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the relation among gonadal steroids, immunocompetence, body mass, and behavior in young black-headed gulls (larus ridibundus).we experimentally examined the effect of testosterone on the antibody response to a single immunization with sheep red blood cells in young black-headed gulls. this species performs a number of testosterone-mediated elaborate postural displays in social interactions and breeds in dense colonies in which there is a high likelihood of infectious diseases. in young chicks, only one-third were capable of responding to immunization. in the responding chicks, testosterone enhanced antibody titers. eve ...199718811282
campylobacter spp. and salmonella spp. in black-headed gulls (larus ridibundus).cloacal examination of 41 juvenile black-headed gulls (larus ridibundus) by cultivation demonstrated campylobacter jejuni in 26 (63%) and salmonella typhimurium in 21 (51%) of them. all the bird samples were collected in a breeding colony near the town hodonin, south moravia, czech republic in 1996. twenty six campylobacter isolates were tested for antibiotic and drug sensitivity: all were resistant to at least three agents (penicillin, tetracyclin and sulfomethoxazol-trimethoprim) while all wer ...19979151001
campylobacter spp. and salmonella spp. in black-headed gulls (larus ridibundus).cloacal examination of 41 juvenile black-headed gulls (larus ridibundus) by cultivation demonstrated campylobacter jejuni in 26 (63%) and salmonella typhimurium in 21 (51%) of them. all the bird samples were collected in a breeding colony near the town hodonin, south moravia, czech republic in 1996. twenty six campylobacter isolates were tested for antibiotic and drug sensitivity: all were resistant to at least three agents (penicillin, tetracyclin and sulfomethoxazol-trimethoprim) while all wer ...19979151001
phenotypic characteristics of riemerella anatipestifer and similar micro-organisms from various hosts.a total of 199 riemerella anatipestifer (ra) and ra-like field strains isolated culturally from birds of 12 different species and from pigs were characterized using classical phenotypic and chemotaxonomic tests. the ra reference strain atcc 11845 was included in the study. on the basis of the classical phenotypic characteristics studied and the numerical analysis of the whole-cell fatty acid patterns, the ra reference strain and 123 field isolates were assigned to the indole negative (in) varian ...199818483963
keep the chicks moving: how sandwich terns can minimize kleptoparasitism by black-headed gulls.sandwich terns, sterna sandvicensis, often nest in association with black-headed gulls, larus ridibundus. the gulls provide protection against predators, but can also adversely affect the terns' reproductive success through predation and piracy of fish. to test whether leading the chicks away from the nest site is an evasive strategy used by the parents to reduce the incidence of robbery by the gulls, we kept one group of sandwich tern chicks at their original breeding site, while, with a wire-n ...199910328801
[the development of the genital system in ichthyocotylurus variegatus (trematoda: strigeidae)].the development of ichthyocotylurus variegatus from metacercariae to ovigerous adults in the natural definitive host (larus ridibundus) was examined at 24 h intervals. the metacercariae develop to the adults through a somatic growth of hindbody; the gametogeny and vitellogenesis take 4-6 days. during the first day of development the pair of testes are separated from the genital anlage. the ovary differentiates one day later. genital ducts are completely differentiated on 4th day after the beginn ...200010862396
[the development of the genital system in ichthyocotylurus variegatus (trematoda: strigeidae)].the development of ichthyocotylurus variegatus from metacercariae to ovigerous adults in the natural definitive host (larus ridibundus) was examined at 24 h intervals. the metacercariae develop to the adults through a somatic growth of hindbody; the gametogeny and vitellogenesis take 4-6 days. during the first day of development the pair of testes are separated from the genital anlage. the ovary differentiates one day later. genital ducts are completely differentiated on 4th day after the beginn ...200010862396
accumulation profiles of persistent organochlorines in waterbirds from an estuary in korea.persistent organochlorine pollutants (pops), such as polychlorinated dibenzo-p-dioxins (pcdds), polychlorinated dibenzofurans (pcdfs), polychlorinated biphenyls (pcbs), and organochlorine (oc) pesticides such as ddts (dichlorodiphenyltrichloroethane), hchs (hexachlorocyclohexane isomers), chls (chlordane compounds) and hcb (hexachlorobenzene), were measured in subcutaneous fat of resident and migratory birds collected from the nakdong river estuary (nre) in korea. black-tailed gull, a resident b ...200111503073
maternal androgens in black-headed gull (larus ridibundus) eggs: consequences for chick development.we tested the hypothesis that mother birds counterbalance the negative effects of hatching asynchrony for later-hatched chicks by increasing the yolk androgen concentrations in consecutive eggs of their clutch. in doing so, they may adaptively tune each offspring's competitive ability and, thus, growth and survival. however, evidence in support of this hypothesis is contradictory. the yolk concentrations of maternal androgens in the eggs of black-headed gulls increase significantly with the layi ...200111345330
maternal androgens in black-headed gull (larus ridibundus) eggs: consequences for chick development.we tested the hypothesis that mother birds counterbalance the negative effects of hatching asynchrony for later-hatched chicks by increasing the yolk androgen concentrations in consecutive eggs of their clutch. in doing so, they may adaptively tune each offspring's competitive ability and, thus, growth and survival. however, evidence in support of this hypothesis is contradictory. the yolk concentrations of maternal androgens in the eggs of black-headed gulls increase significantly with the layi ...200111345330
hatching date influences age at first reproduction in the black-headed gull.in long-lived colonial birds, age at recruitment is an important life-history character. variation in this parameter may reflect differences in several factors, including competitive ability and breeding strategies. further, these differences may be due to timing of hatching (for instance through differences in competitive ability). we investigated the age of first-time breeders in relation to hatching date in a black-headed gull larus ridibundus colony situated in central france, from 1979 to 1 ...200128547170
social stimuli, testosterone, and aggression in gull chicks: support for the challenge hypothesis.we tested the challenge hypothesis for the hormonal regulation of aggression in chicks of the black-headed gull, larus ridibundus. chicks of this species are highly aggressive toward conspecifics, but never to peers that hatched from the same clutch (modal clutch size is three). therefore, in the first experiment small families were housed together in large groups (challenged condition) and compared to families kept isolated (nonchallenged condition). as expected, in the challenged condition dur ...200211971668
social stimuli, testosterone, and aggression in gull chicks: support for the challenge hypothesis.we tested the challenge hypothesis for the hormonal regulation of aggression in chicks of the black-headed gull, larus ridibundus. chicks of this species are highly aggressive toward conspecifics, but never to peers that hatched from the same clutch (modal clutch size is three). therefore, in the first experiment small families were housed together in large groups (challenged condition) and compared to families kept isolated (nonchallenged condition). as expected, in the challenged condition dur ...200211971668
campylobacter jejuni in black-headed gulls (larus ridibundus): prevalence, genotypes, and influence on c. jejuni epidemiology.campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. we investigated the prevalence of campylobacter jejuni subsp. jejuni in black-headed gulls (larus ridibundus) in southern sweden with the aim of examining the nature of c. jejuni infection in this bird species. birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). longitudinally sampled c. jejuni isolates from individual gulls were subject ...200212454158
campylobacter jejuni in black-headed gulls (larus ridibundus): prevalence, genotypes, and influence on c. jejuni epidemiology.campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. we investigated the prevalence of campylobacter jejuni subsp. jejuni in black-headed gulls (larus ridibundus) in southern sweden with the aim of examining the nature of c. jejuni infection in this bird species. birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). longitudinally sampled c. jejuni isolates from individual gulls were subject ...200212454158
potential for individual recognition in acoustic signals: a comparative study of two gulls with different nesting patterns.we test relationships between structure of acoustic signal used for individual recognition and nesting ecology among two gulls: the black-headed gull (larus ridibundus), in which chicks remain in the nest, and the slender-billed gull (l. genei), in which chicks leave the nest after hatching to form crèches. a striking difference between both species is the presence of two fundamental frequencies in the slender-billed gull's call and only one in the black-headed gull's call. our study shows that ...200312806840
potential for individual recognition in acoustic signals: a comparative study of two gulls with different nesting patterns.we test relationships between structure of acoustic signal used for individual recognition and nesting ecology among two gulls: the black-headed gull (larus ridibundus), in which chicks remain in the nest, and the slender-billed gull (l. genei), in which chicks leave the nest after hatching to form crèches. a striking difference between both species is the presence of two fundamental frequencies in the slender-billed gull's call and only one in the black-headed gull's call. our study shows that ...200312806840
persistent organochlorine pollutants in liver of birds of different trophic levels from coastal areas of campania, italy.liver samples of 12 species of birds of different trophic levels, collected during the period 1998-2000 from coastal areas of the campania region, southern italy, were analyzed for organochlorine pesticides (ocs), such as dichlorodiphenyltrichloroethane (ddt) and its metabolites, hexachlorobenzene (hcb), gamma-hexachlorocycloexane (gamma-hch), aldrin, dieldrin, endrin, and the seven pcb "target" congeners, iupac nos. 28, 52, 101, 118, 138, 153 and 180. p,p'-dde was present in all the samples ana ...200314674594
persistent organochlorine pollutants in liver of birds of different trophic levels from coastal areas of campania, italy.liver samples of 12 species of birds of different trophic levels, collected during the period 1998-2000 from coastal areas of the campania region, southern italy, were analyzed for organochlorine pesticides (ocs), such as dichlorodiphenyltrichloroethane (ddt) and its metabolites, hexachlorobenzene (hcb), gamma-hexachlorocycloexane (gamma-hch), aldrin, dieldrin, endrin, and the seven pcb "target" congeners, iupac nos. 28, 52, 101, 118, 138, 153 and 180. p,p'-dde was present in all the samples ana ...200314674594
steroids for free? no metabolic costs of elevated maternal androgen levels in the black-headed gull.within- and between-clutch variation in yolk titres of hormones of maternal origin has been found in many avian species. so far, experiments have revealed mainly beneficial effects of maternal androgens. this would also apply to black-headed gulls (larus ridibundus). previous experiments have shown that chicks benefit from these higher levels since their competitive abilities are improved and growth and survival probabilities thus enhanced. however, not all females show the same increase in yolk ...200312909702
steroids for free? no metabolic costs of elevated maternal androgen levels in the black-headed gull.within- and between-clutch variation in yolk titres of hormones of maternal origin has been found in many avian species. so far, experiments have revealed mainly beneficial effects of maternal androgens. this would also apply to black-headed gulls (larus ridibundus). previous experiments have shown that chicks benefit from these higher levels since their competitive abilities are improved and growth and survival probabilities thus enhanced. however, not all females show the same increase in yolk ...200312909702
spontaneous and benzo[a]pyrene-induced micronuclei in the embryos of the black-headed gull (larus ridibundus l.).the spontaneous levels of micronuclei in erythrocytes were established in embryos of the black-headed gull of two natural populations. in total 216 blood samples from the same number of individuals were examined. a statistically significant decrease in the number of spontaneous micronucleated erythrocytes was found after 13 days of incubation. we found no statistically significant difference in the spontaneous frequencies of micronucleated erythrocytes in the embryos of the two colonies studied, ...200312834752
spontaneous and benzo[a]pyrene-induced micronuclei in the embryos of the black-headed gull (larus ridibundus l.).the spontaneous levels of micronuclei in erythrocytes were established in embryos of the black-headed gull of two natural populations. in total 216 blood samples from the same number of individuals were examined. a statistically significant decrease in the number of spontaneous micronucleated erythrocytes was found after 13 days of incubation. we found no statistically significant difference in the spontaneous frequencies of micronucleated erythrocytes in the embryos of the two colonies studied, ...200312834752
occurrence of intermediate hosts and structure of digenean communities of the black-headed gull, larus ridibundus (l.).the factors contributing to the similarity between digenean parasite assemblages parasitizing the black-headed gull were investigated. thirteen different digenean species from the digestive tract and the bursa of fabricus were found. we predicted that the structure of parasite communities is not random at either component community or infracommunity levels. we searched for nested patterns in the digenean community, and explored the possible factors contributing to nestedness. we found that digen ...200312613765
occurrence of intermediate hosts and structure of digenean communities of the black-headed gull, larus ridibundus (l.).the factors contributing to the similarity between digenean parasite assemblages parasitizing the black-headed gull were investigated. thirteen different digenean species from the digestive tract and the bursa of fabricus were found. we predicted that the structure of parasite communities is not random at either component community or infracommunity levels. we searched for nested patterns in the digenean community, and explored the possible factors contributing to nestedness. we found that digen ...200312613765
lymphoid distribution in the migratory gull larus ridibundus.we studied the distribution of lymphocytes in the main lymphoid tissues (blood, spleen and thymus) of the gull larus ridibundus, searching for variations that might depend on the migratory cycle. we also looked for sex- and age-associated differences in lymphoid redistribution. in l. ridibundus, lymphocytes are the most commonly observed leukocyte subpopulation in blood. moreover, changes in the distribution of lymphocytes in the lymphoid tissue occur, depending on the migratory period. the prop ...200314613802
effect of migratory cycle and 17beta-estradiol on splenic leukocyte functions in female black-headed gulls.the immune function of wild birds is practically unknown. we have studied several functions of splenic leukocytes from the gull larus ridibundus. considering that avian physiology is strikingly affected by the seasonal migratory cycle, those functions were analyzed throughout the seasonal cycle. the functions assayed were: adherence to substrate, chemotaxis and lymphoproliferative response to mitogens. estrogens have been reported to modulate the immune response in mammals; therefore serum level ...200312632185
kinematic parameters of the walking of herons, ground-feeders, and waterfowl.the kinematic gait characteristics of six species of birds in three groups were compared. the groups studied were herons (gray herons and little egrets), ground-feeders (domestic pigeons and gray starlings), and waterfowl (pintails and black-headed gulls). the results showed that the relative stride frequency was greater in the waterfowl than in the other species. complementary to this, the amplitude of the movements was smaller in the waterfowl than in the others. these differences between the ...200415471689
parent-offspring conflict and the coordination of siblings in gulls.offspring solicit food from their parents by begging behaviours. studies on birds suggest that these displays are 'honest signals of need' and adults provide food according to the begging level. however, siblings may compete for parental resources and the begging intensity is expected to change with brood size. here, we show that in the black-headed gull (larus ridibundus) an increase of the numbers of siblings can result in a decrease of individual begging cost through nestlings' synchronized s ...200415252967
parent-offspring conflict and the coordination of siblings in gulls.offspring solicit food from their parents by begging behaviours. studies on birds suggest that these displays are 'honest signals of need' and adults provide food according to the begging level. however, siblings may compete for parental resources and the begging intensity is expected to change with brood size. here, we show that in the black-headed gull (larus ridibundus) an increase of the numbers of siblings can result in a decrease of individual begging cost through nestlings' synchronized s ...200415252967
influence of a mine tailing accident near doñana national park (spain) on heavy metals and arsenic accumulation in 14 species of waterfowl (1998 to 2000).this article presents the impact on waterbirds in doñana national park (spain) of an accidental release of 5 million m3 acid waste produced by the processing of pyrite ore. heavy metals (zinc, copper, cadmium, and lead) and arsenic were measured in several soft tissues (liver, kidney, and muscle) taken from 14 waterfowl species collected between april 1998 and may 2000. the main source of copper and zinc found in the waterfowl species examined was the spill waste, whereas cadmium, lead, and arse ...200415499503
influence of a mine tailing accident near doñana national park (spain) on heavy metals and arsenic accumulation in 14 species of waterfowl (1998 to 2000).this article presents the impact on waterbirds in doñana national park (spain) of an accidental release of 5 million m3 acid waste produced by the processing of pyrite ore. heavy metals (zinc, copper, cadmium, and lead) and arsenic were measured in several soft tissues (liver, kidney, and muscle) taken from 14 waterfowl species collected between april 1998 and may 2000. the main source of copper and zinc found in the waterfowl species examined was the spill waste, whereas cadmium, lead, and arse ...200415499503
european starling chicks benefit from high yolk testosterone levels during a drought year.avian egg yolk contains androgenic hormones, such as testosterone, of maternal origin. experimental elevation of yolk testosterone levels enhances growth of canary chicks. success in sibling competition, due to increased begging, is presumed to underlie this growth enhancement, because canary hatchlings from testosterone-treated eggs beg longer in response to vibrational stimuli than controls. furthermore, experimental elevation of both yolk androstenedione and testosterone increased chick growt ...200415256308
investigation of outbreaks of highly pathogenic h5n1 avian influenza in waterfowl and wild birds in hong kong in late 2002.outbreaks of highly pathogenic h5n1 avian influenza have occurred in hong kong in chickens and other gallinaceous poultry in 1997, 2001, twice in 2002 and 2003. high mortality rates were seen in gallinaceous birds but not in domestic or wild waterfowl or other wild birds until late 2002 when highly pathogenic h5n1 avian influenza occurred in waterfowl (geese, ducks and swans), captive greater flamingo (phoenicopterus ruber) and other wild birds (little egret egretta garzetta) at two waterfowl pa ...200415545029
investigation of outbreaks of highly pathogenic h5n1 avian influenza in waterfowl and wild birds in hong kong in late 2002.outbreaks of highly pathogenic h5n1 avian influenza have occurred in hong kong in chickens and other gallinaceous poultry in 1997, 2001, twice in 2002 and 2003. high mortality rates were seen in gallinaceous birds but not in domestic or wild waterfowl or other wild birds until late 2002 when highly pathogenic h5n1 avian influenza occurred in waterfowl (geese, ducks and swans), captive greater flamingo (phoenicopterus ruber) and other wild birds (little egret egretta garzetta) at two waterfowl pa ...200415545029
characterization of a novel influenza a virus hemagglutinin subtype (h16) obtained from black-headed gulls.in wild aquatic birds and poultry around the world, influenza a viruses carrying 15 antigenic subtypes of hemagglutinin (ha) and 9 antigenic subtypes of neuraminidase (na) have been described. here we describe a previously unidentified antigenic subtype of ha (h16), detected in viruses circulating in black-headed gulls in sweden. in agreement with established criteria for the definition of antigenic subtypes, hemagglutination inhibition assays and immunodiffusion assays failed to detect specific ...200515709000
within clutch co-variation of egg mass and sex in the black-headed gull.female birds of several species have control over the production of daughters and sons. however, most studies failed to find a relationship between egg size and sex. this is intriguing as adjustment of egg size would constitute a powerful tool for the female to meet different resource demands of the sexes, particularly in size dimorphic species. our results show that, within clutches of black-headed gulls (larus ridibundus) the proportion of males was positively associated with egg mass. this ap ...200515842495
within clutch co-variation of egg mass and sex in the black-headed gull.female birds of several species have control over the production of daughters and sons. however, most studies failed to find a relationship between egg size and sex. this is intriguing as adjustment of egg size would constitute a powerful tool for the female to meet different resource demands of the sexes, particularly in size dimorphic species. our results show that, within clutches of black-headed gulls (larus ridibundus) the proportion of males was positively associated with egg mass. this ap ...200515842495
prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks.avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. as androgens may suppress immune functions, they may also entail costs for the chick. this is particularly relevant for colonial species, such as the black-headed gull (larus ridibundus), in which the aggregation of large numbers of birds during the breeding season enhances the risk of infectious diseases for the hatching chick. to test th ...200516191605
prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks.avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. as androgens may suppress immune functions, they may also entail costs for the chick. this is particularly relevant for colonial species, such as the black-headed gull (larus ridibundus), in which the aggregation of large numbers of birds during the breeding season enhances the risk of infectious diseases for the hatching chick. to test th ...200516191605
the hormonal control of begging and early aggressive behavior: experiments in black-headed gull chicks.the hormonal control of begging and sibling competition is largely unknown, but recent evidence suggests a role for steroid hormones. we tested the influence of the aromatizable androgen testosterone (t), the non-aromatizable androgen 5alpha-dihydrotestosterone (dht), and 17beta-estradiol (e) on both begging behavior and aggressive behavior in black-headed gull chicks (larus ridibundus). chicks of this species have a conspicuous begging display, while their frequently performed early aggressive ...200515878577
the hormonal control of begging and early aggressive behavior: experiments in black-headed gull chicks.the hormonal control of begging and sibling competition is largely unknown, but recent evidence suggests a role for steroid hormones. we tested the influence of the aromatizable androgen testosterone (t), the non-aromatizable androgen 5alpha-dihydrotestosterone (dht), and 17beta-estradiol (e) on both begging behavior and aggressive behavior in black-headed gull chicks (larus ridibundus). chicks of this species have a conspicuous begging display, while their frequently performed early aggressive ...200515878577
balancing between costs and benefits of maternal hormone deposition in avian eggs.avian eggs contain substantial amounts of maternal androgens, and several studies have indicated that these are beneficial for the chick. nevertheless, there is a large and systematic variation in maternal hormone concentrations both within and between clutches. if maternal androgens also involve costs, this might explain why not all mothers put high levels of androgens in their clutches. however, the simultaneous occurrence of both benefits and costs has not yet been convincingly demonstrated. ...200517148133
energetic influence on gull flight strategy selection.during non-migratory flight, gulls (larids) use a wide variety of flight strategies. we investigate the extent to which the energy balance of a bird explains flight strategy selection. we develop a model based on optimal foraging and aerodynamic theories, to calculate the ground speeds and airspeeds at which a gull is expected to flap or soar during foraging flight. the model results are compared with observed flight speeds, directions, and flight strategies of two species of gulls, the black-he ...200616943489
energetic influence on gull flight strategy selection.during non-migratory flight, gulls (larids) use a wide variety of flight strategies. we investigate the extent to which the energy balance of a bird explains flight strategy selection. we develop a model based on optimal foraging and aerodynamic theories, to calculate the ground speeds and airspeeds at which a gull is expected to flap or soar during foraging flight. the model results are compared with observed flight speeds, directions, and flight strategies of two species of gulls, the black-he ...200616943489
multiple pathways of maternal effects in black-headed gull eggs: constraint and adaptive compensatory adjustment.we investigated in the black-headed gull whether female deposition of antioxidants and immunoglobulins (enhancing early immune function), and testosterone (suppressing immune function and increasing early competitive skills) correlate suggesting that evolution has favoured the mutual adjustment of different pathways for maternal effects. we also took egg mass, the position of the egg in the laying sequence and offspring sex into account, as these affect offspring survival. yolk antioxidant and i ...200616780531
salmonella in black-headed gulls ( larus ridibundus); prevalence, genotypes and influence on salmonella epidemiology.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 ...200616238820
salmonella in black-headed gulls ( larus ridibundus); prevalence, genotypes and influence on salmonella epidemiology.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 ...200616238820
flock-feeding on fish schools increases individual success in gulls.flock-foraging and the role of white plumage in gulls and other seabirds have been the subject of much debate. at first sight it seems that competition within the flock would render flock formation against the interest of the bird who finds the fish school, as the fish must then be shared with birds joining the flock. however, it is also possible that flock formation is neutral or even beneficial to the individual members, including the bird that found the fish (the 'first finder'). here we show ...20063945345
head-bobbing and non-bobbing walking of black-headed gulls (larus ridibundus).head-bobbing walking (hbw) and non-bobbing walking (nbw) of black-headed gulls were compared from kinematic and behavioral/environmental viewpoints. the birds walked with a longer stride length and lower stride frequency during the hbw than during the nbw. with respect to these two parameters, the hbw of black-headed gulls was similar to that of other head-bobbers, and the nbw was similar to that of other non-bobbers. the stride length and the amplitude of head bobbing were correlated. these res ...200616432727
avian mothers create different phenotypes by hormone deposition in their eggs.an increasing number of studies in a variety of taxa demonstrate the role of maternal sex steroids on offspring development. in avian species, mothers deposit substantial amounts of androgens in their eggs, and experimental evidence indicates that these maternal androgens influence the chick's early development. despite the well-known organizing role of sex steroids on brain and behaviour, studies on avian maternal egg hormones almost exclusively focus on the chick phase. here, we show experimen ...200617148315
high prevalence of antimicrobial-resistant genes and integrons in escherichia coli isolates from black-headed gulls in the czech republic.to carry out an assessment of the occurrence of resistance to antimicrobials in escherichia coli that has been isolated from young black-headed gulls in three nesting colonies.200717584448
bioaccumulation, temporal trend, and geographical distribution of synthetic musks in the marine environment.bioaccumulation of synthetic musks in a marine food chain was investigated by analyzing marine organisms at various trophic levels, including lugworm, clam, crustacean, fish, marine mammal, and bird samples collected from tidal flat and shallow water areas of the ariake sea, japan. two of the polycyclic musks, hhcb and ahtn, were the dominant compounds found in most of the samples analyzed, whereas nitro musks were not detected in any of the organisms, suggesting greater usage of polycyclic musk ...200717438766
nereidid polychaetes as the major diet of migratory shorebirds on the estuarine tidal flats at fujimae-higata in japan.the dietary items of five migratory shorebirds, dunlin (calidris alpina), red-necked stint (c. ruficollis), grey plover (pluvialis squatarola), whimbrel (numenius phaeopus) and black-headed gull (larus ridibundus), were examined by analyses of fecal droppings during the birds' migration or wintering and by surveys of macrobenthic fauna around their foraging sites on the tidal flats of fujimae-higata, nagoya, central japan. body parts of nereidid, capitellid, and spionid polychaetes and crustacea ...200717824775
nereidid polychaetes as the major diet of migratory shorebirds on the estuarine tidal flats at fujimae-higata in japan.the dietary items of five migratory shorebirds, dunlin (calidris alpina), red-necked stint (c. ruficollis), grey plover (pluvialis squatarola), whimbrel (numenius phaeopus) and black-headed gull (larus ridibundus), were examined by analyses of fecal droppings during the birds' migration or wintering and by surveys of macrobenthic fauna around their foraging sites on the tidal flats of fujimae-higata, nagoya, central japan. body parts of nereidid, capitellid, and spionid polychaetes and crustacea ...200717824775
an evaluation of techniques to control problem bird species on landfill sites.birds feeding on landfill sites cause problems in terms of nuisance to neighbors, flight safety, a threat to public health, and affecting the day to day site operation. a number of control measures exist to deter problem species; however, research into their effectiveness across sites and for multiple species has been limited. we use a modeling approach in order to assess the effectiveness of nine techniques--pyrotechnics, hand-held distress calls, static distress calls, blank ammunition, a comb ...200818256779
an evaluation of techniques to control problem bird species on landfill sites.birds feeding on landfill sites cause problems in terms of nuisance to neighbors, flight safety, a threat to public health, and affecting the day to day site operation. a number of control measures exist to deter problem species; however, research into their effectiveness across sites and for multiple species has been limited. we use a modeling approach in order to assess the effectiveness of nine techniques--pyrotechnics, hand-held distress calls, static distress calls, blank ammunition, a comb ...200818256779
serologic survey of potential vertebrate hosts for west nile virus in poland.a survey for antibodies to west nile virus (wnv; genus ,flavivirus) was carried out by plaque-re-duction neutralization microtesting in 78 horses, 20 domestic chickens, and 97 wild birds belonging to 10 species from different areas in poland. specific antibodies were detected in five juvenile (hatching-year) birds collected in 2006: three white storks (ciconia ciconia) in a wildlife rehabilitation center (5.4% of all examined storks; the antibody titers in each bird were 1:320, 1:160, and 1:20), ...200818433332
serologic survey of potential vertebrate hosts for west nile virus in poland.a survey for antibodies to west nile virus (wnv; genus ,flavivirus) was carried out by plaque-re-duction neutralization microtesting in 78 horses, 20 domestic chickens, and 97 wild birds belonging to 10 species from different areas in poland. specific antibodies were detected in five juvenile (hatching-year) birds collected in 2006: three white storks (ciconia ciconia) in a wildlife rehabilitation center (5.4% of all examined storks; the antibody titers in each bird were 1:320, 1:160, and 1:20), ...200818433332
maternal yolk androgens stimulate territorial behaviour in black-headed gull chicks.avian eggs contain substantial amounts of maternal androgens. the concentrations of these yolk androgens are affected by the maternal environment, such as the level of social competition, parasite exposure or food conditions. since yolk androgens have been shown to affect a wide array of offspring traits, they may adjust the chicks to the expected post-hatching environment, but experimental evidence is still scarce. we investigate in colonial breeding black-headed gulls whether high concentratio ...200919515649
metastatic hepatocellular carcinoma and subcutaneous fibrosarcoma in a black-headed gull (larus ridibundus). 200919202174
metastatic hepatocellular carcinoma and subcutaneous fibrosarcoma in a black-headed gull (larus ridibundus). 200919202174
characterization of low pathogenicity avian influenza viruses isolated from wild birds in mongolia 2005 through 2007.since the emergence of h5n1 high pathogenicity (hp) avian influenza virus (aiv) in asia, numerous efforts worldwide have focused on elucidating the relative roles of wild birds and domestic poultry movement in virus dissemination. in accordance with this a surveillance program for aiv in wild birds was conducted in mongolia from 2005-2007. an important feature of mongolia is that there is little domestic poultry production in the country, therefore aiv detection in wild birds would not likely be ...200919891786
characterization of low pathogenicity avian influenza viruses isolated from wild birds in mongolia 2005 through 2007.since the emergence of h5n1 high pathogenicity (hp) avian influenza virus (aiv) in asia, numerous efforts worldwide have focused on elucidating the relative roles of wild birds and domestic poultry movement in virus dissemination. in accordance with this a surveillance program for aiv in wild birds was conducted in mongolia from 2005-2007. an important feature of mongolia is that there is little domestic poultry production in the country, therefore aiv detection in wild birds would not likely be ...200919891786
antibiotic-resistant salmonella and escherichia coli isolates with integrons and extended-spectrum beta-lactamases in surface water and sympatric black-headed gulls.to examine surface water from a pond in the northeastern part of the czech republic and young black-headed gulls (larus ridibundus) nesting on the same pond for the presence of antibiotic-resistant salmonella and escherichia coli.200919245407
antibiotic-resistant salmonella and escherichia coli isolates with integrons and extended-spectrum beta-lactamases in surface water and sympatric black-headed gulls.to examine surface water from a pond in the northeastern part of the czech republic and young black-headed gulls (larus ridibundus) nesting on the same pond for the presence of antibiotic-resistant salmonella and escherichia coli.200919245407
experience modulates both aromatase activity and the sensitivity of agonistic behaviour to testosterone in black-headed gulls.in young black-headed gulls (larus ridibundus), exposure to testosterone increases the sensitivity of agonistic behaviour to a subsequent exposure to this hormone. the aim of this paper is twofold: to analyze whether social experience, gained during testosterone exposure, mediates this increase in hormonal sensitivity (priming), and whether this in turn is mediated by an increase in central aromatase activity. to this end, we performed three experiments. in the first juvenile gulls were exposed ...200919419676
campylobacter volucris sp. nov., isolated from black-headed gulls (larus ridibundus).during a study of the prevalence of campylobacter jejuni in black-headed gulls (larus ridibundus) in sweden, three isolates, strains lmg 24379, lmg 24380t and lmg 24381, were initially identified as campylobacter lari. further characterization by both aflp and whole-cell protein sds-page analyses revealed that they formed a distinct group in the genus campylobacter. this unique position was confirmed by phenotypic characterization, 16s rrna and hsp60 gene sequence analysis and dna-dna hybridizat ...201019767353
campylobacter volucris sp. nov., isolated from black-headed gulls (larus ridibundus).during a study of the prevalence of campylobacter jejuni in black-headed gulls (larus ridibundus) in sweden, three isolates, strains lmg 24379, lmg 24380t and lmg 24381, were initially identified as campylobacter lari. further characterization by both aflp and whole-cell protein sds-page analyses revealed that they formed a distinct group in the genus campylobacter. this unique position was confirmed by phenotypic characterization, 16s rrna and hsp60 gene sequence analysis and dna-dna hybridizat ...201019767353
multiple introduction of asian h5n1 avian influenza virus in croatia by wild birds during 2005-2006 and isolation of the virus from apparently healthy black-headed gulls (larus ridibundus).this study describes the introduction and spread of avian influenza a (h5n1) subtype in croatia. seventeen isolates were identified during the period from october 2005 to march 2006, all originating from wild birds. the full-length nucleotide sequence analysis of the hemagglutinin (ha) gene of seven representative isolates revealed that three distinct genetic strains involved in the outbreaks, implicating at least three independent introductions of the virus into croatia during a relatively shor ...201020370426
multiple introduction of asian h5n1 avian influenza virus in croatia by wild birds during 2005-2006 and isolation of the virus from apparently healthy black-headed gulls (larus ridibundus).this study describes the introduction and spread of avian influenza a (h5n1) subtype in croatia. seventeen isolates were identified during the period from october 2005 to march 2006, all originating from wild birds. the full-length nucleotide sequence analysis of the hemagglutinin (ha) gene of seven representative isolates revealed that three distinct genetic strains involved in the outbreaks, implicating at least three independent introductions of the virus into croatia during a relatively shor ...201020370426
prevalence and subtypes of influenza a viruses in wild waterfowl in norway 2006-2007.the prevalence of influenza a virus infection, and the distribution of different subtypes of the virus, were studied in 1529 ducks and 1213 gulls shot during ordinary hunting from august to december in two consecutive years, 2006 and 2007, in norway. the study was based on molecular screening of cloacal and tracheal swabs, using a pan-influenza a rt-pcr. samples found to be positive for influenza a virus were screened for the h5 subtype, using a h5 specific rt-pcr, and, if negative, further subt ...201020426812
characterization, and comparison, of human clinical and black-headed gull (larus ridibundus) extended-spectrum beta-lactamase-producing bacterial isolates from kalmar, on the southeast coast of sweden.antibiotic resistance is one of the great challenges for modern healthcare. in gram-negative bacteria, ctx-m-type extended-spectrum beta-lactamases (esbls) have been rapidly spreading through europe since the early 2000s. in sweden, esbl-producing escherichia coli are still rare, but a 3-fold increase has been seen from 2004 to 2007. enterobacteria and normal flora of wild animals, with or without antibiotic resistance traits, constitute a potential source of human infection and colonization. we ...201020615928
characterization, and comparison, of human clinical and black-headed gull (larus ridibundus) extended-spectrum beta-lactamase-producing bacterial isolates from kalmar, on the southeast coast of sweden.antibiotic resistance is one of the great challenges for modern healthcare. in gram-negative bacteria, ctx-m-type extended-spectrum beta-lactamases (esbls) have been rapidly spreading through europe since the early 2000s. in sweden, esbl-producing escherichia coli are still rare, but a 3-fold increase has been seen from 2004 to 2007. enterobacteria and normal flora of wild animals, with or without antibiotic resistance traits, constitute a potential source of human infection and colonization. we ...201020615928
mercury concentration in 3 species of gulls, larus ridibundus, larus minutus, larus canus, from south coast of the caspian sea, iran.in this study, the mercury concentrations of liver, breast feathers and tail feathers in three species of gull; black-headed gull (larus ridibundus), common gull (larus canus) and little gull (larus minutus) from the south coast of the caspian sea in iran were assayed. mercury accumulation in liver, breast feathers and tail feathers of species were 1.69-3.16, 2.88-7.18 and 2.09-5.66 mg/kg, respectively. mercury concentration hierarchy in tissues we tested was as follows: breast feather > tail fe ...201020424818
mercury concentration in 3 species of gulls, larus ridibundus, larus minutus, larus canus, from south coast of the caspian sea, iran.in this study, the mercury concentrations of liver, breast feathers and tail feathers in three species of gull; black-headed gull (larus ridibundus), common gull (larus canus) and little gull (larus minutus) from the south coast of the caspian sea in iran were assayed. mercury accumulation in liver, breast feathers and tail feathers of species were 1.69-3.16, 2.88-7.18 and 2.09-5.66 mg/kg, respectively. mercury concentration hierarchy in tissues we tested was as follows: breast feather > tail fe ...201020424818
studying dispersal at the landscape scale: efficient combination of population surveys and capture-recapture data.researchers often rely on capture-mark-recapture (cmr) data to study animal dispersal in the wild. yet their spatial coverage often does not encompass the entire dispersal range of the study individuals, sometimes producing misleading results. information contained in population surveys and variation in population spatial structure can be used to overcome this issue. we build an integrated model in a multisite context in which cmr data are only collected at a subset of sites, but numbers of bree ...201021141197
begging coordination between siblings in black-headed gulls.communication behaviours are now considered from a signallers-receivers network perspective. this concept seems well suited to the study of interactions between parents and offspring in birds, so far mainly treated as a dyadic signalling system involving the brood or a single chick as a signaller and the parent as a receiver. family conflicts over resource allocation drive parent-offspring and sib-sib communication. in the black-headed gull larus ridibundus, parents respond to the whole-brood be ...201020816649
begging coordination between siblings in black-headed gulls.communication behaviours are now considered from a signallers-receivers network perspective. this concept seems well suited to the study of interactions between parents and offspring in birds, so far mainly treated as a dyadic signalling system involving the brood or a single chick as a signaller and the parent as a receiver. family conflicts over resource allocation drive parent-offspring and sib-sib communication. in the black-headed gull larus ridibundus, parents respond to the whole-brood be ...201020816649
breeding dispersal in black-headed gull: the value of familiarity in a contrasted environment.1. some species (e.g. migratory species with high movement ability) are unlikely to experience any physical cost when dispersing, at least at the landscape scale. in these species dispersal is nevertheless behaviourally constrained to avoid non-physical costs such as the loss of familiarity with the breeding environment, and these constraints can be maladaptive in a fast-changing environment. 2. we evaluated such constraints using multievent modelling of a 20-year capture-mark-recapture data set ...201019891713
eggshell permeability: a standard technique for determining interspecific rates of water vapor conductance.typically, eggshell water vapor conductance is measured on whole eggs, freshly collected at the commencement of a study. at times, however, it may not be possible to obtain whole fresh eggs but rather egg fragments or previously blown eggs. here we evaluate and describe in detail a technique for modern laboratory analysis of eggshell conductance that uses fragments from fresh and museum eggs to determine eggshell water vapor conductance. we used fresh unincubated eggs of domesticated chickens (g ...201020939733
eggshell permeability: a standard technique for determining interspecific rates of water vapor conductance.typically, eggshell water vapor conductance is measured on whole eggs, freshly collected at the commencement of a study. at times, however, it may not be possible to obtain whole fresh eggs but rather egg fragments or previously blown eggs. here we evaluate and describe in detail a technique for modern laboratory analysis of eggshell conductance that uses fragments from fresh and museum eggs to determine eggshell water vapor conductance. we used fresh unincubated eggs of domesticated chickens (g ...201020939733
complete genome analysis of an avian paramyxovirus type 1 strain isolated in 1994 from an asymptomatic black-headed gull (larus ridibundus) in southern sweden.the complete genome sequence of an avian paramyxovirus serotype 1 (apmv-1) isolated from a black-headed gull (larus ridibundus) in sweden was determined and compared with other apmv-1 sequences. sequence analyses showed that this isolate consists of six genes in the order 3'-np-p-m-f-hn-l-5', is 15,186 nucleotides long, and contains a typical, avirulent fusion protein cleavage site. it was also shown to have a hemagglutinin-neuraminidase protein with a length of 585 amino acids (aa) instead of t ...201020608541
complete genome analysis of an avian paramyxovirus type 1 strain isolated in 1994 from an asymptomatic black-headed gull (larus ridibundus) in southern sweden.the complete genome sequence of an avian paramyxovirus serotype 1 (apmv-1) isolated from a black-headed gull (larus ridibundus) in sweden was determined and compared with other apmv-1 sequences. sequence analyses showed that this isolate consists of six genes in the order 3'-np-p-m-f-hn-l-5', is 15,186 nucleotides long, and contains a typical, avirulent fusion protein cleavage site. it was also shown to have a hemagglutinin-neuraminidase protein with a length of 585 amino acids (aa) instead of t ...201020608541
avian embryonic development does not change the stable isotope composition of the calcite eggshell.the avian embryo resorbs most of the calcium for bone formation from the calcite eggshell but the exact mechanisms of the resorption are unknown. the present study tested whether this process results in variable fractionation of the oxygen and carbon isotopes in shell calcium carbonate, which could provide a detailed insight into the temporal and spatial use of the eggshell by the developing embryo. despite the uncertainty regarding changes in stable isotope composition of the eggshell across de ...201121211467
avian embryonic development does not change the stable isotope composition of the calcite eggshell.the avian embryo resorbs most of the calcium for bone formation from the calcite eggshell but the exact mechanisms of the resorption are unknown. the present study tested whether this process results in variable fractionation of the oxygen and carbon isotopes in shell calcium carbonate, which could provide a detailed insight into the temporal and spatial use of the eggshell by the developing embryo. despite the uncertainty regarding changes in stable isotope composition of the eggshell across de ...201121211467
tissue tropism and pathology of natural influenza virus infection in black-headed gulls (chroicocephalus ridibundus).black-headed gulls (chroicocephalus ridibundus) are a suitable host species to study the epidemiology of low-pathogenic avian influenza virus (lpaiv) infection in wild waterbirds because they are a common colony-breeding species in which lpaiv infection is detected frequently, limited mainly to the h13 and h16 subtypes. however, the sites of virus replication and associated lesions are poorly understood. we therefore performed virological and pathological analyses on tissues of black-headed gull ...201223237367
development of an improved method for trace analysis of quinolones in eggs of laying hens and wildlife species using molecularly imprinted polymers.a sensitive, selective, and efficient method was developed for simultaneous determination of 11 fluoroquinolones (fqs), ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, flumequine, marbofloxacin, norfloxacin, ofloxacin, oxolinic acid, pipemidic acid, and sarafloxacin, in eggs by molecularly imprinted polymer (mip) and column liquid chromatography-electrospray ionization-tandem mass spectrometry (lc-esi-ms/ms). samples were diluted with 50 mm sodium dihydrogen phosphate at ph 7.4, followed ...201223009602
first report of (homo)anatoxin-a and dog neurotoxicosis after ingestion of benthic cyanobacteria in the netherlands.in april and may 2011, three dogs died and one dog became ill after swimming in lake ijmeer (the netherlands). at the time, the lake was infested with the benthic cyanobacterial species phormidium. a eurasian coot (fulica atra) and a black-headed gull (chroicocephalus ridibundus) also died near lake ijmeer in the same period. one of the dogs and both birds were subjected to a pathological investigation. furthermore, the phormidium mat; algal samples from the dikes; contents of the animals' diges ...201222534073
effect of rapid modulation of circulating plasma testosterone concentration on begging, aggressive behavior and competition for food in black-headed gull (larus ridibundus) chicks.sibling competition mediated by begging behavior is extremely common in avian species and recent studies have highlighted the role of endogenous testosterone in regulating such phenomenon. however, current literature depicts an inconsistent pattern in altricial vs. semi-precocial species, with stimulating versus inhibitory effects of the hormone respectively. this is possibly due to a difference in the methodology of hormone treatment (short-term moderate dose versus a long-term stronger elevati ...201323962563
effect of rapid modulation of circulating plasma testosterone concentration on begging, aggressive behavior and competition for food in black-headed gull (larus ridibundus) chicks.sibling competition mediated by begging behavior is extremely common in avian species and recent studies have highlighted the role of endogenous testosterone in regulating such phenomenon. however, current literature depicts an inconsistent pattern in altricial vs. semi-precocial species, with stimulating versus inhibitory effects of the hormone respectively. this is possibly due to a difference in the methodology of hormone treatment (short-term moderate dose versus a long-term stronger elevati ...201323962563
avian influenza virus surveillance in wild birds in georgia: 2009-2011.the caucasus, at the border of europe and asia, is important for migration and over-wintering of wild waterbirds. three flyways, the central asian, east africa-west asia, and mediterranean/black sea flyways, converge in the caucasus region. thus, the caucasus region might act as a migratory bridge for influenza virus transmission when birds aggregate in high concentrations in the post-breeding, migrating and overwintering periods. since august 2009, we have established a surveillance network for ...201323516501
trophic transfer of dechloranes in the marine food web of liaodong bay, north china.dechloranes are of particular concern because of their ubiquity in environmental matrices, but little is known about their trophic transfer in aquatic food web. this study investigated the trophic transfer of seven dechloranes in a marine food web from liaodong bay, china. dechloranes were determined in sediments and 15 marine species including benthic invertebrates, fish and gulls collected from liaodong bay. biomagnification factors (bmftl) of dechloranes in black-headed gulls were calculated ...201424702310
epidemiology of influenza a virus among black-headed gulls, the netherlands, 2006-2010.we sampled 7,511 black-headed gulls for influenza virus in the netherlands during 2006-2010 and found that subtypes h13 and h16 caused annual epidemics in fledglings on colony sites. our findings validate targeted surveillance of wild waterbirds and clarify underlying factors for influenza virus emergence in other species.201424377955
prevalence of antibody to toxoplasma gondii in black-headed gulls (chroicocephalus ridibundus), dianchi lake, china.sera from 659 black-headed gulls (chroicocephalus ridibundus) in dianchi lake, china were assayed for toxoplasma gondii antibodies using the modified agglutination test (mat). specific t. gondii antibodies were detected in 131 (19.9%) black-headed gulls (mat titer ≥ 1 ∶ 5). these results indicate that t. gondii infection is common in black-headed gulls.201424807354
molecular identification of cryptosporidium spp. in seagulls, pigeons, dogs, and cats in thailand.zoonotic cryptosporidium spp., particularly c. meleagridis, c. canis, and c. felis, are enteric protozoa responsible for major public health concerns around the world. to determine the spread of this parasite in thailand, we conducted molecular identification of cryptosporidium spp. from animal samples around the country, by collecting and investigating the feces of seagulls (chroicocephalus brunnicephalus and chroicocephalus ridibundus), domestic pigeons (columba livia domestica), dogs, and cat ...201425297887
experimental infection of highly pathogenic avian influenza virus h5n1 in black-headed gulls (chroicocephalus ridibundus).historically, highly pathogenic avian influenza viruses (hpaiv) rarely resulted in infection or clinical disease in wild birds. however, since 2002, disease and mortality from natural hpaiv h5n1 infection have been observed in wild birds including gulls. we performed an experimental hpaiv h5n1 infection of black-headed gulls (chroicocephalus ridibundus) to determine their susceptibility to infection and disease from this virus, pattern of viral shedding, clinical signs, pathological changes and ...201425135340
antimicrobial resistance in wildlife: implications for public health.the emergence and spread of antimicrobial-resistant (amr) bacteria in natural environments is a major concern with serious implications for human and animal health. the aim of this study was to determine the prevalence of amr escherichia coli (e. coli) in wild birds and mammalian species. thirty faecal samples were collected from each of the following wildlife species: herring gulls (larus argentatus), black-headed gulls (larus ridibundus), lesser black-back gulls (larus fuscus), hybrid deer spe ...201525639901
long-term effect of serial infections with h13 and h16 low-pathogenic avian influenza viruses in black-headed gulls.infections of domestic and wild birds with low-pathogenic avian influenza viruses (lpaivs) have been associated with protective immunity to subsequent infection. however, the degree and duration of immunity in wild birds from previous lpaiv infection, by the same or a different subtype, are poorly understood. therefore, we inoculated h13n2 (a/black-headed gull/netherlands/7/2009) and h16n3 (a/black-headed gull/netherlands/26/2009) lpaivs into black-headed gulls (chroicocephalus ridibundus), thei ...201526339062
antimicrobial resistance in wildlife: implications for public health.the emergence and spread of antimicrobial-resistant (amr) bacteria in natural environments is a major concern with serious implications for human and animal health. the aim of this study was to determine the prevalence of amr escherichia coli (e. coli) in wild birds and mammalian species. thirty faecal samples were collected from each of the following wildlife species: herring gulls (larus argentatus), black-headed gulls (larus ridibundus), lesser black-back gulls (larus fuscus), hybrid deer spe ...201525639901
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