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1
Ryu, Hodon, John F. Griffith, Izhar U. H. Khan, Stephen Hill, Thomas A. Edge, Carlos Toledo-Hernandez, Joel Gonzalez-Nieves, and Jorge Santo Domingo. "Comparison of Gull Feces-Specific Assays Targeting the 16S rRNA Genes of Catellicoccus marimammalium and Streptococcus spp." Applied and Environmental Microbiology 78, no. 6 (January 6, 2012): 1909–16. http://dx.doi.org/10.1128/aem.07192-11.
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ABSTRACTTwo novel gull-specific quantitative PCR (qPCR) assays were developed using 16S rRNA gene sequences from gull fecal clone libraries: a SYBR green assay targetingStreptococcusspp. (gull3) and a hydrolysis TaqMan assay targetingCatellicoccus marimammalium(gull4). The objectives of this study were to compare the host specificity of a previousC. marimammaliumqPCR assay (gull2) with that of the new markers and to examine the presence of the three gull markers in environmental water samples from different geographic locations. Most of the gull fecal samples tested (n= 255) generated positive signals with the gull2 and gull4 assays (i.e., >86%), whereas only 28% were positive with gull3. Low prevalence and abundance of tested gull markers (0.6 to 15%) were observed in fecal samples from six nonavian species (n= 180 fecal samples), whereas the assays cross-reacted to some extent (13 to 31%) with other (nongull) avian fecal samples. The gull3 assay was positive against fecal samples from 11 of 15 avian species, including gull. Of the presumed gull-impacted water samples (n= 349), 86%, 59%, and 91% were positive with the gull2, the gull3, and the gull4 assays, respectively. Approximately 5% of 239 non-gull-impacted water samples were positive with the gull2 and the gull4 assays, whereas 21% were positive witg the gull3 assay. While the relatively high occurrence of gull2 and gull4 markers in waters impacted by gull feces suggests that these assays could be used in environmental monitoring studies, the data also suggest that multiple avian-specific assays will be needed to accurately assess the contribution of different avian sources in recreational waters.
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Källander, Hans. "Interspecific kleptoparasitism by four species of gull Larus spp. in South Sweden." Ornis Svecica 16, no. 3 (July 1, 2006): 127–49. http://dx.doi.org/10.34080/os.v16.22716.
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Data are presented on interspecific kleptoparasitism by Black-headed Gull Larus ridibundus, Common Gull L. canus, Herring Gull L. argentatus and Great Black-backed Gull L. marinus, collected in South Sweden from the late 1950s to the present day. The basis for the presentation is the various host species exploited by the four gull species. For each host species, information is given on species of gull kleptoparasitising it, seasonal occurrence of kleptoparasitism, details of behaviour and, when available, data on gulls’ success rates. The paper is intended as a sort of catalogue. For this reason, relevant literature is reviewed under each of the host-species headings. Gulls’ success rates varied between 55% for Black-headed Gulls and Common Gulls parasitising Northern Lapwings Vanellus vanellus, the most often observed kleptoparasitic association, and 15% on the few occasions that Black-headed Gulls parasitised Curlews Numenius arquata in grassland. When the same two gull species parasitised Common Starlings Sturnus vulgaris, their success rate varied with robbing tactic used (16% vs 45%). Beside the association of the two small gull species with Lapwings and Golden Plovers Pluvialis apricaria, the most frequently observed associations were those of Herring Gulls with Common Eiders Somateria mollissima and Great Black-backed Gulls and Herring Gulls with diving fish-eaters (Great Cormorant Phalacrocorax carbo, mergansers Mergus spp.). Kleptoparasitism often occurred during periods of food scarcity, being most common in harsh winter conditions (the two large gull species) and during cold spells in early spring (some associations of the two small gull species). As in other studies, gulls’ success rate was strongly dependent on the size of hosts’ prey, and thus, normally on handling time. It is suggested that success rate can often be used as a substitute for profitability in studies of kleptoparasitism.
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Coulson, Ruth, and Graeme Coulson. "Population change among Pacific, kelp and silver gulls using natural and artificial feeding sites in south-eastern Tasmania." Wildlife Research 25, no. 2 (1998): 183. http://dx.doi.org/10.1071/wr97027.
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The kelp gull, Larus dominicanus, which is widely distributed around the southern hemisphere, has become established in Australia only in the past half-century. The greatest numbers of kelp gulls in Australia are now found in south-eastern Tasmania in sympatry with the two endemic species, the morphologically similar Pacific gull, L. pacificus, and the smaller silver gull, L. novaehollandiae. We examined populations of the three species in this area. We surveyed large refuse tips and specific shoreline sites in the Hobart area regularly during the winter months in 1981 and again in 1992, recording numbers of each species, and age classes of kelp and Pacific gulls. Between the two survey periods, the number of Pacific gulls and the total number of all gulls present at refuse tips remained unchanged. There was, however, a marked increase in the number of kelp gulls at tips, equivalent to an annual rate of increase of 22.8%, and a corresponding decrease in the number of silver gulls. Kelp gulls of all ages were over-represented at refuse tips, while adult Pacific gulls fed preferentially at more natural shoreline sites. At shoreline sites, adult Pacific gulls appeared to exclude kelp gulls from small bays in 1981, but kelp gulls were present in most of these bays eleven years later. Reducing access to food at refuse tips may be an effective means of controlling the kelp gull population in this area.
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Massaro, Melanie, John W. Chardine, Ian L. Jones, and Gregory J. Robertson. "Delayed capelin (Mallotus villosus) availability influences predatory behaviour of large gulls on black-legged kittiwakes (Rissa tridactyla), causing a reduction in kittiwake breeding success." Canadian Journal of Zoology 78, no. 9 (September 1, 2000): 1588–96. http://dx.doi.org/10.1139/z00-085.
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During 1998 and 1999, the impact of predation by herring gulls (Larus argentatus) and great black-backed gulls (Larus marinus) on breeding success of black-legged kittiwakes (Rissa tridactyla) at Gull Island, Witless Bay, southeastern Newfoundland, was quantified in relation to the timing of the annual arrival of capelin (Mallotus villosus) to spawn. The frequency of predation attempts by large gulls on kittiwakes was compared among three periods: before the mean hatching date for herring gulls, between the mean hatching date for herring gulls and the arrival of the capelin, and following capelin arrival. The frequency varied significantly among the three periods, being highest after gull chicks hatched but before the capelin arrived. The frequency of gull predation was significantly correlated with the percentage of kittiwake eggs and chicks that disappeared each week. We estimated that 43 and 30% of kittiwake eggs and chicks at Gull Island were taken by gulls in 1998 and 1999, respectively. Kittiwakes have been indirectly (through increased predation by gulls) affected by the delayed arrival and lower abundance of capelin in recent years, which underlines the need to understand multispecies interactions when interpreting the effects of human alteration of the marine environment.
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Seamans, Mark E., and Chris Dwyer. "Annual Mortality Limit for Four Gull Species in the Atlantic Flyway." Journal of Fish and Wildlife Management 12, no. 2 (July 20, 2021): 453–63. http://dx.doi.org/10.3996/jfwm-20-088.
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Abstract We estimated the allowable annual take of great black-backed gulls Larus marinus, herring gulls L. argentatus, ring-billed gulls L. delawarensis, and laughing gulls Leucophaeus atricilla in the U.S. portion of the Atlantic Flyway to help meet human safety and resource management goals. Gulls can pose a serious threat to aviation, negatively impact other colonial-nesting migratory bird species, and conflict with other human activities. We estimated an annual take limit using a model that incorporated intrinsic population growth rate, minimum population size, and a recovery factor for each species. We estimated intrinsic population growth by combining allometric with life table approaches. We used the recovery factor to restrict the take level of the great black-backed gull beyond that of the other species because of poor data quality and concern about its population status. The herring gull was the only species with comprehensive demographic data. Population sizes used in estimating potential take limit varied greatly among the four species, but estimates of intrinsic population growth rate were similar (range 0.118 to 0.197). The annual potential take limits for the four gull species were 7,963 for herring gulls, 2,081 for great black-backed gulls, 15,039 for laughing gulls, and 14,826 for ring-billed gulls. Comparing average annual take from 2012–2019 to our modeled potential take limit, overharvest has not occurred for great black-backed and laughing gulls, occurred once every 8 y for ring-billed gulls, and occurred over half the time for herring gulls.
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Smith, Paul A., H. Grant Gilchrist, James N. M. Smith, and Erica Nol. "Annual Variation in the Benefits of a Nesting Association Between Red Phalaropes (Phalaropus Fulicarius) and Sabine's Gulls (Xema Sabini)." Auk 124, no. 1 (January 1, 2007): 276–90. http://dx.doi.org/10.1093/auk/124.1.276.
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AbstractBy nesting near aggressive birds, timid species can reap the benefits of aggressive nest defense while avoiding the costs. Red Phalaropes (Phalaropus fulicarius; hereafter “phalaropes”) typically nest in grass-sedge marshes, but nests have also been noted in rocky coastal habitats. We studied the reproductive ecology of phalaropes at East Bay, Southampton Island, Nunavut, to determine whether their use of coastal nest areas reflected a protective nesting association with an aggressive larid, the Sabine's Gull (Xema sabini; hereafter “gull”). From 2000 to 2002, we found and monitored 29 phalarope nests with gull nests nearby (≤150 m away) and 26 without gulls nearby. Coastal phalarope nests were nearer to gull nests than expected by chance. No habitat differences were detected between coastal areas with and without gull nests, but only three phalarope nests were found in coastal areas without gull nests. Thermistor probes inserted in phalarope nests revealed that incubators with gulls nearby behaved less cryptically, taking more frequent and longer incubation recesses. In human-approach experiments, phalaropes with gulls nearby flushed earlier than those without gulls. In 2000 and 2001, hatch success was 17–20% higher for phalaropes with gulls nearby, but these nests had lower success rates than those without nearby gulls in 2002. These gulls are able to defend their nests from avian predators only; in 2002, arctic foxes (Alopex lagopus) were abundant, and their primary prey, collared lemmings (Dicrostonyx torquatus), were scarce. We suggest that phalaropes select coastal areas near gulls, but that this association is beneficial to phalaropes only in years when egg predation by arctic foxes is low.Variation Annuelle des Bénéfices d'une Association pour Nicher entre Phalaropus fulicarius et Xema sabini
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Robertson, Gregory J., David Fifield, Melanie Massaro, and John W. Chardine. "Changes in nesting-habitat use of large gulls breeding in Witless Bay, Newfoundland." Canadian Journal of Zoology 79, no. 12 (December 1, 2001): 2159–67. http://dx.doi.org/10.1139/z01-180.
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We counted herring gull (Larus argentatus) and great black-backed gull (Larus marinus) nests in the Witless Bay Seabird Ecological Reserve in southeastern Newfoundland, Canada, in 1999 and 2000 and compared our results with previous nest counts from the 1970s. On Gull Island, herring gull nest numbers were 27.5% (1999) and 30.0% (2000) lower than in 1979. Similarly, on Great Island, by 2000 the numbers of herring gull nests had declined 40.8% from numbers in 1979. Counts of great black-backed gull nests were more variable, but suggest a slight or no reduction since 1979. Numbers of herring gulls nesting in rocky and puffin-slope habitats were much reduced (5070%), while numbers nesting in meadows and forests have actually increased since the 1970s. Great black-backed gulls showed a similar change in nesting distribution. For herring gulls, these changes in nesting numbers matched differences in reproductive success previously documented in these habitats. We suggest that the decline in gull numbers and the change in breeding-habitat selection were caused by changes in the food availability for gulls. Reduced amounts of fisheries offal and the delayed arrival onshore of capelin (Mallotus villosus), an important fish prey species for gulls, have all likely led to the decline in gull reproductive output. Gulls nesting in meadows and forests may be maintaining adequate reproductive output by focusing on alternative prey, such as adult Leach's storm-petrels (Oceanodroma leucorhoa), rather than scarce refuse and fish.
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Pérez-Mellado, Valentín, Mario Garrido, Zaida Ortega, Ana Pérez-Cembranos, and Abraham Mencía. "The yellow-legged gull as a predator of lizards in Balearic Islands." Amphibia-Reptilia 35, no. 2 (2014): 207–13. http://dx.doi.org/10.1163/15685381-00002945.
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Lizards and gulls cohabit in several Mediterranean islands. The yellow-legged gull, Larus michahellis, was found to prey several vertebrate species. However, precise information about the interaction between gulls and other vertebrates, particularly with lizards is still scarce. The Balearic lizard, Podarcis lilfordi, shares several coastal islets with the yellow-legged gull. Using two different sources of information, we studied the interaction of both species in Colom Island (Menorca, Balearic Islands, Spain). We studied the diet of the yellow-legged gull and learnt that the Balearic lizard is not a common prey of the yellow-legged gull. On the other hand, we studied the potential predation pressure of gulls on lizards, using plasticine models of lizards. We did two different experiments from which we can conclude that yellow-legged gulls rarely attack lizards and, consequently, cannot be considered a major threat for this endemic lizard species, at least in the population under study. Finally, we obtained evidence that plasticine models can only be employed with caution to assess predation pressure of opportunistic scavengers, much as gulls are. The majority of marks on models were not the consequence of true attacks by gulls, but the result of ground exploratory behaviour of gulls in search of any edible matter. Therefore, contrary to popular belief, in the case of the yellow-legged gull, the proportion of marked models would be an indication of ground-based wandering activity, rather than a result of its predation pressure on lizards.
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González-Solís, Jacob, Xavier Ruiz, and Lluis Jover. "Influence of food availability on interactions between Larus cachinnans and L. audouinii." Canadian Journal of Zoology 75, no. 5 (May 1, 1997): 719–24. http://dx.doi.org/10.1139/z97-092.
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Predatory and (or) kleptoparasitic interactions are greatly facilitated in mixed-species gulleries, particularly when one of the species is larger than the others. Larus audouinii, the Audouin's gull, is a threatened species breeding in sympatry with the larger L. cachinnans, the yellow-legged gull, throughout the Mediterranean. The yellow-legged gull has often been cited as the main threat to the Audouin's gull. On the Chafarinas Islands, the second largest breeding place for Audouin's gulls in the world, both gull species depend largely on commercial fisheries for food. We analyze the influence of food availability, assessed through fishery activity, on the frequency and intensity of interaction pressure by yellow-legged gulls upon Audouin's gulls during the breeding season. We studied five different types of interaction: (1) flyovers of yellow-legged gulls; (2) ground intrusions; (3) egg predation; (4) chick predation, and (5) aerial kleptoparasitism. Moreover, intensity of interaction pressure was assessed using logistic regression analysis to build a model of the"relationship between Audouin's gulls' response to yellow-legged gull flyovers as a dependent variable and fishing fleet activity as an independent variable. All interactions except aerial kleptoparasitism were significantly more frequent during days without sardine fishery activity. However, chick predation is significantly higher only during the period when yellow-legged gull has fledglings. Overall, the results of the estimated logistic model indicate a positive association between depleted food and the response by Audouin's gulls to aerial intrusions.
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Hobson, Keith A. "Use of stable-carbon isotope analysis to estimate marine and terrestrial protein content in gull diets." Canadian Journal of Zoology 65, no. 5 (May 1, 1987): 1210–13. http://dx.doi.org/10.1139/z87-187.
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Stable-carbon isotope analyses of bone collagen of gulls (Larus spp.) were used to estimate the relative proportion of marine and terrestrial protein in the diets of gulls that are known to use both types of food sources. Mean δ13C values for Glaucous-winged Gulls (n = 23) collected at a Vancouver dump and for Western Gulls (n = 18) from Southeast Farallon Island were −15.0 ± 1.3 and −15.1 ± 0.5‰, respectively. No significant difference in δ13C values was found between adult male and female Western Gulls. Archaeological gull bones (n = 3) show a mean δ13C value of −13.6 ± 1.0‰ and support the assumed marine end point of −13.0‰. The range of terrestrial protein in the diets of coastal gulls was 0–61%. The narrow distribution of δ13C values for Western Gulls from the Southeast Farallon Island colony suggests that gull colonies may be calibrated so that changes in dependence on terrestrial protein can be monitored.
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Goumas, Madeleine, Isabella Burns, Laura A. Kelley, and Neeltje J. Boogert. "Herring gulls respond to human gaze direction." Biology Letters 15, no. 8 (August 2019): 20190405. http://dx.doi.org/10.1098/rsbl.2019.0405.
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Human–wildlife conflict is one of the greatest threats to species populations worldwide. One species facing national declines in the UK is the herring gull ( Larus argentatus ), despite an increase in numbers in urban areas. Gulls in urban areas are often considered a nuisance owing to behaviours such as food-snatching. Whether urban gull feeding behaviour is influenced by human behavioural cues, such as gaze direction, remains unknown. We therefore measured the approach times of herring gulls to a food source placed in close proximity to an experimenter who either looked directly at the gull or looked away. We found that only 26% of targeted gulls would touch the food, suggesting that food-snatching is likely to be conducted by a minority of individuals. When gulls did touch the food, they took significantly longer to approach when the experimenter's gaze was directed towards them compared with directed away. However, inter-individual behaviour varied greatly, with some gulls approaching similarly quickly in both treatments, while others approached much more slowly when the experimenter was looking at them. These results indicate that reducing human–herring gull conflict may be possible through small changes in human behaviour, but will require consideration of behavioural differences between individual gulls.
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Conover, Michael R. "Acquisition of Predator Information By Active and Passive Mobbers in Ring-Billed Gull Colonies." Behaviour 102, no. 1-2 (1987): 41–57. http://dx.doi.org/10.1163/156853986x00036.
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AbstractMobbing flocks of ring-billed gulls consisted to two groups: individuals whose nests were near to and threatened by the predator (active mobbers) and others from more distant parts of the colony (passive mobbers). This study examined whether either group can learn about the predator from their mobbing experience. The active mobbers quickly habituated to a human intruder near their nests when the intruder was inactive and empty-handed. Conversely, the gulls responded with a greater flock size and flight distance and fewer swoops when the intruder was holding an adult gull. These response patterns persisted even after the adult gull was removed and the human intruder reappeared alone. When the human intruder held a chick, the gulls approached more closely and swooped more than when the intruder held an adult gull. To examine whether passive mobbers learned anything about the human intruder during the earlier tests, the intruder (now empty-handed) moved to a new location 50 m away and repeated the test. The gulls at these sites, also were significantly less wary than naive gulls of the human intruder following tests in which the intruder was empty-handed, and more wary following tests in which the intruder held an adult gull. Because the earlier test sites were situated so that they could not be seen from the ground at the 50 m sites, a gull at the latter sites could only have learned details about the intruder if it or some of its neighbors had become mobbers. Gulls whose nests were 100 m from an owl model or human intruder learned less about it than gulls at 50 m: perhaps because fewer gulls became passive mobbers as the distance between them and the owl or intruder increased. Costs of becoming a passive mobber include an energetic and time cost and some risk of personal injury due to mid-air collisions with other gulls. The number of passive mobbers increased on breezy days perhaps because strong updrafts on those days reduced the energetic costs of flight within the colonies (and hence of being a mobber). These results support the hypothesis that the gulls' predator-attraction behavior allows them to learn about predators from watching predator-conspecific interactions. The opportunity to witness such interactions and learn about predators may be an important secondary benefit of coloniality for these birds.
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Juozaitytė-Ngugu, Evelina, and Petras Prakas. "The Richness of Sarcocystis Species in the Common Gull (Larus canus) and Black-Headed Gull (Larus ridibundus) from Lithuania." Parasitologia 3, no. 2 (May 10, 2023): 172–80. http://dx.doi.org/10.3390/parasitologia3020018.
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The common gull (Larus canus) and the black-headed gull (Larus ridibundus) are common waterbird species in Lithuania. Until now, the composition of Sarcocystis species in these birds was unknown. The current study aimed to identify Sarcocystis spp. by the morphological examination of sarcocysts found in the muscle tissues and by DNA sequence analysis. Between 2011 and 2019, the leg muscles of 42 common gulls and 63 black-headed gulls were tested for Sarcocystis spp. Based on the methylene blue staining of squashed muscle samples, sarcocysts were detected in six common gulls (14.3%) and in six black-headed gulls (9.5%). Under a light microscope, one type of microcyst was observed. Sarcocysts were thread-like (2860–8250 × 40–180 μm) and had a smooth and thin (0.8–1.4 μm) cyst wall, while bradyzoites were banana-shaped and 5.0–9.2 × 1.3–2.4 μm in size. The sequencing of complete ITS1 showed the presence of S. columbae, S. halieti and S. wobeseri in the common gull and S. columbae and S. halieti in the black-headed gull. The highest intraspecific genetic variability was established for S. halieti, which is characterized by a wide host range. This species is considered to be pathogenic, therefore further histopathological examination of the various organs of gulls is needed.
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Given, Andrew D., James A. Mills, and Allan J. Baker. "Molecular Evidence for Recent Radiation in Southern Hemisphere Masked Gulls." Auk 122, no. 1 (January 1, 2005): 268–79. http://dx.doi.org/10.1093/auk/122.1.268.
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Abstract Masked gulls are believed, on the basis of morphological and recent molecular work, to be a monophyletic group within the Laridae, but relationships of species within the group are not well resolved. We used sequence data from four mitochondrial DNA genes (ND2, ND5, ATPase6, and ATPase 8) totaling >3,600 base pairs to clarify relationships among the species and test competing hypotheses about their origin and biogeography. Monophyly of the masked gulls was confirmed. We also found strong support for a clade including all Southern Hemisphere masked gulls as well as a lone Northern Hemisphere representative, the Black-headed Gull (Larus ridibundus). The Australasian taxa form a well-supported clade, in which the Black-billed Gull (L. bulleri) is sister to the Red-billed Gull (L. novaehollandiae scopulinus) of New Zealand and the Australian Silver Gull (L. n. novaehollandiae). Another well-supported clade includes the Black-headed Gull as sister to the South African Hartlaub's Gull (L. hartlaubii) and the Gray-hooded Gull (L. cirrocephalus) of Africa and South America. The strongly supported position of L. ridibundus within the “southern clade” suggests that it originated from a Southern Hemisphere ancestor and recently dispersed into the Northern Hemisphere. Estimates of divergence times using rate-smoothing methods are consistent with those from previous molecular work and suggest that (1) masked gulls diverged from other gulls <2 mya and (2) much of the radiation in the group occurred in the last 600,000 years. Preuve moléculaire de la radiation récente chez les mouettes “masquées” de l'hémisphère sud
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Burger, Joanna, and Joan Galli. "Factors Affecting Distribution of Gulls (Larus spp.) on Two New Jersey Coastal Bays." Environmental Conservation 14, no. 1 (1987): 59–65. http://dx.doi.org/10.1017/s0376892900011115.
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The distribution and abundance of gulls were examined on Raritan and Delaware Bays from 20 April to 26 October 1982. Gull numbers were affected by seasonal, tidal, weather-related, and human disturbance, factors on both Bays. Gulls comprised from about 40 to 60% of the avifauna on the census areas, and shorebirds accounted for most of the other individuals. Peak numbers of gulls were present on Delaware Bay from May through July, and on Raritan Bay in September. Laughing Gulls (Larus atricilla) were the dominant species on both Raritan (90%) and Delaware (70%) Bays, with Herring Gulls (L. argentatus) second in abundance.
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Jordi, O., A. Herrero, A. Aldalur, J. F. Cuadrado, and J. Arizaga. "The impact of non–local birds on yellow–legged gulls (Larus michahellis) in the Bay of Biscay: a dump–based assessment." Animal Biodiversity and Conservation 37, no. 2 (December 2014): 183–90. http://dx.doi.org/10.32800/abc.2014.37.0183.
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Understanding how animals exploit non–natural feeding sources such as garbage dumps is necessary from many perspectives, including conservation, and population dynamics and management. Several large predatory gulls (Larus spp.) are among the species which most clearly benefit from using dumps. The yellow–legged gull (L. michahellis) is the most abundant gull in the southwestern Palaearctic, and its fast population increase until at least the 2000s was partly due large waste dumps becoming more numerous. The Bay of Biscay is an area that hosts resident local and also wintering non–local yellow–legged gulls. Using data collected over a period of eight years (bird counts, identification of colour–ringed individuals) at four dumps situated within a 60–km radius from the colonies of Gipuzkoa (southwestern Bay of Biscay), we aimed to answer: (1) the origin of gulls using dumps at the Bay of Biscay; (2) the impact of local and non–local gulls at these dumps; (3) the possible age–dependent use of these sites; and (4) the possible seasonal fluctuations in the use of dumps by gulls. Gulls in our area (study dumps) came from nearby colonies in Gipuzkoa, Atlantic Iberia, the Mediterranean region, and other areas such as Atlantic France and inland colonies (Navarra, Germany). Our study dumps seemed to be used mostly by local gulls.
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Jeter, Sonja N., Colleen M. McDermott, Patricia A. Bower, Julie L. Kinzelman, Melinda J. Bootsma, Giles W. Goetz, and Sandra L. McLellan. "Bacteroidales Diversity in Ring-Billed Gulls (Laurus delawarensis) Residing at Lake Michigan Beaches." Applied and Environmental Microbiology 75, no. 6 (January 16, 2009): 1525–33. http://dx.doi.org/10.1128/aem.02261-08.
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ABSTRACT This study investigated the occurrence and diversity of Bacteroidales fecal bacteria in gulls residing in the Great Lakes region. Members of this bacterial order have been widely employed as human and bovine host-specific markers of fecal pollution; however, few studies have focused on gulls, which can be a major source of fecal indicator bacteria and pathogens at beaches. We found a low but consistent occurrence of Bacteroidales in gulls at five beaches in three different counties spanning the Wisconsin shoreline of Lake Michigan. The percentages of gulls positive for Bacteroidales were 4 to 8% at beaches in the southern part of the state and 8 to 50% at beaches in the north. Sequencing of 931 clones from seven gull Bacteroidales 16S rRNA gene libraries revealed a large amount of diversity in both individual and pooled gull fecal samples. Two libraries constructed from pooled gull fecal samples (n = 5 and n = 6) did not have a greater richness of sequences than individual samples, suggesting that even within a single gull diversity is high and an extensive sequencing effort is needed to characterize the populations. Estimates of the numbers of operational taxonomic units (OTUs) for the libraries obtained using different similarity levels revealed a large amount of microdiveristy with a limited number of OTUs at the 95% similarity level. Gull sequences were clustered by the beach from which they were collected, suggesting that there were geographic effects on the distribution of Bacteriodales. More than 53% of the 16S rRNA gene sequences from gulls at the southern beaches were associated with the family Porphyromonadaceae, primarily the genus Parabacteroides, whereas sequences from gulls at the northern beaches were comprised of Bacteroidaceae and Prevotellaceae sequences. Comparison of gull sequences with sequences from goose, canine, raccoon, and sewage sources revealed distinct clusters of closely related gull sequences; however, these sequences were widely dispersed across a dendrogram that included all other sources, including previously characterized gull Bacteroidales from other studies, suggesting that geographic influence or simply sample representation plays a greater role in the observed population structure than strictly the host gut environment.
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Karlsson, Thomas. "Mås- och kråkfågelförekomsten på en soptipp." Ornis Svecica 13, no. 2–3 (July 1, 2003): 67–73. http://dx.doi.org/10.34080/os.v13.22809.
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The present study presents results from counts of gulls and corvids once a week on a refuse dump just outside the city of Skövde in southwestern Sweden during 1992—1999. The most common gull was Herring Gull Larus argentatus, which visited the dump during the whole year. The most common corvid was Jackdaw Corvus monedula with a peak in late June and July. All species except Jackdaw and Raven Corvus corax were found in small numbers during August. High numbers of gulls and corvids were seen on the refuse dump during the winter months. After that the community stopped dumping food rests on the refuse dump in January 1999, Herring Gull, Jackdaw, Hooded Crow Corvus cornix, and Black-headed Gull Larus ridibundus decreased during the spring and summer 1999, however not significantly. In the same time the number of Magpies Pica pica, Great Black-backed Gulls Larus marinus and Ravens increased.
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Goumas, Madeleine, Neeltje J. Boogert, and Laura A. Kelley. "Urban herring gulls use human behavioural cues to locate food." Royal Society Open Science 7, no. 2 (February 2020): 191959. http://dx.doi.org/10.1098/rsos.191959.
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While many animals are negatively affected by urbanization, some species appear to thrive in urban environments. Herring gulls ( Larus argentatus ) are commonly found in urban areas and often scavenge food discarded by humans. Despite increasing interactions between humans and gulls, little is known about the cognitive underpinnings of urban gull behaviour and to what extent they use human behavioural cues when making foraging decisions. We investigated whether gulls are more attracted to anthropogenic items when they have been handled by a human. We first presented free-living gulls with two identical food objects, one of which was handled, and found that gulls preferentially pecked at the handled food object. We then tested whether gulls' attraction to human-handled objects generalizes to non-food items by presenting a new sample of gulls with two non-food objects, where, again, only one was handled. While similar numbers of gulls approached food and non-food objects in both experiments, they did not peck at handled non-food objects above chance levels. These results suggest that urban gulls generally show low levels of neophobia, but that they use human handling as a cue specifically in the context of food. These behaviours may contribute to gulls’ successful exploitation of urban environments.
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Adriaens, Peter, Amar Ayyash, and Mars Muusse. "Extensive Prealternate Molts in Peruvian Kelp Gulls." Western Birds 54, no. 3 (August 15, 2023): 227–47. http://dx.doi.org/10.21199/wb54.3.6.
Full textAbstract:
According to current literature, the Kelp Gull (Larus dominicanus) matures at the same rate and molts according to the same patterns as most other large gulls, such as the American Herring (L. argentatus smithsonianus) and Western (L. occidentalis). The Kelp Gull, however, is widespread through the Southern Hemisphere, with separate populations occupying no fewer than four different climate zones and breeding at different times of the year; the molt of some of those populations appears to have not been studied yet. Here we demonstrate that many immature Kelp Gulls of the Peruvian population undergo much more extensive first and second prealternate molts than has been known so far and achieve an adult-like plumage aspect in as soon as 2.5 years rather than the usual 4. In these respects, these Kelp Gulls recall the Yellow-footed Gull (L. livens) or subspecies heuglini and fuscus of the Lesser Black-backed Gull (L. fuscus).
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Clark, N. B., and L. L. Mok. "Renal excretion in gull chicks: effect of parathyroid hormone and calcium loading." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 250, no. 1 (January 1, 1986): R41—R50. http://dx.doi.org/10.1152/ajpregu.1986.250.1.r41.
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Renal clearance experiments were performed on herring gull (Larus argentatus) and great black-backed gull chicks (L. marinus) to test the importance of parathyroid hormone (PTH), parathyroidectomy (PTX), and calcium loading on excretion patterns of sodium, potassium, calcium, and phosphate. PTX reduced the relative clearance of phosphate to near zero within 2 h. Conversely, PTH stimulated net secretion of phosphate within 40 min. Calcium loading caused a drop in phosphate excretion identical to that of PTX, presumably by inhibiting PTH secretion by the parathyroid glands. This also could be reversed by administration of PTH. Serum phosphate values were highest in PTX gulls and lowest in calcium-loaded gulls. The relative clearance of calcium (CCa/CIn) was elevated in calcium-loaded birds. However, CCa/CIn did not change significantly in response to either PTX or PTH in the sham-operated or PTX birds. Serum calcium values were highest in calcium-loaded gulls and lowest in PTX gulls, the reciprocal of the effects on serum phosphate.
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Remírez, Xabier, Francisco del Campo, Javier del Campo, and Juan Arizaga. "Movement patterns of immature Yellow-legged Gulls Larus michahellis from Gran Canaria, Canary Islands." Seabird Journal 35 (2023): 14–30. http://dx.doi.org/10.61350/sbj.35.14.
Full textAbstract:
The Yellow-legged Gull subspecies Larus michahellis atlantis is thought to be resident in the Macaronesia islands, however, the movement patterns of the population remain largely unknown. We conducted an eight-year (2010–19) ringing and re-sighting program on the island of Gran Canaria (GC), Canary Islands, with an aim of estimating the movement patterns of its gull populations. Re-sighting data revealed that most gulls were observed within 50 km of their natal sites; the farthest locality where studied gulls were seen was Dakhla (500 km from GC) in northwestern Africa. Our findings are compatible with the Yellow-legged Gulls adopting either a GC residency with some dispersal to other islands within the Canary Islands archipelago or to northern Africa, or a true partial migration strategy. Return to GC by some of the gulls that were observed outside GC suggests that philopatry to their natal site could be high, though this should be the focus of further investigation.
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Stenhouse, Iain J., H. Grant Gilchrist, and William A. Montevecchi. "Reproductive Biology of Sabine's Gull in the Canadian Arctic." Condor 103, no. 1 (February 1, 2001): 98–107. http://dx.doi.org/10.1093/condor/103.1.98.
Full textAbstract:
Abstract We studied the reproductive biology of Sabine's Gulls (Xema sabini) breeding on Southampton Island, in the eastern Canadian Arctic, from May to August in 1998 and 1999, and compared our results to information collected from the same region in 1980. Breeding phenology was 10 days earlier in 1998 than in these other years, and reflects an earlier onset of snowmelt in that year. Nests were dispersed, with a density of 7.6 to 8.7 nests per km2. Sabine's Gulls exhibited strong interannual fidelity to breeding sites. Mean clutch size was lower in 1999 than 1998, and lower in both these years than in 1980. Hatching success was 63% in 1998, but only 21% in 1999 due to increased predation, most likely by arctic fox (Alopex lagopus). Adult gulls and chicks abandoned nest-sites within a few hours of the hatching of the last chick and relocated to coastal ponds, where adults continued to attend chicks. In comparisons of the reproductive biology of Sabine's Gull to closely related “tern-like” gull species and other “black-headed” gulls, Sabine's Gull showed a number of distinct ecological and behavioral differences and represents an ecological outlier within the Laridae.
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Bergeron, Andrea, and Julie Ellis. "Body Size and Hematological Values for Herring Gulls (Larus argentatus) Breeding in the Northeastern United States." Wildlife Rehabilitation Bulletin 27, no. 1 (June 30, 2009): 34–41. http://dx.doi.org/10.53607/wrb.v27.118.
Full textAbstract:
With a substantial number of herring gulls (Larus argentatus) being seen each year at wildlife clinics and wildlife rehabilitation facilities, it is clear that there is a need for hematological reference values for this species. Being able to compare values from gulls in these settings to reference ranges available from healthy, actively breeding gulls will provide useful information regarding their health. Surprisingly, there are very few published studies with hematological data specific to herring gulls. In this study, serum chemistry values and body size measurements were obtained from approximately 20 incubating herring gulls at two breeding islands—Appledore Island, Maine, USA and Kent Island, New Brunswick, Canada. The values found were compared to those in the published literature obtained from a number of similar species. This comparison indicated that the hematological values from the herring gulls sampled on Appledore and Kent Islands are similar to those found in other gull species. Therefore, the data collected in this study represent ranges of normal hematological values for healthy, breeding herring gulls.
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Tuckwell, Joanne, and Erica Nol. "Intra- and inter-specific interactions of foraging American oystercatchers on an oyster bed." Canadian Journal of Zoology 75, no. 2 (February 1, 1997): 182–87. http://dx.doi.org/10.1139/z97-025.
Full textAbstract:
We compared the rates of intraspecific and interspecific kleptoparasitism of foraging American oystercatchers (Haematopus palliatus) on a commercial oyster (Crassostrea virginica) bed during two seasons and between 1979 and 1995. In 1979 most conspecific kleptoparasites were immature oystercatchers and victims were adults. Both intra- and inter-specific parasitism were more common in 1979 than in 1994 or 1995. Kleptoparasitism by conspecifics was more common than by gulls (Larus argentatus, L. marinus) but was not density dependent. Gulls primarily kleptoparasitized oystercatchers foraging on mussels (Geukensia demissa), with their longer handling times. Kleptoparasitism by gulls increased as the number of gulls on the oyster bed increased, and the presence of gulls significantly depressed intake rates and sizes of mussels taken by oystercatchers during autumn. Oystercatchers ate smaller oysters in autumn than in winter in both the presence and absence of gulls. The presence of conspecific and gull kleptoparasites changed the oystercatchers' relative preference for oysters over mussels in their diet. The presence of gulls only partly explained the oystercatchers' lower rates of intake of oysters in autumn than in winter.
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Smith, H. V., J. Brown, J. C. Coulson, G. P. Morris, and R. W. A. Girdwood. "Occurrence of oocysts ofCryptosporidiumsp. inLarusspp. gulls." Epidemiology and Infection 110, no. 1 (February 1993): 135–43. http://dx.doi.org/10.1017/s0950268800050767.
Full textAbstract:
SUMMARYBetween November 1990 and February 1991 101 gull faecal samples, collected in central Scotland, and 50 cloacal lavages, from gulls captured at two refuse tips near Durham, England were examined for the presence ofCryptosporidiumsp. oocysts. Five of 101 (c 5%) of faecal samples and 11 of 50 (22%) of cloacal lavages contained oocysts, of which 64% and 83%, respectively were considered viable when examined with propidium iodide and 4′-6-diamidino-2-phenylindole. Since there is insufficient evidence to ascribe these oocysts to a recognized species they are therefore referred to asCryptosporidiumsp. oocysts. There were significant differences in the occurrence of oocysts between gulls captured at the different refuse tips (P < 0.01), but no significant difference between the distribution of oocysts in two species of gull,Larus argentatus(Herring Gull) andL. ridibundus(Black-head Gull). The differences may be explained by different food sources and feeding habits. The contribution of gulls to environmental contamination withCryptosporidiumsp. oocysts is probably generally small, but may be more significant when large numbers roost on surface waters.
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Litwiniak, Klaudia, and Marcin Przymencki. "Long-eared Owl Asio otus breeding in a Caspian Gull Larus cachinnans colony: Reversed roles in protective nesting association?" Ornis Svecica 30 (December 31, 2020): 73–78. http://dx.doi.org/10.34080/os.v30.22033.
Full textAbstract:
We describe the event of Long-eared Owls Asio otus nesting on an island within a colony of Caspian Gulls Larus cachinnans at the Mietków Reservoir (SW Poland). The owls nested in an old (possible corvid) nest in a willow and raised two owlets. They probably did not hunt gulls, neither adults nor chicks. We suggest that, in this case, the Long-eared Owls benefitted from breeding within a gull colony because of the added security against predators that the gulls provided.
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MARTÍNEZ-ABRAÍN, ALEJANDRO, DANIEL ORO, DAVID CONESA, and JUAN JIMÉNEZ. "Compromise between seabird enjoyment and disturbance: the role of observed and observers." Environmental Conservation 35, no. 2 (June 2008): 104–8. http://dx.doi.org/10.1017/s0376892908004748.
Full textAbstract:
SUMMARYNatural areas are increasingly visited by people, and urban human visitors expect to watch wildlife as close as possible, but this may have associated disturbance costs. Here, effects of number of visitors and bird density on flight initiation distance (FID) as a proxy of disturbance vulnerability were evaluated in the large ground-nesting yellow-legged gull,Larus michahellis. Mean FID decreased with increasing number of visitors and with increasing gull densities, suggesting that (1) ground-nesting gulls habituate to massive human presence, while retaining their antipredatory mechanisms, and (2) dense groups of gulls were more reluctant to fly away. This density effect may be due to the increased risk of clutch predation by conspecifics at high densities and, if so, FID is a reliable metric of disturbance vulnerability in ground-nesting gulls. In conclusion, set-back distances are specific to local populations and it is unnecessary to ban or restrict human visits to ground-nesting gull colonies; redistributing visits, taking into account both the number of visitors and gull density, is preferable.
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Dierschke, Volker. "Large gulls as predators of passerine landbirds migrating across the southeastern North Sea." Ornis Svecica 11, no. 3 (July 1, 2001): 171–80. http://dx.doi.org/10.34080/os.v11.22855.
Full textAbstract:
The predation by large gulls on passerines migrating across the southeastern North Sea was studied on the offshore island Helgoland throughout 1999; 15,307 pellets of Herring Gull Larus argentatus and Great Black-backed Gull L. marinus were examined. The main prey was fish and crustaceans, but during migratory seasons of passerines (March to May, August to November) up to 7% of the pellets contained remnants of passerines (mainly thrushes Turdus spp. and Starlings Sturnus vulgaris, but few species of <50 g body mass). For half-month periods, the number of pellets containing passerines correlated with the number of passerines stopping over on Helgoland for both size categories of <50 g and >50 g. Pellets containing passerines were mainly found during weather conditions favourable for migration, when many birds were aloft, rather than during adverse conditions. Based on the number of large gulls present, an estimated 5,200 passerines might have fallen victim to gulls during the year. Although some passerines may be scavenged rather than captured, gulls must be important potential predators for passerines migrating across the sea.
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Bensch, Steffan, Thomas Karlsson, Hans Källander, and Robert Lager. "Predation och störningar i skrattmåskolonier." Ornis Svecica 6, no. 1–2 (April 1, 1996): 67–73. http://dx.doi.org/10.34080/os.v6.22998.
Full textAbstract:
The frequency of disturbance and predation was studied during one breeding season at six Black-headed Gull Larus ridibundus colonies and during two breeding seasons at four colonies. The level of disturbance, i.e. when at least part of the gulls were put on the wing, varied from just above once an hour to nearly ten times an hour. Marsh Harriers Circus aeruginosus elicited the strongest response with respect to number of gulls leaving the nest (mean 57% of colony) while mink Mustela vison caused the longest disturbances (mean 4.6 min). Among the frequently occurring potential predators of Black-headed Gull eggs and chicks, large gulls (L. argentatus, L. marinus) normally caused disturbance much less often than once an hour and Hooded Crows Corvus corone cornix less often than once an hour (except at one locality in 1992 when a breeding pair entered a colony as often as 5.5 times an hour). Marsh Harriers were lacking at three, caused disturbance c. 0.1-1.2 times per hour at eight, and up to three times an hour at three colonies. On average 3% of predation attempts by large gulls were successful versus 14% for both crows and Marsh Harriers (neither the frequency of visits nor predation by mink could be estimated because of difficulties in observing this species). A crude estimate of the number of gull eggs and chicks taken by the three avian predators showed that large gulls had a negligible impact in all colonies, crows normally took less than 10% of eggs laid (33% in one colony) and Marsh Harriers mostly 0-10%. Even though predation by crows and/or Marsh Harriers can be considerable, it is concluded that increased avian predation cannot explain the decrease in Black-headed Gull numbers in Sweden; the mink's role remains to be evaluated.
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Garthe, Stefan, and Birgit Scherp. "Utilization of discards and offal from commercial fisheries by seabirds in the Baltic Sea." ICES Journal of Marine Science 60, no. 5 (January 1, 2003): 980–89. http://dx.doi.org/10.1016/s1054-3139(03)00099-7.
Full textAbstract:
Abstract The distribution and abundance of scavenging seabirds and their utilization of discards and offal between June and December 1998 were studied in the western Baltic Sea. Herring gulls were clearly the most numerous scavenging species in all areas and all seasons, followed by great black-backed gulls, lesser black-backed gulls and mew gulls. High percentages of discarded gadoids (cod, whiting), clupeids (herring, sprat), scad, rockling and offal were consumed by seabirds during experimental discarding on fishing boats, whereas the percentages of flatfish consumed were extremely low. There was a clear effect of cod length on total and species-specific consumption by birds but this pattern was hardly evident for clupeids or dab. By combining official discard and offal statistics and our experimental discarding, we estimate that 6500 t of fish discards and 16 000 t of offal were consumed annually by seabirds in the Baltic Sea. Bivalves, especially blue mussels Mytilus edulis, were the most frequently represented food item in herring gull pellets. Fish identified in the pellets consisted mainly of gadoids, in particular cod. The proportion of discards in herring gull pellets was on average 1.6% (range: 0–4.5%) at Laboe and 17.5% at Warnemünde (range: 9.4–25.5%), but pellets bias diet assessment as offal and other soft prey (including clupeids) will be under-represented. Scavenging on discards and offal is a widespread phenomenon in the Baltic Sea as it is in other shelf areas of Europe, but the number of bird species involved is generally lower and strongly biased towards gulls, especially herring gulls.
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Gilchrist, H. Grant, and Anthony J. Gaston. "Effects of murre nest site characteristics and wind conditions on predation by glaucous gulls." Canadian Journal of Zoology 75, no. 4 (April 1, 1997): 518–24. http://dx.doi.org/10.1139/z97-064.
Full textAbstract:
Glaucous gulls, Larus hyperboreus, are the primary predator of thick-billed murre, Uria lomvia, eggs at arctic breeding colonies. This study used eggs placed experimentally on murre nesting ledges to test the effects on glaucous gull foraging success of (i) murre nesting density; (ii) murre group defence; (iii) nesting ledge width; (iv) timing of murre laying; and (v) wind speed. Defensive responses by murres increased egg survival times, and gull foraging success was reduced by high murre nesting density. The timing of murre egg laying and ledge width also influenced the effectiveness of murre defence within the colony. Eggs placed following the peak of murre egg laying survived longer than eggs placed on the same nest sites prior to the peak. Murres without eggs early in the season often abandoned the group when attacked, leaving experimental eggs and brooding murres vulnerable to gulls. Gulls had difficulty reaching exposed eggs on narrow ledges when foraging on foot. At wind speeds greater than 15 km/h, however, egg survival was independent of ledge width because wind increased the maneuverability of gulls in flight and enabled them to reach narrow ledges. Murre defence at high nesting densities was also less effective on narrow ledges. Apparently, murres had difficulty rotating on their nest sites to face attacking gulls without dislodging their eggs. We conclude that moderate wind speeds enhanced the ability of gulls to reach narrow ledges and avoid contact with defending murres while stealing eggs. Consequently, the vulnerability of murre nest sites depended on wind conditions at the colony.
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Snellen, C. L., P. J. Hodum, and E. Fernández-Juricic. "Assessing western gull predation on purple sea urchins in the rocky intertidal using optimal foraging theory." Canadian Journal of Zoology 85, no. 2 (February 2007): 221–31. http://dx.doi.org/10.1139/z06-203.
Full textAbstract:
Purple sea urchins ( Strongylocentrotus purpuratus (Stimpson, 1857)) are abundant grazing invertebrates that can have a major impact on the rocky intertidal community. Predators can control the urchin population and indirectly reduce grazing activity. We determined the effects of western gull ( Larus occidentalis Audubon, 1839) predation on purple sea urchins in the rocky intertidal using the framework of optimal foraging theory and taking into account different prey-handling techniques. We recorded the foraging behavior of gulls, measured urchin availability, and estimated prey caloric content with bomb calorimetry. Western gulls selected purple sea urchins significantly more than other prey items (snails (genus Tegula Lesson, 1835), limpets (genus Collisella Dall, 1871), sea stars ( Pisaster giganteus (Stimpson, 1857) and Pisaster ochraceus (Brandt, 1835))). Larger urchins contained relatively more calories. Gulls foraged optimally when pecking by frequently selecting the most profitable size class. However, gulls chose smaller urchins than expected when air-dropping, which could have been influenced by group size and age. Gulls selected smaller purple sea urchins when foraging in larger groups likely owing to the risk of kleptoparasitism. Adults chose larger, and juveniles smaller, urchins when air-dropping, suggesting that juveniles are less experienced in foraging techniques. We estimated that gull predation could affect up to one third of the sea urchin populations locally, which could increase species diversity in the rocky intertidal community.
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Borboroglu, Pablo García, and Pablo Yorio. "Habitat Requirements and Selection by Kelp Gulls (Larus Dominicanus) in Central and Northern Patagonia, Argentina." Auk 121, no. 1 (January 1, 2004): 243–52. http://dx.doi.org/10.1093/auk/121.1.243.
Full textAbstract:
Abstract We analyzed habitat requirements and selection of Kelp Gulls (Larus dominicanus) breeding at 68 colonies along 2,500 km of coastline in Patagonia, Argentina. Kelp Gulls use a wide range of nesting habitats that include areas with shrub, grass, and herbs which provide different degrees of cover; open ground of various substrate types; and slopes of widely different gradients, confirming the plasticity of the species with respect to habitat recorded elsewhere in the Southern Hemisphere. Eighty percent of the colonies were on islands, the probability of occupation of which increased with distance from mainland and availability of vegetation. Vegetation cover was a key component of nesting habitat for Kelp Gulls in Argentina. Gulls occupied areas with higher cover than random areas; but within vegetated areas, they showed preference for sparser cover that increased visibility and facilitated escape. Kelp Gulls often nested with other species of seabirds and seals and had a positive association with the Olrog's Gull (L. atlanticus).
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Higdon, Jeff W., and Stefan Romberg. "Observations of juvenile ivory gulls (Pagophila eburnea) in Resolute Bay, Nunavut, Canada, August 2005." Polar Record 42, no. 2 (April 2006): 170–72. http://dx.doi.org/10.1017/s0032247406225294.
Full textAbstract:
Canadian ivory gull (Pagophila eburnea) populations have declined ca. 80% since the early 1980s, and observations, especially of juveniles, are noteworthy. From 20 to 26 August 2005 adult and juvenile ivory gulls were observed and photographed at Resolute Bay, Nunavut, Canada. The numbers of gulls observed reached a peak on 23 August when 18 birds (13 adults and 5 juveniles) were present. A minimum of 7 juveniles and 13 adults were present on 21 and 23 August, respectively, for a total minimum estimate of 20 ivory gulls. The highest numbers were observed during the stormiest days, suggesting that the gulls were taking shelter in the protected bay. Ivory gulls were observed in close proximity to other seabirds, and one fish capture attempt was observed. These are the first reported juveniles for Resolute Bay since 2000, and the first reported for the Canadian High Arctic since 2002, suggesting that breeding success in 2005 may have been better than in previous years.
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PALMGREN, H., A. ASPÁN, T. BROMAN, K. BENGTSSON, L. BLOMQUIST, S. BERGSTRÖM, M. SELLIN, R. WOLLIN, and B. OLSEN. "Salmonella in Black-headed gulls (Larus ridibundus); prevalence, genotypes and influence on Salmonella epidemiology." Epidemiology and Infection 134, no. 3 (October 20, 2005): 635–44. http://dx.doi.org/10.1017/s0950268805005261.
Full textAbstract:
During a period of 3 years, 1998–2000, 1047 faecal swabs from Black-headed gulls were sampled at one location in Southern Sweden. Salmonella spp. was found in 28 individuals (2·7%) and the dominating serotype found was S. Typhimurium (83%). Twenty-five per cent of the Salmonella-infected gulls were later recaptured and re-sampled. We found that Salmonella infection in Black-headed gulls was of short duration, and that infection in this bird species was predominantly expressed as carriage without disease manifestations. All S. Typhimurium isolates were subjected to antibiotic resistance profiling and molecular characterization by pulsed-field gel electrophoresis and IS200 polymerase chain reaction. The S. Typhimurium gull isolates were compared to human and domestic animal isolates of the same serotype and phage type. We found genetic relatedness of S. Typhimurium DT195 isolates from gulls, domestic animals and humans, indicating that Black-headed gulls might play a role in the spread of S. Typhimurium in Sweden.
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Whittam, Rebecca M., and Marty L. Leonard. "Characteristics of Predators and Offspring Influence Nest Defense by Arctic and Common Terns." Condor 102, no. 2 (May 1, 2000): 301–6. http://dx.doi.org/10.1093/condor/102.2.301.
Full textAbstract:
Abstract Nest defense is a critical aspect of parental care that entails both costs and benefits. The purpose of this study was to examine patterns of nest defense in a colony of Arctic and Common Terns (Sterna paradisaea and S. hirundo, respectively) using observations of natural predators: Herring Gulls (Larus argentatus) and Great Black-backed Gulls (L. marinus). Tern nest-defense scores were higher for hunting gulls than for overflying gulls and for gull flights closer to the ground. Defense scores also were significantly higher during the chick stage than during the egg stage. Within the chick stage, response score initially increased with age, but then declined. The results of this study indicate that terns vary their defense in relation to characteristics of predators and offspring that influence the costs and benefits of defense.
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Chávez Villavicencio, César Lautaro, and María Fernanda Márquez Bahamonde. "Mew Gull Larus canus breeding in a residential area of Malmö, Sweden." Ornis Svecica 29 (November 12, 2019): 72–75. http://dx.doi.org/10.34080/os.v29.19924.
Full textAbstract:
The Mew Gull Larus canus is both a coastal and inland breeder and can be found on many different substrates, including man-made structures. It is known since long to nest in urban areas of Sweden, but neither the number of urban breeding pairs nor their behaviour have been well documented. We made some observations of breeding Mew Gulls in the city of Malmö in south Sweden and asked the chair of the tenant owners’ association that comprised one of the buildings with Mew Gull nest about the tenants’ experience of the species. Some perceive Mew Gulls as harmful because they dirty the roofs, leave a bad smell, are noisy, and defend their young with aggressive behaviours. Given the often-conflicting interests of gulls and humans, a better documentation of the nesting population in urban areas of Sweden, as well as their behaviour and interaction with people, is called for.
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Blight, Louise K., Douglas F. Bertram, and Edward Kroc. "Evaluating UAV-based techniques to census an urban-nesting gull population on Canada’s Pacific coast." Journal of Unmanned Vehicle Systems 7, no. 4 (December 1, 2019): 312–24. http://dx.doi.org/10.1139/juvs-2019-0005.
Full textAbstract:
The use of unmanned aerial vehicles, or drones, in wildlife monitoring has increased in recent years, particularly in hard-to-access habitats. We used fixed-wing and quadcopter drones to census an urban-nesting population of Glaucous-winged Gulls in Victoria, Canada. We conducted our study over 2 years and asked whether (i) drones represent a suitable survey method for rooftop-nesting gulls in our study region; and (ii) Victoria’s urban gull population had increased since the last survey >30 years earlier. Using orthomosaic imagery derived from drone overflights, we estimated at least a threefold increase over the 1986 count reported for the entire city (from 114 to 346 pairs), and an approximate tenfold increase in the number of gulls nesting in the downtown core. Drones proved to be an excellent platform from which to census rooftop-nesting birds: occupied nests were readily discernible in our digital imagery, and incubating birds were undisturbed by drones. This lack of disturbance may be due to Victoria’s location in an aerodrome; gulls experience dozens of floatplane and helicopter flights per day and are likely habituated to air traffic. Glaucous-winged Gulls have declined considerably at their natural island colonies in the region since the 1980s. Our results indicate that although urban roofs provide replacement nesting habitat for this species, local gull populations have not simply relocated en masse from islands to rooftops in the region.
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Álvarez-Laó, C. "A review of the status of the Herring Gull Larus argentatus in Spain." Seabird Journal, no. 24 (2011): 72–82. http://dx.doi.org/10.61350/sbj.24.72.
Full textAbstract:
The Herring Gull Larus argentatus is considered a regular but scarce visitor to Spain, but its detailed status is uncertain. Here I present a compilation of published (primarily annual bird reports) and unpublished information (internet forums, direct communications by local ornithologists, ringing recoveries) to clarify the distribution and numbers of Herring Gulls in Spain, and their origins. More detailed information on age composition and phenology is presented for Asturias (NW Spain), perhaps the region where the species is most studied. According to ring recoveries (n = 43), the majority of Herring Gulls visiting Spain belong to the subspecies L. a. argenteus (mainly from the British Isles), with only 7% coming from breeding areas of the Nordic subspecies L. a. argentatus. Most observations occur in autumn and winter, being scarcer in spring and summer, and numbers vary between years. Two-thirds of birds recorded were in their first two years of life, with adults comprising only a quarter of the total. Ringing recoveries suggest Herring Gulls were more common in Spain 30+ years ago than at present. Data from winter censuses in Asturias between 2002 and 2007 gave a mean proportion of 1.06% Herring Gulls amongst the Yellow-legged Gull L. michahellis contingent. It is estimated that between 250 and 400 Herring Gulls are present in Asturias in mid January, and between 500 and 700 in the whole of Spain at the time of the winter censuses. There are two possible but unconfirmed attempts of breeding.
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Clewley, Gary, Nigel Clark, Chris Thaxter, Ros Green, Emily Scragg, and Niall Burton. "Development of a weak-link wing harness for use on large gulls (Laridae): methodology, evaluation and recommendations." Seabird Journal, no. 33 (2021): 18–34. http://dx.doi.org/10.61350/sbj.33.18.
Full textAbstract:
Both for the welfare of the birds studied and the validity of the results obtained, it is important that biologging attachment methods should be suitably safe and effective. We describe a weak-link wing harness, designed for long-term attachment, which safely detaches from the bird without need for recapture, and a UK field trial on two species of gull with contrasting life-histories, Herring Gull Larus argentatus and Lesser Black-backed Gull L. fuscus. We fitted 15 GPS devices to Herring Gulls in 2014 using three different weak-link materials: cotton thread, cotton piping cord and nitrile rubber. Productivity and return rates were compared against those fitted with permanent harnesses and a control group. A further 36 weak-link harnesses were fitted to Lesser Black-backed Gulls in 2017 and 2018 using GPS-GSM devices that provided more accurate attachment durations. The weak-link design was suitable for Herring and Lesser Black-backed Gulls and harnesses detached completely. Devices fitted with cotton piping cord or nitrile weak-link harnesses remained attached to Herring Gulls for up to four years. Cotton thread was less durable, with harnesses detaching in 1–2 years. We did not detect any significant effects on breeding success or return rates from the harnesses, although small effects sizes cannot be discounted. Devices fitted to Lesser Black-backed Gulls with 6-ply cotton, 18-ply cotton or piping cord weak- link harnesses had respective mean (± standard error) minimum attachment durations of 102 ± 13.6 days (N = 15), 358 ± 42 days (N = 18) and 596 ± 225 days (N = 2). The use of weak-link harnesses can provide a flexible and favourable alternative to permanent designs mitigating some of the associated risks.
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Hey, Jessica, Erpur Snær Hansen, and Mark Bolton. "Gull Predation on Leach’s Hydrobates leucorhous and European Storm-petrels H. pelagicus on Elliðaey Island, Iceland." Seabird Journal, no. 32 (2019): 59–71. http://dx.doi.org/10.61350/sbj.32.59.
Full textAbstract:
Studies of predator-prey interactions, and quantification of predation frequencies can be crucial to understanding prey population declines. We present a study of gull Larus spp. predation on Leach’s Storm-petrels Hydrobates leucorhous and European Storm petrels H. pelagicus, relative to other prey types. We studied a population of approximately 160 gulls in mixed colonies of Herring Gulls L. argentatus and Lesser Blackbacked Gulls L. fuscus, on Elliðaey Island, Iceland. We dissected 191 pellets and found gulls fed mostly on avian prey, insects and molluscs. We estimate that the total consumption of Leach’s Storm-petrels by all gulls in the colonies amounted to approximately two individuals per day, over the course of the study. European Stormpetrels were not preyed upon in high quantity during the study period, with a minimum of one individual depredated within a four-day study period, potentially reflecting the later breeding season of this species. We also provide a correction factor of pellets produced per storm-petrel consumed, which could be used to quantify the number of individual storm-petrels consumed from counts of pellets in future studies.
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Rice, Jake. "Behavioural responses of Common Puffins to kleptoparasitism by Herring Gulls." Canadian Journal of Zoology 65, no. 2 (February 1, 1987): 339–47. http://dx.doi.org/10.1139/z87-053.
Full textAbstract:
Herring Gulls (Larus argentatus) varied their rates of kleptoparasitic attack depending on Common Puffin (Fratercula arctica) foraging success. Attacks were more frequent on days when many puffins brought back food. However, puffins also varied their behaviour when approaching nest sites with food, so the rate of food loss to gulls per puffin remained constant as the number of puffins with food increased. Site differences in puffin activities after landing reflected only direct consequences of puffin and gull abundances and slope topography. After chick provisioning commenced, puffins at all sites showed increased vigilance after landing and more rapid burrow entries. Behaviour of puffins when approaching the slopes showed adaptations to the presence of gulls. On days when many puffins had food, puffins in areas of high gull density swamped the kleptoparasite. On days when few had food, puffins approached the slopes much as they did before chick provisioning commenced. Hosts as well as kleptoparasites may show closely tuned adaptations to potential food supply and likelihood of attacks.
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Wrege, Peter H., W. David Shuford, David W. Winkler, and Robert Jellison. "Annual Variation in Numbers of Breeding California Gulls at Mono Lake, California: the Importance of Natal Philopatry and Local and Regional Conditions." Condor 108, no. 1 (February 1, 2006): 82–96. http://dx.doi.org/10.1093/condor/108.1.82.
Full textAbstract:
Abstract The California Gull (Larus californicus) breeding colony at Mono Lake, California, is the second largest in the world, but its size can fluctuate annually by >45%. We examined six groups of factors that potentially could affect the numbers of pairs nesting each year, including availability of nesting habitat, numbers of potential breeding gulls, environmental conditions along the Pacific coast in the preceding winter, spring conditions at the lake, food availability at the lake, and prior breeding experience. Four variables explained >80% of the variation in the numbers of breeding gulls at Mono Lake between 1987 and 2003: the potential number of four-year-old gulls returning to the lake to breed for the first time, winter coastal conditions associated with the Pacific Decadal Oscillation, density of endemic brine shrimp (Artemia monica) close to the time of egg-laying, and mean temperature in the month before egg-laying. Of the four factors the latter two, which reflect local conditions near the time of egg-laying, had the most profound direct effect on the numbers of breeding gulls. Yearly variation in the snow pack and spring runoff affects brine shrimp numbers through changes in limnological conditions, thus regional climate patterns may indirectly influence gull numbers.
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Ječmenica, Biljana, Jelena Kralj, Louie Thomas Taylor, and Luka Jurinović. "Habitat use of urban nesting yellow-legged gulls in Croatia during the breeding season." Natura Croatica 32, no. 2 (December 30, 2023): 399–412. http://dx.doi.org/10.20302/nc.2023.32.25.
Full textAbstract:
Because of increasing urbanization, some opportunistic birds such as gulls, started to exploit various artificial marine and terrestrial food sources. To better understand urban gull ecology and habitat use, a study was done on a yellow-legged gull (Larus michahellis) during the breeding season in Zadar, a coastal city on the Adriatic Sea. Ten adult breeding yellow-legged gulls (five females and five males) were caught on building rooftops during the late incubation period and were fitted with GPS-GSM solar power transmitters. In total, 2377 trip segments (no. GPS points = 19906) were analyzed, with most of them being classified as nest attendance (56.32 %) and foraging movements (37.10 %). Tracking data showed that the gulls mostly use marine and urban areas, agricultural lands, a dump site, and grasslands. Females were more active while foraging, with a longer duration and trip segment length, travelling further away from the breeding colony, while males tended to rest more than females. Both males and females exploit various habitats for foraging and resting, however females used agricultural lands significantly more than males. Even though gulls are generalists, some individuals showed a preference for certain habitats. After calculating the proportional similarity index, individuals showed high specialization for a certain habitat.
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Baak, Julia E., Allison Patterson, H. Grant Gilchrist, and Kyle H. Elliott. "First evidence of diverging migration and overwintering strategies in glaucous gulls (Larus hyperboreus) from the Canadian Arctic." Animal Migration 8, no. 1 (January 1, 2021): 98–109. http://dx.doi.org/10.1515/ami-2020-0107.
Full textAbstract:
Abstract Many seabird populations differ in their migration strategies, where individuals travel in different directions to separate wintering areas. These migratory strategies may expose individuals to different threats, thus understanding migratory connectivity is crucial to assess risks to populations. Glaucous gulls (Larus hyperboreus) are generalist predators with flexible migratory behaviour that may alter these behaviours in response to climate change and anthropogenic activities, such as access to landfills, yet little is known about their migration. We deployed GPS and GLS tracking devices on glaucous gulls from Coats Island, Nunavut, Canada to obtain the first insights into their migration and habitat use outside of the breeding season. Gulls used two migration strategies during the non-breeding season, where one migrated as far as the Sea of Okhotsk in the Pacific and the remainder (n = 7) wintered in the North Atlantic. Gulls primarily overwintered in pelagic (56%) and coastal (38%) habitats. While in coastal habitats, one gull visited one landfill once, but visits increased with a 1 km and 3 km buffer, suggesting that urban glaucous gulls primarily used non-landfill habitats. This research can be used as a baseline to explore changes in migratory behaviour and inform future conservation of Arctic-breeding gulls.
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Smith, GC, and N. Carlile. "Methods for population control within a silver gull colony." Wildlife Research 20, no. 2 (1993): 219. http://dx.doi.org/10.1071/wr9930219.
Full textAbstract:
Silver gulls can threaten the welfare of humans and other wildlife. Current superabundant gull numbers should be managed to reduce this risk. Denying gulls access to food at artificial sites, combined with direct population control, may reduce silver gull numbers in the long term. Control measures implemented at gull colonies overseas were trialled. Human disturbance in the colony associated with routine visits to study plots led to reduced nesting density. Egg-pricking reduced nesting success; it did not induce adults to incubate for extended periods even though gulls were recorded sitting on nonviable (although not pricked) eggs for up to 76 days. Removal of eggs from nests within experimental plots did not affect overall nesting success for these plots. Habitat modification, by mowing of long grass at the colony site prior to the commencement of breeding, decreased both the density of nests in mowed areas and nesting success. Selective culling of breeding adults from experimental plots was effective in reducing population size immediately and suppressed nesting by other individuals that attempted to breed later in the breeding season. The combination of habitat modification, culling and human disturbance reduced breeding success at colonies.
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Sutton, Luke J., Ryan A. Burrell, and Seb Loram. "Spatio-temporal trends in the predation of large gulls by peregrine falcons (Falco peregrinus) in an insular breeding population." Slovak Raptor Journal 11, no. 1 (December 1, 2017): 103–9. http://dx.doi.org/10.1515/srj-2017-0002.
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Abstract Individual diet specialization occurs in many populations of generalist predators, with specific individuals developing specialist strategies in their feeding behaviour. Intraspecific resource partitioning is hypothesised to be common amongst species in higher trophic levels where competition for resources is intense, and a key driver in breeding success and community structure. Though well-studied in other predators, there is sparse data on ecological specialization in raptors, which are important drivers of community and trophic structure. In this study, the breeding season diet of an insular population of peregrine falcons (Falco peregrinus) was determined from indirect analysis of prey remains collected over three years. An unexpected result was the high proportion of large gulls (Laridae), of the genus Larus, in the diet of two breeding pairs of peregrines. Large gulls made up 18.44% by frequency of total prey recorded and 30.81% by biomass. Herring gulls (Larus argentatus) were the most common large gull prey, with immatures most frequent (67.95%) compared to adults (19.23%). Overall, most gulls predated were immatures (80.77%). Frequency of predation varied between breeding pairs and months, but was consistent over the three years. Most gulls were taken in April (37.17%), followed by May (19.23%), with a smaller peak of immature herring gulls taken in August and September. The pattern of regular predation by peregrines on large gulls is a new observation with important implications for understanding individual diet specialization in raptors, and its effect on bird populations and community structure.
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Alderisio, K. A., and N. DeLuca. "Seasonal Enumeration of Fecal Coliform Bacteria from the Feces of Ring-Billed Gulls (Larus delawarensis) and Canada Geese (Branta canadensis)." Applied and Environmental Microbiology 65, no. 12 (December 1, 1999): 5628–30. http://dx.doi.org/10.1128/aem.65.12.5628-5630.1999.
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ABSTRACT Water suppliers have often implicated roosting birds for fecal contamination of their surface waters. Geese and gulls have been the primary targets of this blame although literature documenting the fecal coliform content of these birds is quite limited. To determine the actual fecal coliform concentrations of these birds, fecal samples from 249 ring-billed gulls and 236 Canada geese in Westchester County, N.Y., were analyzed over a 2-year period. Results indicate that gull feces contain a greater average concentration of fecal coliform bacteria per gram (3.68 × 108) than do goose feces (1.53 × 104); however, average fecal sample weights of the geese were more than 15 times higher than those of the gulls.
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Jurinović, Luka, Sanja Duvnjak, Gordan Kompes, Silvija Šoprek, Borka Šimpraga, Fani Krstulović, Marina Mikulić, and Andrea Humski. "Occurrence of Campylobacter jejuni in Gulls Feeding on Zagreb Rubbish Tip, Croatia; Their Diversity and Antimicrobial Susceptibility in Perspective with Human and Broiler Isolates." Pathogens 9, no. 9 (August 24, 2020): 695. http://dx.doi.org/10.3390/pathogens9090695.
Full textAbstract:
Campylobacteriosis is the most common gastrointestinal bacterial disease in the European Union (EU). Wild birds are one of the natural reservoirs of these pathogens. In this study we tested cloacal swabs of 643 gulls captured on rubbish tip in Zagreb, Croatia for the presence of Campylobacter spp. and found 168 Campylobacter positive samples. We used multilocus sequence typing (MLST) to genotype 62 random C. jejuni isolates from gulls, 24 isolates from broiler caeca, 27 isolates from broiler neck skins and 23 human isolates. Altogether, we identified 44 different STs, from which 19 were newly described. Most of the new STs (14) originate from gulls. Although humans and broilers share the majority of STs and isolates from gulls are separated from these, there was one ST present in all three hosts: 45. Additionally antimicrobial susceptibility to six antimicrobials was performed on 123 C. jejuni strains isolated from broiler caeca (n = 22), neck skins of broilers (n = 20), gulls cloacal swabs (n = 50) and human faeces (n = 31) by the broth microdilution method. Results show lower resistance of gull isolates to NAL and CIP, while resistance to TET was as high as in human and broiler isolates.