Mapping pre- and post-fledging foraging locations of thick-billed murres in the North Water polynya
In this study of thick-billed murres in high-arctic Greenland we used electronic data loggers and satellite transmitters (PTTs) to identify the foraging areas of chick-rearing adults, and to map the routes and staging areas of adults accompanying post-fledging chicks during their swimming migration within the North Water (NOW) polynya. During the pre-fledging period the majority of 19 foraging trips performed by 8 birds went to a shelf area north of the colony where 83% of all dives took place. Individual birds headed in different directions during successive trips, and went up to 47 km from the colony. Upon fledging the four PTT-tagged adult/chick pairs initiated swimming migration by heading south-west from the colony. All pairs moved fast until they arrived at a shallow bank area ca 180 km from the colony, where at least two of the pairs remained for more than a week. Speed during the active migration averaged 2.5 km h−1 with a peak of 6.6 km h−1. In the pre-fledging period the birds utilised a feeding area outside the normal foraging range of murres from other colonies. Similarly, post-fledging adult/chick pairs may have benefitted from reduced food competition when they moved to a staging area situated at the only shallow area in the polynya without any adjacent murre colony. This initial study suggested that the high-arctic murres did not hasten towards the wintering grounds, and that the NOW remained important even to post-fledging murres.
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Document Type: Research Article
Publication date: December 1, 2001