The Avian Working Class

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Science  12 Feb 2010:
Vol. 327, Issue 5967, pp. 762
DOI: 10.1126/science.327.5967.762-a

Shearwaters are ocean going birds that hunt small pelagic fish and squid. They forage the continental shelf off eastern Spain, flying several hundred kilometers a day in search of their peripatetic prey. On the weekdays; that is, from Monday to Friday; the food supply is more reliable and comes from the waste discarded from fishing boats. Although bad weather can be disruptive, the fishermen's routines and foraging patterns are constrained into temporal and spatial regularity by legislation and by their neighbors' fishing rights. Thus, by coupling satellite data on the birds' movements in a random walk model, Bartumeus et al. show how shearwaters respond to trawler discard and exploit an otherwise inaccessible food source. Thus, during weekdays, shearwaters feed in the trawler fishing grounds and consequently can make more return trips to feed their young, because they can trust the fishing boats to supply the next meal. In contrast, during weekends and public holidays, unaided by boats, the birds have to undertake lengthy exploratory trips to seek food.

Curr. Biol. 20, 10.1016/j.cub.2009.11.073 (2010).

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