Brent Geese Research Articles

The influence of diet on gut microbiome and body mass dynamics in a capital-breeding migratory bird.

Gut-associated microbial communities are known to play a vital role in the health and fitness of their hosts. Though studies investigating the factors associated with among-individual variation in microbiome structure in wild animal species are increasing, knowledge of this variation at the individual level is scarce, despite the clear link between microbiome and nutritional status uncovered in humans and model organisms. Here, we combine detailed observational data on life history and foraging preference with 16S rRNA profiling of the faecal microbiome to investigate the relationship between diet, microbiome stability and rates of body mass gain in a migratory capital-breeding bird, the light-bellied Brent goose (Branta bernicla hrota). Our findings suggest that generalist feeders have microbiomes that are intermediate in diversity and composition between two foraging specialisms, and also show higher within-individual plasticity. We also suggest a link between foraging phenotype and the rates of mass gain during the spring staging of a capital breeder. This study offers rare insight into individual-level temporal dynamics of the gut microbiome of a wild host. Further work is needed to uncover the functional link between individual dietary choices, gut microbiome structure and stability, and the implications this has for the reproductive success of this capital breeder.

A vadlúd monitoring eredményei a 2020/2021-es idényben Magyarországon

Results of Geese Monitoring in Hungary in the season 2020/2021. The author presents the results of the HUNGARIAN GEESE MONITORING (Table 1.) for 2020/2021 in the form of a data base. After reviewing the basic data recorded at each site of observation (Table 3-21.) he analyse the obtained data separately for each species, i.e. Brent Goose (Branta bernicla) (Table 22., Map 1., Figure 1-2.), Barnacle Goose (Branta leucopsis) (Table 23., Map 2., Figure 3-4.), Red-breasted Goose (Branta ruficollis) (Table 24, Map 3., Figure 5-6.), Bar-headed Goose (Anser indicus) (Table 25, Map 4, Figure 7.), Greylag Goose (Anser anser) (Table 26., Map 5., Figure 8-10.), Tundra Bean Goose (Anser serrirostris rossicus) (Table 27., Map 6., Figure 11-13.), Taiga Bean Goose (Anser fabalis) (Table 28, Map 7, Figure 14.), Pink-footed Goose (Anser brachyrhynchus) (Table 29., Map 8., Figure 15.), White-fronted Goose (Anser albifrons) (Table 30., Map 9., Figure 16-18.), Lesser White-fronted Goose (Anser erythropus) (Table 31., Map 10., Figure 19-20.), as well as for the total of observed geese (Table 32., Figure 21-24.). In respect of dominance – when data recorded monthly in each of the observed sites (Table 3-21., Figure 25.) or those referring to the total of geese present in Hungary (Table 33., Figure 25.) are analysed, it is found that in conformity with the numbers of individuals, also in the season 2020/2021 White-fronted Goose was the most common goose species in Hungary (max. 265 010 birds, max. 96%), followed by Greylag Goose (max. 39 261 birds, max. 100%), Tundra Bean Goose (max. 711 birds, max. 0-1%) ranking third. Dominance of Red-breasted Goose and Lesser White-fronted Goose – both are globally threatened species – ranged both from 0% to <1% (max. 147 and 10 birds). If the data obtained for the season 2020/2021 are fitted into the data series of long-term monitoring, the following conclusions can be drawn from the actual changes in population numbers of the geese species in the Pannon region. In the season 2020/2021, we observed max. 2 Brent Geese, max. 1 Barnacle Goose, max. 1 Bar-headed Goose, max. 1 Pink-footed Goose and max. 6 Taiga Bean Goose. For the globally threatened Red-breasted Goose may be considered higher (+40% – 147 birds) to the maximum counted in the season 2019/2020 (105 birds), but much lower to the record number counted in the season 2014/2015 (1258 birds). Greylag Goose continued to be present with high numbers in Hungary. However, in the new season its peaks (39 261 birds) were found to be higher (+4%) those counted in the previous 2019/2020 season (37 707 birds). Peak number of Tundra Bean Goose (711 birds) was lower (–8%) as the maximum counted in the season 2019/2020 (769 birds). The dramatic decline in the dynamics of the Tundra Bean Goose population continued and stabilized in the Pannon Region. Peak number of White-fronted Goose (265 010 birds) was 5% higher as the maximum counted in 2019/2020 (250 888 birds). For the globally threatened Lesser White-fronted Goose may be considered higher (10 birds) to the maximum counted in the season 2019/2020 (9 birds). The maximum numbers of total geese in the season 2020/2021 registered simultaneously (306 526 birds) was 11% higher to the maximum number of the season 2019/2020 (275 164 birds).

Remote sensing in seagrass ecology: coupled dynamics between migratory herbivorous birds and intertidal meadows observed by satellite during four decades

AbstractTaking into account trophic relationships in seagrass meadows is crucial to explain and predict seagrass temporal trajectories, as well as for implementing and evaluating seagrass conservation policies. However, this type of interaction has been rarely investigated over the long term and at the scale of the whole seagrass habitat. In this work, reciprocal links between an intertidal seagrass species, Zostera noltei, and a herbivorous bird feeding on this seagrass species, the migratory goose Branta bernicla bernicla, were investigated using an original combination of long‐term Earth Observation (EO) and bird census data. Seagrass Essential Biodiversity Variables (EBVs) such as seagrass abundance and phenology were measured from 1985 to 2020 using high‐resolution satellite remote sensing over Bourgneuf Bay (France), and cross‐analysed with in situ measurements of bird population size during the goose wintering season. Our results showed a mutual relationship between seagrass and Brent geese over the four last decades, suggesting that the relationship between the two species extends beyond a simple grass—herbivore consumptive effect. We provided evidence of two types of interactions: (i) a bottom‐up control where the late‐summer seagrass abundance drives the wintering population of herbivorous geese and (ii) an indirect top‐down effect of Brent goose on seagrass habitat, where seagrass development is positively influenced by the bird population during the previous wintering season. Such a mutualistic relationship has strong implications for biodiversity conservation because protecting one species is beneficial to the other one, as demonstrated here by the positive trajectories observed from 1985 to 2020 in both seagrass and bird populations. Importantly, we also demonstrated here that exploring the synergy between EO and in situ bird data can benefit seagrass ecology and ecosystem management.

The influence of migratory birds on the distribution of the seagrass Zostera japonica

Abstract Grazing pressure by animals can change the distribution and biomass of seagrass. We examined grazing pressure by conducting transect surveys and acquiring aerial images by drone before and after the arrival of migratory birds along the Asadokoro tide flats, Aomori Prefecture, Japan. The distribution and biomass of the seagrass Zostera japonica decreased sharply between October and November 2018, which was when migrating waterfowl arrived. We hypothesized that grazing pressure by migrating birds such as the Anatidae, including whooper swans (Cygnus cygnus) and brent geese (Branta bernicla), had a major effect on the decline in Z. japonica in late October. Shortly after the Anatidae arrived, most of the Z. japonica in the shallows disappeared, including the belowground parts. The abundance of Z. japonica in this area was insufficient to support wintering swans. Swans likely need food other than Z. japonica for overwintering.

Evidence of Brent Geese Branta bernicla Moving between an Autumn Staging Area in East Hokkaido and Wintering Sites in West Hokkaido and Northern Honshu

The Brent Goose Branta bernicla population of East Asia is the least studied. We banded 24 Brent Geese at Notsuke Bay, east Hokkaido, Japan, in autumn, and collected six opportunistic sightings of these birds during winter, contributing to an understanding of their migratory movements to wintering sites in Japan. Birds were resighted at five widely distributed wintering sites in west Hokkaido and northeast Honshu. While this study showed that birds moved between Notsuke Bay and wintering sites elsewhere in Japan, further studies are needed to understand the migration patterns and routes used during autumn and spring in East Asia.

‘Come here, it sang, listen’: Juliana Spahr’s commons poetics in That Winter the Wolf Came

ABSTRACT The work of contemporary American poet, critic, and essayist Juliana Spahr is concerned with politically charged questions of connection, collectivity, and community across disparate ontological domains and ecological boundaries. This essay argues that Spahr’s 2015 poetry collection That Winter the Wolf Came, which has to date garnered less critical attention than her previous work, combines lyric, intertextual reference, asequential narrative, parataxis, and other formal techniques and compositional practices into a commons poetics. This poetics, in turn, allows Spahr to effectively represent a commons which finds space for plural subjects as diverse as the activists of the 2011–2012 Occupy Movement, oil rigs, and Brent geese. Despite Spahr’s own fundamental reservations about the political efficacy of poetry, her unique use of lyric, in particular, cultivates radical connections and oppositional tactics for these plural subjects, offering a vision of a utopian commons beyond capitalism.

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 oxidative balance and fitness outcomes. Here we examined the consistency of commonly used measures of oxidative balance in longitudinally sampled free-living individuals of a long-lived, long-distance migrant, the Brent goose Branta bernicla hrota over periods of months to years. Although inter-individual and temporal variation in measures of oxidative balance were substantial, we found high consistency in measures of lipid peroxidation and circulating non-enzymatic antioxidants in longitudinally sampled individuals. This suggests the potential for the existence of individual oxidative phenotypes. Given intra-individual consistency, we then examined how these physiological measures relate to survival and reproductive success across all sampled individuals. Surprisingly, lower survival was predicted for individuals with lower levels of damage, with no measured physiological metric associated with reproductive success. Our results demonstrate that snapshot measurements of a consistent measure of oxidative balance can inform our understanding of differences in a key demographic trait. However, the positive relationship between oxidative damage and survival emphasises the need to investigate the relationships between the oxidative system and fitness outcomes in other species undergoing similar physiologically challenging life cycles. This would highlight the extent to which variation in such traits and resource allocation trade-offs is a result of adaptation to different life-history strategies.

Banding survey at colonies of Brent Goose, <i>Branta bernicla</i> in the Lena Delta, Russia and a recovery record

Banding survey at colonies of Brent Goose, <i>Branta bernicla</i> in the Lena Delta, Russia and a recovery record

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 individuals of a long-distance migrant (the brent goose Branta bernicla hrota) during wintering and spring staging. We found that air temperature and migratory stage were the strongest predictors of oxidative state. This emphasizes the importance of extrinsic factors in regulating the oxidative state of migrating birds, with differential effects across the migration. The significance of abiotic effects demonstrates an additional mechanism by which changing climates may affect migratory costs.

Effects of harness-attached tracking devices on survival, migration, and reproduction in three species of migratory waterfowl

BackgroundTracking devices have enabled researchers to study unique aspects of behavior in birds. However, it has become clear that attaching these devices to birds often affects their survival and behavior. While most studies only focus on negative effects on return rates, tracking devices can also affect the behavior under study, and it is therefore important to measure potential negative effects of tracking device attachment on the full range of behavioral aspects of birds. At the same time, we should aim to improve our current attachment methods to reduce these effects.ResultsWe used a modified harness to attach tracking devices to a total of 111 individuals of three goose species (Greater White-fronted Geese, Brent Geese, and Barnacle Geese) to study their migratory behavior. By creating control groups of birds marked with colored leg bands, geolocators, and/or neck collars, we were able to compare return rates, body condition, and migratory and reproductive behavior, thus allowing a much broader comparison than return rates alone. Birds with harness-attached tracking devices had lower return rates, which could partly be explained by increased rates of divorce, but is likely also the result of reduced survival induced by the harness and device. A comparison between Barnacle Geese equipped with harness-attached tracking devices and individuals fitted with geolocators attached to leg bands showed that birds equipped with tracking devices were only slightly delayed in timing of migration and reproduction and otherwise were not affected in reproductive output.ConclusionsWe argue that tracking devices can be used for studies on migration timing. Nevertheless, given the effect of tracking devices on survival and divorce rate, which may differ between sexes and species, we stress that researchers should carefully consider which birds to tag in order to reduce potential negative effects.

Brent Geese (Branta bernicla) Breeding Associations with Pomarine Skuas (Stercorarius pomarinus) on the Mainland Tundra

This article is based on data that were collected in the years 2000−2007, 2012, and 2014 in the vicinities of Medusa Bay (73°21′ N, 80°32′ E) and in 2002 at the mouth of the Uboynaya River (73°37′ N, 82°10′ E), in the northwestern part of the Taimyr Peninsula. In years when the abundance of lemmings is high, brent geese may breed not only near nests of snowy owls and rough-legged buzzards, but also sparsely in the mainland tundra, often without any protection. Some such nests are successfully incubated until hatching. A considerable part of these dispersed nests appears to be associated with a nest or territory of pomarine skuas that are able to scare away the main tundra predator, the arctic fox, to a distance of about 500 m from their nests. Brent geese that breed within this distance to theses nests gain additional protection against arctic foxes. However, brent geese do not display a tendency to place their nests closer to pomarine skua nests. The mean distance from geese nests to pomarine skua nests or centers of their territories comprised 2/3 of the mean distance between nests of pomarine skuas and turned out to be quite stable over the years and in two different tundra areas.

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.

Spring Migration of Brent Geese Wintering in Japan Extends into Russian High Arctic

Abstract The spring migration routes of the Brent Goose Branta bernicla nigricans wintering in Japan can extend beyond those of earlier-published trajectories from satellite data (Shimada et al. 2016). This conclusion is based on a ring recovered from a goose shot by a hunter, found south of the Lena Delta in the Russian high arctic. Building on the previously published satellite-tracking data from the same population, we suggest that the geese migrate northward in Russia following an interior route along the Lena and Yana rivers after arriving at the northern coast of the Sea of Okhotsk from Japan during spring migration.

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 changing climatic conditions. Here, we employed integrated population models to demonstrate that the environmental conditions experienced during a short but critical period play a central role in the demography of a long-distance migrant, the light-bellied Brent goose (Branta bernicla hrota). Female survival was positively associated with June North Atlantic Oscillation (NAO) values, whereas male survival was not. In contrast, breeding productivity was negatively associated with June NAO, suggesting a trade-off between female survival and reproductive success. Both adult female and adult male survival showed low temporal variation, whereas there was high temporal variation in recruitment and breeding productivity. In addition, while annual population growth was positively correlated with annual breeding productivity, a sensitivity analysis revealed that population growth was most sensitive to changes in adult survival. Our results demonstrate that the environmental conditions experienced during a relatively short-time window at the start of the breeding season play a critical role in shaping the demography of a long-distant Arctic migrant. Crucially, different demographic rates responded in opposing directions to climatic variation, emphasising the need for integrated analysis of multiple demographic traits when understanding population dynamics.

Long-term Patterns of Eelgrass (Zostera marina) Occurrence and Associated Herbivorous Waterbirds in a Danish Coastal Inlet

Seagrasses in coastal areas have substantial importance for the marine environment and also serve as food for herbivorous waterbirds. We investigated potential relationships between the autumn population of herbivorous waterbirds and eelgrass (Zostera marina) abundance in the EU protected area, Nibe-Gjol Bredning, a broad of the Limfjorden estuarine complex in Denmark.This is an important site for migratory herbivorous waterbirds such as mute swan (Cygnus olor), coot (Fulica atra), brent goose (Branta bernicla), and wigeon (Anas penelope). We explored long-term (27 yr) changes in eelgrass and bird-populations and relationships between eelgrass- and bird abundance. We applied trend- and correlative analyses of yearly monitoring data on eelgrass and waterbirds between 1989 and 2015 coupled with estimates of the potential grazing pressure exerted by the birds. Around 1990 eelgrass was abundant in this area covering more than 40 km2, but eelgrass coverage and biomass declined drastically around 1995 and remained low until 2011 when natural recolonization accelerated and by 2015 had restored the lost meadows. The number of herbivorous waterbirds also fluctuated substantially during the monitoring period with large abundance until the mid-end 1990s followed by reduced abundance in the 2000s and recovery after 2010. The number of bird-days showed a positive relationship with the same year’s eelgrass abundance in the 1-2 m depth stratum. For the 0-1 m depth stratum, where the eelgrass meadows are most exposed to bird grazing but also to physical control from e.g. wind and ice, only a particularly detailed eelgrass data set available for a subset of the study period, showed a significant relationship with bird grazing. The potential waterbird consumption of eelgrass, estimated by multiplying average intake rate and number of bird-days for each species, ranged from less than 16 % of the eelgrass biomass in most years to more than 40 % of the eelgrass biomass in years with extremely sparse eelgrass populations. Hence, the study suggests that dense eelgrass populations stimulate herbivorous waterbirds whereas top-down control is only likely when abundant bird populations graze on sparse eelgrass populations.

The spatial structure of the brent (Branta bernicla) and red-breasted (Branta ruficollis) geese (Anseriformes, Anatidae) breeding settlements on Taimyr Peninsula: Single-species colonies and associations with large gulls

The studies were carried out in 2000–2007, 2010 and 2012–2014 along the Agapa River from the upper reaches downstream to the mouth, the western part of the central Taimyr Peninsula, and in the vicinities of the Medusa Bay, in the northwestern part of the Taimyr Peninsula. On the off-shore islands, brent geese nest in pairs or in small groups that join the colonies of the Taimyr herring gull (Larus argentatus taimyrensis). In addition, these geese form their own colonies of several dozens of nests. These colonies are not related to gull colonies even if the latter exist on the same island. Mixed multi-species colonies with the brent goose prevalence are less dense than those where gulls prevail. The gulls that breed near the colonies, where brent geese prevail, place their nests at such distances from the nearest geese nests that are approximately identical to the distances between the nests of brent geese. In the colonies with the prevalence of gulls, brent geese also nest with approximately the same density as gulls, fitting into the colony as a spatially equal element. In the red-breasted geese, in contrast to brent geese, the nesting density does not correspond to that of the gulls. Red-breasted geese behave either as a foreign element within a gull colony and establish their own nests very close to gull nests up to evicting gulls from their places or as outside strangers that breed at some distance from gull colonies.

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 goose species could not be fully resolved. We sequenced nineteen goose genomes (representing seventeen species of which three subspecies of the Brent Goose, Branta bernicla) and used an exon-based phylogenomic approach (41,736 exons, representing 5887 genes) to unravel the evolutionary history of this bird group. We thereby provide general guidance on the combination of whole genome evolutionary analyses and analytical tools for such cases where previous attempts to resolve the phylogenetic history of several taxa could not be unravelled. Identical topologies were obtained using either a concatenation (based upon an alignment of 6,630,626 base pairs) or a coalescent-based consensus method. Two major lineages, corresponding to the genera Anser and Branta, were strongly supported. Within the Branta lineage, the White-cheeked Geese form a well-supported sub-lineage that is sister to the Red-breasted Goose (Branta ruficollis). In addition, two main clades of Anser species could be identified, the White Geese and the Grey Geese. The results from the consensus method suggest that the diversification of the genus Anser is heavily influenced by rapid speciation and by hybridization, which may explain the failure of previous studies to resolve the phylogenetic relationships within this genus. The majority of speciation events took place in the late Pliocene and early Pleistocene (between 4 and 2millionyears ago), conceivably driven by a global cooling trend that led to the establishment of a circumpolar tundra belt and the emergence of temperate grasslands. Our approach will be a fruitful strategy for resolving many other complex evolutionary histories at the level of genera, species, and subspecies.

Determining if Irish Winter Migrant Waterbirds are Changing Their Duration of Stay as Temperature Warms

Changes in the timing of arrival and departure of migrant bird species to and from breeding and wintering grounds in response to rising temperature have often been reported. A recent study from Ireland found earlier indications of spring departure for some waterbirds but not for all. In order to examine if it is possible to determine any change in the length of time these birds spend at their wintering grounds, we examined indicators of the timing of autumn arrival and the subsequent duration of stay. We used the earliest reporter dates in autumn from BirdWatch Ireland's East Coast Bird reports (1980–2003) as an indicator of the timing of arrival and determined the duration of stay as the number of days between arrival and departure for each species. Although these reports did not specifically document earliest and latest dates–and therefore make it difficult to conclusively determine duration of stay–the data extracted may still provide some useful indications of changes in the ‘tails’ of a distribution. Of the nineteen species examined, two arrived earlier and one later, whereas none extended their duration of stay. In addition we analysed average autumn (August-October) and average annual (July-June) temperature from within the study area and correlated these with autumn arrival and duration of stay, respectively. In response to average autumn temperature, two waterfowl (Brent Goose (P = 0.023) and Eurasian Teal (P = 0.037)) delayed arrival by approximately 10 and 11d/°C respectively whereas one wader (Bar-tailed Godwit (P = 0.008)) advanced its arrival by roughly 22d/°C. Even though the majority (six out of eight) of the birds examined revealed a reduction in their duration of stay with increasing annual temperature, none were statistically significant. Due to the highly variable nature of these data, the limitations associated with dealing with the ‘tails’ of a distribution and difficulties with extracting specific earliest and latest records, we recommend using more robust data from dedicated bird observatories where possible. Overall, this analysis revealed the difficulty in finding suitable data by which to examine the influence of climate change on bird migration and highlighted the value of systematically tracking the timing of arrival and departure of a range of bird species as an indication of what may be expected in a warmer future in relation to Ireland's bird diversity.

Satellite-Tracking of the Spring Migration and Habitat Use of the Brent GooseBranta berniclain Japan

Abstract Japan hosts more than 40% population of Brent Goose Branta bernicla wintering in East Asia. We used satellite-tracking technology to monitor the seasonal movements and habitat usage of Brent Goose wintering in northern Japan. We marked five geese on the Oya sandy beach, Miyagi Prefecture, northeast Honshu, on 21 January 2014. The geese utilized areas along the seacoast, especially concentrating at a small bay, close to the capture site. Most of the geese offshore were found at fishery rafts. No geese were found more than 2 km offshore or more than 6 km from the capture site along the seacoast. In early April, the geese left the southern Sanriku coast and moved up to eastern Hokkaido, crossing the sea directly or via the coastal areas of Iwate and Aomori Prefectures. The geese predominantly remained in the vicinity of the Veslovskiy Peninsula, Kunashiri (Kunashir) Island, while some were distributed along the northern coast of the Nemuro Peninsula. We identified eastern Hokkaido and Kunashiri Isla...

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 breeding grounds in Svalbard the onset of spring advanced 2 weeks during the 24-year period, whereas no significant trend was found in the temperate staging areas. The timing of migration was constant throughout the study period, mirroring the static climatic conditions in the spring staging areas. These findings indicate a global warming-induced phenological mismatch in light-bellied brent geese, as these might arrive on their breeding grounds well beyond optimal breeding conditions. Our data indicated that productivity was negatively influenced by phenological delay and positively influenced by prolonged snow cover. We argue that both these effects might be representative of a negative influence of the growing phenological mismatch, because years with later thaw might partly offset the effects of increasingly earlier Svalbard springs. During the study period reproduction fell below annual mortality, and the population declined in recent years. The wider implications of these findings may extend to many migrating species, and highlight the urgent need to clarify how global change may influence cues and the associated timing of important life history activities.