Ardea
Official journal of the Netherlands Ornithologists' Union

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Hübner C.E. (2006) The importance of pre-breeding areas for the arctic Barnacle Goose Branta leucopsis. ARDEA 94 (3): 701-713
Before the final move to their breeding sites, many arctic-nesting geese visit staging areas close by, so called pre-breeding areas. The present study investigated the timing of migration by Barnacle Geese Branta leucopsis in relation to the dynamics in body stores during this period. The study area was located on the south-facing slopes of Ingeborgfjellet, Vårsolbukta, on the west coast of Spitsbergen, Svalbard (77°45'N, 14°24'E). During spring 2003 and 2004, staging geese were counted and body fat stores were estimated by scoring abdominal profiles on a daily basis. In total, almost one fifth of the Svalbard Barnacle Goose visited the area. Mean goose arrival was on 26 May in both years and peak numbers were recorded in the last week of May. Geese arrived at a time when fat deposition rates in their staging area in mid-Norway dropped rapidly and geese staging in Vårsolbukta could achieve higher deposition rates. This supports the green wave hypothesis. An advantage of early arrival in the Arctic is the better predictability of the snow conditions at the breeding sites. Accordingly, geese departed earlier from Vårsolbukta in the year with advanced snow melt. Late arriving geese stayed shorter than early arriving geese and mean duration of staging was 3.9 d and 2.5 d in 2003 and 2004, respectively. Despite the short staging period, individuals gained considerable body fat stores. Males were apparently more sensitive to environmental conditions than females and deposited fat stores only in the year with early snow melt. This study suggests that Barnacle Geese can afford to arrive early in Svalbard without trading the benefit of being early against low body condition, provided that they stage in favourable pre-breeding areas before moving to the breeding sites. It also underlines the critical role of such pre-breeding areas, since they may function as a buffer between southern staging areas and the breeding site.


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