Moult and moult migration of Greylag Geese<i>Anser anser</i>from a population in Scania, south Sweden

Nilsson, Leif; Kahlert, Johnny; Persson, Henrik

doi:10.1080/00063650109461211

Cited by 20 publications

(22 citation statements)

References 2 publications

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“…With the dramatic increase in the greater snow goose population over the past 30 years , either molting areas have seen an increase in the number of geese using them, or the number of sites used has increased. A shift in molting area of greylag geese (Anser anser) in southern Sweden was linked to an increase in population size, possibly because the carrying capacity of the traditional molting site had been reached (Nilsson et al, 2001). Therefore, increase in goose use in some molting areas may have important ecological implications.…”

Section: Discussionmentioning

confidence: 99%

Molt Migration in Relation to Breeding Success in Greater Snow Geese

Reed¹,

Bêty²,

Mainguy³

et al. 2003

ARCTIC

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ABSTRACT. We describe summer migratory movements by female greater snow geese (Chen caerulescens atlantica) breeding on Bylot Island, Nunavut. We followed 121 radio-collared females between 1997 and 2001 to determine the frequency and timing of their departure from the colony in relation to breeding status, nesting success, and molting chronology. We found that 90% (n = 51) of non-breeders (no nest found) and 97% (n = 29) of failed nesters (nest destroyed or abandoned before hatch) departed the island before molting. The few non-breeders that remained on Bylot Island all summer molted earlier than adults with young, and they appeared to initiate the fall migration before breeding geese. In contrast, only 2% of successful nesters (n = 41) left Bylot Island to molt, and those that did presumably had lost their offspring in the early stages of brood rearing. Thus, the occurrence of a molt migration in greater snow geese appears to be strongly dependent on reproductive status and nesting success. The area used by molt migrants and their habitat requirements during molt remain unknown. We suggest that the paucity of predator-safe areas (such as large water bodies) on Bylot Island may be an important factor that drives the geese to molt elsewhere.Key words: breeding effort, greater snow goose, Chen caerulescens atlantica, migration, molt, nesting success, Nunavut, telemetry RÉSUMÉ. Nous décrivons les mouvements migratoires estivaux de la grande oie des neiges (Chen caerulescens atlantica) nichant à l'île Bylot (Nunavut). De 1997 à 2001, 121 femelles munies de radio-émetteurs ont été suivies afin de déterminer la fréquence et le moment de leur départ de la colonie relativement à leur statut reproducteur, leur succès de nidification et la chronologie de la mue. Nous avons trouvé que 90 p. cent (n = 51) des non-reproducteurs (pas de nid trouvé) et 97 p. cent (n = 29) des femelles dont le nid a été détruit ou abandonné avant l'éclosion ont entrepris leur migration avant la mue. Les quelques non-reproducteurs ayant demeuré à l'île Bylot tout l'été ont mué et apparemment entrepris la migration automnale plus tôt que les adultes accompagnés de jeunes. Par contraste, seulement 2 p. cent (n = 41) de femelles ayant niché avec succès ont quitté l'île Bylot pour la mue, après avoir probablement perdu leurs jeunes au début de l'élevage. La migration de mue chez la grande oie des neiges semble donc fortement dépendante du statut reproducteur et du succès de nidification. Nous ne connaissons pas les sites utilisés ni les conditions d'habitat requises pour la mue de ces individus. Nous suggérons que la rareté de refuges contre les prédateurs à l'île Bylot, tels que de grandes étendues d'eau, pourrait être un facteur important qui incite les oies à muer ailleurs.

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Section: Discussionmentioning

confidence: 99%

Molt Migration in Relation to Breeding Success in Greater Snow Geese

Reed¹,

Bêty²,

Mainguy³

et al. 2003

ARCTIC

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“…For our analysis we consequently only differentiated between two groups, juveniles and adults, with our estimates for adult survival being lower than previously reported for this population (Nilsson & Persson 1993). It is worth noting that juveniles return with their parents to the breeding grounds during their first spring and then disperse to moulting areas before returning towards the end of the breeding season (Nilsson et al . 2001).…”

Section: Discussionmentioning

confidence: 99%

A demographic comparison of two Nordic populations of Greylag GeeseAnser anser

Pistorius

Follestad

Nilsson

et al. 2007

Ibis

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Greylag Geese Anser anser have been neck‐banded on an annual basis in Scania, southern Sweden since 1984 and in Norway since 1986 as part of a Nordic Greylag project. This has yielded a large database of resightings, which we used here to estimate and compare survival rates between the two populations by means of mark–recapture models. Estimated adult survival was sex‐dependent in the Scanian population, probably a result of differential neck band retention rates in this population. Mean juvenile survival was about 12% higher in the Scanian population (0.603 vs. 0.485). Adult survival in the Norwegian population was 0.728 (males 0.733; females 0.725), and in males and females from the Scanian population was 0.711 (0.752 after accounting for higher neck band loss in males) and 0.771, respectively. Over the course of the study, juvenile survival in the Scanian population increased substantially, and adult survival was constant, whereas both these parameters declined in the Norwegian population. This study demonstrates that the two Nordic populations are demographically distinct and gives further support to the notion that they should be treated as separate management units. The decline of 10% in adult survival in the Norwegian population, the cause of which still remains uncertain, is likely to have had a major impact on the growth of this population.

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“…Nonetheless, we found no evidence that fidelity rates declined over time and our data demonstrate a process by which molting distributions can shift over time while individual level site fidelity remains high and stable. Nilsson et al (2001) documented that molting Greylag Geese shifted their molting distributions across a similar distance, and attributed the shift to increasing population size and associated increases in intraspecific competition for forage. Our scenario is similar in that we may have experienced a >50% increase in the number of molting Brant on the ACP corresponding with the observed increase in the molting distribution (i.e., range).…”

Section: Recapture Location In 2012mentioning

confidence: 99%

High fidelity does not preclude colonization: range expansion of molting Black Brant on the Arctic coast of Alaska

Flint

Meixell

Mallek

2014

Journal of Field Ornithology

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High rates of site fidelity have been assumed to infer static distributions of molting geese in some cases. To test this assumption, we examined movements of individually marked birds to understand the underlying mechanisms of range expansion of molting Black Brant (Branta bernicla nigricans) on the Arctic Coastal Plain (ACP) of Alaska. The Teshekpuk Lake Special Area (TLSA) on the ACP was created to protect the primary molting area of Brant. When established in 1977, the TLSA was thought to include most, if not all, wetlands used by molting Brant on the ACP. From 2010 to 2013, we surveyed areas outside the TLSA and counted an average of 9800 Brant per year, representing 29–37% of all molting Brant counted on the ACP. We captured and banded molting Brant in 2011 and 2012 both within the TLSA and outside the TLSA at the Piasuk River Delta and Cape Simpson to assess movements of birds among areas across years. Estimates of movement rates out of the TLSA exceeded those into the TLSA, demonstrating overall directional dispersal. We found differences in sex and age ratios and proportions of adult females with brood patches, but no differences in mass dynamics for birds captured within and outside the TLSA. Overall fidelity rates to specific lakes (0.81, range = 0.49–0.92) were unchanged from comparable estimates obtained in the early 1990s. We conclude that Brant are dispersing from the TLSA into new molting areas while simultaneously redistributing within the TLSA, likely as a consequence of changes in relative habitat quality. Shifts in distribution resulted from colonization of new areas by young birds as well as low levels of directional dispersal of birds that previously molted in the TLSA. Based on combined counts, the overall number of molting Brant across the ACP has increased substantially.

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Moult and moult migration of Greylag GeeseAnser anserfrom a population in Scania, south Sweden

Cited by 20 publications

References 2 publications

Molt Migration in Relation to Breeding Success in Greater Snow Geese

Molt Migration in Relation to Breeding Success in Greater Snow Geese

A demographic comparison of two Nordic populations of Greylag GeeseAnser anser

High fidelity does not preclude colonization: range expansion of molting Black Brant on the Arctic coast of Alaska

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