Common Gull Larus Canus Research Articles

Long-term impact on the breeding birds of a semi-offshore island-based wind farm in Åland, Northern Baltic Sea

Breeding bird populations were monitored at a wind farm in the Båtskär area of the southern Åland archipelago in 2006–2017. The area is situated in the outer archipelago and comprises four islands with six wind turbines in total. The wind turbines began operating in autumn 2007. An environmental impact assessment for the area was conducted in 2002. A control area called Stenarna, located 22 km NW of Båtskär, was used for comparison. The Båtskär area annually recorded 850–1,050 pairs of breeding birds. Four species showed significantly decreasing trends in Båtskär, namely the Common Eider Somateria mollissima, Lesser Black-backed Gull Larus fuscus, Herring Gull L. argentatus , and Black Guillemot Cepphus grylle. In Stenarna, only the Common Eider significantly decreased over the same period. The Arctic Tern Sterna paradisaea increased in both areas, while the Velvet Scoter Melanitta fusca, Red-breasted Merganser Mergus serrator, Common Gull Larus canus, Rock Pipit Anthus petrosus, and White Wagtail Motacilla alba increased in Stenarna, the control area. The Herring Gull population decline is unlikely to be related to the wind farm. However, the proximity of a wind turbine to a breeding colony of the Lesser Black-backed Gull has most likely contributed to its decline. The reason for the Black Guillemot decline in Båtskär is unknown. The decline of Common Eider in both areas may be connected to increasing predation from White-tailed Eagles Haliaeetus albicilla. Some species, such as the House Martin Delichon urbicum and auks, have benefitted from the wind farm construction. They can utilize new microhabitats created by the construction, while other species, such as the Common Eider, gain protection against predation because of human activities.

Habitat and Nest Site Selection in the Common Gull Larus canus in Southern Poland: Significance of Man-Made Habitats for Conservation of an Endangered Species

The Common Gull is a rare and endangered breeding species at inland habitats in Poland as well as in some other countries in Europe. Breeding biology, habitat and nest site selection were studied in this species in southern Poland. Almost all birds nested on industrial water bodies (gravel pits, sedimentation basins), although fishponds and reservoirs were the most abundant habitat in the study area. Birds built their nests mainly on islets, man-made constructions and dry land on the shores of water bodies. The islets occupied by birds were smaller and were covered by lower vegetation than the unoccupied ones. When occupied islets on industrial water bodies were compared with a random sample of islets on fishponds, the latter were found to be larger, with taller and denser vegetation. This may explain why Common Gulls did not breed on fishponds in southern Poland. Shore-breeding birds nested in open areas with sparse vegetation, occupying sites with less vegetation cover and closer to shrubs or trees than randomly selected points. Breeding performance (mean date of clutch initiation, clutch size, clutch volume, hatching success and breeding success) did not differ among nests built on islets, man-made constructions or on the shores of the water bodies. Breeding success was more than twice as high as in large riverine colonies. Industrial water bodies may become important alternative breeding habitats for this species in Poland.

Preen oil chemical composition in herring gull Larus argentatus, common gull Larus canus and black-headed gull Chroicocephalus ridibundus confirms their status as two separate genera

Fatty acid and alcohol components of preen oil were determined in three gull species that belong to two systematic genera: herring gull Larus argentatus, common gull Larus canus and black-headed gull Chroicocephalus ridibundus. All gulls were captured in winter, in Gdańsk, Poland. All gulls produced monoesters composed of C7–C16 saturated fatty acids and C11–C20 saturated alcohols, with n-octanoic acid and n-hexadecanol as the major fatty acid and alcohol, respectively. Preen oils of black-headed gull had higher content of trimethyl fatty acids, 2,8-dimethylundecanoic acid, 2,6-dimethylundecanoic acid and 2,6-dimethylnonanoic acid, and lower content of 2-methyl fatty acids than oils of herring gull and common gull. Preen oils produced by black-headed gull also had lower content of 2-methyl alcohols. The relative contents of n-octanoic acid and n-hexadecanol did not differ among species. The differences among species are probably not a result of different diet, as all gulls fed mainly on household refuse. Hence, preen oil analysis confirmed the taxonomic relations among these gull species, that recently were placed into two different genera.

Flock-fishing deep-diving piscivores (Great Crested Grebe Podiceps cristatus, Great Cormorant Phalacrocorax carbo, Common Merganser Mergus merganser) at Lake Vombsjön, southern Sweden, and those that exploit them

Lake Vombsjön in southern Sweden is visited by large numbers of Great Crested Grebes Podiceps cristatus (>2000), Great Cormorants Phalacrocorax carbo (sometimes >1000) and Common Mergansers Mergus merganser (up to 2000) in late autumn and early winter. Different species exploit them. Great Crested Grebes are used especially by commensal Common Gulls Larus canus; the gulls take advantage of fish that flee towards the surface. Common Gulls also use cormorants and mergansers in the same way but also try to kleptoparasitize them. Both Herring Gulls Larus argentatus and Great Black-backed Gulls Larus marinus kleptoparasitize these two species, while Red Kites Milvus milvus, Grey Herons Ardea cinerea and Carrion Crows Corvus corone use them commensally. White-tailed Eagles Haliaeetus albicilla seem to use both methods to obtain fish. On 50% of one hundred visits during November to March, eagles were seen flying low over the fishing flocks. They would fly a metre or so above the flocks and then accelerate and attack a bird holding a fish. The bird would then either try to escape by a rush or by diving, dropping the fish which the eagle seized. Interestingly, the flock-fishing birds showed no fear reactions towards the eagles but appeared to regard them similarly to large gulls.

A small badge of longevity: opposing survival selection on the size of white and black wing markings

According to handicap principle, exaggerated ornamental traits are supposed to exert costs on their bearers. However, there is much less theoretical and practical consensus about whether and under which conditions ornament expression should positively correlate with survival. We measured age‐related variation and survival selection on the size of white wing patches and black wing tips in a long‐lived monogamous seabird, the common gull Larus canus. Males had larger white patches than females but patch size showed concave relationship with age irrespective of sex, suggesting that white patch size was prone to senescence in both sexes. Extent of wing tip abrasion correlated negatively with the size of white patch, suggesting, in agreement with the Zahavian handicap hypothesis that only individuals with largest ornaments are able of maintaining them and not paying cost of displaying them. Areas of white wing patches and black wing tips correlated negatively. Irrespective of sex, survival selection favored birds with larger white wing patches and smaller black wing tips, which suggests that white and black wing markings may have coevolved as reverse components of a single ornament. Altogether, our results provide an evidence for the case where survival selection on ornamental traits in females is not weaker than in males. Absence of sex differences with respect to most of observed patterns is consistent with a prediction that among monogamous long‐lived species with biparental care, mutual mate choice leads to evolution of elaborate ornamental traits in both sexes.

Bird communities at two marshes in Øvre Forra, today and 40 years ago

In the protected area Ovre Forra in Central Norway, birds were surveyed at two marshes in two succeeding years at the beginning of the 1970s. By following the same survey procedure 40 years later in these unchanged marsh habitats, I sought changes in the breeding bird community. While the total number of waders seems to have been quite stable, the abundance of some of the involved species might have changed during this period of time. Due to low numbers, and annual variations, the implications for some of the involved species have to be taken cautiously. The most abundant species in Ovre Forra is now the Common Redshank Tringa totanus . This species has outnumbered the earlier most abundant species in this bird community, the Meadow Pipit Anthus pratensis . The numbers of the Meadow Pipit, Northern Lapwing Vanellus vanellus , European Golden Plover Pluvialis apricaria and Common Sandpiper Actitis hypoleucos all tend to be lower than for 40 years ago. The Common Gull Larus canus and two Tringa species, the Common Redshank T. totanus and Common Greenshank T. nebularia , seem to have increased in numbers, while the situation for the Common Snipe Gallinago gallinago and the Whimbrel Numenius phaeopus appears to be stable. The Ruff Calidris pugnax used to be a characteristic species on the Ovre Forra’s bogs in the 1970s, but has since vanished. Altogether, the study shows an apparently quite stable avifauna over the time span of 40 years in this environmentally stable reserve.

Diversity and abundance of water birds in a subarctic lake during three decades

The numbers of divers, ducks, gulls, terns and waders in the 15 km2 oligotrophic lake Takvatn, North Norway were estimated six times during 1983-2012. Systematic mapping surveys were done by boat within the first week after ice-break in June. Twenty-one species were observed over the years and 12 were regarded as breeding on the lake. Red-breasted merganser Mergus serrator was the dominant diving bird, with estimated minimum number of pairs varying from 15 to 39 among years. Black-throated diver Gavia arctica (1-3 pairs), tufted duck Aythya fuligula (2-15 pairs) and common scoter Melanitta nigra (1-5 pairs) bred regularly, while velvet scoter Melanitta fusca (1-2) and goldeneye Bucephala clangula (2-4) were found in some years and mallard Anas platyrhynchos (1 pair) and wigeon Anas penelope (1 pair) in one year. Common gull Larus canus (6-30 pairs) and arctic tern Sterna paradisaea (2-35 pairs) bred in all years. Common sandpiper Tringa hypoleucos (3-9 pairs) and redshank Tringa totanus (1-4 pairs) were regular waders. Density variations of mergansers, gulls and terns are possibly related to density variations of three-spined sticklebacks Gasterosteus aculeatus, their dominant fish prey. The water birds are important links in the food web of the lake.

TiMixed clutches at seabird colonies in west Scotland 1996–2009tle

In counts of gulls, terns, wildfowl and waders breeding on about 100 small islands along the mainland coast of west Scotland during 1996–2009, 123 clutches containing the eggs of two species (‘mixed clutches’) were found among 69,775 clutches of 20 species (0.18%). The annual percentage varied between 0.09% and 0.33%. Most (89%) mixed clutches contained only one egg of one of the species. The 123 mixed clutches involved 13 species, 19 species-pairs and at least 31 permutations of guest and host species. The most frequent species-pairs were Common Gull Larus canus and Eurasian Oystercatcher Haematopus ostralegus, Herring Gull Larus argentatus and Common Eider Somateria mollissima, and Common Gull and Black-headed Gull Larus ridibundus, these together accounting for 54% of cases. Sixteen species-pairs had been recorded in an earlier study in 1990–95, and a further six were found in 1996–2009: Common Eider and Mallard Anas platyrhynchos (4 mixed clutches), Herring Gull and Great Black-backed Gull Larus marinus (3), Common Tern Sterna hirundo and Arctic Tern Sterna paradisaea (2), Canada Goose Branta canadensis and Common Eider (2), Common Eider and Greylag Goose Anser anser (1), and Canada Goose and Greylag Goose (1). The appearance of goose eggs in mixed clutches reflected large increases in breeding numbers of both species in the area. The most frequent guest species were Eurasian Oystercatcher and Common Eider and the most frequent hosts were Common Gull and Herring Gull. Mixed clutches probably arise from attempted egg parasitism. There are records of chicks from guest eggs being reared successfully in some closely related species-pairs, but other species-pairs seem incompatible.

Indexing winter gull numbers in Great Britain using data from the 1953 to 2004 Winter Gull Roost Surveys

Capsule Winter Gull Roost Survey data spanning 50 years were used to generate population indices. Aims To evaluate how wintering numbers of five gull species have changed in Great Britain over the last five decades. Methods Generalized linear models were used to relate gull numbers to habitat, site and year factors, and so derive species‐specific indices for nine regions of Great Britain. Regional models considered data from different timescales depending on coverage. Results Patterns of change varied by species and region. All species showed increases in number over the period 1953 to 2004. In most regions, Black‐headed Gull Chroicocephalus ridibundus numbers have declined since peaks between 1973 and 1993; Common Gulls Larus canus have also declined recently in some regions. Lesser Black‐backed Gull L. fuscus numbers have increased dramatically since 1953, whereas numbers of Herring Gull L. argentatus showed large declines between 1963 and 1983. Great Black‐backed Gull L. marinus numbers have increased in the west and the Midlands, but recently declined in eastern regions. Conclusions Numbers of wintering gulls in Great Britain have shown rapid changes over the last five decades, reflecting changes in the sizes of breeding populations. These changes are likely to be associated with changes in human activities and resource availability.

“HIDDEN” REPRODUCTIVE CONFLICT BETWEEN MATES IN A WILD BIRD POPULATION

Environmental conditions experienced by a female prior to reproducing may be influenced by her mate. Part of such an indirect effect of a male on his partner's reproduction may be genetic (indirect genetic effect). However, a female's direct and a male's indirect genetic effects need not align. We analyzed 10,652 records of seasonal timing of laying, an important reproductive trait in many organisms, of 1864 male and 1916 female common gulls Larus canus collected during 37 years. We show that there is both a direct (female) and an indirect (male) genetic effect (explaining 14.5% and 4.8% of the REML estimated variance in laying date, respectively), but these are significantly negatively correlated (-0.53+/-0.22 SE), indicating that genes for early laying in females are associated with genes for a delaying male effect on his partner's laying date (and vice versa). There is strong selection for laying early in this population, and these sexually antagonistic genetic effects may contribute in maintaining the variation in laying date. Our findings provide an empirical demonstration of a hitherto largely unstudied level of conflict between mates, with important ramifications for our understanding of evolutionary dynamics and mate choice in nature.

Exploring plasticity in the wild: laying date–temperature reaction norms in the common gull Larus canus

Exploration of causal components of plasticity is important for insight into evolutionary dynamics and an organism's ability to respond to climate change. Among individuals, variation in plasticity can be due to genotype-environment interaction (GxE) or a result from environmental effects associated with an individual. We investigated plasticity for laying date in the common gulls Larus canus, using data collected in Estonia during 37 years (n=11624 records on 2262 females, with 472 relatives). We used a sliding window approach to find the period in spring during which mean temperature best explained the annual mean laying date. Then, considering the spring temperature as a quantitative description of the environment, we used pedigree information and a random regression animal model to determine the variation in plasticity for the laying date-temperature relationship. We found that individuals differ in the plasticity of laying date (such that there is increased variation among individuals for the laying date in warmer springs), and that approximately 11% of variation in the laying date is heritable, but we found no statistical support for GxE. Plasticity in this species is not constrained by warmer springs.

Increased nest predation in a declining and threatened Temminck's Stint Calidris temminckii population

We measured nesting success of the Temminck's Stint Calidris temminckii along the Finnish Bothnian Bay coast during 19 breeding seasons (1983–2001) and conducted a population census (1999–2002). We found 105 pairs, showing a marked decline from the previous survey (170 pairs 1987–95). Of the 424 ‘known‐fate’ nests, 47% hatched. Depredation caused 79.9% of the nest losses. Nesting failures increased from 1983–91 to 1992–2001 owing to a rise in nest predation. The proportion of failed nests that failed because of predation rose from 48.9 to 87.7%. When only depredated nests were considered as losses, Mayfield nest survival probability over the incubation period dropped from 69 to 31% (461 nests). This pattern emerged both in man‐made and in natural habitats. Survival probability was independent of habitat type (natural vs. man‐made). In an experiment involving videotaping of dummy nests, Common Gull Larus canus and Ruddy Turnstone Arenaria interpres were found to be the most important egg predators.

Use of time-lapse video cameras to determine causes of nest failure of Slavonian Grebes Podiceps auritus

Capsule Few clutches were predated, with Otter Lutra lutra the most frequent predator filmed. Aims To determine the rate of nest predation and identify predators of the Slavonian Grebe Podiceps auritus in Scotland. Methods Miniature 24-hour time-lapse video cameras were placed next to 23 Slavonian Grebe nests on five lakes to record nest failure events and to identify predators that depredated the contents of nests. For comparison, ten nests without cameras were also monitored and their outcomes recorded. Results The probabilities of clutch failure due to predation, and wave damage or water level rise were 19% and 30%, respectively. Otters took two clutches and an adult grebe plus chicks from nests. Other predators filmed at nests were Stoat Mustela erminea, Carrion Crow Corvus corone, Common Gull Larus canus and Coot Fulica atra. No difference in predation rates between nests with and without cameras was detected. Otters were recorded at eight of 13 lakes studied. An American Mink Mustela vison was recorded at one lake. Conclusion The nest predation rate of Slavonian Grebe in Scotland was not high compared with other studies and is not of conservation concern.

Factors affecting escape distances of staging waterbirds

Abstract Escape distances (EDs) have been used to study sensitivity of waterbirds to different sources of disturbance, to design reserves for waterbirds, and to define eco-targets for the Wadden Sea management plan. However, the use of ED as an index of sensitivity has been criticised because it can be highly variable. Although some factors affecting variation in the EDs of species have been studied, there is still a need for further analysis of factors that may affect it. In this study, we analysed the EDs of 19 waterbird species (geese, ducks, waders and gulls) exposed to a walking person (N = 1,371) during autumn and spring 1980–1984 under controlled conditions in the Danish Wadden Sea. We analysed how EDs varied between species in relation to body mass and hunting and within species in relation to flock size and weather conditions. EDs increased significantly with species body mass, and quarry species (dabbling ducks, curlew Numenius arquata, golden plover Pluvialis apricaria, common gull Larus canus ...

Genetic affinities within the herring gull Larus argentatus assemblage revealed by AFLP genotyping.

To date, the taxonomic status of circumpolar breeding populations of the Herring Gull Larus argentatus, the Lesser Black-backed Gull Larus fuscus, and the closely related Yellow-legged Gull Larus cachinnans has been based on differences or similarities in phenotype, morphology, and feeding and premating behavior. To shed some new light on the many taxonomic uncertainties surrounding these taxa, we describe the results of a large DNA study based on comparing the distribution of 209 biallelic markers among 109 gulls, representing 11 gull taxa of the Herring Gull assemblage and the Common Gull Larus canus. A detailed phylogenetic analysis failed to show clustering of individuals into groups representing either geographic origin or phenotype. Alternatively, birds were grouped into taxa defined on the basis of phenotype and geographic origin or phenotype alone. Genetic analyses revealed significantly different genetic distances between all pairs of taxa. However, based on these genetic distances, again no consistent phylogenetic tree could be constructed. Analysis of molecular variance indicated that about 77% of the total genetic variability among these gulls could be explained by within-taxon differences. Only 23% of the total genetic variability was due to genetic differences between taxa, irrespective of their species or subspecies status. Although this seems to challenge the current taxonomic treatment of the herring gull assemblage, our results are too premature and too incomplete to recommend a drastic change.

Migration patterns of Common Gulls Larus canus ringed in the non‐breeding season in Copenhagen and the surrounding area

In the greater Copenhagen area (54°59'‐56°07'N, 11°55'12°40'E) 4899 Common Gulls were ringed from September to April in 1976 to 1993. Up to 31 December 1993, 11,824 ring‐recoveries from 2,388 gulls (49% of the total number ringed) had been received. Copenhagen lies on the Common Gull migration route from northeastern to western Europe. The directions of migration are southwest in autumn and northeast in spring. The autumn migration in some years lasts up to mid‐January, possibly longer. Older birds migrate farther from the wintering grounds and further north than younger ones. The data suggest that annual mortality rate for second‐year and older birds has not increased during the last two or three decades. Common Gull mortality rate steadily decreases with age at least up to maturity. Common Gulls, ringed in any part of the Copenhagen area, have almost equal likelihood of being found in any part of the recovery range. Gulls from different breeding localities or from different wintering grounds fly across the Copenhagen area in different days. The dates of movements of these groups vary from year to year and, possibly, depend on the particular year conditions. There are almost no recoveries from some regions in northern Europe of the birds ringed in the Copenhagen area, but the number of recoveries in the Copenhagen area from those regions is very large. At the same time, there are quite a few recoveries from northeastern Europe and central Russia. Since the numbers of Common Gulls in central Russia are currently increasing, one of the possible explanations of those facts is that young Common Gulls that were in some areas of northern Europe never return to breed. They hatched to breed southeast of their natal area, some in areas southeast of the White Sea. We suggest that a redistribution process within the European Common Gull breeding population is taking place but this problem needs further investigation.

Östliga fiskmåsars Larus canus heinei uppträdande i Öresundsregionen

The common gull Larus canus occurs in the Western Palaearctic with two subspecies. L .c. canus breeds from Britain to western Russia where it is replaced by the slightly larger and darker L. c. heinei. The zone of contact is probably not distinctive and there is therefore a wide zone where birds with characters of both subspecies and intermediate individuals can be found. We have analysed ringing recoveries of birds ringed during the non-breeding season in southern Sweden and Denmark. We demonstrate that this area is frequently visited by birds which return to breeding grounds well into the geographical range of L. c. heinei. This is further supported by data on morphology showing that birds caught during winter are larger than the locally breeding birds. Observations of colour ringed individuals show that birds with a morphology suggesting heinei mainly occur between November and March, though a few, especially younger birds, have been sighted in the area around Oresund throughout the summer months.

Heritability of head size in the common gull Larus canus in relation to environmental conditions during offspring growth

We studied the heritability of head length in a common gull (Larus canus) population breeding in western Estonia. Heritability estimates obtained from offspring-parent regressions were moderate to high and significantly different from zero. Head size might hence respond evolutionarily to phenotypic selection. Offspring-mother and offspring-father regressions yielded similar heritability estimates. This indicated that size-related maternal or paternal effects were absent or weak. Heritability and additive genetic variance estimates obtained from offspring-parent regressions and full-sib analyses were higher when offspring had grown up under good environmental conditions than under poor environmental conditions. Such a pattern has previously been found in some other studies of birds. This suggests that genotype-environment interactions might be frequent within the range of conditions experienced by natural bird populations.

Heritability of head size in the common gull Larus canus in relation to environmental conditions during offspring growth

We studied the heritability of head length in a common gull (Larus canus) population breeding in western Estonia. Heritability estimates obtained from offspring-parent regressions were moderate to high and significantly different from zero. Head size might hence respond evolutionarily to phenotypic selection. Offspring-mother and offspring-father regressions yielded similar heritability estimates. This indicated that size-related maternal or paternal effects were absent or weak. Heritability and additive genetic variance estimates obtained from offspring-parent regressions and full-sib analyses were higher when offspring had grown up under good environmental conditions than under poor environmental conditions. Such a pattern has previously been found in some other studies of birds. This suggests that genotype-environment interactions might be frequent within the range of conditions experienced by natural bird populations.

Distribution of ship-following seabirds and their utilization of discards in the North Sea in summer

Prey availability is one of the factors determining the distribution of seabirds at sea. Northern fulmars Fulmarus glaclalis and black-legged kittiwakes Rissa tridactyla were the most regular and frequent ship-followers across the central and northern North Sea during 2 surveys with a fishery research vessel in May-June and July-August 1992. Sixteen other species occurred less often and/or in lower numbers. Birds consumed 84 % of experimentally discarded roundfish and 8 % of discarded flatfish. On average, northern gannets Morus bassanus took the largest individuals of most fish specles, black-legged kittywakes the smallest The average size choices of herring gulls Larus argentatus, lesser black-backed gulls Larus fuscus and northern fulmars lay between these 2 extremes. The choice of fish lengths by birds vaned with different fish species. Northern gannet was the most successful species in consuming discards. Northern fulmars success rates decreased with the presence of larger ship-followers but were never high. Black-headed gull Larus ridibundus and common gull Larus canus were less successful than the more frequent typical ship-following species.