, the number of nesting stilts increased, which is apparently due to rainy weather at the beginning of the reproductive period. For the purpose of more effective protection, the nesting settlements of the stilt should be protected and the appearance of people in the nesting places should be prohibited.
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Ayorinde, K. L., and U. K. Oke. "THE INFLUENCE OF JUVENILE BODY WEIGHT AND TWO FEEDING REGIMES DURING THE GROWING PHASE ON GROWTH PERFORMANCE AND EARLY LAY CHARACTERISTICS OF PULLETS." Nigerian Journal of Animal Production 22, no. 2 (January 10, 2021): 101–7. http://dx.doi.org/10.51791/njap.v22i2.2414.
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TWO experiments were conducted using 500
Black Olympian pullets to determine the effects of Juvenile body weight (Trial 1) and feeding regime (Trial 2) on growth and early lay performances. Results in trial 1 indicated significantly (P < 0.05) higher body weight at first egg (1489.9 vs 1383.8g) and 32 weeks of age (17833 vs 1655.2g) in heavybody weight (HBW) than LightBodyweight (LBW) groups but not on other parameters. Feeding the birds ad libitum also resulted in significantly (P < 0.05) higher feed intake during the first 18 weeks of age (9036.4 vs 6803.70. 18 -32 weeks of age (14,065.9 vs 11,420.9g), weight of first egg (47.43 vs. 43.16g), hen-housed average (53.9 vs 38.7%), egg mass (2,88039 vs. 211038g), feed/ dozen eggs (22853 vs. 1768.1g), grain feed /egg (190.4 vs. 14730 and body weight at 32 weeks of age (1808.1 vs 1716.6g). The results indicated earlier age at sexual maturity,lower mortality and higher body weights in H BW and ad lib feed (AF) groups but better production efficiency (feed/dozen eggs, cost/dozen eggs) in LBW and restricted feed (RF) groups.
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Oliveira, Cleyton Washington da Silva, Glaudson Pereira Almeida, Luciana Vieira de Paiva, and Leonardo Fernandes França. "Predation on artificial nests in open habitats of central Brazil: effects of time and egg size." Biota Neotropica 13, no. 1 (March 2013): 142–46. http://dx.doi.org/10.1590/s1676-06032013000100016.
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The accuracy of artificial nests in representing natural patterns of nest predation has been widely studied in temperate regions and egg size is one of the most tested sources of bias. In the neotropics, experiments with artificial nests usually used larger than natural eggs, despite suggestions in literature that the eggs should be similar to those of the local species. Here, we tested the hypothesis of spatial-temporal variation in predation risk of artificial nests in relation to egg size. We used quail (Coturnix coturnix; large), Chestnut-bellied Seed-finch (Oryzoborus angolensis; small) and plasticine (both sizes) eggs placed in artificial nests. We analyzed daily nest survival using models in the Program MARK. The best-fit model included the effects of egg size and the reproductive period on daily survival of artificial nests. Nests with large eggs had greater Daily Survival Estimates (DSE) than nests with small eggs during two times and DSE were smaller early in the reproductive period. DSE of 0.82 (95% CI = 0.76 to 0.86) and 0.91 (0.87 to 0.93) were recorded for large eggs at the beginning and end periods compared to 0.72 (0.65 to 0.78) and 0.84 (0.79 to 0.88) for small eggs. Birds were more important predators (40% of records) than mammals and reptiles based on signs left on the plasticine eggs. Our results support the hypothesis that larger eggs are less depredated than small ones in artificial bird nests, even when main predators (birds) are different from those commonly observed in the Neotropics (mammals and reptiles). However, controlling the egg size in experiments with artificial nests may not be sufficient to obtain similar time patterns observed in natural nests studied in the Cerrado.
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Dobson, Joanna C. "‘A Menace to England’: The Egg Collector as Arch-Villain in Two 1940s Bird Novels." Literature & History 30, no. 2 (November 2021): 121–37. http://dx.doi.org/10.1177/03061973211041256.
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This paper examines the figure of the egg collector as an arch-villain in two novels about rare birds that were published in the 1940s: Adventure Lit Their Star by Kenneth Allsop, and The Awl Birds by J.K. Stanford. Drawing on insights from birdwatching literature published in the same period, I demonstrate that the extreme vilification of the egg collector in both texts represents a dramatic change in attitude towards a pastime that was previously considered beneficial for both adults and children. This about-face, I suggest, can be explained by reading the desperate rush to protect the birds’ eggs as an expression of deep contemporary anxieties over the future of Britain after the Second World War, and in particular a concern that the failures of the period after the First World War should not be repeated.
11
Falke, Cassandra. "Thinking with Birds: John Clare and the Phenomenology of Perception." Romanticism 26, no. 2 (July 2020): 180–90. http://dx.doi.org/10.3366/rom.2020.0463.
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John Clare's bird's nest poems create much of their dramatic interest by emphasising the vulnerability of the birds, the fragility of the eggs, and the interdependence of the surrounding ecosystem. This essay draws on concepts from French phenomenology to discuss the poet-speaker's embeddedness in a particular moment within that ecosystem and the extent to which his own vulnerability facilitates empathy with the birds he meets. Clare foregrounds the tension between pre-reflective processes, which Maurice Merleau-Ponty calls ‘operative intentionality’, and the categorical concepts or expectations that fail to account for these. He establishes the birds' own perceptive acts as part of what is given within operative intentionality, without claiming that his understanding is adequate to thinking with a bird or conceptualizing the delight of discovery. Jean-Luc Marion's concept of ‘saturated phenomenality’ provides a means of describing the surplus of what phenomenologists call ‘intuition’, to which Clare's bird's nest poems often attest.
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Cucco, Marco, Marco Grenna, and Irene Pellegrino. "Egg Characteristics in Relation to Skipped Days of Laying in the Grey Partridge." Avian Biology Research 10, no. 4 (November 2017): 231–40. http://dx.doi.org/10.3184/175815617x15036738758853.
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Birds sometimes skip a day along the sequence of egg laying, which may vary the mass or the composition of delayed eggs compared with those that were laid consecutively. Our literature review shows that this has been interpreted as a short-term adaptation that enables females to overcome energetic constraints during the laying period, but other hypotheses implying the influence of weather, pollution, or hormonal cycles have also been proposed. We collected freshly laid Grey Partridge Perdix perdix eggs to determine the effects of laying gaps on egg characteristics. Egg shape, as well as egg components (beta-carotene, avidin and lysozyme concentrations) did not vary in relation to skipped days. Eggs were slightly heavier when one or two days were skipped (0.72% and 0.45%, respectively). However, when examining the hatching rate, we found a significant decrease in relation to skipped days, hence eggs following laying gaps showed a lower hatching rate than other eggs. The pattern observed could indicate the presence of some physiological stress that caused females to skip one or two days and to lay eggs that hatched less.
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Robertson, H. A., R. M. Colbourne, P. Graham, P. J. Miller, and R. J. Pierce. "Survival of brown kiwi exposed to 1080 poison used for control of brushtail possums in Northland, New Zealand." Wildlife Research 26, no. 2 (1999): 209. http://dx.doi.org/10.1071/wr97001.
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All 35 radio-tagged adult brown kiwi (Apteryx mantell i) survived at least three months after being exposed to 1080 poison (sodium monofluoroacetate) during a brushtail possum (Trichosurus vulpecul a) control operation; 22 birds were exposed to 1080 in pollard baits at a loading of 0.15% w/w, and 13 birds were exposed to 1080 presented in jam baits, at a loading of 0.08% w/w. A radio-tagged juvenile was killed by a predator 2.5 months after being exposed to jam baits. In the three months after the 1080 operation, the weights of adult kiwi in the poisoned area were no different from those in neighbouring bush patches. No traces of 1080 were found in six eggs collected from the poisoned area. From subsequent captures of birds, all 35 birds are known to have survived at least six months after the operation, and 33 (94%) survived one year after exposure to 1080 baits. These results are consistent with other similar, but smaller, studies of the survival of radio-tagged kiwi exposed to 1080 poison in pollard or carrot baits. We conclude that possum-control operations using green-dyed and cinnamon-lured pollard or jam baits laced with 1080 poison pose a very low risk to brown kiwi through accidental primary or secondary poisoning, or by starvation due to a diminished supply of large invertebrates.
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Link, Jessica, Sibylle Herzog, Anna Maria Gartner, Bianca Bücking, Matthias König, and Michael Lierz. "Factors Influencing Vertical Transmission of Psittacine Bornavirus in Cockatiels (Nymphicus hollandicus)." Viruses 14, no. 12 (December 6, 2022): 2721. http://dx.doi.org/10.3390/v14122721.
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The transmission of parrot bornavirus is still not fully understood. Although horizontal transmission through wounds can be one route, vertical transmission is still discussed. PaBV RNA and PaBV antigen were detected in psittacine embryos, but isolation of the virus failed, raising doubts about this route. In this study, cockatiels were infected either as adults (adult group) or during the first 6 days after hatching (juvenile group) and raised until sexual maturity to breed and lay eggs. A total of 92 eggs (adult group: 49, juvenile group: 43) were laid and incubated until day 17. The embryos and yolk samples were examined by RT-PCR for PaBV RNA and by infectivity assay for infectious virus. In the adult group, 14/31 embryos (45.2%) and 20/39 (51%) of the yolk samples demonstrated PaBV RNA in the PCR. Isolation of PaBV was not possible in any embryo of this group, but it was achieved in six yolk samples from one female. Anti-PaBV antibodies were detected in the yolk samples after seroconversion of all female parents. In the juvenile group, 22/29 embryos (74.9%) were positive for PaBV RNA. In 9/21 embryos (42.9%), PaBV isolation was possible. PaBV RNA was detected in 100% and infectious virus in 41% of the yolk samples. Anti-PaBV antibodies were detected in all yolk samples. For the first time, successful vertical transmission of PaBV was proven, but it seems to depend on the age when the parent birds are infected. Therefore, the age of the bird at time of infection may be an important factor in the occurrence of vertical transmission.
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Horváthová, Terézia, Shinichi Nakagawa, and Tobias Uller. "Strategic female reproductive investment in response to male attractiveness in birds." Proceedings of the Royal Society B: Biological Sciences 279, no. 1726 (June 2011): 163–70. http://dx.doi.org/10.1098/rspb.2011.0663.
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Life-history theory predicts that individuals should adjust their reproductive effort according to the expected fitness returns on investment. Because sexually selected male traits should provide honest information about male genetic or phenotypic quality, females may invest more when paired with attractive males. However, there is substantial disagreement in the literature whether such differential allocation is a general pattern. Using a comparative meta-regression approach, we show that female birds generally invest more into reproduction when paired with attractive males, both in terms of egg size and number as well as food provisioning. However, whereas females of species with bi-parental care tend to primarily increase the number of eggs when paired with attractive males, females of species with female-only care produce larger, but not more, eggs. These patterns may reflect adaptive differences in female allocation strategies arising from variation in the signal content of sexually selected male traits between systems of parental care. In contrast to reproductive effort, female allocation of immune-stimulants, anti-oxidants and androgens to the egg yolk was not consistently increased when mated to attractive males, which probably reflects the context-dependent costs and benefits of those yolk compounds to females and offspring.
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Greeney, Harold Francis, Fernando Angulo P., Robert C. Dobbs, S. Crespo, Eliot T. Miller, D. Caceres, Rudolphe A. Gelis, B. Angulo, and Luis A. Salagaje M. "NOTES ON THE BREEDING BIOLOGY OF THE TUMBESIAN AVIFAUNA IN SOUTHWEST ECUADOR AND NORTHWEST PERU." Revista Ecuatoriana de Ornitología, no. 6 (March 22, 2020): 1–54. http://dx.doi.org/10.18272/reo.vi6.1146.
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This paper contributes to the growing body of literature on the reproductive biology of South American birds by providing 823 records of reproduction for 197 species breeding within the Tumbesian biome of Peru and Ecuador. Where applicable, we include notes on adult behaviour, nest architecture, eggs, nestlings, and fledglings. In general, our observations support previous reports of the seasonal nature of avian reproduction in the region.
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Nowaczewski, Sebastian, Tomasz Szablewski, Renata Cegielska-Radziejewska, and Helena Kontecka. "Egg Morphometry and Eggshell Quality in Ring-Necked Pheasants Kept in Cages / Budowa jaja i jakość skorupy u bażantów obrożnych utrzymywanych w klatkach." Annals of Animal Science 13, no. 3 (July 1, 2013): 531–41. http://dx.doi.org/10.2478/aoas-2013-0034.
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Abstract The aim of the study was to evaluate the morphometry and shell quality of eggs laid by pheasants kept in cages, and also to analyse the dependence between egg shell colour parameters, its quality and morphometric characteristics. Four groups of 15 eggs (60 eggs), each classified according to their eggshell colours, i.e. blue, light brown, dark brown and olive, were examined. The eggs did not differ significantly between each other in their mean weight and olive-coloured eggs had a higher shape index (about 8.91 percentage points) than blue eggs. Blue and light brown coloured eggs had thinner shells than the dark brown eggs (by 33.57 and 27.97 μm, respectively). Blue eggs had the lightest shells (L* = 67.97) and the highest proportion of green colour in their shells since the a* parameter value for blue eggs was negative. A significant positive correlation was observed between the egg shape and the shell colour saturation (C*) and the proportion of yellow colour (b*) in it. In addition, a negative correlation was found between lightness in eggshell colour, its thickness and the egg shape (r = from -0.338* to -0.480**). In comparison with the data obtained from the literature concerning the quality of eggs laid by pheasants kept in aviaries and eggs laid by birds kept in cages, the eggs were described as having similar weights and morphometries along with greater shell thicknesses. Furthermore, our study confirmed that pheasant eggs with blue and light brown colour have poorer shell quality, a fact which has been shown already in earlier research. However, this fact is related to the lightness of the shell pigment rather than its colour.
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Slagsvold, Tore, and Karen L. Wiebe. "Social learning in birds and its role in shaping a foraging niche." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1567 (April 12, 2011): 969–77. http://dx.doi.org/10.1098/rstb.2010.0343.
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We briefly review the literature on social learning in birds, concluding that strong evidence exists mainly for predator recognition, song, mate choice and foraging. The mechanism of local enhancement may be more important than imitation for birds learning to forage, but the former mechanism may be sufficient for faithful transmission depending on the ecological circumstances. To date, most insights have been gained from birds in captivity. We present a study of social learning of foraging in two passerine birds in the wild, where we cross-fostered eggs between nests of blue tits, Cyanistes caeruleus and great tits, Parus major . Early learning causes a shift in the foraging sites used by the tits in the direction of the foster species. The shift in foraging niches was consistent across seasons, as showed by an analysis of prey items, and the effect lasted for life. The fact that young birds learn from their foster parents, and use this experience later when subsequently feeding their own offspring, suggests that foraging behaviour can be culturally transmitted over generations in the wild. It may therefore have both ecological and evolutionary consequences, some of which are discussed.
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Lugovaya, Inessa S., Sergey V. Pozyabin, Tatyana O. Azarnova, Mark S. Naidensky, and Zoya N. Nikiforova. "NON-INVASIVE METHOD OF BIOSTIMULANT ADMINISTRATION INTO THE EGG: AN ALTERNATIVE TO IN OVO INJECTIONS." Journal of Biological & Scientific Opinion 10, no. 3 (June 30, 2022): 21–25. http://dx.doi.org/10.7897/2321-6328.103154.
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This article discusses practical aspects of a non-invasive method to administer biostimulants inside the egg versus an injection method. Considering literature data and our own long-term studies, benefits and disadvantages were identified for each method of biostimulant administration. Given a large number of small poultry farms, the non-invasive method is technologically simple and cost-effective for the poultry industry. The purpose of this research was to determine the effectiveness of certain biostimulants composition for different types of poultry in a non-invasive way of its administration. The studies were conducted on different poultry farms in the Russian Federation. The experiments used eggs of Hybrid Converter turkeys, Japanese quails, grey-speckled guineafowls, and Ross 308 broilers. Biological control indicators of incubation were recorded against hatched eggs by a method generally accepted on the poultry farms. We received positive results that proved the high efficiency of the non-invasive method of delivering biostimulants into eggs, which contributed to the increased hatchability of young birds. Thus, considering all advantages of the presented method, it can be recommended for use on poultry farms.
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Štrkolcová, Gabriela, Mária Goldová, Viliam Šnábel, Marta Špakulová, Tatiana Orosová, Miloš Halán, and Jana Mojžišová. "A frequent roundworm Baylisascaris transfuga in overpopulated brown bears (Ursus arctos) in Slovakia: a problem worthy of attention." Acta Parasitologica 63, no. 1 (March 26, 2018): 167–74. http://dx.doi.org/10.1515/ap-2018-0019.
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Abstract The genus Baylisascaris (order Ascaridida) includes numerous relatively host-specific nematodes, which are common in intestines of wild mammals. Some of them may have impact on veterinary and public health, as their larvae have the potential to cause visceral, ocular, and/or neural larva migrans in a wide range of mammals, birds, and humans. Baylisascaris transfuga is a parasite occurring in a range of bear species throughout the world. We present the current data on B. transfuga occurrence in brown bears from a relatively restricted territory of the Poľana Protected Landscape Area in Central Slovakia, obtained by traditional methods (faecal examination, morphology). Species affiliation was confirmed by employing molecular markers generating nuclear 28S and mitochondrial cox1 sequences in adult worms. Based on 17 examined samples (15 excrements and two intestines of young bear females), the occurrence of B. transfuga in the surveyed area was assessed as 52.9%. Both bear females were infected with adult and juvenile worms. Due to the high density of bears in the locality, the high infection rate with ascarids, and the huge number of eggs produced by the parasites, it is apparent that the respective environment, including the inhabited areas, might be markedly contaminated by Baylisascaris eggs. The ability of B. transfuga to serve as a zoonotic agent has not been unambiguously proved; however, this attribute should be considered and subjected to further research.
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Irfan, Muhammad, Nasir Mukhtar, Tanveer Ahmad, and Muhammad Tanveer Munir. "Gastric impaction: an important health and welfare issue of growing ostriches." Agricultura Tropica et Subtropica 53, no. 4 (December 1, 2020): 161–73. http://dx.doi.org/10.2478/ats-2020-0016.
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AbstractOstrich farming serves as a source for meat, feathers, skin, eggs, and oil. In general, ostriches are hardy birds that can resist a wide range of climatic harshness and some diseases. However, musculoskeletal and digestive complications, including the gastric impaction, remain the major cause of mortality. The gastrointestinal impaction alone is responsible for 30 – 46% of spontaneous deaths in growing ostriches. The literature review of 21 publications on this subject has shown that 90% of these incidents happen during first six months of life. The aetiology of this problem is mostly stress and behaviour-related gorging of feed and picking on non-feeding materials such as stone, sand, wood pieces, plastic, glass, and metallic objects. Conservative therapy or surgical approaches show good results with almost 70 to 100% recovery depending upon the clinical presentation and timely diagnosis. Overall, this literature review describes impaction in farmed ostriches, along with diagnosis, treatment, and control and preventive measures. This information will help stakeholders understand the gastrointestinal impaction in ratites to better manage this issue, reduce economic losses, and improve welfare of the birds.
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Giraudeau, Mathieu, and Simon Ducatez. "Co-adjustment of yolk antioxidants and androgens in birds." Biology Letters 12, no. 11 (November 2016): 20160676. http://dx.doi.org/10.1098/rsbl.2016.0676.
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Mothers can shape the developmental trajectory of their offspring through the transmission of resources such as hormones, antioxidants or immunoglobulins. Over the last two decades, an abundant literature on maternal effects in birds has shown that several of these compounds (i.e. androgens, glucocorticoids and antioxidants) often influence the same offspring phenotypic traits (i.e. growth, immunity or oxidative stress levels), making interaction effects between egg components a likely scenario. However, the potential interactive effects of maternally transmitted compounds on offspring development and potential co-adjustment of these compounds within an egg are still poorly understood. Here, we report the results of an interspecific comparative analysis on birds' egg yolk composition (i.e. androgens and antioxidants) where we found that yolk carotenoid and vitamin E concentrations are positively associated, supporting the hypothesis that these two antioxidants act in synergy. The concentrations of vitamin E also increased with increasing concentrations of testosterone. This last result confirms the emerging idea that androgens and antioxidants are co-adjusted within eggs and that maternally transmitted antioxidants might limit the potential direct and indirect effects of prenatal exposure to high testosterone levels on oxidative stress.
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Wada, Haruka, Buddhamas P. Kriengwatana, Todd D. Steury, and Scott A. MacDougall-Shackleton. "Incubation temperature influences sex ratio and offspring’s body composition in Zebra Finches (Taeniopygia guttata)." Canadian Journal of Zoology 96, no. 9 (September 2018): 1010–15. http://dx.doi.org/10.1139/cjz-2017-0099.
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Incubation temperature has the potential to influence offspring sex, phenotype, and survival, particularly in species with temperature-dependent sex determination. However, relatively little is known about how incubation temperature affects sex ratio and offspring condition in other animals. Incubating birds allocate varying time for egg incubation depending on the parents’ condition and ambient temperature, likely altering nest microclimate. To understand how incubation temperature impacts offspring phenotype in birds, we artificially incubated Zebra Finch (Taeniopygia guttata (Vieillot, 1817)) eggs at 36.2, 37.4, or 38.4 °C during the entire incubation period and examined sex ratio and offspring quality. We found that incubation temperature of 36.2 °C resulted in a greater likelihood of a young being male compared with 37.4 °C, indicating that it is more likely for males to survive until the juvenile stage compared with females in the 36.2 °C group. We also found sex-specific effects of incubation temperature on body composition. Although incubation temperature did not affect fat or lean mass of female young, male offspring from the 38.4 °C group had significantly less lean mass throughout their lives compared with males from 37.4 or 36.2 °C. This study shows that there are sex differences in the effects of incubation temperature, and variable incubation temperature has a capacity to influence offspring secondary sex ratio and body condition in songbirds.
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Chepiha, A. M., S. O. Kostenko, P. V. Korol, M. S. Doroshenko, O. M. Konoval, Lu Lizhi, Bu Xingcheng, Huang Linlin, Huang Xuetao, and Li Liumeng. "ANALYSIS OF PHYSICO-MORPHOLOGICAL PARAMETERS AND INCUBATION ABILITY OF EGGS OF DUCKS BREEDS SHAOXING IN DIFFERENT AGES." Animal Breeding and Genetics 54 (November 29, 2017): 119–26. http://dx.doi.org/10.31073/abg.54.15.
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The main biological functions of eggs include its ability to create optimal conditions for embryos, which, accordingly, contributes to the preservation and reproduction of the species. It is recommended for incubation to take eggs from physiologically healthy, mature birds, because the quality of the incubation eggs depends on the yield of the young, the vitality and productivity of the poultry. A prerequisite for a successful incubation is the assessment of eggs for a variety of morphological characteristics, but this can not be done without taking into account the biological features of incubation eggs associated with breed, crossbreed and bird age. It is known that with the age of the bird, the morphological parameters of the egg and its incubation capacity are changing. In particular, the weight and shape of the egg vary during the period of increasing the bird's egg-laying. The chicken egg has been extensively studied in the world and national scientific literature, its quality and composition, but over the past decades eggs of various types of poultry have been entered into the field of research: turkeys, guinea fowl, quails, ostriches and ducks. The Shaoxing Species (Shaoxing) belongs to the main Chinese egg rocks. Ducks of this breed are characterized by high performance, such as early maturity (130–140 days), long-term peak period of laying eggs (8–10 months) and good breeding (290–310 eggs for 500 days). Such indicators are some of the best for egg bird. That is why the purpose of the work was to determine the effect of the physico-morphological indices of the egg, the age of the bird and the color of the shell on the incubation properties of the eggs of the ducks of the Shaoxing breed. Three comparative analyzes of morphological parameters and their influence on the incubation capacity of eggs were selected from three experimental groups of ducks of the Shaoxing of different ages. Group number 1 carried eggs from females age 41 week, group number 2–63 weeks, and females group number 3 had an age of 71 weeks. The study of changes in the physico-morphological parameters of eggs and incubation ability was investigated within three months. A total of 360 eggs were analyzed. As a result of the experiment, the mass of experimental eggs ranged from 65.83 g (group 1) to 71.13 g (group 3). Between these indicators, a significant difference was found (p ˂ 0,01). Comparison of the studied physico-morphological characteristics of the groups number 1, number 2 and number 3 showed that there is a significant difference between the indices of longitudinal and transverse diameters in the eggs of the studied groups (p ˂ 0,01). Investigation of the thickness of the egg shell has shown that, according to the results, this ostentatious decreases with age (p ˂ 0,05). The obtained data coincide with the results of other researchers. After analyzing the data of the egg shape index, it was found that in the birds of the three studied groups, the average figures were in line with the norm. However, a significant difference was found between the characteristics of groups 1 and 3 (p ˂ 0.1). After analyzing the results of the incubation of eggs from the experimental groups of ducks, we found that the highest fertility of the eggs of group 3 was 92.5%, compared with the group 2–89.16% and 1–87.5%. According to the index of egg output and ducklings, the leader, the group was 3 (75.0%). The results obtained fully correspond to the data obtained from these physical and morphological studies of these eggs. The worst indices of both egg and duckin removal were in group 1. It should also be noted that this group had the largest number of choked (6.67%) and unfertilized eggs (15 pcs.), But these parameters decreased with the age of bird. Consequently, we have established that with the age of birds there is a change in the physical and morphological parameters of eggs (increase in weight, decrease in the thickness of the shell and increase in the index of suitability of eggs for incubation). The general tendency to reduce the embryonic viability of the duckies associated with the mass (group 1) and the form index (group 2) has also shown that eggs of medium size that are not below the standards for the breed standard by mass and index should be selected for incubation forms (group 3). There was a correlation between the incidence of egg incubation and the index of form in group 3, which had a direct impact on incubation and egg output.
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Kjelland, Michael E., Ben Novak, Alice Blue-McLendon, Salvador Romo, and Duane C. Kraemer. "Manipulating the Avian Egg: Applications for Embryo Transfer, Transgenics, and Cloning." Avian Biology Research 10, no. 3 (August 2017): 146–55. http://dx.doi.org/10.3184/175815617x14951979279268.
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In vitro production of germline chimeras and avian cloning may utilise the transfer of avian embryos from their original eggshell to a surrogate eggshell for culture during incubation. Such embryo transfer is valuable for avian cloning as the only alternative would be to transfer the cloned avian embryos into the infundibulum of recipient birds. Given the advances in paleogenomics, synthetic biology, and gene editing, a similar approach might be used to generate extinct species, i.e. de-extinction. One objective of the present research was to examine if ratite eggs could be manipulated via windowing and sham injection, similar to that which could allow for avian genome manipulation and subsequent development. The efficiency of interspecific avian embryo transfer using Chicken ( Gallus gallus domesticus) donor eggs and Turkey ( Meleagris gallopavo) recipient eggshells was also investigated. Egg windowing and embryo transfer techniques utilised in the present research were adapted from those found in the scientific literature. Presumed fertile eggs from Rhode Island Red ( n = 40), Silkie ( n = 2), and White Leghorn Chickens ( n = 18), Turkey ( n = 48), Emu ( Dromaius novaehollandiae) ( n = 79), and Ostrich ( Struthio camelus) ( n = 89) were used in this research. Of the 41 Chicken eggs used for transfers into recipient Turkey eggshells, only one (2.4%) produced a chick. Of 31 windowed Emu eggs, one embryo survived for 25 d but no chicks were produced. Of 36 windowed Ostrich eggs, one embryo survived and hatched. The efficiency of the windowing and embryo transfers to produce chicks was low and further refinements are needed. Importantly, the results herein establish that manipulating ratite embryos is possible.
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Schoenjahn, Jonny, Chris R. Pavey, and Gimme H. Walter. "Why female birds of prey are larger than males." Biological Journal of the Linnean Society 129, no. 3 (January 16, 2020): 532–42. http://dx.doi.org/10.1093/biolinnean/blz201.
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Abstract The causes of the reversed sexual size dimorphism (RSD; females larger than males) in birds of prey are subject to a centuries-old, passionate debate. A crucial difficulty is to distinguish whether the postulated benefits derive from the proposed causal process(es) or are incidental. After reviewing the existing literature, we present a methodology that overcomes this difficulty and renders unnecessary any speculative a priori distinctions between evolved function and incidental effects. We can thus justify the following novel version of the well-known nest defence hypothesis as the most likely to explain the phenomenon in all birds of prey that show RSD: if the female predominates in actively defending the eggs and young against predators, then she is the heavier sex, and her relatively greater body mass is adaptive. That is, heavier females are favoured (independently of males) by natural selection. The attractiveness of this hypothesis is that it has the potential to explain the phenomenon in all raptors exhibiting RSD, can deal with the exceptional cases in this group, explains the direction of the dimorphism, focuses on a key factor in the reproductive success of most raptors, is parsimonious, i.e. does not require supporting hypotheses, and is supported by a substantial body of evidence.
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Tyler, Stephanie J., and L. Tyler. "The Rufous-throated Dipper Cinclus schulzi on rivers in north-west Argentina and southern Bolivia." Bird Conservation International 6, no. 2 (June 1996): 103–16. http://dx.doi.org/10.1017/s0959270900003014.
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SummarySurveys of river birds were made in north-west Argentina in October 1993 and in southern Bolivia in December 1994. Data were collected on foraging behaviour, breeding biology and breeding abundances of the Rufous-throated Dipper Cinclus schulzi (a threatened species) on three river systems in Tucumán and Jujuy provinces in Argentina and on two river systems in Tarija department in Bolivia. Rufous-throated Dippers foraged from wetted rocks and when standing in water in riffles and on the edges of cascades and waterfalls; swimming or diving was not observed. Five nests were found in Argentina, two of which were incomplete. One had a clutch of two eggs and another contained two well-grown, feathered nestlings; the fifth was inaccessible. These records indicate that breeding starts early in the Argentinian spring. Nests of adjacent pairs of Rufous-throated Dippers were from c.650–1,200 m apart. Juvenile plumage resembles that of the adult. Some information is provided on the biometrics of seven birds caught in mist-nets, and on vocalizations and on the relative abundance of dippers, Torrent Ducks Merganetta armata and two species of Cinclodes. Possible threats to rivers within the range of the Rufous-throated Dipper include reservoir construction, hydroelectric and irrigation schemes, eutrophication, deforestation and stock-grazing. Pollution, reduced flows and river channel modification are more prevalent at lower altitudes below the breeding range of the Rufous-throated Dipper.
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Du, Wei-Guo, Richard Shine, Liang Ma, and Bao-Jun Sun. "Adaptive responses of the embryos of birds and reptiles to spatial and temporal variations in nest temperatures." Proceedings of the Royal Society B: Biological Sciences 286, no. 1915 (November 20, 2019): 20192078. http://dx.doi.org/10.1098/rspb.2019.2078.
Full textAbstract:
Natural nests of egg-laying birds and reptiles exhibit substantial thermal variation, at a range of spatial and temporal scales. Rates and trajectories of embryonic development are highly sensitive to temperature, favouring an ability of embryos to respond adaptively (i.e. match their developmental biology to local thermal regimes). Spatially, thermal variation can be significant within a single nest (top to bottom), among adjacent nests (as a function of shading, nest depth etc.), across populations that inhabit areas with different weather conditions, and across species that differ in climates occupied and/or nest characteristics. Thermal regimes also vary temporally, in ways that generate differences among nests within a single population (e.g. due to seasonal timing of laying), among populations and across species. Anthropogenic activities (e.g. habitat clearing, climate change) add to this spatial and temporal diversity in thermal regimes. We review published literature on embryonic adaptations to spatio-temporal heterogeneity in nest temperatures. Although relatively few taxa have been studied in detail, and proximate mechanisms remain unclear, our review identifies many cases in which natural selection appears to have fine-tuned embryogenesis to match local thermal regimes. Developmental rates have been reported to differ between uppermost versus lower eggs within a single nest, between eggs laid early versus late in the season, and between populations from cooler versus warmer climates. We identify gaps in our understanding of thermal adaptations of early (embryonic) phases of the life history, and suggest fruitful opportunities for future research.
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Habachi, Rachid, Abdellah Boulal, Achraf Touil, Abdelkabir Charkaoui, and Abdelwahed Echchatbi. "Economic and emission dispatch using cuckoo search algorithm." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 5 (October 1, 2019): 3384. http://dx.doi.org/10.11591/ijece.v9i5.pp3384-3390.
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<p class="Default">The economic dispatch problem of power plays a very important role in the exploitation of electro-energy systems to judiciously distribute power generated by all plants. This paper proposes the use of Cuckoo Search Algorithm (CSA) for solving the economic and Emission dispatch. The effectiveness of the proposed approach has been tested on 3 generator system. CSA is a new meta-heuristic optimization method inspired from the obligate brood parasitism of some cuckoo species by laying their eggs in the nests of other host birds of other species.The results shows that performance of the proposed approach reveal the efficiently and robustness when compared results of other optimization algorithms reported in literature</p>
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Zimmermann, Karen, and J. Mark Hipfner. "Egg Size, Eggshell Porosity, and Incubation Period in the Marine Bird Family Alcidae." Auk 124, no. 1 (January 1, 2007): 307–15. http://dx.doi.org/10.1093/auk/124.1.307.
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Abstract Although the ultimate factors that influence the duration of avian incubation periods are well known, we know much less about the proximate mechanisms by which birds adjust incubation period in response to selection. We tested the hypothesis that an adjustment in eggshell porosity is one such proximate mechanism (i.e., that avian species with higher ratios of incubation period to egg size lay eggs with less porous shells). Eggshell porosity affects the rate of gaseous exchange between the developing embryo and the external environment; thus, to the extent that embryonic metabolism is diffusion-limited, eggshell porosity could directly determine incubation period. To test that hypothesis, we collected eggs from seven species of Alcidae, a family of marine birds that exhibits an unusual degree of interspecific variation in incubation period, and measured egg mass and eggshell porosity (determined by the number and size of pores and the thickness of the shell). Incubation periods were obtained from the literature. Egg mass and eggshell porosity combined explained 87% of the variation in incubation period among the seven species, which included at least one member of each of the six main alcid lineages. As predicted, eggshell porosity and incubation period were negatively related, after controlling for egg mass. Our results are consistent with the hypothesis that evolutionary changes in avian incubation period may be attributed, at least in part, to adjustments in eggshell porosity. Taille de l’Œuf, Porosité de la Coquille et Période d’Incubation chez les Oiseaux Marins de la Famille des Alcidés
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Horner, John R. "Dinosaur behavior and growth." Paleontological Society Special Publications 6 (1992): 135. http://dx.doi.org/10.1017/s247526220000695x.
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Geological and paleontological data derived from the Upper Cretaceous Two Medicine Formation of Montana indicates that at least some dinosaur species exhibited complex social behaviors comparable to many living birds. Two species of duck-billed dinosaurs, a hypsilophodontid and a troodontid, nested in colonies and attended their respective young. Duckbilled dinosaurs had altricial young, whereas the hypsilophodontid and troodontid had precocial young. Morphological evidence indicates that several of the cranial elements of the nestling duckbills experienced retarded development, and a retention of juvenile features. Following their respective nesting periods duck-billed and horned dinosaurs aggregated into large herds, and apparently migrated seasonally. Cranial ornamentations possessed by duck-billed and horned dinosaurs were most likely used for sexual display and mate recognition.Osteohistological data indicates that the duck-billed dinosaurs hatched from their eggs at .50 to .75 meters in length, and exited their nests at 1.5 to 2 meters in length, at an age of about one month. These dinosaurs reached 3 to 4 meters in length their first year, and 7 to 8 meters in length after about 5 years. Growth and metabolic rates decreased substantially upon reaching adult size.
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Karthik, N., A. K. Parvathy, and R. Arul. "Non-convex Economic Load Dispatch using Cuckoo Search Algorithm." Indonesian Journal of Electrical Engineering and Computer Science 5, no. 1 (January 1, 2017): 48. http://dx.doi.org/10.11591/ijeecs.v5.i1.pp48-57.
Full textAbstract:
<p>This paper presents cuckoo search algorithm (CSA) for solving non-convex economic load dispatch (ELD) problems of fossil fuel fired generators considering transmission losses and valve point loading effect. CSA is a new meta-heuristic optimisation technique inspired from the obligate brood parasitism of some cuckoo species by laying their eggs in the nests of other host birds of other species. The strength of the proposed meta-heuristic optimization technique CSA has been tested and validated on the standard IEEE 14-bus, 26-bus and 30-bus system with several heuristic load patterns. The results have indicated that the proposed approach is able to obtain significant economic load dispatch solutions than those of Firefly Algorithm (FFA) and other soft computing techniques reported in the literature.</p>
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MacDonald, Ian F., Bethany Kempster, Liana Zanette, and Scott A. MacDougall-Shackleton. "Early nutritional stress impairs development of a song-control brain region in both male and female juvenile song sparrows ( Melospiza melodia ) at the onset of song learning." Proceedings of the Royal Society B: Biological Sciences 273, no. 1600 (August 15, 2006): 2559–64. http://dx.doi.org/10.1098/rspb.2006.3547.
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Birdsong is a sexually selected trait and is often viewed as an indicator of male quality. The developmental stress hypothesis proposes a model by which song could be an indicator; the time during early development, when birds learn complex songs and/or local variants of song, is of rapid development and nutritional stress. Birds that cope best with this stress may better learn to produce the most effective songs. The developmental stress hypothesis predicts that early food restriction should impair development of song-control brain regions at the onset of song learning. We examined the effect of food restriction on song-control brain regions in fledgling (both sexes, 23–26 days old) song sparrows ( Melospiza melodia ). Food restriction selectively reduced HVC volume in both sexes. In addition, sex differences were evident in all three song-control regions. This study lends further support to a growing body of literature documenting a variety of behavioural, physiological and neural detriments in several songbird species resulting from early developmental stress.
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Pener, M. P., S. S. Tobe, and B. Stay. "Effects of a synthetic precocene on late embryos and subsequent development of the cockroach Diploptera punctata." Canadian Journal of Zoology 66, no. 10 (October 1, 1988): 2295–300. http://dx.doi.org/10.1139/z88-340.
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Precocene III (PIII, 7-ethoxy-precocene II), dissolved in acetone, was applied to eggs in the brood sac of Diploptera punctata females, at 55–56 days or 62–63 days (about 83.5 ± 1.0% or 95.5 ± 1.0% of the gestation period, respectively) after the mother's ecdysis to adult. Controls received acetone alone or no treatment. Acetone itself induced abortion in many instances and reduced the number of surviving progeny from those females that did give birth. These lethal effects were more pronounced after PIII treatment. A portion of the surviving nymphs that had been treated as eggs with PIII developed normally up to the fourth stadium, although the duration of this development, especially that of the first stadium, was longer than in the controls. In contrast, another portion of the nymphs that had hatched from precocene-treated eggs exhibited disturbed development. Treatment of the eggs in 55- to 56-day-old mothers with the highest dose still permitting hatching (40 μg of PIII in 2 μL of acetone, into the brood sac) yielded the highest proportion of disturbed development. In almost all instances of such disturbed development, the moult from the second to the third stadium was greatly delayed and the insects died in or shortly after an unsuccessful ecdysis, some of them exhibiting slightly prothetelic wings. No sign of precocious metamorphosis was observed in the first or second stadium. These results are compared with those in the literature on the effects of surgical allatectomy of the second and later instars of D. punctata. The morphogenetic role of the juvenile hormone in the early part of postembryonic development is also discussed.
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Spencer, KA, S. Harris, PJ Baker, and IC Cuthill. "Song development in birds: the role of early experience and its potential effect on rehabilitation success." Animal Welfare 16, no. 1 (February 2007): 1–13. http://dx.doi.org/10.1017/s0962728600030876.
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AbstractEnvironmental conditions during the early life stages of birds can have significant effects on the quality of sexual signals in adulthood, especially song, and these ultimately have consequences for breeding success and fitness. This has wide-ranging implications for the rehabilitation protocols undertaken in wildlife hospitals which aim to return captive-reared animals to their natural habitat. Here we review the current literature on bird song development and learning in order to determine the potential impact that the rearing of juvenile songbirds in captivity can have on rehabilitation success. We quantify the effects of reduced learning on song structure and relate this to the possible effects on an individual's ability to defend a territory or attract a mate. We show the importance of providing a conspecific auditory model for birds to learn from in the early stages post-fledging, either via live- or tape-tutoring and provide suggestions for tutoring regimes. We also highlight the historical focus on learning in a few model species that has left an information gap in our knowledge for most species reared at wildlife hospitals.
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Stegeman, Nadia, Emily Christiansen, and Mark Pokras. "Emaciation as a Manifestation of Acanthocephaliasis in the Common Eider (Somateria mollissima)." Wildlife Rehabilitation Bulletin 26, no. 2 (December 31, 2008): 36–41. http://dx.doi.org/10.53607/wrb.v26.152.
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An annual die–off of juvenile common eiders (Somateria mollissima) occurs during late winter/early spring in coastal New England. Abnormally high mortality events, including significant numbers of adult birds, have occurred concurrently with die–offs of eiders’ primary food source, blue mussels (Mytilus edulis). In these situations, eiders are forced to switch to less preferred prey such as shore crabs (Carcinus and Hemigrapsus spp.). This species of shore crabs are a known intermediate host for acanthocephalan parasites (thorny–headed worms). Severe emaciation following infection with the acanthocephalan (Polymorphus botulus) is the common finding of an elevated mortality event in spring of 2006. This paper describes clinical presentations of eiders found during annual die–off periods and discusses possible treatment approaches identified in literature.
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Klop, Erik, Eberhard Curio, and Lucia L. Lastimoza. "Breeding biology, nest site characteristics and nest spacing of the Visayan Tarictic Hornbill Penelopides panini panini on Panay, Philippines." Bird Conservation International 10, no. 1 (March 2000): 17–27. http://dx.doi.org/10.1017/s0959270900000022.
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Monitoring of nests of the Visayan Tarictic Hornbill Penelopides panini panini on the Philippine island of Panay revealed thus far undescribed information on the breeding biology of this species. Females occupied nest holes in March–April, after which two or three eggs are laid. Although cooperative breeding is suspected for the genus, at two nests no helpers were recorded. Nest-concealment behaviour was observed in the adult male. After a nestling period of 55–58 days, the adult female and one juvenile left the nest simultaneously. Immature birds resemble their respective sex. Nest site characteristics of 24 nests of the Tarictic Hornbill and two of the Writhed-billed Hornbill Aceros waldeni, respectively, were recorded on Mt Balabag, Panay Mountain Range. Tarictic Hornbill nests were situated in living as well as dead trees, at an average height of 11 m. Cavity compass direction was uniformly distributed around the circle. Nests are aggregated within the habitat, with a mean nearest-neighbour distance of 190 m. Writhed-billed Hornbills may require larger trees for nesting than Tarictic Hornbills. Nest density was calculated to be around three Tarictic Hornbill nests and 0.2–0.3 Writhed-billed Hornbill nests per square kilometre. Given a total amount of suitable hornbill habitat on Panay of 225–450 km2, about 750–1,000 Tarictic Hornbill breeding pairs and 60-100 Writhed-billed Hornbill breeding pairs may remain on Panay.
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Morandin, Lora A., and Patrick D. O’Hara. "Offshore oil and gas, and operational sheen occurrence: is there potential harm to marine birds?" Environmental Reviews 24, no. 3 (September 2016): 285–318. http://dx.doi.org/10.1139/er-2015-0086.
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Hydrocarbon discharges into the ocean, both regulated and accidental, occur from offshore drilling and production operations, and can result in oil sheen (≤3 μm thick) and slick (>3 μm thick) formation, potentially harming marine birds. Sheens may commonly occur around offshore oil and gas platforms in Atlantic Canada, however, there is little information on regularity of occurrence. Further, there are few direct studies on potential impacts of sheens, associated with offshore oil and gas operations, on marine birds. We reviewed potential sources and frequency of hydrocarbon accumulation on sea surfaces from offshore oil and gas operations in Atlantic Canada, and the likelihood of overlap with marine birds. We conducted a literature review on lethal and sub-lethal effects of low levels of oil contact and ingestion on marine birds, focusing on studies that describe measured dosages of oil. We extrapolated from these data on low-dose oil exposure to link possible effects to marine birds resulting from exposure to sheens. We found that sheens occur around production operations in Atlantic Canada at allowable levels of oil concentrations in produced water. Frequency and extent of occurrence cannot be estimated from current monitoring practices. While immediate lethal effects to seabirds likely are not common from external oiling of feathers from sheens, added stressors, such as cold weather, can result in external oiling from sheens having significant impact on seabird metabolic rate and can be ultimately lethal. Ingestion of small amounts of oil, doses that realistically could be expected from exposure to sheens, in some cases resulted in sub-lethal effects to adult seabirds, primarily affecting metabolic rate, sub-lethal health impacts, and reproductive output. Nestlings and eggs do not come in direct contact with sheens, yet these life stages are highly sensitive to oil, and transfer of oil from adults exposed to sheens likely is above tolerance levels at times. Negative effects to reproductive output from small doses of ingested oil could be causing undetected impacts on marine birds and marine bird populations. Lack of standardized monitoring of marine bird contact with sheens and potential harm makes assessments of magnitude and extent of impact problematic.
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Tubelis, Dárius P. "Citizen Science for the Knowledge of Brazilian Birds: Breeding Aspects of the Horned Sungem (Heliactin bilophus) (Aves, Trochilidae) in the Brazilian Cerrado." International Journal of Zoology and Animal Biology 5, no. 3 (2022): 1–6. http://dx.doi.org/10.23880/izab-16000375.
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Photographic records produced by citizen scientists have been used by professional ornithologists to study tropical birds. Near 90 species of hummingbirds occur in Brazil, and few of them have had aspects of their breeding investigated in detail. The Horned Sungem Heliactin bilophus is a small hummingbird commonly found in central Brazil, and remains poorly known. This study aimed to investigate breeding aspects of H. bilophus in the Brazilian Cerrado through the use of citizen science data. Searches for photographic records were conducted in three online databases in April 2022. Records with evidences of breeding activities (n = 35) were obtained by citizens along 15 years, and included in this study. Most of them (89%) were obtained in the WikiAves database. They were obtained mainly in central and southeastern Cerrado. Nests were cup-shaped, and fixed to forking branches of shrubs. Most records involved nests, while a minor portion referred to young photographed outside nests. Only female adults were associated with nests or young. Clutch size was always two eggs (n = 6). One or two young were found per nest (n = 10). Most records (66%) occurred in the dry season, and fewer of them (34%) were obtained in the rainy season. They were concentrated during the whole dry season, and the late rainy season, having occurred scarcely in other periods of the year. Each phase of the breeding season (nest building, nests with eggs, downy young, greenish young in nests, and fledged young) lasted for 5-7 months. The breeding season of the Horned Sungem in the Brazilian Cerrado comprises at least 10 months, a period much longer than that considered in previous literature. This study suggests that photographic records available in citizen science databases can improve the knowledge of breeding aspects of hummingbird species found in Brazil.
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Ruffino, Lise, Diane Zarzoso-Lacoste, and Eric Vidal. "Assessment of invasive rodent impacts on island avifauna: methods, limitations and the way forward." Wildlife Research 42, no. 2 (2015): 185. http://dx.doi.org/10.1071/wr15047.
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Bird conservation is nowadays a strong driving force for prioritising rodent eradications, but robust quantitative estimates of impacts are needed to ensure cost-effectiveness of management operations. Here, we review the published literature to investigate on what methodological basis rodent effects on island bird communities have been evaluated for the past six decades. We then discuss the advantages and limitations of each category of methods for the detection and quantification of impacts, and end with some recommendations on how to strengthen current approaches and extend our knowledge on the mechanisms of impacts. Impact studies (152 studies considered) emphasised seabirds (67%), black rats (63%) and the Pacific Ocean (57%). Among the most commonly used methods to study rodent impacts on birds were the observation of dead eggs or empty nests while monitoring bird breeding success, and the analyses of rodent diets, which can both lead to misleading conclusions if the data are not supported by direct field evidence of rodent predation. Direct observations of rodent–bird interactions (19% of studies) are still poorly considered despite their potential to reveal cryptic behaviours and shed light on the mechanisms of impacts. Rodent effects on birds were most often measured as a change or difference in bird breeding parameters (74% of studies), while estimates of bird population growth rates (4%) are lacking. Based on the outcomes of this literature review, we highlight the need for collecting unbiased population-level estimates of rodent impacts, which are essential prerequisites for predicting bird population growth scenarios and prioritising their conservation needs. This could be achieved by a more systematic integration of long-term monitoring of bird populations into rodent management operations and modelling bird population dynamics. We also strongly recommend including various complementary methods in impact assessment strategies to unravel complex interactions between rodents and birds and avoid faulty evidence. Finally, more research should be devoted to a better understanding of the cases of non-impacts (i.e. long-term coexistence) and those impacts mediated by mechanisms other than predation and ecosystem-level processes.
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Noske, Richard A. "Breeding biology, demography and success of the rufous-banded honeyeater, Conopophila albogularis, in Darwin, a monsoonal tropical city." Wildlife Research 25, no. 4 (1998): 339. http://dx.doi.org/10.1071/wr97070.
Full textAbstract:
The rufous-banded honeyeater, Conopophila albogularis, is probably the commonest small bird species in the suburbs of Darwin, Northern Territory. Nearly twenty pairs of this species were colour-banded on the Casuarina campus of the Northern Territory University, where they occupied territories of 0.15–0.47 ha all year-round, indicating a density of up to 12 birds ha-1. Six out of 48 birds survived 5 or more years, one individual being 9 years old at the time of writing. Males were larger in the four morphological dimensions measured. Breeding behaviour was recorded in every month of the year, but was concentrated in the late dry and wet seasons (September–March), commencing about two months before the rains. Over half of 274 nests were built in black wattles, Acacia auriculiformis, a common pioneer species both within urban Darwin and monsoon rainforest ecotones of the Northern Territory. Contrary to the literature, both sexes participated in building the nest, and the incubation and nestling periods each lasted 14 days. The clutch size was usually two (78%), and mean clutch size for 85 nests was 2.1 eggs. Nest success was about 70%, hatching success of eggs was 74% and fledging rate of nestlings 87%. Four broods per season were common, and two pairs successfully raised five broods in one season. Average annual pair productivity was 5.8 fledglings (possibly the highest yet recorded for an Australian passerine species), one pair raising a remarkable 32 young over five seasons (6.4 fledglings per season). The exceptionally high nest success and productivity were probably mainly due to the scarcity of predators, and the long breeding season, respectively, the latter being facilitated by artificial watering of gardens and lawns during the dry season. The colonising success of this species in Darwin is attributed to Darwin’s coastal location and the close proximity of favoured natural habitats, as well as the generalised diet of the species and its predilection for the abundant black wattle.
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Kimura, Thais Harumi, Gabriel Aquino Rocha, Hermínio José da Rocha Neto, Miguel Ferreira Cavalcante Filho, Marcelo Campos Rodrigues, and Lilian Silva Catenacci. "Prolapse and amputation of phallus in a greater rhea (Rhea americana) kept in captivity: Case report." Research, Society and Development 11, no. 3 (March 1, 2022): e41411326015. http://dx.doi.org/10.33448/rsd-v11i3.26015.
Full textAbstract:
Rheas are the largest birds in South America. Belonging to the order of Struthioniformes, they are bred in captivity for their beauty and also for the quality and use of their meat, leather, feathers and eggs. The objective of this report was to describe a case of prolapse and amputation of the phallus after clinical and surgical care of a greater rhea (Rhea americana), to contribute to the literature on the occurrence of this condition in ratites. The animal was raised and is kept in captivity at Federal University of Piauí (UFPI), in Teresina, Piaui state, Brazil. The animal relapsed after two attempts to reduce the phallus prolapse, requiring amputation, since the animal’s organ presented areas of necrosis. After the intervention, the animal was returned to the previous enclosure, regrouping with the flock without complications and maintained a normal pre-surgery behavior. To the author’s knowledge, this is the first case of phallus and cloaca prolapse reported in Rhea americana.
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Lenanton, RC, SG Ayvazian, AF Pearce, RA Steckis, and GC Young. "Tailor (Pomatomus saltatrix) off Western Australia: where does it Spawn and how are the Larvae Distributed?" Marine and Freshwater Research 47, no. 2 (1996): 337. http://dx.doi.org/10.1071/mf9960337.
Full textAbstract:
Tailor is a key finfish resource in Western Australia and is heavily exploited, but there has been no information either on the location and timing of spawning of the species in these waters or on the subsequent distribution and movements of the larvae. The present study has reviewed the literature to elucidate where tailor typically spawn and in which salinities and water temperatures they are most likely to be found. These data have then been collated with new data on the biology of juvenile and adult tailor in Western Australia, and on the salinities, temperatures and water movements off the coast. This has enabled a hypothesis to be developed delineating where spawning is likely to occur in this region and where the larvae are distributed. It is proposed that spawning occurs in inner-shelf waters between spring and autumn. Eggs and larvae are most likely to be transported to coastal nursery areas by wind-driven northward coastal currents that predominate during the main spawning period.
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Calik, Jolanta. "Capon Production – Breeding Stock, Rooster Castration And Rearing Methods, And Meat Quality – A Review." Annals of Animal Science 14, no. 4 (October 1, 2014): 769–77. http://dx.doi.org/10.2478/aoas-2014-0050.
Full textAbstract:
Abstract Over the last decade, there has been an increased consumer interest in niche food products with special aroma and flavour, and rich in nutrients. Poland has a large (19 lines) and valuable collection of laying hens enrolled in the genetic resources conservation programme. Research to date has shown these hen breeds to vary in phenotype, productivity, and biological quality of hatching eggs and meat. A significant problem in using hens for both egg and meat production is that the number of unwanted cockerels increases with increasing intensity of egg production. This problem can be overcome by castration of cockerels. Roosters were sterilized long before Christ, first as a religious ritual and then to increase the body weight of birds. The qualities of capon meat were noticed much later when it turned out to be more delicate, juicy and tender compared to rooster meat. The aim of this paper was to review the literature on capon production, including the effects of castration on the bird’s body and on the quality of meat obtained.
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Brand, TS, GA Tesselaar, LC Hoffman, and Z. Brand. "The effect of different dietary vitamin and mineral levels on certain production parameters, including egg shell characteristics of breeding ostriches." South African Journal of Animal Science 44, no. 5 (January 19, 2015): 51–57. http://dx.doi.org/10.4314/sajas.v44i5.11.
Full textAbstract:
Earlier studies on breeding birds indicated no effect of dietary energy-content on feed intake. This observation is contradictory to results for other animals and/or poultry where feed intake decreases with an increase in dietary energy level. Literature revealed that a lack of certain nutrients may cause animals to consume more feed than necessary to satisfy their nutrient requirements for these limiting nutrients. In this study eight diet groups were evaluated. A standard commercial diet plus one of the following supplements: (i) Standard diet without a vitamin and mineral premix pack (control diet), (ii) with a normal premix pack, (iii) with normal vitamin and 2 x trace elements (M x 2), (iv) with normal trace elements and 2 x vitamins, (v) with a normal premix pack and limestone added as calcium source; (vi) with a normal premix pack and monocalcium phosphate added as phosphorus source, (vii) with a normal premix pack and soybean oilcake added as crude protein source, (viii) with a normal premix pack and linseed added as a fatty acid source. Significant differences were recorded in the quantity of feed ingested by birds between the diet with surplus minerals (M x 2) (Group 3) (2.3 ± 0.3 kg/bird/day), the diet with no vitamins and minerals added (Group 1) (2.7 ± 0.3 kg/bird/day) and the diet with added fatty acids in the form of linseed (Group 5) (2.9 ± 0.5 kg/bird/day). This indicates the possibility that ostriches may adjust feed intake to satisfy their mineral requirements. No statistically significant relationship was found between the thickness and strength of the shell. Significant differences in shell strength (mean value of 154.7, 109.9, 140.4, 142.7, 153.0, 143.4, 138.4 and 151.1 N/cm2, respectively) were found between all treatments, but no specific pattern could be identified. Results further revealed no effect of dietary treatment on egg production, dead-in-shell eggs (DIS), infertile eggs or chick production. Further experiments that include certain dietary treatments during the five months rest period are currently being done to quantify the effect of the addition of minerals and vitamins during this period on the production of breeding ostriches.Keywords: Eggshell strength; feed intake, minerals, vitamins
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Ottersen, Geir, Bjarte Bogstad, Natalia A. Yaragina, Leif Christian Stige, Frode B. Vikebø, and Padmini Dalpadado. "A review of early life history dynamics of Barents Sea cod (Gadus morhua)." ICES Journal of Marine Science 71, no. 8 (April 1, 2014): 2064–87. http://dx.doi.org/10.1093/icesjms/fsu037.
Full textAbstract:
Abstract The Barents Sea stock of Atlantic cod (Gadus morhua) is currently the world's largest cod stock. It is also a stock for which long time-series are available and much research has been carried out. With this review, we wish to present an overview and evaluation of the knowledge on Barents Sea cod early life dynamics. The focus is on the effects of the biotic and abiotic drivers, which jointly determine the strength of a year class. A stage-by-stage approach is employed. We summarize and assess the significance of the different processes described in the literature to be at play during each specific life stage, from spawning stock, through eggs, larvae, and pelagic juvenile, to demersal juvenile and recruitment at age 3. Also Russian work is included, some of which until now has not been available to non-Russian readers. Physical drivers examined include sea temperature, advection and dispersal, wind-induced turbulence, and light. Biotic mechanisms studied range from maternal effects and skipped spawning in the adult stock through egg quantity and quality, to prey availability for the larvae and effects of cannibalism on the juveniles. Finally, we evaluate the main hypotheses put forth by Johan Hjort a hundred years ago in the light of our synthesis of present knowledge. A main conclusion is that it is unlikely that there is any one single life stage during which recruitment with any generality is determined.
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Salkuti, Surender Reddy. "Optimal Reactive Power Scheduling Using Cuckoo Search Algorithm." International Journal of Electrical and Computer Engineering (IJECE) 7, no. 5 (October 1, 2017): 2349. http://dx.doi.org/10.11591/ijece.v7i5.pp2349-2356.
Full textAbstract:
<p>This paper solves an optimal reactive power scheduling problem in the deregulated power system using the evolutionary based Cuckoo Search Algorithm (CSA). Reactive power scheduling is a very important problem in the power system operation, which is a nonlinear and mixed integer programming problem. It optimizes a specific objective function while satisfying all the equality and inequality constraints. In this paper, CSA is used to determine the optimal settings of control variables such as generator voltages, transformer tap positions and the amount of reactive compensation required to optimize the certain objective functions. The CSA algorithm has been developed from the inspiration that the obligate brood parasitism of some Cuckoo species lay their eggs in nests of other host birds which are of other species. The performance of CSA for solving the proposed optimal reactive power scheduling problem is examined on standard Ward Hale 6 bus, IEEE 30 bus, 57 bus, 118 bus and 300 bus test systems. The simulation results show that the proposed approach is more suitable, effective and efficient compared to other optimization techniques presented in the literature.</p>
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Ward, David, and James N. M. Smith. "Brown-Headed Cowbird Parasitism Results in a Sink Population in Warbling Vireos." Auk 117, no. 2 (April 1, 2000): 337–44. http://dx.doi.org/10.1093/auk/117.2.337.
Full textAbstract:
Abstract The Warbling Vireo (Vireo gilvus) is one of the most heavily parasitized host species of the Brown-headed Cowbird (Molothrus ater), suffering up to 80% parasitism in some areas. Warbling Vireo nests that are parasitized by cowbirds typically produce no vireo young. To make predictions about the consequences of brood parasitism on local host populations, we investigated factors that allow such high parasitism to occur. The major factors leading to high levels of brood parasitism on Warbling Vireos in the Okanagan Valley, British Columbia, are habitat overlap with cowbirds and the lack of response of vireos to cowbird eggs. Warbling Vireos responded more strongly to a cowbird dummy placed near the nest than to a dummy of a “neutral” species (junco) or to a common nest predator (crow). Preliminary simulation models based on population parameters obtained from three summers of fieldwork suggest that Warbling Vireos are in danger of extirpation from the Okanagan Valley if little movement of birds occurs between areas with different levels of brood parasitism. The models also indicate the sensitivity of this species to variation in adult and juvenile survival rates and number of successful broods produced per season. Our results emphasize the need for a metapopulation analysis that compares the population ecology of Warbling Vireos at high elevations (and probably with low parasitism) with that at low elevations (high parasitism) and that ascertains whether sufficient dispersal occurs between these populations to prevent extinction at lower elevations. Sufficient dispersal is indicated by apparently stable vireo populations in the Okanagan Valley and by Breeding Bird Survey data that show an overall increasing trend for this species in British Columbia.
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Dijkstra, Cor, Serge Daan, and Joost M. Tinbergen. "Family Planning in the Kestrel (Falco Tinnunculus): the Ultimate Control of Covariation of Laying Date and Clutch Size." Behaviour 114, no. 1-4 (1990): 83–116. http://dx.doi.org/10.1163/156853990x00068.
Full textAbstract:
AbstractThe theory that individual birds maximize their fitness by the two major decisions in reproduction concerning date (when to start laying eggs) and clutch size (when to stop laying eggs) is empirically approached in the Kestrel by quantifying Fisher's Reproductive Value for both the clutch (Vc = c. Vo/2) and the parents (Vp). The reproductive value of an egg (Vo) was found to decrease monotonically with laying date (d) due to significant associations with d of the components So (probability for an egg to survive till fledging), S1 (probability to survive from fledging till age 1), S2 (survival age 1 till age 2), and P1 (probability of breeding at age 1). Vp declined negligibly with laying date, although there were significant associations between d (laying date) and N (probability of the nest to produce at least one fledging), Pr (probability of a repeat clutch following nest failure), and La (probability of local survival of the parents following breeding). In experiments where brood size at day 10 after hatching was increased or reduced, Vc increasing experimental brood size, while Vp simultaneously decreased. Total reproductive value (V = Vc + Vp) remained unaffected by the experiments. This result suggests that a rather broad range of clutch sizes maximizes total reproductive value, as far as detectable by the data. While the yield of kestrel hunting, and hence the number of young raisable with constant parental effort (and constant Vp), increased with the spring increase in vole population density, reproductive value of the clutches decreased. For any particular food situation (hunting yield) this leads to a unique combination of clutch size and laying date maximizing V. This could be worked out by calculating fitness contours for all combinations and for different yields (Fig. 12). The optimal solutions are on a declining slope, with smaller clutches associated with later dates. 59.4% of all clutches observed obeyed the maximization criteria. Furthermore, there was a reasonable, unbiased association between predicted laying dates and clutch sizes based on individual male hunting yields and observed dates and clutches as laid by the females. Qualitatively, any method predicts a seasonal decrease in the optimal clutch size when the environment improves while reproductive value declines with progressive date. Preliminary results from an experimental approach to test the assumption of a causal effect of date on Vo, using the release of juvenile kestrels reared in captivity under artificial light schedules, are presented.
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Sandercock, Brett K., and Alvaro Jaramillo. "Annual Survival Rates of Wintering Sparrows: Assessing Demographic Consequences of Migration." Auk 119, no. 1 (January 1, 2002): 149–65. http://dx.doi.org/10.1093/auk/119.1.149.
Full textAbstract:
AbstractThe demographic consequences of migration have important implications for both evolutionary ecology and conservation biology. We investigated local survival rates for six populations of sparrows at a wintering site. Recent developments in mark–recapture statistics were applied to a 13 year dataset with large numbers of marked individuals (n = 1,632 to 4,394). The study taxa were closely related, and included one resident species (Song Sparrow [Melospiza melodia gouldii]), one short-distance migrant (“Puget Sound” White-crowned Sparrow [Zonotrichia leucophrys pugetensis]), two moderate-distance migrants (Lincoln's [Melospiza lincolnii] and Fox [Passerella iliaca] sparrow), and two long-distance migrants (“Gambel's” White-crowned [Zonotrichia leucophrys gambelii] and Golden-crowned [Zonotrichia atricapilla] sparrow). A literature review demonstrated a cline in fecundity among these sparrows: resident and short-distance migrants laid multiple clutches of few eggs, whereas long-distance migrants tended to produce one large clutch. Annual rates of local survival were low in the interval after first capture (<0.35), possibly because of variation in true survival, site-fidelity, presence of transients and heterogeneity of capture. Estimates of local survival among birds that returned at least once were more robust and were comparable among Song (0.558 ± 0.054 SE), Puget Sound White-crowned (0.461 ± 0.026), Lincoln's (0.456 ± 0.066), Fox (0.352 ± 0.0), Golden-crowned (0.422 ± 0.023) and Gambel's White-crowned (0.432 ± 0.0) sparrows. Estimates of survivorship for Lincoln's and Fox sparrows are among the first values available for those species. Local survival was not higher among resident than migratory taxa, nor did it covary with migration distance among migratory species. These results did not support the time-allocation hypothesis of Greenberg (1980), but are consistent with aspects of bet-hedging theory. While these analyses have potential implications for conservation of migratory birds, further work is required to establish whether these patterns are applicable to Neotropical migrants.