Branta Leucopsis Research Articles

Impacts of "supermoon" events on the physiology of a wild bird.

The position of the Moon in relation to the Earth and the Sun gives rise to several predictable cycles, and natural changes in nighttime light intensity are known to cause alterations to physiological processes and behaviors in many animals. The limited research undertaken to date on the physiological responses of animals to the lunar illumination has exclusively focused on the synodic lunar cycle (full moon to full moon, or moon phase) but the moon's orbit—its distance from the Earth—may also be relevant. Every month, the moon moves from apogee, its most distant point from Earth—and then to perigee, its closest point to Earth. Here, we studied wild barnacle geese (Branta leucopsis) to investigate the influence of multiple interacting lunar cycles on the physiology of diurnally active animals. Our study, which uses biologging technology to continually monitor body temperature and heart rate for an entire annual cycle, asks whether there is evidence for a physiological response to natural cycles in lunar brightness in wild birds, particularly “supermoon” phenomena, where perigee coincides with a full moon. There was a three‐way interaction between lunar phase, lunar distance, and cloud cover as predictors of nighttime mean body temperature, such that body temperature was highest on clear nights when the full moon coincided with perigee moon. Our study is the first to report the physiological responses of wild birds to “supermoon” events; the wild geese responded to the combination of two independent lunar cycles, by significantly increasing their body temperature at night. That wild birds respond to natural fluctuations in nighttime ambient light levels support the documented responses of many species to anthropogenic sources of artificial light, that birds seem unable to override. As most biological systems are arguably organized foremost by light, this suggests that any interactions between lunar cycles and local weather conditions could have significant impacts on the energy budgets of birds.

Density-dependent population dynamics of a high Arctic capital breeder, the barnacle goose.

Density regulation of the population growth rate occurs through negative feedbacks on underlying vital rates, in response to increasing population size. Here, we examine in a capital breeder how vital rates of different life-history stages, their elasticities and population growth rates are affected by changes in population size. We developed an integrated population model for a local population of Svalbard barnacle geese, Branta leucopsis, using counts, reproductive data and individual-based mark-recapture data (1990-2017) to model age class-specific survival, reproduction and number of individuals. Based on these estimates, we quantified the changes in demographic structure and the effect of population size on age class-specific vital rates and elasticities, as well as the population growth rate. Local density regulation at the breeding grounds acted to reduce population growth through negative effects on reproduction; however, population size could not explain substantial variation in survival rates, although there was some support for density-dependent first-year survival. With the use of prospective perturbation analysis of the density-dependent projection matrix, we show that the elasticities to different vital rates changed as population size increased. As population size approached carrying capacity, the influence of reproductive rates and early-life survival on the population growth rate was reduced, whereas the influence of adult survival increased. A retrospective perturbation analysis revealed that density dependence resulted in a positive contribution of reproductive rates, and a negative contribution of the numbers of individuals in the adult age class, to the realised population growth rate. The patterns of density dependence in this population of barnacle geese were different from those recorded in income breeding birds, where density regulation mainly occurs through an effect on early-life survival. This indicates that the population dynamics of capital breeders, such as the barnacle goose, are likely to be more reproduction-driven than is the case for income breeders.

Effects of fleas on nest success of Arctic barnacle geese: experimentally testing the mechanism

Parasites have detrimental effects on their hosts’ fitness. Therefore, behavioural adaptations have evolved to avoid parasites or, when an individual is already in contact with a parasite, prevent or minimize infections. Such anti‐parasite behaviours can be very effective, but can also be costly for the host. Specifically, ectoparasites can elicit strong host anti‐parasite behaviours and interactions between fleas (Siphonaptera) and their hosts are one of the best studied. In altricial bird species, nest fleas can negatively affect both parent and offspring fitness components. However, knowledge on the effects of fleas on precocial bird species is scarce. Research on geese in the Canadian Arctic indicated that fleas have a negative impact on reproductive success. One possible hypothesis is that fleas may affect female incubation behaviour. Breeding females with many fleas in their nest may increase the frequency and/or duration of incubation breaks and could even totally desert their nest. The aim of our study was to 1) determine if a similar negative relationship existed between flea abundance and reproductive success in our study colony of Arctic breeding barnacle geeseBranta leucopsisand 2) experimentally quantify if such effects could be explained by a negative effect of nest fleas on female behaviour. We compared host anti‐parasite and incubation behaviour between experimentally flea‐reduced and control nests using wildlife cameras and temperature loggers. We found that flea abundance was negatively associated with hatching success. We found little experimental support, however, for changes in behaviour of the breeding female as a possible mechanism to explain this effect.

Potential Effect of Migration Strategy on Pollutant Occurrence in Eggs of Arctic Breeding Barnacle Geese ( Branta leucopsis).

Arctic-breeding geese acquire resources for egg production from overwintering grounds, spring stopover sites and breeding grounds, where pollutant exposure may differ. We investigated the effect of migration strategy on pollutant occurrence of lipophilic polychlorinated biphenyls (PCBs) and protein-associated poly- and perfluoroalkyl substances (PFASs) and mercury (Hg) in eggs of herbivorous barnacle geese ( Branta leucopsis) from an island colony on Svalbard. Stable isotopes (δ13C and δ15N) in eggs and vegetation collected along the migration route were similar. Pollutant concentrations in eggs were low, reflecting their terrestrial diet (∑PCB = 1.23 ± 0.80 ng/g ww; ∑PFAS = 1.21 ± 2.97 ng/g ww; Hg = 20.17 ± 7.52 ng/g dw). PCB concentrations in eggs increased with later hatch date, independent of lipid content which also increased over time. Some females may remobilize and transfer more PCBs to their eggs, by delaying migration several weeks, relying on more polluted and stored resources, or being in poor body condition when arriving at the breeding grounds. PFAS and Hg occurrence in eggs did not change throughout the breeding season, suggesting migration has a greater effect on lipophilic pollutants. Pollutant exposure during offspring production in arctic-breeding migrants may result in different profiles, with effects becoming more apparent with increasing trophic levels.

Birds in Medieval English Poetry: Metaphors, Realities, Transformations by Michael J. Warren

Reviewed by: Birds in Medieval English Poetry: Metaphors, Realities, Transformations by Michael J. Warren Wendy Matlock Michael J. Warren. Birds in Medieval English Poetry: Metaphors, Realities, Transformations. Cambridge: D. S. Brewer, 2018. Pp. 269. $99.00. Birds have fascinated medievalists since before the "animal turn"— witness Beryl Rowland's Birds with Human Souls (1978)—and monographs on the subject have proliferated since scholars such as Jeffrey Jerome Cohen, Gillian Rudd, and Dorothy Yamamoto invited us to engage with nature. Michael J. Warren's Birds in Medieval English Poetry is a welcome addition to such scholarship. Warren is familiar with theoretical work by Gilles Deleuze and Félix Guattari, Jacques Derrida, and Claude Lévi-Strauss, and well-versed in ornithology, but his argument relies on careful and nuanced close readings of five early English poems. Warren maintains that birds in these poems cannot be read as purely metaphorical, and so scholars must attend to how they reveal real birds in ways that "hint at diverse, interpenetrating orientations" where "natural and cultural histories overlap, reciprocate and interweave" (5). After an introduction, Warren focuses each chapter around a central poetic work: (1) The Seafarer, (2) the Exeter Book Riddles, (3) The Owl and the Nightingale, (4) Chaucer's Parliament of Fowls, and (5) the "Tale of Tereus" in Gower's Confessio Amantis. Reveling in contact between human and avian, between bodies and thought, and between science and art, Birds in Medieval English Poetry attends to both allegorical figuration and natural philosophy to argue [End Page 436] that because birds resist categorization with their penchant for transformation via flight, migration, molting, singing, and oviparous reproduction, they are "crucial to the potentialities, effects and limitations" of human imagination and experience (18). As Warren explains near the end of the Chaucer chapter, "If animal imagery has long been understood as casting the nonhuman in human terms in order to explore human matters, sometimes we catch something of the animal terms, too, reversing our attempts to superimpose so that some of what we intend for the human tenor … rubs off on the feathered vehicle" (175). In essence, Warren enacts the Nightingale's reminder that fables are never completely fictional (line 128 in The Owl and the Nightingale), taking medieval ornithology seriously while also giving due diligence to medieval secular and religious concerns and to modern scholarly debates. Chapter 1 begins with Bede's story of the sparrow from the Historia ecclesiastica to establish a connection between bird and soul in biblical and Anglo-Saxon allegory that is relevant for understanding The Seafarer: "As in the famous sparrow analogy, we encounter the same fluctuations between hall-life and the daunting outside world, the mind that weighs up the two in opposition, and birds that are associated with both these worlds" (28). This foundation allows Warren to read the poem as a unified whole, whereby "a curious avian materiality" inhabits both the naming of seabirds in the ocean setting at the beginning of the poem and the figure of the lone-flier that marks the turn from seascape to contemptus mundi (29). Attending to bird habits and habitations, Warren reads both passages as simultaneously "factual and figurative," so that the obscurity of the afterlife inheres in the acknowledgment that birds cannot replace human companions in the first passage (63). Literal and figurative modes converge to reveal that the deprivation and loneliness of embodied physical journeying prepare the speaker for a posthumous unknown. Building on observations about avian foreignness, Chapter 2 argues that "in being both nameable and anonymous [birds] suit riddles' tendencies to obfuscate and disambiguate concurrently" (66). When combined with the lack of solutions in the Exeter manuscript, the swan (Riddle 7), the barnacle goose (Riddle 24), the jay (Riddle 8), the elusive Riddle 57, and especially the fingers and quill of Riddle 51, for Warren, "encourage willingness to admit uncertainties, to recognize but not circumscribe the web of sprawling, inclusive contiguities between animate [End Page 437] and inanimate individuals" (84). Birds, like riddles, then, inspire wonder and irresolution. The Owl and the Nightingale, subject of Chapter 3, depicts a famously unresolved debate, and Warren offers new insight into how the poem intertwines "the natural...

Stress behaviour and physiology of developing Arctic barnacle goslings ( Branta leucopsis) is affected by legacy trace contaminants.

Natural populations are persistently exposed to environmental pollution, which may adversely impact animal physiology and behaviour and even compromise survival. Responding appropriately to any stressor ultimately might tip the scales for survival, as mistimed behaviour and inadequate physiological responses may be detrimental. Yet effects of legacy contamination on immediate physiological and behavioural stress coping abilities during acute stress are virtually unknown. Here, we assessed these effects in barnacle goslings (Branta leucopsis) at a historical coal mine site in the Arctic. For three weeks we led human-imprinted goslings, collected from nests in unpolluted areas, to feed in an abandoned coal mining area, where they were exposed to trace metals. As control we led their siblings to feed on clean grounds. After submitting both groups to three well-established stress tests (group isolation, individual isolation, on-back restraint), control goslings behaved calmer and excreted lower levels of corticosterone metabolites. Thus, legacy contamination may decisively change stress physiology and behaviour in long-lived vertebrates exposed at a young age.

Rare birds in Slovenia in 2017 –Slovenian Rarities Committee's Report

Summary This report by the Slovenian Rarities Committee presents records of rare bird species in Slovenia in 2017, with some addenda for previous years. The numbers in brackets refer to the number of records (first number) and individuals (second number) recorded between 1 Jan 1950 and 31 Dec 2016. Since 1 Jan 2013, submission to the Committee has been required for 37 additional species, 17 of which are regional rarities. Records of these species are not numbered, since records from previous years were not collected by the Committee. The Barnacle Goose Branta leucopsis was first recorded in Category A, in addition to previous Category D and E records. Other notable observations were the third record of Red-breasted Goose Branta ruficollis, fifth records of Lammergeier Gypaetus barbatus and Pomarine Skua Stercorarius pomarinus, and seventh records of Greater Blackbacked Gull Larus marinus and Red Phalarope Phalaropus fulicarius. The list of birds recorded in Slovenia (as of 31 Dec 2017) contains 390 species (375 in Category A, 6 in Category B, 9 exclusively in Category C; 4 species are both in Categories A and C). Category D contains 7 species, while Category E contains 39, two of which are classified into Subcategory E*. These two categories are not part of the list.

Flight feather moult drives minimum daily heart rate in wild geese.

Waterfowl undergo an annual simultaneous flight-feather moult that renders them flightless for the duration of the regrowth of the flight feathers. In the wild, this period of flightlessness could restrict the capacity of moulting birds to forage and escape predation. Selection might therefore favour a short moult, but feather growth is constrained and presumably energetically demanding. We therefore tested the hypothesis that for birds that undergo a simultaneous flight-feather moult, this would be the period in the annual cycle with the highest minimum daily heart rates, reflecting these increased energetic demands. Implantable heart rate data loggers were used to record year-round heart rate in six wild barnacle geese (Branta leucopsis), a species that undergoes a simultaneous flight-feather moult. The mean minimum daily heart rate was calculated for each individual bird over an 11-month period, and the annual cycle was divided into seasons based on the life-history of the birds. Mean minimum daily heart rate varied significantly between seasons and was significantly elevated during wing moult, to 200 ± 32 beats min-1, compared to all other seasons of the annual cycle, including both the spring and autumn migrations. The increase in minimum daily heart rate during moult is likely due to feather synthesis, thermoregulation and the reallocation of minerals and protein.

Arctic Geese Tune Migration to a Warming Climate but Still Suffer from a Phenological Mismatch

Climate warming challenges animals to advance their timing of reproduction [1], but many animals appear to be unable to advance at the same rate as their food species [2, 3]. As a result, mismatches can arise between the moment of largest food requirements for their offspring and peak food availability [4-6], with important fitness consequences [7]. For long-distance migrants, adjustment of phenology to climate warming may be hampered by their inability to predict the optimal timing of arrival at the breeding grounds from their wintering grounds [8]. Arrival can be advanced if birds accelerate migration by reducing time on stopover sites [9, 10], but a recent study suggests that most long-distance migrants are on too tight a schedule to do so [11]. This may be different for capital-breeding migrants, which use stopovers not only to fuel migration but also to acquire body stores needed for reproduction [12-14]. By combining multiple years of tracking and reproduction data, we show that a long-distance migratory bird (the barnacle goose, Branta leucopsis) accelerates its 3,000km spring migration to advance arrival on its rapidly warming Arctic breeding grounds. As egg laying has advanced much less than arrival, they still encounter a phenological mismatch that reduces offspring survival. A shift toward using more local resources for reproduction suggests that geese first need to refuel body stores at the breeding grounds after accelerated migration. Although flexibility in body store use allows migrants to accelerate migration, this cannot solve the time constraint they are facing under climate warming.

Can common forest bird species tolerate disturbances in neighbouring areas? A case study of the Vuosaari Harbour construction in southern Finland

We studied the population growth and expansion of Barnacle Goose (Branta leucopsis) in Helsinki archipelago, southern Finland. Barnacle Goose breeding was first recorded in Helsinki in 1989. During our study 1996–2013 the number of nesting geese increased from 24 to 740 pairs.We analyzed the role of protected islands in the population growth, and the factors behind differences in growth rates. Our study data consisted of 104 islands. Of these, 29 are protected from private recreational activity (nature reserve ormilitary areas) and were established prior to the start of our study.We predicted that protected areas would have a positive impact on Barnacle Goose population growth. In part of the study period (2002–2013) the population growth in our study area was much steeper in protected islands compared to islands with open access.Results indicate that early breeders likeBarnacleGeese do not benefit from island protection probably because the recreational use of the islands is scant early in the spring.

Avian Influenza Virus Surveillance in High Arctic Breeding Geese, Greenland.

The connectedness in Arctic regions between migratory waterbird populations originating from different continents and the potential for virus exchange at their shared Arctic breeding ground point to the need to explore the largely unstudied circumpolar circulation of avian influenza viruses (AIV). We here report the investigation of AIV in wild birds and lakes in a high Arctic area of Northeast Greenland. No AIV could be detected in the fecal, feather, and water samples collected from large flocks of pink-footed geese Anser brachyrhynchus and barnacle geese Branta leucopsis in and around refuge lakes, where they congregate at high density during their flightless molting period in summer.

Nesting of Barnacle Goose (<i>Branta leucopsis</i>) in the Russian Part of the Gulf of Finland

Until the end of the 1980s, the Barnacle Goose (Branta leucopsis) was an extremely rare migrating species in the Russian part of the Gulf of Finland, but in recent years it has become one of the mass migrants there. The first nest of a Barnacle Goose in the region was found on Dolgy Reef Island close to the Russian-Finnish border in 1995. Barnacle Geese then started expanding onto the islands in the eastern part of the Gulf of Finland. They occupied islands mostly in the northern part of the gulf, but nests were found in its central parts and close to the southwest coast as well. Barnacle Geese nested mostly on small, rocky, forest-free islands. By 2006, the size of the breeding population of this species had increased to 31 pairs. Forty nests were found in 2014, and an explosive population growth to 76 nests was observed in 2015. In 2010, Barnacle Geese started to breed on Ladoga Lake, and in 2015 the first nest was found on Onega Lake. Until 2010 Barnacle Geese had nested in the eastern part of the Gulf of Finland almost exclusively on the islands lying at a distance of 2.4 – 10.1 km from the coast. The population growth that occurred in subsequent years was due primarily to the birds’ breeding on islands closest to the coast, no farther than 2 km away from the shore. After hatching, broods from inshore islets moved to feed on coastal meadows, but nonbreeding birds and failed breeders generally remained on offshore islands for the molting period. Further expansion of the Barnacle Goose in the eastern part of the Gulf of Finland is expected. However, expansion could ultimately be restricted by the limited food resources for broods and molting birds.

Migratory birds are the source of highly toxic organic pollutants for indigenous people in the Russian Arctic

Polychlorinated biphenyls are highly toxic organic contaminants. Due to their chemical properties they had wide application in industry and agriculture in the 20th century. In 2001 the production of PCBs has been prohibited almost worldwide. Environmental contamination has been found in soils, water, and air where there were PCB production sites. They have been detected in fish, birds and animals of migratory species, retaining transboarding transfer. Several migratory species of birds (Taiga bean goose, greater white-fronted goose, lesser white fronted goose and barnacle goose) are a diet for indigenous people. PCBs accumulating in the human body affect all systems and organs. This article reviews the contribution of migratory bird species in transboarding transfer of highly toxic contaminants in the Nenets Autonomous Area, Kolguev island (Russian Arctic).

The Barnacle Goose (Branta leucopsis) in the archipelago of southern Finland – population growth and nesting dispersal

Urbanization and other human activities can lead to decreasing animal populations in nearby areas. The impact of human activities may vary depending on the characteristics of the areas and region or on the strength of the disturbance. We investigated forest bird population changes in an EU Natura 2000 area during the construction of the new Helsinki Vuosaari Harbour in southern Finland in 2002-2011 as part of an environmental impact assessment. We evaluated whether the changes observed were linked with the harbour construction work by comparing the populations at sites near the development with those corresponding values obtained from national common bird monitoring in southern Finland. The mean population changes of 23 boreal forest bird species that inhabited the Natura 2000 area and southern Finland were significantly and positively correlated, but the population inside the Natura 2000 study area also showed lower mean numbers (a mean decline of 9% occurred over the study period). Our case study emphasizes the importance of intensive monitoring before, during and after work at the construction site and in the surrounding areas to detect actual changes in the populations.

Mercury associated neurochemical response in Arctic barnacle goslings (Branta leucopsis)

There remains great concern over mercury pollution in the Arctic, though relatively little is known about impacts on biota that inhabit Arctic terrestrial systems. To help address this, the current study was performed with barnacle goslings (Branta leucopsis) from a coal mine-impacted site and a control site near Ny-Ålesund, Spitsbergen (Svalbard). The works focused mainly on mercury, as coal contains trace levels of this element. Total mercury concentrations were quantified in soil and vegetation from the two sites, as well as feces and liver from the goslings. Next, the mercury exposures were related to dopamine 2 (D2)- and NMDA-receptors in the brain, given that mercury is a proven neurotoxicant. Soil and vegetation in the mining area contained mercury levels that were approximately 3- and 2.2-times higher than in the control site. Despite a significant difference between the sites, the soil and vegetation mercury levels where were within ranges found at other Arctic locations. Goslings grazing in the mine-impacted area contained significantly higher hepatic mercury levels than those sampled from the control site. Compared to other species, the hepatic concentrations were relatively low possibly due to dilution of the mercury in growing goslings (growth dilution) and deposition of mercury in the growing feathers. Hepatic mercury concentrations were positively related to D2-neuroreceptor levels but not to NMDA-receptor levels thus suggesting a possible subtle neurological effect. To our knowledge, this is among the first studies on mercury exposure in Arctic terrestrial organisms, and one of the first to document potential subtle neurological responses associated with exposure to low, environmentally relevant mercury levels, which also can be found at other locations in the Arctic. However, as a pilot effort, the results here need to be examined in additional studies that include, for example, lager study designs, different geographic sites and other terrestrial species.

High goose abundance reduces nest predation risk in a simple rodent-free high-Arctic ecosystem

Breeding geese are the preferred prey of the Arctic fox Vulpes lagopus in the high-Arctic Svalbard archipelago. According to the apparent competition hypothesis (ACH), less-abundant prey species (e.g. ptarmigan, waders and small passerines) will experience higher predation rates when breeding in association with the more common prey (geese), due to spill-over predation by the shared predator. As many of these less-abundant species are endemic and/or red-listed, increased predation can have negative repercussions on their populations. We used a one-year baited artificial nest study to assess relative nest predation risk on Svalbard Rock Ptarmigan Lagopus muta hyperborea, small waders (Purple Sandpiper Calidris maritima, Dunlin Calidris alpina, plovers Charadrius spp., and phalaropes Phalaropus spp.) and Snow bunting Plectrophenax nivalis in two study locations contrasted by nesting density of Arctic breeding geese (Pink-footed Goose Anser brachyrhynchus and Barnacle Goose Branta leucopsis). We predicted higher predation risk for the less-abundant species in the study location with higher goose abundance. However, we found that relative nest predation risk was lower in the study location with higher goose abundance, thus being compatible with apparent mutualism and/or prey swamping mechanisms. Our results contrast with those from more structurally complex Arctic ecosystems and suggest that allochtonous subsidies from temperate ecosystems structure the predation pattern in this high-Arctic tundra ecosystem.

Results of the January 2017 waterbird census in Slovenia

Summary In 2017, the International Waterbird Census (IWC) was carried out in Slovenia on January 14 and 15. Waterbirds were counted on all larger rivers, along the entire Slovenian Coastland and on most of the major standing waters in the country. During the census, in which 235 observers took part, 413 sections of the rivers and coastal sea with a total length of 1,427 km and 200 other localities (164 standing waters and 36 streams) were surveyed. The census was characterized by harsh winter conditions and high proportion of frozen water bodies. Altogether, 51,790 waterbirds of 61 species were counted. Thus, the number of waterbirds and the number of species recorded were close to the 21-year average. The highest numbers of waterbirds were counted in the Drava count area, i.e. 20,064 individuals (38.7% of all waterbirds in Slovenia). By far the most numerous species was Mallard Anas platyrhynchos (46.1% of all waterbirds), followed by Coot Fulica atra (6.8% of all waterbirds), Cormorant Phalacrocorax carbo (5.9% of all waterbirds), Black-headed Gull Chroicocephalus ridibundus (5.7% of all waterbirds) and Mute Swan Cygnus olor (3.9% of all waterbirds). The number of 1,000 counted individuals was also surpassed by Yellow-legged Gull Larus michahellis, Teal An. crecca, Tufted Duck Aythya fuligula, White-fronted Goose Anser albifrons, Pygmy Cormorant P. pygmeus and Grey Heron Ardea cinerea. Among the rarer recorded species, the Red-breasted Goose Branta ruficollis (registered for the first time during the January Waterbird Censuses and only for the third time ever in Slovenia) and Barnacle Goose Branta leucopsis (the first probable A category individual for IWC and Slovenia) deserve special mention. Numbers of the following species were the highest so far recorded during the IWC: Mandarin Duck Aix galericulata (together with 2006 and 2012), Pintail An. acuta, Ferruginous Duck Ay. nyroca, Long-tailed Duck Clangula hyemalis (together with 2003), Goosander Mergus merganser, Pygmy Cormorant, Herring Gull L. argentatus and Caspian Gull L. cachinnans. Number of Pochards Ay. ferina was the lowest so far recorded during the IWC.

A history of hybrids? Genomic patterns of introgression in the True Geese

BackgroundThe impacts of hybridization on the process of speciation are manifold, leading to distinct patterns across the genome. Genetic differentiation accumulates in certain genomic regions, while divergence is hampered in other regions by homogenizing gene flow, resulting in a heterogeneous genomic landscape. A consequence of this heterogeneity is that genomes are mosaics of different gene histories that can be compared to unravel complex speciation and hybridization events. However, incomplete lineage sorting (often the outcome of rapid speciation) can result in similar patterns. New statistical techniques, such as the D-statistic and hybridization networks, can be applied to disentangle the contributions of hybridization and incomplete lineage sorting. We unravel patterns of hybridization and incomplete lineage sorting during and after the diversification of the True Geese (family Anatidae, tribe Anserini, genera Anser and Branta) using an exon-based hybridization network approach and taking advantage of discordant gene tree histories by re-sequencing all taxa of this clade. In addition, we determine the timing of introgression and reconstruct historical effective population sizes for all goose species to infer which demographic or biogeographic factors might explain the observed patterns of introgression.ResultsWe find indications for ancient interspecific gene flow during the diversification of the True Geese and were able to pinpoint several putative hybridization events. Specifically, in the genus Branta, both the ancestor of the White-cheeked Geese (Hawaiian Goose, Canada Goose, Cackling Goose and Barnacle Goose) and the ancestor of the Brent Goose hybridized with Red-breasted Goose. One hybridization network suggests a hybrid origin for the Red-breasted Goose, but this scenario seems unlikely and it not supported by the D-statistic analysis. The complex, highly reticulated evolutionary history of the genus Anser hampered the estimation of ancient hybridization events by means of hybridization networks. The reconstruction of historical effective population sizes shows that most species showed a steady increase during the Pliocene and Pleistocene. These large effective population sizes might have facilitated contact between diverging goose species, resulting in the establishment of hybrid zones and consequent gene flow.ConclusionsOur analyses suggest that the evolutionary history of the True Geese is influenced by introgressive hybridization. The approach that we have used, based on genome-wide phylogenetic incongruence and network analyses, will be a useful procedure to reconstruct the complex evolutionary histories of many naturally hybridizing species groups.

The changing environment of conservation conflict: Geese and farming in Scotland

Abstract Conflict between conservation objectives and human livelihoods is ubiquitous and can be highly damaging, but the processes generating it are poorly understood. Ecological elements are central to conservation conflict, and changes in their dynamics — for instance due to anthropogenic environmental change — are likely to influence the emergence of serious human–wildlife impacts and, consequently, social conflict. We used mixed‐effects models to examine the drivers of historic spatio‐temporal dynamics in numbers of Greenland barnacle geese (Branta leucopsis) on the Scottish island of Islay to identify the ecological processes that have shaped the environment in which conflict between goose conservation and agriculture has been triggered. Barnacle goose numbers on Islay increased from 20,000 to 43,000 between 1987 and 2016. Over the same period, the area of improved grassland increased, the number of sheep decreased and the climate warmed. Goose population growth was strongly linked to the increasing area of improved grassland, which provided geese with more high quality forage. Changing climatic conditions, particularly warming temperatures on Islay and breeding grounds in Greenland, have also boosted goose numbers. As the goose population has grown, farms have supported geese more frequently and in larger numbers, with subsequent damaging effects on grassland. The creation of high‐quality grassland appears to have largely driven the problem of serious economic damage by geese. Our analysis also reveals the drivers of spatial variation in goose impacts: geese were more likely to occur on farms closer to roosts and those with more improved grassland. However, as geese numbers have increased they have spread to previously less favoured farms. Synthesis and applications. Our study demonstrates the primary role of habitat modification in the emergence of conflict between goose conservation and agriculture, alongside a secondary role of climate change. Our research illustrates the value of exploring socio‐ecological history to understand the processes leading to conservation conflict. In doing so, we identify those elements that are more controllable, such as local habitat management, and less controllable, such as climate change, but which both need to be taken into account when managing conservation conflict.

Diel pattern of corticosterone metabolites in Arctic barnacle goslings (Branta leucopsis) under continuous natural light.

Here we describe the excretion pattern of corticosterone metabolites collected from droppings in barnacle goslings (Branta leucopsis) raised under 24 hours of continuous natural light in the Arctic. In lower latitudes, circulating corticosterone peaks around waking and shows a nadir between midnight and 4:00, whereas the peak and nadir are time-delayed slightly when measuring corticosterone metabolites from droppings. Photoperiod, along with other environmental factors, helps to entrain an animal’s endogenous rhythm to that of the natural world. North of the Arctic Circle, photoperiod may not be a reliable cue as light is continuously absent during the winter and continuously present during the summer. Here, for the first time, we used droppings to describe a 24-hour excretion pattern of corticosterone metabolites (CORTm). By applying circular statistics for dependent data, we found a diel rhythmic pattern even under continuous natural light. We discuss potential alternative ‘Zeitgeber’ that may function even in the polar regions, focusing on melatonin. We propose a line of research to measure melatonin non-invasively from droppings. We also provide a validation of the adopted enzyme immunoassay (EIA) that was originally developed for greylag geese.