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Gjerdrum, Carina. "Parental Provisioning and Nestling Departure Decisions: A Supplementary Feeding Experiment in Tufted Puffins (Fratercula Cirrhata) on Triangle Island, British Columbia". Auk 121, n.º 2 (1 de abril de 2004): 463–72. http://dx.doi.org/10.1093/auk/121.2.463.
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Abstract I used a supplemental feeding experiment to determine whether adult Tufted Puffins (Fratercula cirrhata) would decrease provisioning effort in response to a reduction in nestling nutritional requirements, and to investigate the relationship between parental provisioning effort and timing of fledging. As predicted, parents of the supplemented nestlings decreased the number of provisioning trips but did not alter bill-load size or prey composition. Supplemental feeding significantly increased the growth of the culmen and tarsus but had no detectable effect on wing growth or body mass of chicks. Supplemented nestlings fledged significantly older than control nestlings. The maximum mass attained by the nestling and the age at which mass peaked also influenced timing of fledging. These results demonstrate that fledging age is influenced by both the energy provided by the parents and the nestling's developmental state and are consistent with the hypothesis that nestlings time their departure from the nest based on the costs and benefits of remaining.
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Colby, C., D. L. Kilgore y S. Howe. "Effects of hypoxia and hypercapnia on VT, f, and VI of nestling and adult bank swallows". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 253, n.º 6 (1 de diciembre de 1987): R854—R860. http://dx.doi.org/10.1152/ajpregu.1987.253.6.r854.
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The effects of hypoxia, hypercapnia, and hypoxic hypercapnia on ventilation, and breathing pattern in adult and nestling bank swallows (Riparia riparia) were assessed. The CO2 threshold above which inhaled minute volume (VI) increased significantly in adults and nestlings was 0.045. At each level of fractional concentration of inspired CO2 (FICO2), ventilation in nestlings was lower than that in adults. At a FICO2 of 0.09, VI of adults increased by 284%, whereas VI in nestlings changed 238%. Adult bank swallows also showed a blunted ventilatory response to hypoxia, and the nestling's response was similar to other birds. Adults exhibited greater changes in VI at all levels of hypoxic hypercapnia compared with nestlings. Combined hypoxic and hypercapnic stimuli had an additive effect on ventilation in both groups. Chronic exposure of nestlings to the hypercapnia and hypoxia within burrows seems to significantly alter their ventilatory response to these respiratory stimuli.
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Taylor, Jan R. E., Allen R. Place y Daniel D. Roby. "Stomach oil and reproductive energetics in Antarctic prions, Pachyptila desolata". Canadian Journal of Zoology 75, n.º 3 (1 de marzo de 1997): 490–500. http://dx.doi.org/10.1139/z97-060.
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We studied energy-provisioning rates and energy requirements of nestlings, as well as energy-expenditure rates of adults in Antarctic prions (Pachyptila desolata) on sub-Antarctic Bird Island, South Georgia. Special emphasis was placed on investigating the role of stomach oil as an energy source for nestlings. Nestlings were periodically weighed overnight (n = 91 nestling-nights, 5 nights), and the mass of food consumed by nestlings was estimated from the sum of positive mass increments recorded over 3-h intervals. Prion nestlings consumed, on average, 36.6 g food per day at the age of peak body mass. The probability of each parent feeding its nestling overnight was 0.57, but feeding frequency varied significantly among nights. The median volume of stomach oil in proventriculi of nestlings was 0.9 mL (n = 44), and was negatively correlated with nestling age. Prion nestlings had a relatively high conversion efficiency of food mass to body mass (0.615), indicating a high energy density of nestling meals. Nestling energy budgets revealed that nestling energy requirements could not be met unless a portion of the food mass delivered by the parents consisted of stomach oil. We conclude that Antarctic prions represent an intermediate position in the spectrum of procellariiform dependency on stomach oil during nestling rearing, with diving petrels (which do not produce stomach oil) at one extreme and storm-petrels at the other. Field metabolic rates of adults feeding nestlings, measured by means of the doubly labeled water technique, averaged 4.16 mL CO2/(g∙h), or 391 kJ/day. We suggest that this relatively low metabolic rate while foraging at sea is important for stomach oil formation, as it permits adults to allocate a greater proportion of energy from ingested food to their young.
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Verheyen, Rudolf Frans, Marcel Eens y Rianne Pinxten. "Response of Male European Starlings To Experimental Removal of Their Mate During Different Stages of the Breeding Cycle". Behaviour 132, n.º 3-4 (1995): 301–17. http://dx.doi.org/10.1163/156853995x00748.
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AbstractWe experimentally removed females from monogamous European starling Sturnus vulgaris pairs during different stages of the breeding cycle and recorded the effect of these removals on male behaviour and on offspring survival in order to assess the possibilities for female mate desertion. Removal of the female during the laying, incubation and early nestling stage (1- to 5-day-old nestlings) invariably resulted in complete failure of the brood. The survival of the nestlings improved slightly if the female was removed during the middle nestling stage (6- to 10-day-old nestlings), but mortality rate of nestlings was still significantly higher than in control two-parent broods. About 80% of the males widowed during the laying/incubation period removed all eggs from the nest, while only 49% of all males widowed during the early and middle nestling stage removed all dead nestlings. Removal of eggs/dead nestlings by a widowed male starling probably functions to increase the chance on a successful re-mating, since replacement clutches were found only in nests whereof the clutch/brood was removed. We recorded one definite and at least nine suspected cases of parental infanticide, the killing of own offspring, by experimentally widowed male starlings. After nestlings reached 10 days of age (late nestling stage), there was no longer a significant difference in nestling mortality rate between male-only and two-parent broods. This crucial point coincides with the time when (1) the nestlings are functionally homeothermic, and (2) the exponential growth of the nestlings begins to moderate. Moreover, at this time, late in the season, the only viable option for deserted males is to care for the young because the probability of renesting successfully is low. Our results thus indicate that after nestlings reach 10 days of age, female starlings may have the opportunity to desert their mate. However, at that time, the benefits of female mate desertion are reduced as opportunities for renesting succesfully are low.
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Ruiz-Rodríguez, Magdalena, Manuel Martín-Vivaldi, Manuel Martínez-Bueno y Juan José Soler. "Gut Microbiota of Great Spotted Cuckoo Nestlings is a Mixture of Those of Their Foster Magpie Siblings and of Cuckoo Adults". Genes 9, n.º 8 (27 de julio de 2018): 381. http://dx.doi.org/10.3390/genes9080381.
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Diet and host genetic or evolutionary history are considered the two main factors determining gut microbiota of animals, although studies are scarce in natural populations. The system of great spotted cuckoos (Clamator glandarius) parasitizing magpies (Pica pica) is ideal to study both effects since magpie adults feed cuckoo and magpie nestlings with the same diet and, consequently, differences in gut microbiota of nestlings of these two species will mainly reflect the importance of genetic components. Moreover, the diet of adults and of nestling cuckoos drastically differ from each other and, thus, differences and similarities in their microbiotas would respectively reflect the effect of environmental and genetic factors. We used next-generation sequencing technologies to analyze the gut microbiota of cuckoo adults and nestlings and of magpie nestlings. The highest α-diversity estimates appeared in nestling cuckoos and the lowest in nestling magpies. Moreover, despite the greatest differences in the microbiome composition of magpies and cuckoos of both ages, cuckoo nestlings harbored a mixture of the Operational Taxonomic Units (OTUs) present in adult cuckoos and nestling magpies. We identified the bacterial taxa responsible for such results. These results suggest important phylogenetic components determining gut microbiome of nestlings, and that diet might be responsible for similarities between gut microbiome of cuckoo and magpie nestlings that allow cuckoos to digest food provided by magpie adults.
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Pires, Bárbara A., Anabela DF Belo, Fernanda Diamantino, João E. Rabaça y Santiago Merino. "Development of nestling blue tits (Cyanistes caeruleus) is affected by experimental addition of aromatic plants". Avian Biology Research 13, n.º 3 (2 de junio de 2020): 44–48. http://dx.doi.org/10.1177/1758155920921075.
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Some passerines incorporate aromatic plants in their nest cups, and several hypotheses have been formulated to explain this behaviour. One of those, the Drug Hypothesis, states that aromatic plants present in nests have positive effects on nestlings’ development through increased immune function. In this study, we aimed to examine if experimental addition of aromatic plants had positive effects on reproductive performance (the number of fledglings produced and nestling survival rate) and nestling development (weight and tarsus length). In addition, we study whether those potential effects were more noticeable in different brood sizes–small and large–through an observational approach. We expect that large broods, due to increased resource competition between nestlings, will benefit more from aromatic plant incorporation, as compared to small broods. Nestlings were significantly heavier in 2015 as compared to 2016 and 2017 and in small broods. No effect of treatment was observed in nestling weight. Although there was no overall effect of treatment on nestling tarsus length, nestlings from aromatic nests had significantly longer tarsi as compared to nestlings from control nests, in large broods.
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Ramos, Jaime A., John Bowler, Laura Davis, Sarah Venis, John Quinn y Carole Middleton. "Activity Patterns and Effect of Ticks on Growth and Survival of Tropical Roseate Tern Nestlings". Auk 118, n.º 3 (1 de julio de 2001): 709–16. http://dx.doi.org/10.1093/auk/118.3.709.
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Abstract Patterns of abundance of the seabird tick Amblyomma loculosum and their effects on Roseate Tern (Sterna dougallii) nestling growth, fledging age, and survival are described on Aride Island, Seychelles, in 1997–1999. Female ticks attached to nestlings from 4 to 14 days (to engorge) whereas male ticks attached for 1–3 days. The linear growth rate of birds carrying female ticks (0.24 g/day) was significantly different from that of nonparasitized nestlings of the same age and similar (or even lower) hatching weight (4.07 g/day). Parasitized nestlings that fledged did so 5.2 days later than nonparasitized nestlings of similar age. Only 37.5% of the nestlings infested with female ticks fledged compared with 83.3% of the noninfested nestlings. During the successful 1998 breeding season, around 100 nestlings died from tick infestation (24.3% of the nestling deaths). Ticks appeared to accelerate nestling mortality during periods of food shortage. Despite an annual difference of two weeks in the timing of breeding of the Roseate Terns between 1997 and 1998, adult ticks parasitized nestlings in July, with an infestation peak occurring between 8–12 July in both years. However, in 1997, nestlings were parasitized at a younger age, suggesting that ticks (nymph stage) must attach to Roseate Tern adults as soon as they make a nest scrape (usually in May). Ironically, the frequent breeding failures of the Roseate Terns will result in lower infestation levels in subsequent years, which will benefit the birds.
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O’Connor, Jody A., Jeremy Robertson y Sonia Kleindorfer. "Video analysis of host–parasite interactions in nests of Darwin’s finches". Oryx 44, n.º 4 (octubre de 2010): 588–94. http://dx.doi.org/10.1017/s0030605310000086.
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AbstractParasites place their hosts under strong selection for adaptive traits that increase parasite resistance. The initial impact of invasive parasites has rarely been observed and can be particularly strong on naïve hosts with limited prior exposure to parasites.Philornis downsiis an introduced fly to the Galapagos Islands whose parasitic larvae cause high mortality in nestlings of Darwin's finches. We used a within-nest camera system and nest monitoring data to examine this new host–parasite interaction in the wild. ManyP. downsiflies entered finch nests with incubated eggs or nestlings but only when parent finches were not present. ParasiticP. downsilarvae were observed to emerge from the nest base at night to feed both internally and externally on nestlings. Adult and nestling Darwin’s finches exhibit grooming and avoidance behaviours in the presence ofP. downsiparasites. Specifically, in nests with high parasite intensity, nestlings increased self-preening behaviour, ate larvae and stood on top of one another. Female finches probed into their nestling’s nares (first instar larvae reside in the nares) and probed into the nest base (second and third larvae reside in the nest base during the day). These findings shed light on the emergence of anti-parasite behaviour as well as host–parasite relationships after recent parasitism in a naïve host.
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Smith, H. G. y K. J. Wettermark. "Heritability of nestling growth in cross-fostered European Starlings Sturnus vulgaris." Genetics 141, n.º 2 (1 de octubre de 1995): 657–65. http://dx.doi.org/10.1093/genetics/141.2.657.
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Abstract In altricial birds, growth rates and nestling morphology vary between broods. For natural selection to produce evolutionary change in these variables, ther must exist heritable variation. Since nestling traits are not any longer presents in parents, traditional offspring-parent regressions cannot estimate heritabilities of these. In this study, a partial cross-fostering experiment was performed, where nestlings of the European Starling (Sturnus vulgaris) were reciprocally exchanged between nests. The experiment demonstrated a significant heritability of nestling tarsus length and body mass, but not of the growth trajectories followed by individual nestlings. the heritability estimate for tarsus length obtained in the cross-fostering experiment using full-sib analysis was lower than those obtained by offspring-parent regressions. This is likely due to a genotype-by-environment effect on tarsus length, with nestlings destined to become large but in poor condition having a low probability of appearing as parents. The main reason for the low heritability of growth was probably the large within-brood variation in growth pattern due to the initial size hierarchy of nestlings. Nestlings demonstrated targeted growth, where small-sized nestlings that initially grew slower than their siblings, managed to catch up.
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Lu, Guang, Xinjie Zhang, Xinyu Li y Shuping Zhang. "Immunity and Growth Plasticity of Asian Short-Toed Lark Nestlings in Response to Changes in Food Conditions: Can It Buffer the Challenge of Climate Change-Induced Trophic Mismatch?" Animals 13, n.º 5 (27 de febrero de 2023): 860. http://dx.doi.org/10.3390/ani13050860.
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Passerine nestlings frequently suffer from sub-optimal food conditions due to climate change-induced trophic mismatch between the nestlings and their optimal food resources. The ability of nestlings to buffer this challenge is less well understood. We hypothesized that poor food conditions might induce a higher immune response and lower growth rate of nestlings, and such physiological plasticity is conducive to nestling survival. To test this, we examined how food (grasshopper nymphs) abundance affects the expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-1 β (IL-1β) genes, plasma IGF-1 levels, body mass, and fledging rates in wild Asian short-toed lark (Alaudala cheleensis) nestlings. Linear mixed models revealed that nymph biomass significantly influenced the expression of IFN-γ, TNF-α, and IL-1β genes, and the level of plasma IGF-1. The expressions of IFN-γ, TNF-α, and IL-1β genes were negatively correlated with nymph biomass and plasma IGF-1 level. Plasma IGF-1 level, nestling body mass growth rate, was positively correlated with nymph biomass. Despite a positive correlation between the nestling fledge rate and nymph biomass, more than 60% of nestlings fledged when nymph biomass was at the lowest level. These results suggest that immunity and growth plasticity of nestlings may be an adaptation for birds to buffer the negative effects of trophic mismatch.
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Grabarczyk, Erin E., Sharon A. Gill, Maarten J. Vonhof, Magdy S. Alabady, Zengyan Wang y Jason M. Schmidt. "Diet composition and diversity does not explain fewer, smaller urban nestlings". PLOS ONE 17, n.º 3 (1 de marzo de 2022): e0264381. http://dx.doi.org/10.1371/journal.pone.0264381.
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The reproductive success of animals breeding in cities is often lower compared to counterparts that inhabit rural, suburban, and peri-urban areas. Urban dwelling may be especially costly for offspring development and survival. Diet composition and diversity may underlie factors that lead to lower fitness, particularly if prey abundance and quality decline in modified environments. Moreover, breeding success may change over the course of a season, an effect that may be augmented in urban areas. In this study, we tested the hypothesis that habitat and date affected nestling house wren (Troglodytes aedon) body condition and survival, and examined whether diet explained differences in nestling success. We monitored urban and rural populations of house wrens breeding in nest boxes, and tested whether clutch size, nestling survivorship, and nestling body condition varied by habitat or by date, and then characterized the diet of a subset of nestlings with DNA metabarcoding of fecal samples. Urbanization had clear impacts on house wren nestling fitness: urban broods contained fewer, smaller nestlings. Early nestling survival decreased as the breeding season progressed, and this effect was more pronounced in the urban population. However, the diets of urban and rural nestlings were similar and did not explain differences in body condition. Instead, across populations, diet changed with date, becoming less diverse, with fewer Lepidoptera and more Orthoptera. Regardless of habitat, adult house wrens provide nestlings with similar types of foods, but other factors, such as quantity or quality of prey delivered, may lead to fitness disparities between urban and rural nestlings.
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Teather, Kevin L. "The influence of sibling gender on the growth and survival of Great-tailed Grackle nestlings". Canadian Journal of Zoology 68, n.º 9 (1 de septiembre de 1990): 1925–30. http://dx.doi.org/10.1139/z90-271.
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Growth and survival of Great-tailed Grackle (Quiscalus mexicanus) nestlings were monitored over 3 years to determine if greater food demands of sons influenced nestling success. I predicted that (i) the growth rates of nestlings would be lower in nests containing mostly males, and (ii) the chance of all nestlings in predominantly male broods fledging would be less than that in predominantly female broods. Sibling gender and the overall sex ratio of the brood had little effect on nestling growth. There was no evidence that starvation was more frequent if the oldest nestlings were males rather than females, although there was some evidence that broods of three containing two or three males were less likely to fledge all nestlings than those containing two or three females. Mass at fledging for both males and females was influenced most strongly by hatching sequence and to a lesser extent by egg mass and hatching date.
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DUNN, JENNY C., JENNIFER E. STOCKDALE, EMMA L. BRADFORD, ALEXANDRA MCCUBBIN, ANTONY J. MORRIS, PHILIP V. GRICE, SIMON J. GOODMAN y KEITH C. HAMER. "High rates of infection by blood parasites during the nestling phase in UK Columbids with notes on ecological associations". Parasitology 144, n.º 5 (12 de diciembre de 2016): 622–28. http://dx.doi.org/10.1017/s0031182016002274.
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SUMMARYStudies of blood parasite infection in nestling birds rarely find a high prevalence of infection. This is likely due to a combination of short nestling periods (limiting the age at which nestlings can be sampled) and long parasite prepatent periods before gametocytes can be detected in peripheral blood. Here we examine rates of blood parasite infection in nestlings from three Columbid species in the UK. We use this system to address two key hypotheses in the epidemiology of avian haemoparasites: first, that nestlings in open nests have a higher prevalence of infection; and second, that nestlings sampled at 14 days old have a higher apparent infection rate than those sampled at 7 days old. Open-nesting individuals had a 54% infection rate compared with 25% for box-nesters, probably due to an increased exposure of open-nesting species to dipteran vectors. Nestlings sampled at 14 days had a 68% infection rate compared with 32% in nestlings sampled at 7 days, suggesting that rates of infection in the nest are high. Further work should examine nestlings post-fledging to identify rates of successful parasite infection (as opposed to abortive development within a dead-end host) as well as impacts on host post-fledging survival and behaviour.
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Whitworth, Terry L. y Gordon F. Bennett. "Pathogenicity of larval Protocalliphora (Diptera: Calliphoridae) parasitizing nestling birds". Canadian Journal of Zoology 70, n.º 11 (1 de noviembre de 1992): 2184–91. http://dx.doi.org/10.1139/z92-295.
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Controlled tests showed that feeding by larvae of several species of Protocalliphora lowered haematocrit and haemoglobin levels of nestling magpies and bank swallows. Subsequent studies showed that natural populations of nestling magpies and Bank Swallows infested by P. asiovora and P. chrysorrhoea, respectively, experienced significantly reduced blood levels at the P0.05 and P0.01 levels except in the youngest nestlings. Despite the presumed heavy blood loss, most nestlings are not killed by larvae of Protocalliphora. Studies of natural populations of Protocalliphora in 48 species of birds indicate that the larval populations are usually too small to kill or seriously injure most nestlings.
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Franke, Alastair, Vincent Lamarre y Erik Hedlin. "Rapid Nestling Mortality in Arctic Peregrine Falcons due to the Biting Effects of Black Flies". ARCTIC 69, n.º 3 (2 de septiembre de 2016): 281. http://dx.doi.org/10.14430/arctic4580.
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This note describes nestling mortality in Arctic Peregrine Falcons (Falco peregrinus tundrius) due to the biting effects of blood-feeding black flies (Diptera: Simuliidae). At a nest site near Rankin Inlet, Nunavut, Canada (62˚49′ N, 92˚05′ W), a brood of four nestlings died on 20 July 2013 from the direct effects of severe bites attributed to black flies. Within three hours of the onset of blood-feeding, black flies had caused widespread, uniformly distributed hemorrhagic coalescent lesions over the head and body of all nestlings. Approximately seven hours after the first flies appeared, the female falcon removed the carcasses of the dead nestlings from the nest. Nestlings at eight additional sites also suffered the effects of biting black flies in 2013, resulting in the deaths of 13 of 35 nestlings. A less pronounced outbreak also occurred in 2012 and resulted in the deaths of seven nestlings at four sites. No nestling mortality due to black flies has been documented in any other year from 1982 through 2015. To our knowledge, these observations document the northernmost lethal attack by ornithophilic black flies in North America.
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Rosivall, Balázs, János Török y Eszter Szöllősi. "Food Allocation in Collared Flycatcher (Ficedula Albicollis) Broods: Do Rules Change With The Age of Nestlings?" Auk 122, n.º 4 (1 de octubre de 2005): 1112–22. http://dx.doi.org/10.1093/auk/122.4.1112.
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Abstract Food allocation among nestlings has a strong influence on parental fitness. Maximizing fledging success in a favorable environment requires food distribution based on offspring need signals. However, food limitation, differences among individual nestlings in their quality, or variation in the costs of rearing different young may result in preferential allocation of food by parents. If signals of nestling quality or need change in meaning with age, parents are expected to adjust their feeding rules to those changes. We examined food allocation in broods of Collared Flycatchers (Ficedula albicollis), a sexually size-monomorphic passerine. In a multivariate analysis, we investigated the role of sex, size, condition, position, and begging intensity in two nestling ages. Size, condition, and sex of nestlings did not affect parental decisions. Begging intensity and nestling position, however, had a role in food allocation in both age categories. Both parents preferred the more intensely begging nestlings. Males did not show clear position preference in the “young” age category, but had preferred positions with older nestlings. Female position preference was observed in both age categories. Preferred positions of male and female parents differed; still, we observed overall position preference. Asignación de Alimentos en Nidadas de Ficedula albicollis: ¿Cambian las Reglas con la Edad de los Pichones?
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Liker, András, Márta Márkus, Ágnes Vozár, Eszter Zemankovics y Lajos Rózsa. "Distribution of Carnus hemapterus in a starling colony". Canadian Journal of Zoology 79, n.º 4 (1 de abril de 2001): 574–80. http://dx.doi.org/10.1139/z01-018.
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The distribution of the haematophagous fly Carnus hemapterus among starling (Sturnus vulgaris) broods was investigated in a nest-box colony. Prevalence of infection was 94% among broods and 69% among individual nestlings, while median abundance was 54 flies per brood (range 0284 flies; n = 33) and 8 flies per individual nestling (range 0117 flies; n = 140). Parasites exhibited an aggregated distribution among starling broods. Carnus hemapterus populations changed significantly during the development of nestlings: fly abundance increased rapidly after nestlings hatched, peaked 58 days after hatching, and decreased thereafter. The proportion of winged flies (assumed to be the transmissive form) and the proportion of male flies decreased with increasing nestling mass. Measures of within-colony spatial position of nests were not related to mean brood abundance, proportion of winged flies, or sex ratio of the flies. Parasite abundance did not correlate with mortality rate or growth rate of nestlings. In conclusion, nestling developmental stage was the only significant predictor of variation in C. hemapterus populations in this starling colony.
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Miller, Clinton K. y Jeanne M. Fair. "Effects of blow fly (Protocalliphora spatulata: Diptera: Calliphoridae) parasitism on the growth of nestling savannah sparrows in Alaska". Canadian Journal of Zoology 75, n.º 4 (1 de abril de 1997): 641–44. http://dx.doi.org/10.1139/z97-080.
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We investigated the effect of blow fly larvae (Protocalliphora spatulata) on nestling savannah sparrows (Passerculus sandwichensis) in Alaska subject to biennially fluctuating prey abundance. Grasshopper populations in some regions of interior Alaska can show a strong biennial periodicity. Growth of nestling savannah sparrows, numbers of blow fly larvae in nests and on nestlings, and grasshopper populations were monitored during four breeding seasons (1990–1993) on the Delta Agriculture Project site near Delta Junction, Alaska. Growth parameters for parasitized and nonparasitized nestlings were compared within and between years. There were no significant differences in growth parameters between parasitized and nonparasitized nestlings between any years. There were also no differences in growth parameters within years, except for tarsus length in 1991 and nestling mass in 1993 (low grasshopper years); in 1993, parasitized nestlings were heavier and the sample size was small. Additionally, there were no differences in fledging success within years. Although parasitism combined with other factors (e.g., food limitation) may have an impact on avian reproduction, our data do not support this.
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Kilpatrick, A. Marm. "Variation in growth of Brown-headed Cowbird (Molothrus ater) nestlings and energetic impacts on their host parents". Canadian Journal of Zoology 80, n.º 1 (1 de enero de 2002): 145–53. http://dx.doi.org/10.1139/z01-217.
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I tested several hypotheses about the plasticity of avian growth by comparing growth of Brown-headed Cowbird (Molothrus ater) nestlings in 20 different host species. Growth of cowbird nestlings was not strongly correlated with host adult mass and nearly all hosts were able to provision cowbirds with enough food to grow at nearly the highest observed rate. Cowbird growth was positively correlated with site latitude (which negatively covaried with maximum temperature) and negatively correlated with the nestling period of the host species. The metabolizable energy expenditure of cowbird and host nestlings was estimated as an approximate measure of the food provisioned by parents. As host adult mass varied from 6 to 113 g, one cowbird nestling was equivalent to 3.40.56 host nestlings in terms of peak daily energy intake. Cowbird nestlings impose a substantial energetic demand on smaller host parents that may reduce their future survival or fecundity. The quantity of energy delivered to parasitized nests demonstrates that parents are often willing to provision nests at a much higher rate than for an average clutch of their own young.
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Lozano, G. A. y R. C. Ydenberg. "Transgenerational effects of maternal immune challenge in tree swallows (Tachycineta bicolor)". Canadian Journal of Zoology 80, n.º 5 (1 de mayo de 2002): 918–25. http://dx.doi.org/10.1139/z02-063.
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The fact that avian eggs contain antibody of maternal origin is well documented, but only recently has this phenomenon been considered in an ecological context. We used tree swallows (Tachycineta bicolor) to examine the possibility of transgenerational immunity and its effect on nestling growth and immune development. We measured cell-mediated immunity with a delayed-hypersensitivity assay and antibody-mediated immunity with a hemagglutination test with sheep red blood cells (SRBCs). We tested for differences in immunocompetence and growth between nestlings from females who had been exposed to a novel antigen prior to egg laying and nestlings from unexposed females. To determine whether the effect, if any, resulted from something transferred to the eggs prior to egg laying or from subsequent changes in parental behaviour, nestlings were exchanged so that at each nest half the nestlings were from females who had been injected with SRBCs and half were from females who had not been exposed to SRBCs. Finally, brood sizes were independently manipulated to either 4 or 6 nestlings. We failed to detect maternal antibodies in any nestlings, and whether a female was exposed to SRBCs or not had no effect on the growth or cell-mediated immunity of her brood. However, nestlings in smaller broods grew better than nestlings in larger broods, though we did not find the expected differences in cell-mediated immunity. Furthermore, within each nest, nestlings whose mothers had been exposed to SRBCs grew better than nestlings whose mothers had not been exposed. These results are contrary to the idea of a simple trade-off in the allocation of resources between parasite protection and reproduction; however, they support the idea that exposure of females to parasites prior to egg laying leads to better nestling growth, and are congruous with the possibility of mithridatic parental care.
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McDonald, Paul G. "Nestling growth and development in the brown falcon, Falco berigora: an improved ageing formula and field-based method of sex determination". Wildlife Research 30, n.º 4 (2003): 411. http://dx.doi.org/10.1071/wr02041.
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The accurate determination of nestling age and sex is an important tool for studies that examine life-history traits and ecological interactions. Despite the widespread distribution of the brown falcon, Falco berigora, in Australia, morphological criteria for sexing nestlings of this species have yet to be published and nestling development has not been intensively studied. While an ageing formula for the species exists, the small sample from which it was derived precluded appropriate statistical assessment of independence problems and other potentially confounding variables such as hatch order and sex. This study used a larger sample of free-living nestlings to account for these factors and found the most reliable measure for ageing nestlings to be wing length. Wing length increased linearly with chick age, independent of seven other potentially confounding factors examined. Ageing formulae based on wing length before and after remiges emerge are presented. In addition, an accurate test for determining nestling sex at banding age, based on tarsus width, is proposed. Nestling chronology of this species is also described in detail for the first time. Nestling development was similar to that described for other Falconiformes; however, the chronology of nestling development was too variable to be useful in assigning chick age. Despite this, within 6 days of the eldest chick hatching the relative brightness of down and the degree to which chicks' eyes had opened were useful in assigning hatch order amongst nestlings with similar wing lengths.
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Pichorim, M. y ELA Monteiro-Filho. "Brood size and its importance for nestling growth in the Biscutate Swift (Streptoprocne biscutata, Aves: Apodidae)". Brazilian Journal of Biology 68, n.º 4 (noviembre de 2008): 851–57. http://dx.doi.org/10.1590/s1519-69842008000400022.
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Many Apodidae, including Streptoprocne biscutata (Sclater, 1866), drop eggs from their nests during incubation. This is interpreted as nest site competition or accident. We provide evidence that egg ejection is deliberate and that this behaviour controls the brood size. Brood sizes were manipulated and nestling growth was measured to test the hypothesis that pairs can regulate brood size during incubation based on current ability to rear nestlings. Natural (control) broods with one, two and three nestlings, and manipulated (experimental) broods reduced to one and increased to two and three young were monitored. Growth rates were measured based on weight, and wing, tail and tarsus lengths of natural and manipulated broods. We compared the slopes of each measure's regression lines of the nestlings of each brood size by t-test. Nestling growth of control nests was similar and relatively little associated with brood size. In broods reduced to one nestling, weight, wing and tail had greater growth rates, and in broods increased to three nestlings growth rates were lower. Weight was most, and tarsus length least influenced by brood size. In general, nestling growth of manipulated nests was inversely proportional to brood size. The results suggest that pairs with larger clutches are in better physical conditions than others. Thus, in experimental broods, pairs are over or under-loaded because feeding activities increase or decrease and these changes affect the growth rate of the nestlings. The present study suggests that egg ejection can control brood size. This behaviour is probably stimulated by physical changes in the adult birds during incubation.
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Hannam, Kristina. "Ectoparasitic blow flies (Protocalliphora sp.) and nestling Eastern Bluebirds (Sialia sialis): direct effects and compensatory strategies". Canadian Journal of Zoology 84, n.º 7 (1 de julio de 2006): 921–30. http://dx.doi.org/10.1139/z06-079.
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Variation in environmental factors such as parasitism can have direct effects on an organism’s fitness. Because parasites draw resources directly from their hosts, they are expected to have negative effects; however, several nestling host – parasite systems show no evidence of direct effects. Absence of direct effects may be explained by compensation strategies used by parents or nestlings themselves. In this study evidence for both direct effects and compensatory strategies in a blow fly (genus Protocalliphora Hough, 1899) – Eastern Bluebird (Sialia sialis (L., 1758)) system were examined. Nestlings showed no direct effects of blow flies on survival and on size at fledging; however, parasitized broods were significantly anemic. There was no evidence for compensation by parents in the form of brood reduction and there was no support for compensation by nestlings via a hierarchy of tissue preservation. Nestlings did compensate for parasitism by accelerating growth at the end of the nestling period and delaying fledging.
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Costantini, David. "Effects of diet quality on growth pattern, serum oxidative status, and corticosterone in Pigeons (Columba livia)". Canadian Journal of Zoology 88, n.º 8 (agosto de 2010): 795–802. http://dx.doi.org/10.1139/z10-046.
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Oxidative stress has been suggested to be affected by the growth and developmental period of animals, hence it may play an important role in the trade-off between growth and self-maintenance. In this study, I analysed the effects of two different diet regimes (high-quality diet, HQD; low-quality diet, LQD) on growth pattern, three components of the serum oxidative status (hydroperoxides, antioxidant capacity, and thiols), and serum corticosterone in nestling Pigeons ( Columba livia Gmelin, 1789). The growth pattern was similar in the first week of life, after which HQD nestlings grew faster than LQD nestlings. Although there were no differences in serum corticosterone or thiol concentrations, serum oxidative damage increased faster over the nestling phase in HQD than LQD chicks. Serum antioxidant capacity remained stable over time in LQD nestlings and increased in HQD nestlings. This study provides evidence that different growth rates (induced in the absence of any physiological stress or prior nutritional deprivation) are accompanied by different serum oxidative statuses.
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Thomas, Krista y Dave Shutler. "Ectoparasites, nestling growth, parental feeding rates, and begging intensity of tree swallows". Canadian Journal of Zoology 79, n.º 2 (1 de febrero de 2001): 346–53. http://dx.doi.org/10.1139/z00-206.
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Many studies fail to show relationships between ectoparasite loads and nestling growth rates. One explanation is that parent birds increase feeding rates to compensate for nestling energetic losses to ectoparasites. Nestling begging behaviours could signal need to parents. Accordingly, we tested whether higher flea and blow fly loads in tree swallow (Tachycineta bicolor) nests were associated with smaller nestlings, higher parental feeding rates, and increased nestling begging intensity. The study area was the Gaspereau Valley of Nova Scotia, Canada. When nestlings were 10 days old, parental feeding rates and nestling begging intensity were measured with tape recorders. At 13 days of age, nestlings were weighed and measured. Within 2 days of fledging, nest material was removed from nest boxes and enumerated for adult fleas and blow fly pupae. After including brood size and date of first egg as covariates in general linear models, no significant relationships were found between ectoparasite loads and nestling size, parental feeding rate, or nestling begging intensity. Our results suggest that nestling tree swallows were able to buffer the effects of naturally occurring ectoparasite loads without significant help from their parents. Low levels of virulence may have resulted from relatively benign weather during the study, low numbers of ectoparasites, selection on ectoparasites to avoid killing their hosts, and host defences.
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Watson, Katheryn A. y Gary Ritchison. "Effect of Variation in Nestling Hunger Levels on the Begging Behaviour of Nestlings and the Provisioning Behaviour of Adult American Kestrels". Avian Biology Research 11, n.º 1 (febrero de 2018): 35–43. http://dx.doi.org/10.3184/175815617x15127411523971.
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Little is known about how variation in nestling begging intensity influences the behaviour of adult raptors and how responses of adult males and females to such variation might differ. Our objective was to manipulate the begging intensity of nestling American Kestrels (Falco sparverius) and examine the responses of adults. We studied 12 pairs of American Kestrels nesting in nest boxes from 1 March to 1 July 2014 at the Blue Grass Army Depot, Madison County, Kentucky. Nest boxes were modified with a separate compartment for a camcorder to record nestling behaviour, and a second camcorder was placed outside the nests to monitor adult behaviour. To manipulate nestling hunger levels, 12 to 26-day-old nestlings in six nests were deprived of food for 24 h and those in the other six nests were fed until satiated. At each nest, we alternated control (no treatment) and treatment (fed or food deprived) days over a 4 day period to minimise the possible effect of nestling age on adult and nestling behaviour. Nestling begging intensity differed among treatments, with nestlings in food-deprived nests begging with greater intensity after food deprivation and those in fed-treatment nests begging with less intensity after being fed. Adult male and female American Kestrels provisioned nestlings at similar rates, with both sexes feeding nestlings at higher rates after food deprivation and at lower rates after fed treatments. Thus, the begging behaviour of nestling American Kestrels varied with hunger level, and adult American Kestrels responded by adjusting provisioning rates. Although the response of adults to nestling begging suggests that natural selection might favour ‘dishonest’ begging to obtain more food, the potential costs of ‘dishonest’ begging, such as attracting predators, reduced immunocompetence, and loss of indirect fitness benefits if such begging negatively impacts siblings and parents, may outweigh any possible benefit.
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Wetzel, Daniel P., Ariane Mutzel, Jonathan Wright y Niels J. Dingemanse. "Novel sources of (co)variation in nestling begging behavior and hunger at different biological levels of analysis". Behavioral Ecology 31, n.º 4 (6 de mayo de 2020): 960–70. http://dx.doi.org/10.1093/beheco/araa042.
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Abstract Biological hypotheses predicting patterns of offspring begging typically concern the covariance with hunger and/or development at specific hierarchical levels. For example, hunger drives within-individual patterns of begging, but begging also drives food intake among individuals within broods, and begging and food intake can covary positively or negatively among genotypes or broods. Testing biological phenomena that occur at multiple levels, therefore, requires the partitioning of covariance between traits of interest to ensure that each level-specific relationship is appropriately assessed. We performed a partial cross-fostering study on a wild population of great tits (Parus major), then used multivariate mixed models to partition variation and covariation in nestling begging effort and two metrics of nestling hunger within versus among individual nestlings and broods. At the within-individual level, we found that nestlings begged more intensely when hungrier (positive correlation between begging and hunger). However, among individuals, nestlings that were fed more frequently also begged more intensely on average (negative correlation between begging and hunger). Variation in nestling mass did not give rise to the negative correlation between begging and hunger among nestlings, but we did find that lighter nestlings begged more intensely than their heavier biological siblings, suggesting that this effect may be driven by a genetic component linked to offspring size. Our study illustrates how patterns of covariance can differ across biological levels of analysis and addresses biological mechanisms that could produce these previously obscured patterns.
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Du, Bo, Chang-Jing Liu y Shi-Jie Bao. "Begging form and growth pattern of nestlings correlate with parental food-allocation patterns in the Horned Lark (Eremophilaalpestris)". Canadian Journal of Zoology 93, n.º 4 (abril de 2015): 273–79. http://dx.doi.org/10.1139/cjz-2014-0235.
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Life-history theory assumes that selection favors parents that can maximize their reproductive success via behavioral strategies. As brood size determines the reproductive value of each nestling, parents may adjust their food-allocation patterns according to brood size. We test this assumption in the Horned Lark (Eremophila alpestris (L., 1758)). Our findings revealed that nestling begging forms varied with brood size, by gaping in one-chick broods and postural activity in two- and three-chick broods. Accordingly, parental food-allocation patterns differed in different-sized broods. In one-chick broods, parents increased feeding rates with the gaping duration of nestling. In two-chick broods, parents did not change food-allocation patterns according to nestlings’ begging. In three-chick broods, however, they fed later-hatched nestlings more even when early-hatched nestlings begged more intensely. Horned Larks exhibited obvious sexual differences in parenting style and ability, which resulted in nestlings from two- and three-chick broods changing their begging intensity according to the sex of the provisioning adult. Furthermore, nestling growth pattern diverged with brood sizes, with body mass growing faster in one-chick broods than in two- and three-chick broods. Growth rate of beak gape and tarsus length did not differ significantly among brood sizes, but beak gape was larger and tarsus length was shorter in one-chick broods than in larger broods at fledging. Our results thus support the idea that parents may use food allocation to regulate sibling rivalry, which in turn cause nestlings to beg food in different forms and grow in different patterns so that their reproductive success can be enhanced.
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PALACIOS, M. J., F. VALERA y A. BARBOSA. "Experimental assessment of the effects of gastrointestinal parasites on offspring quality in chinstrap penguins (Pygoscelis antarctica)". Parasitology 139, n.º 6 (6 de febrero de 2012): 819–24. http://dx.doi.org/10.1017/s0031182011002381.
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SUMMARYParasites reduce host fitness and consequently impose strong selection pressures on their hosts. It has been hypothesized that parasites are scarcer and their overall effect on hosts is weaker at higher latitudes. Although Antarctic birds have relatively low numbers of parasites, their effect on host fitness has rarely been investigated. The effect of helminth parasitism on growth rate was experimentally studied in chinstrap penguin (Pygoscelis antarctica) nestlings. In a total of 22 two-nestling broods, 1 nestling was treated with anthelminthics (for cestodes and nematodes) while its sibling was left as a control. Increased growth rate was predicted in de-wormed nestlings compared to their siblings. As expected, 15 days after treatment, the experimental nestlings had increased body mass more than their siblings. These results show a non-negligible negative effect of helminth parasites on nestling body condition that would presumably affect future survival and thus fitness, and it has been suggested there is a strong relationship between body mass and mortality in chinstrap penguins.
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Wiggins, David A. "Food availability, growth, and heritability of body size in nestling tree swallows (Tachycineta bicolor)". Canadian Journal of Zoology 68, n.º 6 (1 de junio de 1990): 1292–96. http://dx.doi.org/10.1139/z90-193.
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I studied the effects of food deprivation on the growth, final size, and inheritance of body size in nestling tree swallows (Tachycineta bicolor). Each experimental brood was divided into deprived and fed nestlings. Deprived nestlings showed relatively poor growth during the experimental stage (days 5–8), but were not significantly different in size from either their nestmates or control young at day 16. Parents of experimental broods did not compensate by increasing their food delivery rate. Heritability estimates of tarsus length were similar for deprived and fed nestlings. For control nestlings, tarsus length was significantly heritable at days 9 and 16, and bill length was heritable at day 16. There were no significant heritability estimates for wing length or body mass. Small sample sizes and single-parent–offspring regression likely inflated the standard errors associated with the heritability estimates. The mechanism that allowed deprived nestlings to grow as large as control and fed nestlings remains unknown.
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Shen, Sheng-Feng, Hsueh-Chen Chen, Sandra L. Vehrencamp y Hsiao-Wei Yuan. "Group provisioning limits sharing conflict among nestlings in joint-nesting Taiwan yuhinas". Biology Letters 6, n.º 3 (6 de enero de 2010): 318–21. http://dx.doi.org/10.1098/rsbl.2009.0909.
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Offspring often compete over limited available resources. Such sibling competition may be detrimental to parents both because it entails wasted expenditure and because it allows stronger offspring to obtain a disproportionate share of resources. We studied nestling conflict over food and its resolution in a joint-nesting species of bird, the Taiwan yuhina ( Yuhina brunneiceps ). We show that adult yuhinas coordinate their feeding visits, and that this coordination limits competition among nestlings, leading to a ‘fairer’ division of resources. Transponder identification and video-recording systems were used to observe adult feeding and nestling begging behaviours. We found that: (i) yuhinas feed nestlings more often in large parties than in small parties; (ii) feeding events occurred non-randomly in bouts of very short intervals; and (iii) food distribution among nestlings was more evenly distributed, and fewer nestlings begged, during large-party feeding bouts compared with small-party feeding bouts. To our knowledge, this is the first study in a cooperative breeding species showing that adults can influence food allocation and competition among nestlings by coordinating their feeding visits. Our results confirm the hypothesis that the monopolizability of food affects the intensity of sibling competition, and highlight the importance of understanding the temporal strategies of food delivery.
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Godwin, Christine M., Robert M. R. Barclay y Judit E. G. Smits. "Tree Swallow (Tachycineta bicolor) nest success and nestling growth near oil sands mining operations in northeastern Alberta, Canada". Canadian Journal of Zoology 97, n.º 6 (junio de 2019): 547–57. http://dx.doi.org/10.1139/cjz-2018-0247.
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Industrial development and contaminant exposure may affect reproductive success and food quality for birds. Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) nesting near oil sands development in northern Alberta (Canada) potentially experience elevated environmental stressors that could influence reproduction. We measured reproductive and growth endpoints in Tree Swallows, predicting reduced reproductive success and nestling growth near oil sands operations compared with reference sites. We also identified the invertebrate prey in the stomach contents of nestlings to understand variability in the diet and its potential effect on growth and survival of nestlings. From 2012 to 2015, clutch initiation varied among years but was not influenced by proximity to oil sands operations. Hatching and fledging success decreased in response to increased precipitation, regardless of location. Measurements of nestling growth reflected the variation associated with nestling sex and possibly asynchronous hatching. The composition of the nestling diet was significantly different; birds near oil sands development consumed Odonata, whereas birds at reference sites consumed Ephemeroptera. Nestlings from all sites consumed relatively high quantities of terrestrial insects. Our results demonstrate that factors such as weather conditions, diet, hatching order, and nestling sex are important when interpreting the potential effects of oil sands development on nest success and nestling growth.
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Norris, Andrea R., Kristina L. Cockle y Kathy Martin. "Evidence for tolerance of parasitism in a tropical cavity-nesting bird, planalto woodcreeper (Dendrocolaptes platyrostris), in northern Argentina". Journal of Tropical Ecology 26, n.º 6 (11 de octubre de 2010): 619–26. http://dx.doi.org/10.1017/s026646741000043x.
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Abstract:Avian hosts may either resist the negative effects of nestling ectoparasites by minimizing the number of parasites, or tolerate parasitism by increasing their fecundity via the reproductive compensation hypothesis. Little is known about the interactions between ectoparasites and their avian hosts in the tropics. We (1) examined nestling development rates, and tested whether (2) parasitism by a subcutaneous ectoparasitic botfly (Philornissp.) had negative effects on the condition of nestlings, and (3) these negative effects were minimized in larger broods in a tropical cavity-nesting bird, the planalto woodcreeper (Dendrocolaptes platyrostris), in primary and secondary Atlantic forests in the northern province of Misiones, Argentina. Nestling mass and ectoparasite load per nestling reached maxima when nestlings (n = 50) were between 10 and 14 d old. General linear mixed models predicted that mass at fledging declined with increasing nestling parasite load, suggesting that botflies had a negative influence on fledging condition. Parasite load per nestling declined with increasing brood size indicating that woodcreepers that increase their reproductive output minimize the negative effects of parasitism. Overall we found evidence to support the tolerance via reproductive compensation hypothesis. Future tests of the reproductive compensation hypothesis may help determine the underlying mechanism of the observed negative correlation between parasite load of nestlings and brood size.
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Eastman, Marjorie D., L. Scott Johnson y L. Henry Kermott. "Ectoparasitism of nestling House Wrens, Troglodytes aedon, by larvae of the blow fly Protocalliphora braueri (Diptera: Calliphoridae)". Canadian Journal of Zoology 67, n.º 10 (1 de octubre de 1989): 2358–62. http://dx.doi.org/10.1139/z89-333.
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We provide the first detailed information concerning ectoparasitism of nestling birds by larvae of the blow fly, Protocalliphora braueri Hendel. This species is unusual among Protocalliphora because its larvae cause a subcutaneous myiasis in small birds. We examined the pattern of infestation, and the effect of parasites on nestling survival and body size at fledging in a population of House Wrens, Troglodytes aedon. Twenty-five of 71 nests (35%) in the population were infested. Infested nestlings hosted an average of five larvae each. Myiases occurred in virtually all parts of nestling bodies, and larvae were visible on hosts for approximately 3 days. Parasitism did not appear to affect nestling survival if larvae appeared after the nestlings were approximately 6 days old. Some young infested at ages younger than this appeared to die as a result of parasitism, but infestation at these ages was rare (only 12% of nests). Comparison with other studies of dipteran ectoparasitism suggests that in most cases, parasite loads in our population are generally too low to have any significant effect on nestling survival. We also found no relationship between the intensity of parasitism and the tarsus size of nestlings at the time that they fledge, as measured by tarsus length.
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Michaud, Trista y Marty Leonard. "The Role of Development, Parental Behavior, and Nestmate Competition in Fledging of Nestling Tree Swallows". Auk 117, n.º 4 (1 de octubre de 2000): 996–1002. http://dx.doi.org/10.1093/auk/117.4.996.
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Abstract Fledging (i.e. leaving the nest) in altricial birds is a major step toward independence. The timing of this important event may be influenced by nestling development, parental behavior, and sibling interactions. In this study, we examine the effect of these factors on fledging in Tree Swallows (Tachycineta bicolor). Wing length explained a significant proportion of the variance in fledging age across broods. Similarly, within broods, longer-winged nestlings fledged before shorter-winged nestlings. Feeding rate per nestling did not decrease in the period leading up to fledging, as might be expected if parents stimulated fledging by decreasing their feeding rate. Parental activity near the nest varied in that the frequency of parental passes and hovers within 1 m of the nest opening increased in the period before fledging. Brood size also explained a significant proportion of the variance in fledging age independent of wing length, although the direction of the relationship was not consistent across years. Finally, longer-winged nestlings spent more time in the nest opening and initiated fledging of the brood more often than did shorter-winged nestlings. Overall, our study suggests that nestling development is the most important determinant of fledging age in this species. Once a critical wing length has been reached, sibling interactions, and possibly parental behavior, may influence the timing of fledging.
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Ardia, Daniel R. "Geographic Variation in the Trade-Off Between Nestling Growth Rate and Body Condition in the Tree Swallow". Condor 108, n.º 3 (1 de agosto de 2006): 601–11. http://dx.doi.org/10.1093/condor/108.3.601.
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AbstractNestlings can exhibit considerable variation in developmental patterns both within and among locations due to differences in environmental conditions and parental investment. I investigated trade-offs between nestling growth rate and residual body mass (body condition) at three locations across the range of the Tree Swallow (Tachycineta bicolor). Nestlings at the northern extreme of the range in Alaska had slower growth rates, lower body mass, and higher residual body mass than nestlings in New York and Tennessee. High insect availability was correlated with increased growth rates of nestlings in New York and Tennessee, but not in Alaska. Conversely, nestlings in Alaska showed increased residual body mass with high insect availability, but nestlings in New York and Tennessee did not. The trade-off between growth rate and residual body mass varied among sites, with fast-growing nestlings in Tennessee maintaining a higher residual body mass than those in Alaska. These results suggest that factors affecting offspring growth and condition vary among sites, leading to geographical differences in offspring development trajectories.
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Merino, Santiago y Jaime Potti. "Growth, nutrition, and blow fly parasitism in nestling Pied Flycatchers". Canadian Journal of Zoology 76, n.º 5 (1 de mayo de 1998): 936–41. http://dx.doi.org/10.1139/z98-013.
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The nutritional status of the host may play a major role in mediating the detrimental effects of parasites. We performed an experiment with the aim of determining whether increased food availability can compensate for the effects of ectoparasites on growth during the late nestling period, final size, and survival until fledging of Pied Flycatcher (Ficedula hypoleuca) nestlings. Nests were provided with supplementary food, treated with insecticide, given both treatments, or given neither treatment (control). Differences in the number of blood-sucking, ectoparasitic blow fly larvae (Protocalliphora azurea) occurred between treated nests. Nestlings in the group given supplementary food and with low numbers of parasites grew faster and had a higher haematocrit value than those in groups that were fumigated and given supplementary food, with nestlings from control nests attaining the lowest values. Nestling measurements did not differ between fumigated and food-supplemented groups. Although the final sizes attained did not differ among nestlings from the different experimental groups, there was a significant difference in the rates of increase in size among groups. Nestlings in nests fumigated and provided with extra food were (nonsignificantly) smaller and leaner than nestlings from the other groups at the beginning of the experiment, but were slightly larger and heavier (again nonsignificantly) at the end of the experiment. Thus, their growth was faster than that of the other groups. The results are discussed, highlighting problems related to the function linking intensity of parasit ism to host fitness and variation in external (climate, food) conditions.
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Dugas, Matthew B. "Detectability matters: conspicuous nestling mouth colours make prey transfer easier for parents in a cavity nesting bird". Biology Letters 11, n.º 11 (noviembre de 2015): 20150771. http://dx.doi.org/10.1098/rsbl.2015.0771.
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An often underappreciated function of signals is to notify receivers of the presence and position of senders. The colours that ornament the mouthparts of nestling birds, for example, have been hypothesized to evolve via selective pressure generated by parents' inability to efficiently detect and feed nestlings without such visually conspicuous targets. This proposed mechanism has primarily been evaluated with comparative studies and experimental tests for parental allocation bias, leaving untested the central assumption of this detectability hypothesis, that provisioning offspring is a visually challenging task for avian parents and conspicuous mouths help. To test this assumption, I manipulated the mouths of nestling house sparrows to appear minimally and maximally conspicuous, and quantified prey transfer difficulty as the total duration of a feeding event and the number of transfer attempts required. Prey transfer to inconspicuous nestlings was, as predicted, more difficult. While this suggests that detectability constraints could shape nestling mouth colour evolution, even minimally conspicuous nestlings were not prohibitively difficult for parents to feed, indicating that a more nuanced explanation for interspecific diversity in this trait is needed.
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Puchala, Peter. "Detrimental effects of larval blow flies (Protocalliphora azurea) on nestlings and breeding success of Tree Sparrows (Passer montanus)". Canadian Journal of Zoology 82, n.º 8 (1 de agosto de 2004): 1285–90. http://dx.doi.org/10.1139/z04-111.
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The effect of bloodsucking parasitic larvae of the blow fly Protocalliphora azurea (Fallén, 1817) (Diptera) on Tree Sparrow, Passer montanus (L., 1758), breeding success was studied in populations breeding in nest boxes in southwestern Slovakia. Out of 52 examined nests only seven broods (13%) were unparasitized. The mean number of larvae per parasitized nest was 22.6 and the total number of parasites per nest ranged from 1 to 80. Large numbers of blow fly larvae and pupae significantly influenced nestling survival and fledging success. In broods with parasite load per chick higher than nine, at least one nestling died. To record the effects of parasites on the body size of nestlings of different ages, nestlings were measured on days 5, 10, and 13 post hatch. First and second broods were analysed separately. A significant negative effect of parasite load per nestling on the body mass, wing length, tarsal length, and tail length of nestlings was found in the second broods only in the 10- and 13-day-old chicks. Tree Sparrow parents did not prolong nestling provisioning time per nestling, as there was no negative relationship between parasite load per nestling and feeding period. Contradictory to most previous studies of the genus Protocalliphora, the present study suggests that these parasites have an important negative impact on the breeding success of the studied Tree Sparrow populations.
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Eens, Marcel y Rianne Pinxten. "Male Feeding of Nestlings in the Facultatively Polygynous European Starling: Allocation Patterns and Effect On Female Reproductive Success". Behaviour 129, n.º 1-2 (1994): 113–40. http://dx.doi.org/10.1163/156853994x00389.
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AbstractParental investment by males is less common among birds with polygynous mating systems than in monogamous species. Here, we examined the contribution of males in feeding nestlings in the facultatively polygynous European starling, Sturnus vulgaris. 1. In nestbox colonies around Antwerp, Belgium, males and females within monogamous pairs divided the feeding duties about equally, with a slight bias towards the female, and responded similarly to changes in brood size and age of nestlings. 2. The proportion of primary females receiving male assistance in feeding nestlings was significantly smaller than the proportion of monogamous females during each of the three nestling age stages (early, mid and late) we considered. In most primary broods, the strong decrease in male assistance was not due to the male directing part of his feeding effort toward the brood of the secondary female, but was due to the fact that the male's investment in feeding primary nestlings was negatively affected by his polygynous behaviour. As prospecting females were present after hatching of the primary broods (as contrasted to other studied starling populations), most males spent time trying to attract and courting additional females instead of giving parental care to the primary brood. This suggests that males trade off the attraction of additional females against giving parental care to an existing brood. The proportion of secondary females receiving male assistance in feeding was significantly smaller than the proportion of monogamous females during the early- and mid nestling stages. Overall, secondary females received less male assistance than primary females. The amount of male help to primary and secondary broods was not related to the hatching interval between the primary and secondary brood. 3. Primary females did not suffer reduced breeding success compared to monogamous females. In secondary broods, nestling mortality (partial brood loss) was significantly higher than in both primary and monogamous broods, while average nestling weights were significantly lower. These results suggest that secondary females, as contrasted to primary females, are not able to compensate fully for the reduction in male assistance. 4. During the mid-nestling stage, when nestlings grow most rapidly, but not during the early- and late-nestling stages, polygynously mated females feeding young without male assistance significantly increased their per-caput feeding rate compared with aided polygynous females and monogamous females, and made as many feeding visits as did polygynous pairs in which the male assisted, and as monogamous pairs. The higher nestling mortality rates in polygynous broods without male help during the early and mid-nestling stages suggest that unaided females cannot compensate fully (in terms of quantity or quality of food delivered), that male starlings can improve female fledging success by assisting in feeding nestlings, and that the reduced reproductive success of secondary females is directly linked to the strongly reduced male assistance in feeding.
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Saunders, Denis A., Rick Dawson, Peter R. Mawson y A. O. Nicholls. "Factors affecting nestling condition and timing of egg-laying in the endangered Carnaby’s cockatoo, Calyptorhynchus latirostris". Pacific Conservation Biology 26, n.º 1 (2020): 22. http://dx.doi.org/10.1071/pc19010.
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Carnaby’s cockatoo, Calyptorhynchus latirostris, is endemic to south-western Australia. It has undergone a major decline in range and abundance as a result of extensive removal of breeding and foraging habitat. It is now classified as endangered by the State of Western Australia, the Australian government, and internationally. In order to plan effective conservation management for the species it is important to assess the success of breeding populations throughout its range. In this paper we examine the efficacy of using the relationship between growth in the length of a nestling’s folded left wing and body mass to assess nestling condition, and examine known breeding failure in relation to nestling condition in two breeding populations: one at Coomallo Creek (studied from 1970–2017), and the other at Manmanning (1969–76). Results demonstrated that the lighter the nestlings, the higher the rate of breeding failure. Data from the Coomallo Creek population were used to prepare a table of nestling folded left wing length and body mass as a benchmark for assessing nestling condition in 10 other breeding populations, based on data collected from 1970 to the present. Following extensive clearing that removed foraging and breeding habitat, two of the 10 populations produced nestlings that were significantly lighter than the benchmark, and both populations subsequently declined to extinction. The commencement of egg-laying each season at Coomallo Creek was strongly influenced by total rainfall in the first half of autumn. The length of the egg-laying period between 1970–76 and 2009–17 increased by 5.2 weeks (40%). This increase was related to changes in rainfall and temperature over more than four decades. Despite the lengthening of the egg-laying period, nestling condition was unaffected, suggesting that, at least in the short term, the Carnaby’s cockatoo population at Coomallo Creek is coping with the effects of climate change.
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Leonard, Marty L. y Andrew G. Horn. "Ambient noise increases missed detections in nestling birds". Biology Letters 8, n.º 4 (22 de febrero de 2012): 530–32. http://dx.doi.org/10.1098/rsbl.2012.0032.
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Ambient noise can mask acoustic cues, making their detection and discrimination difficult for receivers. This can result in two types of error: missed detections, when receivers fail to respond to the appropriate cues, and false alarms, when they respond to inappropriate cues. Nestling birds are error-prone, sometimes failing to beg when parents arrive with food (committing missed detections) or begging in response to stimuli other than a parent's arrival (committing false alarms). Here, we ask whether the frequency of these errors by nestling tree swallows ( Tachycineta bicolor ) increases in the presence of noise. We found that nestlings exposed to noise had more missed detections than their unexposed counterparts. We also found that false alarms remained low overall and did not differ significantly between noise and quiet treatments. Our results suggest that nestlings living in noisy environments may be less responsive to their parents than nestlings in quieter environments.
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Pérez, Jonathan H., Daniel R. Ardia, Elise K. Chad y Ethan D. Clotfelter. "Experimental heating reveals nest temperature affects nestling condition in tree swallows ( Tachycineta bicolor )". Biology Letters 4, n.º 5 (15 de julio de 2008): 468–71. http://dx.doi.org/10.1098/rsbl.2008.0266.
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Investment in one life-history stage can have delayed effects on subsequent life-history stages within a single reproductive bout. We experimentally heated tree swallow ( Tachycineta bicolor ) nests during incubation to test for effects on parental and nestling conditions. Females incubating in heated boxes maintained higher body condition and fed nestlings at higher rates. We cross-fostered nestlings and found that young nestlings (4–7 days old) incubated in heated nests had higher body condition and body mass, regardless of treatment status of their rearing parent. However, older nestlings which were fed by heated females maintained higher condition and body mass regardless of treatment status of their incubating parent. These results indicate that investment in one life-history stage can have multiple pathways of carry-over effects on future life-history stages.
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Luz, Hermes R., Ildemar Ferreira y Pedro Ernesto C. Ventura. "Reprodução do Arapaçu-do-cerrado (Lepidocolaptes angustirostris Vieillot, 1918) (Aves: Dendrocolaptidae) no estado do Rio de Janeiro, Brasil". Lundiana: International Journal of Biodiversity 8, n.º 1 (28 de octubre de 2007): 75–78. http://dx.doi.org/10.35699/2675-5327.2007.23185.
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he breeding behavior of a couple of Narrowbilled Woodcreepers, L. angustirostris, was followed in a nest discovered in an urbanized area in the municipality of Seropédica, Rio de Janeiro state, Brazil. Eggs, nest and nest site are described. Three nestlings were color-banded and parental care received by each of them followed. Parents alternated in incubation and pos-nestling care and cared for the young for 19 days, until they left the nest. Some parts of the nestlings’ bodies were infested by Philornis sp. Reproducion followed the pattern known for the family.
Keywords: Narrow-billed Woodcreeper, reproduction, nest, nestling, Philornis, Diptera.
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Anava, Avner, Michael Kam, Amiram Shkolnik y A. Allan Degen. "Growth Rate and Energetics of Arabian Babbler (Turdoides squamiceps) Nestlings". Auk 118, n.º 2 (1 de abril de 2001): 519–24. http://dx.doi.org/10.1093/auk/118.2.519.
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Abstract Arabian Babblers (Turdoides squamiceps) are territorial, cooperative breeding passerines that inhabit extreme deserts and live in groups all year round. All members of the group feed nestlings in a single nest, and all group members provision at similar rates. Nestlings are altricial and fledge at about 12 to 14 days, which is short for a passerine of its body mass. Because parents and helpers feed nestlings, we hypothesized that the growth rate of nestlings is fast and that they fledge at a body mass similar to other passerine fledglings. Using a logistic growth curve, the growth rate constant (k) of nestlings was 0.450, which was 18% higher than that predicted for a passerine of its body mass. Asymptotic body mass of fledglings was 46 g, which was only 63% of adult body mass, a low percentage compared to other passerines. Energy intake retained as energy accumulated in tissue decreased with age in babbler nestlings and amounted to 0.29 of the total metabolizable energy intake over the nestling period. However, energy content per gram of body mass increased with age and averaged 4.48 kJ/g body mass. We concluded that our hypothesis was partially confirmed. Growth rate of babbler nestlings was relatively fast compared to other passerine species, but fledgling mass was relatively low.
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Pagnucco, Katie, Liana Zanette, Michael Clinchy y Marty L. Leonard. "Sheep in wolf's clothing: host nestling vocalizations resemble their cowbird competitor's". Proceedings of the Royal Society B: Biological Sciences 275, n.º 1638 (5 de febrero de 2008): 1061–65. http://dx.doi.org/10.1098/rspb.2007.1706.
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Nestlings of many avian brood parasites are virtuosos at mimicking host nestling vocalizations, which, like egg mimicry, presumably ensures acceptance by host parents. Having been accepted, parasitic nestlings then often exaggerate the aspects of the host's display to increase parental care. Host nestlings may, in turn, exaggerate their vocalizations to keep up with the parasite, though this possibility has not been evaluated. We experimentally parasitized song sparrow ( Melospiza melodia ) nests with a brown-headed cowbird ( Molothrus ater ) chick to evaluate how host nestlings respond. Vocalizations emitted from experimentally parasitized nests were higher in frequency, and louder, than those from unparasitized nests, consistent with the cowbird exaggerating its signalling. In response, host nestlings exaggerated the frequency and amplitude of their vocalizations, such that they resembled the cowbird's while they ‘scaled back’ on calls per parental provisioning bout. Sparrows in parasitized nests were fed equally often as sparrows in unparasitized nests, suggesting that exaggerating some aspects of vocalization while scaling back on others can help host nestlings confronted with a cowbird. Our results support the recently proposed hypothesis that signalling in parasitized nests involves a dynamic interaction between parasitic and host nestlings, rather than a one-way process of mimicry by the parasite.
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Steen, Ronny, Anne-Marie Austad, Steen Johnny y Bjørn Aksel Bjerke. "Daily activity and nest attendance in a breeding pair of Parrot Crossbills Loxia pytyopsittacus in southern Norway". Ornis Norvegica 40 (25 de abril de 2017): 24. http://dx.doi.org/10.15845/on.v40i0.1206.
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Crossbills Loxia spp. breed during late winter and early spring and feed their nestlings almost exclusively with seeds from conifer cones. In the present paper, we studied a breeding pair of Parrot Crossbills Loxia pytyopsittacus from dawn to dusk in Southern Norway using a time-lapse camera. The study was conducted in the second half of the nestling period, when the nestlings were from 10 to 21 days old and capable of keeping warm without assistance from the female. Almost all recorded parental nest visits involved feeding the nestlings. The average number of feeding visits was about 10 visits per day by each parent and these visits were distributed evenly throughout the day, starting about 30 min after sunrise and ending 60 min before sunset. Parents fed the young regularly at about 1-hour intervals. The female feeding duration was constant throughout the period, whereas the male feeding duration was longer initially, but decreased compared with the female later in the nestling period. In most feeding visits, the male and female arrived at the nest at the same time or shortly after to each other. The probability of parents removing nestlings’ faecal sacs was very high during the early period, but decreased as the nestlings became older. Overall, our use of modern camera monitoring technology enabled a more comprehensive description of a pair of Parrot Crossbill’s daily activity patterns and nest attendance behaviour than previous studies conducted by observations from a hide.
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Fernie, Kimberly J. y David M. Bird. "Effects of Electromagnetic Fields on the Growth of Nestling American Kestrels". Condor 102, n.º 2 (1 de mayo de 2000): 461–65. http://dx.doi.org/10.1093/condor/102.2.461.
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AbstractWe studied nestling American Kestrels (Falco sparverius) in a laboratory setting to determine whether exposure to electromagnetic fields (EMFs) affected their growth. Captive nestlings were raised by their parents under control or EMF conditions similar to those occurring near transmission lines in the wild. Nestlings also were exposed to EMFs as embryos when incubated by their parents. Measurements of body mass, and lengths of tarsi, antebrachia, and feathers were taken every three days after hatching. EMF exposure affected the growth of female and male nestlings. EMF nestlings and fledglings were heavier and had longer tarsi. The periods of maximal weight gain and antebrachial growth were delayed in EMF males compared to controls, although EMF males were heavier and had similarly long antebrachia to controls by 21 days of age. Growth of ninth primaries and central rectrices of nestlings were unaffected by EMF exposure. Growth patterns of male and female kestrel nestlings were similar to those previously reported for this species, although the periods of maximal weight gain and bone growth did not occur earlier in EMF males than females as it did in controls.
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Guilherme, Edson y Jônatas M. Lima. "AN UPDATE ON THE BREEDING BIOLOGY AND BIOMETRY OF HAUXWELL’S THRUSH (TURDUS HAUXWELLI) FROM LOWLAND SOUTHWESTERN BRAZILIAN AMAZON". Ornitología Neotropical 30 (20 de febrero de 2020): 232–39. http://dx.doi.org/10.58843/ornneo.v30i0.475.
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The Neotropical region is home to a large number of species of the genus Turdus. While the breeding biology of this genus is well known in general, data are scant for some Amazonian species, including Hauxwell’s Thrush (Turdus hauxwelli). Here, we present new data on the breeding and biometry of T. hauxwelli based on field observations and captures in a fragment of terra firme forest in southwestern Amazonia, Brazil. We monitored six active nests between 2012 and 2014, and collected data on the incubation and nestling phases on five nests. The nests were built at a mean height of 1.9 m (range: 0.53–3.2 m) above the ground. We estimated incubation time as 13–14 days. We monitored the development of 11 nestlings in four nests. The mean weight of the newly-hatched nestlings was 6.56 g (range: 4.3–9.0 g [SD = 2.27]). The constant (K) of the growth rate in the nestlings was 0.43 (range: 0.31–0.51; SE=0.03), with an asymptote of 51.1 g (range: 45.04 - 62.32; SE= 0.31). The daily survival rate of the nests during the incubation phase was 97%. However, the survival rate during the nestling phase was only 12%. Mayfield’s success was 70% during the incubation phase and 21% during the development of the nestlings, whereas apparent success was 75% in the incubation phase and 27% in the nestling phase. We banded and measured 64 adult individuals, 13 juveniles, and four nestlings in 2005 and between 2009 and 2017. Minimum longevity, calculated from the recapture of banded individuals, was 6 years, 3 months and 11 days (or 2298 days after banding). Our results indicate that T. hauxwelli has a breeding season restricted to a few months of the rainy season (November–March), which overlaps with molt.
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Dawson, Russell D. y Gary R. Bortolotti. "Ecology of parasitism of nestling American kestrels by Carnus hemapterus (Diptera: Carnidae)". Canadian Journal of Zoology 75, n.º 12 (1 de diciembre de 1997): 2021–26. http://dx.doi.org/10.1139/z97-835.
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Little is known about the basic biology of Carnus hemapterus (Diptera: Carnidae), a haematophagous parasite of nestling birds. We therefore explored the patterns of C. hemapterus infestations by repeatedly examining American kestrel (Falco sparverius) nestlings from 50 nests in north-central Saskatchewan. Most infestations occurred before chicks were 12 days old and were more frequent early in the breeding season. Nestlings from larger broods had higher prevalences of C. hemapterus, but we did not detect differences in intensity of infestations between broods of different sizes. Within broods up to 5 days old, the heaviest nestlings were preferentially infested by C. hemapterus. Although evidence suggests that ectoparasite infestations are harmful to hosts, we did not detect any mortality attributable to C. hemapterus. Similarly, we did not observe negative effects of C. hemapterus infestations on nestling mass, length of the tenth primary flight feather, haematocrit, or total plasma protein concentration at 24 days old.