| [the aerobic bacterial intestinal flora of various wintering geese species]. | the aerobic fecal flora of wintering brent goos (branta bernicla), barnacle goose (branta leucopsis), greylag goose (anser anser), white-fronted goose (anser albifrons), pink-footed goose (anser brachyrhynchus), and bean goose (anser fabalis) was studied. there were no specific differences between the various geese. bacterial counts were in the range of 10(5)-10(7) cpu per gram of feces. neither pathogenic bacteria nor rotavirus could be detected in the fecal samples of the wintering geese, so t ... | 1982 | 7136353 |
| [helminth fauna anseriformes (aves) in the lodz zoological garden]. | in the years 1959-1990 429 birds on 30 species of anseriformes were examined post mortem at zoo lódź. the helminths were found in 108 birds (25.17%) of 19 species. in infected birds there were found 4 species of trematodes: one of them, catatropis verrucosa is in poland new for cygnus olor; 9 species of cestodes--7 of them are in poland new for examined hosts; namely: drepanidotaenia lanceolata for dendrocygna viduata, cygnus atratus, branta bernicla, and anas platyrhynchos; microsomacanthus par ... | 1997 | 9424942 |
| impacts of man-made landscape features on numbers of estuarine waterbirds at low tide. | the potential impact of human disturbance on wintering waterbirds using intertidal mudflats was considered by relating their numbers to the presence of nearby footpaths, roads, railroads, and towns. data were obtained for six english estuaries from the wetland bird survey low tide count scheme. counts were undertaken monthly from november to february, and data were available for an average of 2.8 years per estuary for the period 1992-1993 to 1999-2000. count sections and the positions of man-mad ... | 2002 | 12402099 |
| effects of el niño on distribution and reproductive performance of black brant. | climate in low-latitude wintering areas may influence temperate and high-latitude breeding populations of birds, but demonstrations of such relationships have been rare because of difficulties in linking wintering with breeding populations. we used long-term aerial surveys in mexican wintering areas and breeding areas in alaska, usa, to assess numbers of black brant (branta bernicla nigricans; hereafter brant) on their principal wintering and breeding area in el niño and non-el niño years. we us ... | 2006 | 16634306 |
| insights into antimicrobial resistance among long distance migratory east canadian high arctic light-bellied brent geese (branta bernicla hrota). | antimicrobial resistance (amr) is the most significant threat to global public health and ascertaining the role wild birds play in the epidemiology of resistance is critically important. this study investigated the prevalence of amr gram-negative bacteria among long-distance migratory east canadian high arctic (echa) light-bellied brent geese found wintering on the east coast of ireland. | 2015 | 27651892 |
| helminth community structure in two species of arctic-breeding waterfowl. | climate change is occurring rapidly at high latitudes, and subsequent changes in parasite communities may have implications for hosts including wildlife and humans. waterfowl, in particular, harbor numerous parasites and may facilitate parasite movement across broad geographic areas due to migratory movements. however, little is known about helminth community structure of waterfowl at northern latitudes. we investigated the helminth communities of two avian herbivores that breed at high latitude ... | 2016 | 27709067 |
| evidence that life history characteristics of wild birds influence infection and exposure to influenza a viruses. | we report on life history characteristics, temporal, and age-related effects influencing the frequency of occurrence of avian influenza (ai) viruses in four species of migratory geese breeding on the yukon-kuskokwim delta, alaska. emperor geese (chen canagica), cackling geese (branta hutchinsii), greater white-fronted geese (anser albifrons), and black brant (branta bernicla), were all tested for active infection of ai viruses upon arrival in early may, during nesting in june, and while molting ... | 2013 | 23469210 |
| reference intervals for serum biochemistries of molting pacific black brant ( branta bernicla nigricans) in northern alaska, usa. | we determined reference intervals for nine serum biochemistries in samples from 329 molting, after-hatch-year, pacific black brant ( branta bernicla nigricans) in alaska, us. cholesterol and nonesterified fatty acids differed by sex, but no other differences were noted. | 2017 | 28094610 |
| climatic conditions produce contrasting influences on demographic traits in a long-distance arctic migrant. | the manner in which patterns of variation and interactions among demographic rates contribute to population growth rate (λ) is key to understanding how animal populations will respond to changing climatic conditions. migratory species are likely to be particularly sensitive to climatic conditions as they experience a range of different environments throughout their annual cycle. however, few studies have provided fully integrated demographic analyses of migratory populations in response to chang ... | 2017 | 27973683 |
| ultimate regulation of fecundity in species with precocial young: declining marginal value of offspring with increasing brood size does not explain maximal clutch size in black brent geese. | lack 18:125-128 (1967) proposed that clutch size in precocial species was regulated by nutrients available to females during breeding. drent and daan 68:225-252 (1980) proposed the individual optimization hypothesis, whereby individual state determines the optimal combination of breeding date and clutch size. neither hypothesis accounts for variation in nutrients among females at the end of egg laying, strong right truncations in clutch size distributions, or the fact that many species with prec ... | 2017 | 27896480 |
| blood selenium concentrations in female pacific black brant molting in arctic alaska: relationships with age and habitat salinity. | blood samples collected from 81 female pacific black brant (branta bernicla nigricans) molting near teshekpuk lake, alaska, were analyzed for selenium concentration. the concentration of selenium in blood of after second year (hatched two or more years ago) females (0.84μg/g wet weight) was significantly greater than the concentration in second year (hatched the previous year) females (0.61μg/g wet weight). the concentrations of selenium we found in blood of black brant were 1.5 to 2 times great ... | 2016 | 27381988 |
| a tree of geese: a phylogenomic perspective on the evolutionary history of true geese. | phylogenetic incongruence can be caused by analytical shortcomings or can be the result of biological processes, such as hybridization, incomplete lineage sorting and gene duplication. differentiation between these causes of incongruence is essential to unravel complex speciation and diversification events. the phylogeny of the true geese (tribe anserini, anatidae, anseriformes) was, until now, contentious, i.e., the phylogenetic relationships and the timing of divergence between the different g ... | 2016 | 27233434 |
| a likelihood-based approach for assessment of extra-pair paternity and conspecific brood parasitism in natural populations. | genotypes are frequently used to assess alternative reproductive strategies such as extra-pair paternity and conspecific brood parasitism in wild populations. however, such analyses are vulnerable to genotyping error or molecular artefacts that can bias results. for example, when using multilocus microsatellite data, a mismatch at a single locus, suggesting the offspring was not directly related to its putative parents, can occur quite commonly even when the offspring is truly related. some rece ... | 2015 | 24989354 |
| individual heterogeneity in black brant survival and recruitment with implications for harvest dynamics. | we examined individual heterogeneity in survival and recruitment of female pacific black brant (branta bernicla nigricans) using frailty models adapted to a capture-mark-recapture context. our main objectives were (1) to quantify levels of heterogeneity and examine factors affecting heterogeneity, and (2) model the effects of individual heterogeneity on harvest dynamics through matrix models. we used 24 years of data on brant marked and recaptured at the tutakoke river colony, ak. multievent mod ... | 2013 | 24324858 |
| [habitat use patterns of the black brant branta bernicla nigricans (anseriformes: anatidae) in natural and artificial areas of guerrero negro, baja california sur, mexico]. | the black brant is a common inhabitant of the western artic american tundra, which migrates to southern pacific coasts during the winter season. approximately, 31000 birds (31%) constitute the mexican population of brants at guerrero negro, ojo de liebre, and exportadora de sal lagoon complex; nevertheless, there is little information about the distribution patterns and zone usage. at guerrero negro lagoon (gnl), ojo de liebre lagoon (oll, both natural sites), and at exportadora de sal (essa, ar ... | 2013 | 23885600 |
| earlier arctic springs cause phenological mismatch in long-distance migrants. | an uneven change in climate across the northern hemisphere might severely affect the phenology of migrating animals, and especially long-distance migrating birds relying on local climatic cues to regulate the timing of migration. we examine the forward displacement of spring in both staging areas and breeding grounds of one such population, the east atlantic light-bellied brent goose branta bernicla hrota, and evaluate to what extent their migration has made a proportional response. on the breed ... | 2013 | 23660701 |
| faltering lemming cycles reduce productivity and population size of a migratory arctic goose species. | the huge changes in population sizes of arctic-nesting geese offer a great opportunity to study population limitation in migratory animals. in geese, population limitation seems to have shifted from wintering to summering grounds. there, in the arctic, climate is rapidly changing, and this may impact reproductive performance, and perhaps population size of geese, both directly (e.g. by changes in snow melt) or indirectly (e.g. by changes in trophic interactions). dark-bellied brent geese (branta ... | 2013 | 23419215 |
| predicted eelgrass response to sea level rise and its availability to foraging black brant in pacific coast estuaries. | managers need to predict how animals will respond to habitat redistributions caused by climate change. our objective was to model the effects of sea level rise on total eelgrass (zostera marina) habitat area and on the amount of that area that is accessible to brant geese (branta bernicla), specialist grazers of eelgrass. digital elevation models were developed for seven estuaries from alaska, washington, california (usa), and mexico. scenarios of future total eelgrass area were derived from com ... | 2012 | 23092012 |
| are there trade-offs between pre- and post-fledging survival in black brent geese? | 1. the growth period is an important determinant of fitness later in life through its effects on first-year survival and future reproduction. choices by adult females about where to rear their offspring strongly affect growth rates and offspring fitness in geese. 2. individual female black brent (branta bernicla nigricans) tend to raise their broods in the same areas each year, and these areas are consistently ranked with respect to growth rates of goslings. therefore, some females consistently ... | 2012 | 22304760 |
| trade-offs between offspring fitness and future reproduction of adult female black brent. | 1. successful reproduction requires numerous decisions, and some of which may require trade-offs between current and future reproduction. we studied effects of choice of foraging patches on gosling growth and future breeding by mothers in black brent (branta bernicla nigricans) geese. 2. specific foraging areas consistently produced high-quality goslings over 21 years. we found a consistent ranking of gosling mass, corrected for age, across brood rearing areas (bras) and years [akaike model weig ... | 2012 | 22303812 |
| carryover effects associated with winter location affect fitness, social status, and population dynamics in a long-distance migrant. | we used observations of individually marked female black brant geese (branta bernicla nigricans; brant) at three wintering lagoons on the pacific coast of baja california-laguna san ignacio (lsi), laguna ojo de liebre (lol), and bahía san quintín (bsq)-and the tutakoke river breeding colony in alaska to assess hypotheses about carryover effects on breeding and distribution of individuals among wintering areas. we estimated transition probabilities from wintering locations to breeding and nonbree ... | 2011 | 22030737 |
| cultural inheritance drives site fidelity and migratory connectivity in a long-distance migrant. | cultural transmission is thought to be a mechanism by which migratory animals settle into habitats, but little evidence exists in wild populations because of the difficulty of following individuals over successive generations and wide geographical distances. cultural inheritance of migration routes represents a mechanism whereby geographical isolation can arise between separate groups and could constrain individuals to potentially suboptimal sites within their range. conversely, adopting the par ... | 2010 | 21083633 |
| dhea levels and social dominance relationships in wintering brent geese (branta bernicla bernicla). | after testosterone, dehydroepiandrosterone (dhea) is the main hormone involved in aggressive behaviour in birds. while the role of dhea has been verified for wintering territorial passerines, it has not been shown for gregarious species. in wintering geese species, both sexes present very low testosterone levels and aggression in a non-sexual context is not testosterone-related. therefore, testosterone does not seem to be responsible for aggressive behaviour by geese during winter and the role o ... | 2009 | 18771715 |
| fidelity and breeding probability related to population density and individual quality in black brent geese branta bernicla nigricans. | 1. patterns of temporary emigration (associated with non-breeding) are important components of variation in individual quality. permanent emigration from the natal area has important implications for both individual fitness and local population dynamics. 2. we estimated both permanent and temporary emigration of black brent geese (branta bernicla nigricans lawrence) from the tutakoke river colony, using observations of marked brent geese on breeding and wintering areas, and recoveries of ringed ... | 2008 | 18479339 |
| factors influencing route choice by avian migrants: a dynamic programming model of pacific brant migration. | we used stochastic dynamic programming to investigate a spectacular migration strategy in the black brant branta bernicla nigricans, a species of goose. black brant migration is well suited for theoretical analysis since there are a number of existing strategies that easily can be compared. in early autumn, almost the entire population of the black brant gathers at izembek lagoon on the alaska peninsula to stage and refuel before the southward migration. there are at least three distinct strateg ... | 2007 | 17920633 |
| temporal and intrapopulation variation in prey choice of wintering geese determined by stable isotope analysis. | 1. individual variability in prey preferences can have marked effects on many demographic parameters from individual survival and fecundity to the vital rates of entire populations. a population level response is ultimately determined by individual prey choices; however, the effect of individual dietary choice is often overlooked. 2. we determined prey choice by individual consumers, light-bellied brent geese branta bernicla, during the overwintering period. two hundred and eighty-one individual ... | 2006 | 16922855 |
| feedback dynamics of grazing lawns: coupling vegetation change with animal growth. | we studied the effects of grazing by black brant (branta bernicla nigricans) geese (hereafter brant) on plant community zonation and gosling growth between 1987 and 2000 at a nesting colony in southwestern alaska. the preferred forage of brant, carex subspathacea, is only found as a grazing lawn. an alternate forage species, c. ramenskii, exists primarily as meadow but also forms grazing lawns when heavily grazed. we mowed plots of ungrazed c. ramenskii meadows to create swards that brant could ... | 2003 | 12684865 |
| aggregative responses of brent geese on salt marsh and their impact on plant community dynamics. | the aggregative responses and habitat preferences of a generalist herbivore, the dark-bellied brent goose branta bernicla bernicla, feeding on salt marshes are examined in relation to vegetation community characteristics and the abundances of individual plant species. in the autumn, feeding was strongly concentrated on the low marsh, which had the highest biomass of the preferred food plant, salicornia europaea. there was a strong aggregative response of the geese to the abundance of s. europaea ... | 1998 | 28307786 |
| spring staging in brent geese branta bernicla: feeding constraints and the impact of diet on the accumulation of body reserves. | the diet composition of brent geese branta bernicla on a salt-marsh was quantified. puccinellia maritima was the principal food species, while plantago maritima and triglochin maritima were less commonly taken. festuca rubra only acted as a substitute for puccinellia when production of the latter species dropped. the metabolizable energy of the food plants ranged from 5 to 11 kj·g(-1). by assessing the ingestion rates of geese feeding on different food species, the net intake rate could be deriv ... | 1991 | 28313347 |
| an outbreak of schistosomiasis in atlantic brant geese, branta bernicla hrota. | a heavy infection with schistosomes of the genera trichobilharzia and dendritobilharzia was considered the cause of 90% mortality in a group of 40 wild-caught atlantic brant geese (branta bernicla hrota) that were maintained in captivity on a fresh-water pond in aurora, ontario. numerous adult worms and eggs were disseminated in many organs throughout the body of all birds examined. the main pathological findings, attributed to both eggs and adults, included emaciation, thrombosis of the caudal ... | 1987 | 3586202 |
| the depletion of algal beds by geese: a predictive model and test. | the short-term impact of herbivores on plant productivity has been well studied. demonstrating long-term effects of grazing on plant populations is much more difficult, but knowledge of such long-term effects is vital in understanding plant-herbivore interactions. we address this issue in a relatively simple plant herbivore system involving the dark-bellied brent goose branta bernicla bernicla and two marine macroalgae, enteromorpha spp. and ulva lactuca, on which the geese graze. in 3 years of ... | 2001 | 28547107 |
| spring temperature, migration chronology, and nutrient allocation to eggs in three species of arctic-nesting geese: implications for resilience to climate warming. | the macronutrients that arctic herbivores invest in their offspring are derived from endogenous reserves of fat and protein (capital) that females build prior to the period of investment or from foods they consume concurrently with investment (income). the relative contribution from each source can be influenced by temporal and environmental constraints on a female's ability to forage on arctic breeding areas. warming temperatures and advancing arctic phenology may alter those constraints. from ... | 2018 | 30092605 |
| does intensive goose grazing affect breeding waders? | increasing goose population sizes gives rise to conflicts with human socioeconomic interests and in some circumstances conservation interests. grazing by high abundances of geese in grasslands is postulated to lead to a very short and homogeneous sward height negatively affecting cover for breeding meadow birds and impacting survival of nests and chicks. we studied the effects of spring grazing barnacle geese branta leucopsis and brent geese branta bernicla on occupancy of extensively farmed fre ... | 2019 | 31938537 |
| mate fidelity improves survival and breeding propensity of a long-lived bird. | evolutionary and behavioural ecologists have long been interested in factors shaping the variation in mating behaviour observed in nature. although much of the research on this topic has focused on the consequences of mate choice and mate change on annual reproductive success, studies of a potential positive link between mate fidelity and adult demographic rates have been comparatively rare. this is particularly true for long-lived birds with multi-year, socially monogamous pair bonds. we used a ... | 2020 | 32596854 |
| consistent measures of oxidative balance predict survival but not reproduction in a long-distance migrant. | physiological processes, including those that disrupt oxidative balance, have been proposed as key to understanding fundamental life-history trade-offs. yet, examination of changes in oxidative balance within wild animals across time, space and major life-history challenges remains uncommon. for example, migration presents substantial physiological challenges for individuals, and data on migratory individuals would provide crucial context for exposing the importance of relationships between oxid ... | 2020 | 32277838 |
| long-term research and hierarchical models reveal consistent fitness costs of being the last egg in a clutch. | maintenance of phenotypic heterogeneity in the face of strong selection is an important component of evolutionary ecology, as are the consequences of such heterogeneity. organisms may experience diminishing returns of increased reproductive allocation as clutch or litter size increases, affecting current and residual reproductive success. given existing uncertainty regarding trade-offs between the quantity and quality of offspring, we sought to examine the potential for diminishing returns on in ... | 2020 | 32248534 |
| sterile traumatic panniculitis in a captive brent goose. | a captive, adult female brent goose (branta bernicla) with a history of severe feather picking by its mate, was presented with 0.5-2.5 cm skin nodules on the head and neck. histologic examination revealed a well-delineated dermal mass that surrounded an intact feather follicle and was composed of lakes of proteinaceous fluid and fibrin with scattered foamy macrophages and multinucleate giant cells. no bacteria or fungi were identified with histology, microbial culture, or pcr. sterile panniculit ... | 2020 | 32100641 |
| estimating correlations among demographic parameters in population models. | estimating correlations among demographic parameters is critical to understanding population dynamics and life-history evolution, where correlations among parameters can inform our understanding of life-history trade-offs, result in effective applied conservation actions, and shed light on evolutionary ecology. the most common approaches rely on the multivariate normal distribution, and its conjugate inverse wishart prior distribution. however, the inverse wishart prior for the covariance matrix ... | 2019 | 31871663 |
| changes in behavior are unable to disrupt a trophic cascade involving a specialist herbivore and its food plant. | changes in ecological conditions can induce changes in behavior and demography of wild organisms, which in turn may influence population dynamics. black brant (branta bernicla nigricans) nesting in colonies on the yukon-kuskokwim delta (ykd) in western alaska have declined substantially (~50%) since the turn of the century. black brant are herbivores that rely heavily on carex subspathacea (hoppner's sedge) during growth and development. the availability of c. subspathacea affects gosling growth ... | 2019 | 31110679 |
| measures of oxidative state are primarily driven by extrinsic factors in a long-distance migrant. | oxidative stress is a likely consequence of hard physical exertion and thus a potential mediator of life-history trade-offs in migratory animals. however, little is known about the relative importance of intrinsic and extrinsic stressors on the oxidative state of individuals in wild populations. we quantified the relationships between air temperature, sex, body condition and three markers of oxidative state (malondialdehyde, superoxide dismutase and total antioxidant capacity) across hundreds of ... | 2019 | 30958216 |
| migratory goose arrival time plays a larger role in influencing forage quality than advancing springs in an arctic coastal wetland. | with warmer springs, herbivores migrating to arctic breeding grounds may experience phenological mismatches between their energy demands and the availability of high quality forage. yet, how the timing of the start of the season and herbivore arrival influences forage quality is often unknown. in coastal western alaska, approximately one million migratory geese arrive each spring to breed, where foliar %n and c:n ratios are linked to gosling survival and population growth. we conducted a three-y ... | 2019 | 30865725 |
| brood size affects future reproduction in a long-lived bird with precocial young. | estimation of trade-offs between current reproduction and future survival and fecundity of long-lived vertebrates is essential to understanding factors that shape optimal reproductive investment. black brant geese (branta bernicla nigricans) fledge more goslings, on average, when their broods are experimentally enlarged to be greater than the most common clutch size of four eggs. thus, we hypothesized that the lesser frequency of brant clutches exceeding four eggs results, at least partially, fr ... | 2019 | 30794452 |