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Demographic links among fragmented populations are commonly studied as source‐sink dynamics, whereby source populations exhibit net recruitment and net emigration, while sinks suffer net mortality but enjoy net immigration. It is commonly assumed that large, persistent aggregations of individuals must be sources, but this ignores the possibility that they are sinks instead, buoyed demographically by immigration. We tested this assumption using Bayesian integrated population modelling of Greenland white‐fronted geese (Anser albifrons flavirostris) at their largest wintering site (Wexford, Ireland), combining capture–mark–recapture, census and recruitment data collected from 1982 to 2010. Management for this subspecies occurs largely on wintering areas; thus, study of source‐sink dynamics of discrete regular wintering units provides unprecedented insights into population regulation and enables identification of likely processes influencing population dynamics at Wexford and among 70 other Greenland white‐fronted goose wintering subpopulations. Using results from integrated population modelling, we parameterized an age‐structured population projection matrix to determine the contribution of movement rates (emigration and immigration), recruitment and mortality to the dynamics of the Wexford subpopulation. Survival estimates for juvenile and adult birds at Wexford and adult birds elsewhere fluctuated over the 29‐year study period, but were not identifiably different. However, per capita recruitment rates at Wexford in later years (post‐1995) were identifiably lower than in earlier years (pre‐1995). The observed persistence of the Wexford subpopulation was only possible with high rates of immigration, which exceeded emigration in each year. Thus, despite its apparent stability, Wexford has functioned as a sink over the entire study period. These results demonstrate that even large subpopulations can potentially be sinks, and that movement dynamics (e.g. immigration) among winters can dramatically obscure key processes driving subpopulation size. Further, novel population models which integrate capture–mark–recapture, census and recruitment data are essential to correctly ascribing source‐sink status and accurately informing development of site‐safeguard networks.

Mass capture of flightless geese during the summer is a common trapping technique to obtain large numbers of individuals for research and marking, but few studies have assessed the impacts of this method on the survival of afterhatch- year geese. We evaluated the effects of holding time and captured flock size on the survival of >26,000 subadult (second yr) and adult (≥third yr) greater white-fronted geese (Anser albifrons frontalis) banded in Alaska, USA, 1999–2017. We constructed models with and without capture effects to analyze our band-recovery data and used Akaike’s Information Criterion to rank our model set. Models that included both capture-related variables ranked highest. Longer individual holding times negatively affected survival during the first year after banding, and effects were greatest during the earliest years of our study when holding times were generally longer and protocols to minimize negative capture effects were less refined. There was a positive relationship between survival and captured flock size. We suggest practitioners reduce holding times of geese during mass captures to the extent practicable and continually evaluate and refine their methods to minimize negative capture effects.

Migratory flyways sustain waterbird populations by linking critical habitats across their annual cycle. However, stage-specific impacts of climate change on these habitats remain poorly understood. We integrated species distribution models with annual migration data from 30 Greater White-fronted Geese (Anser albifrons frontalis) to assess changes in habitat suitability, distributional shifts, and suitability fluctuations across breeding, stopover, and wintering stages under mid-century (2040–2060) climate scenarios. Suitability fluctuations were quantified as the coefficient of variation (CV) in habitat suitability between current and future projections. Projected habitat responses varied markedly across stages: breeding areas contracted by 29.9%, wintering areas expanded by 62.7%, and stopover sites showed minimal net change. Centroids of all habitats are projected to shift northward by mean distances of 125–492 km under future climate scenarios. Breeding habitats exhibited the greatest suitability fluctuations (CV=30–45; ~50% area affected under SSP585), followed by stopover and wintering grounds (CV ≈ 11), with 35.8% and 23.3% of their areas falling within high-fluctuation zones. These findings highlight the urgent need to prioritize breeding habitats, implement stage-specific conservation strategies, and enhance international cooperation to ensure the protection of waterbirds along the East Asian Flyway.

The Scottish island of Islay hosts 45 000 barnacle geese Branta leucopsis (56% of the Greenland barnacle goose population, plus those passing through on migration), 5000 Greenland white-fronted geese Anser albifrons flavirostris (up to 30% of the world population) and 2500 greylag geese Anser anser, most of which feed on 9000 ha of grassland. The financial impacts of estimated agricultural damage have risen greatly over the past 20 years due to increasing goose numbers and higher farming costs. Mechanisms implemented to resolve conflict over time are reviewed for their effectiveness. Emphasis is placed on coordinating the implementation of strategic national conflict resolution at a local scale where the relative pressure from internationally important concentrations of geese on agriculture is acute. Despite the \"local\" nature of this problem, the benefit from the experience of decades of attempted conflict resolution and the effectiveness of existing programmes can contribute much to the regional and flyway dimensions of this international issue.

Dispersal and migratory behavior are influential factors in determining how genetic diversity is distributed across the landscape. In migratory species, genetic structure can be promoted via several mechanisms including fidelity to distinct migratory routes. Particularly within North America, waterfowl management units have been delineated according to distinct longitudinal migratory flyways supported by banding data and other direct evidence. The greater white‐fronted goose (Anser albifrons) is a migratory waterfowl species with a largely circumpolar distribution consisting of up to six subspecies roughly corresponding to phenotypic variation. We examined the rangewide population genetic structure of greater white‐fronted geese using mtDNA control region sequence data and microsatellite loci from 23 locales across North America and Eurasia. We found significant differentiation in mtDNA between sampling locales with flyway delineation explaining a significant portion of the observed genetic variation (~12%). This is concordant with band recovery data which shows little interflyway or intercontinental movements. However, microsatellite loci revealed little genetic structure suggesting a panmictic population across most of the Arctic. As with many high‐latitude species, Beringia appears to have played a role in the diversification of this species. A common Beringian origin of North America and Asian populations and a recent divergence could at least partly explain the general lack of structure at nuclear markers. Further, our results do not provide strong support for the various taxonomic proposals for this species except for supporting the distinctness of two isolated breeding populations within Cook Inlet, Alaska (A. a. elgasi) and Greenland (A. a. flavirostris), consistent with their subspecies status. We found significant portion of genetic variation (~12%) was explained by flyway delineation. Band recovery data revealed that approximately 1% of banded greater white‐fronted geese switched flyways. This high level of flyway fidelity may be due to life‐history characteristics of geese such as long‐term pair bands and familial associations.

Hybridization between birds in wild nature is an interesting phenomenon in the wild, but not common in waterfowl in the wild. In this study, we report the complete mtDNA of the natural hybridization bird between Anser albifrons and Anser fabalis. The complete mtDNA of the hybridization is 16,740 bp in length, contains the typical set of 37 genes, including 13 PCGs, two rRNAs, 22 tRNAs, and a 1177 bp CR. In the 13 PCGs, ATG is generally as the start codon, TAA is the most frequent stop codon, one of three, TAA, TAG, and T-, commonly observed. All tRNAs can be folded into canonical cloverleaf secondary structures except for tRNA Ser (AGY) and tRNA Leu (CUN) missing the \"DHU\" arm. The new mtDNA sequence contains 12S rRNA and 16S rRNA of rRNAs, separated with tRNA val . The CR is 1177 bp in length, located between tRNA Glu and tRNA Phe . Our phylogenetic trees suggest the hybridization has a close genetic relationship among Anser species.

Extreme changes to key waterfowl habitats in the Klamath Basin (KB) on the Oregon–California border and the Sacramento Valley (SV) in California, USA, have occurred since 1980. The spatial distribution of Pacific greater white-fronted geese (Anser albifrons sponsa; geese) has likewise changed among these areas and population size has grown from 79,000 to >600,000 geese during the same period. To assess the effects of landscape changes and spatial-temporal distribution of geese, we collected Pacific greater white-fronted geese during winters of 2009–2010 and 2010–2011 in the KB and SV and compared their body condition to geese collected during 1979–1980 and 1980–1981. We modeled body and lipid mass to assess body condition for each sex independently and examined the influence of collection day, year, and region. Body condition of geese varied throughout the winter and within years in a nonlinear fashion. We detected an increase in body condition in both sexes during December and January in the SV, which corresponds with improved habitat conditions and increases seen in other species in the region. Body condition upon arrival in fall migration varied by year for females and by year and region for males. Males and females arrived in poorer body condition during 2010–2011 than all other study years and males in the KB during 2010–2011 had extremely low lipid mass, reflecting poor regional habitat conditions induced by drought. Body condition of females varied over spring, by year, and by region and regional effects were evident for males. Body condition was significantly higher for geese in the SV than in the KB during spring. Our results suggest that Pacific greater white-fronted geese have adapted to a changing landscape and have adjusted historical spatial use patterns to take advantage of more favorable conditions in the SV between 1979 and 2010.

Theory predicts persistence of long-term family relationships in vertebrates will occur until perceived fitness costs exceed benefits to either parents or offspring. We examined whether increased breeding probability and survival were associated with prolonged parent–offspring and sibling–sibling relationships in a long-lived Arctic migrant herbivore, the Greenland white-fronted goose (Anser albifrons flavirostris). Although offspring associated with parents for 1–13 years, 79 % of these associations lasted two or less years. Only 65 (9.9 %) of the 656 marked offspring bred once in their lifetime, and just 16 (2.4 %) bred twice or more. The probability of birds with siblings breeding successfully in a subsequent year was credibly greater than that of independent birds at ages 5, 6, and 7. Survival of offspring with parents was credibly greater than that of independent/nonbreeder birds at all possible ages (i.e., ages 2–7+). A cost–benefit matrix model utilizing breeding and survival probabilities showed that staying with family groups was favored over leaving until age 3, after which there were no credible differences between staying and leaving strategies until the oldest ages, when leaving family groups was favored. Thus, most birds in this study either departed family groups early (e.g., at age 2, when the “stay” strategy was favored) or as predicted by our cost–benefit model (i.e., at age 3). Although extended family associations are a feature of this population, we contend that the survival benefits are not sufficient enough to yield clear fitness benefits, and associations only persist because parents and offspring mutually benefit from their persistence.

The majority of Eastern China’s herbivorous geese overwinter in the East Dongting Lake, China, and there is growing concern about how changes in their habitats can affect the goose populations. General linear regressions were used to analyze the relationship between changes in the abundances of three herbivorous geese (Eastern Tundra Bean Goose Anser fabalis serrirostris , Lesser White-fronted Geese Anser erythropus , and Greater White-fronted Goose Anser albifrons frontalis ) and their wintering habitats in the East Dongting Lake during 2002/2003–2014/2015. The fluctuations in three herbivorous goose abundances exhibited negative correlations with changes in interval duration (i.e., days between complete sedge meadow exposure and goose arrival in the study areas), but positive correlations with the normalized difference vegetation index (NDVI) of sedge meadow in late wintering seasons. Comparing to Eastern Tundra Bean Goose, Lesser White-fronted Geese and Greater White-fronted Geese were more sensitive to habitat changes. No significant correlations were observed between goose abundances and both mean water levels and sedge meadow areas. Results indicate that the variations in herbivorous goose abundances may be caused by changes in the NDVI of sedge meadows and the interval durations between sedge meadow exposure and goose arrival. The earlier flood recession can accelerate the exposure, growth, and withering of sedge meadows (low NDVI in late January), thereby creating unsuitable feeding conditions for the geese in the wintering seasons. These findings are important as efforts are made to protect these valuable species from the effects of human intervention, and in particular, the Three Gorges Dam project.

Background For the conservation and management of migratory species that strongly decrease or increase due to anthropological impacts, a clear delineation of populations and quantification of possible mixing (migratory connectivity) is crucial. Usually, population exchange in migratory species is only studied in breeding or wintering sites, but we considered the whole annual cycle in order to determine important stages and sites for population mixing in an Arctic migrant. Methods We used 91 high resolution GPS tracks of Western Palearctic greater white-fronted geese ( Anser A. albifrons ) from the North Sea and Pannonic populations to extract details of where and when populations overlapped and exchange was possible. Overlap areas were calculated as dynamic Brownian bridges of stopover, nest and moulting sites. Results Utilisation areas of the two populations overlapped only somewhat during spring and autumn migration stopovers, but much during moult. During this stage, non-breeders and failed breeders of the North Sea population intermixed with geese from the Pannonic population in the Pyasina delta on Taimyr peninsula. The timing of use of overlap areas was highly consistent between populations, making exchange possible. Two of our tracked geese switched from the North Sea population flyway to the Pannonic flyway during moult on Taimyr peninsula or early during the subsequent autumn migration. Because we could follow one of them during the next year, where it stayed in the Pannonic flyway, we suggest that the exchange was long-term or permanent. Conclusions We have identified long-distance moult migration of failed or non-breeders as a key phenomenon creating overlap between two flyway populations of geese. This supports the notion of previously suggested population exchange and migratory connectivity, but outside of classically suggested wintering or breeding sites. Our results call for consideration of moult migration and population exchange in conservation and management of our greater white-fronted geese as well as other waterfowl populations.