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| Some species of long-distance migrant birds are thought to follow spatiotemporal patterns of high food availability during the non-breeding season, a strategy termed “itinerancy,” instead of being sedentary in one specific site. We tracked the migration of a small Eurasian songbird, the Common Redstart (Phoenicurus phoenicurus), using archival light-level geolocators. The birds showed a distinct counterclockwise loop migration from northern Europe. Fall migration passed west of the Mediterranean Sea and along the northwest African coast before the birds made an abrupt change of direction at the southern edge of the Sahara toward the winter area farther inland in the West African Sahel. Spring migration was more direct: north to the Iberian Peninsula and back to northern Europe. The birds spent more time in only one winter site than they do during the breeding season in northern Europe, and they generally showed no signs of itinerancy—except for one bird that probably avoided an exceptional drought. Their arrival on the winter grounds was well timed with peak vegetation greenness, assumed to reflect food availability, but vegetation greenness declined rapidly during their stay, and resource availability was relatively low throughout most of the non-breeding season. Despite the highly seasonal conditions in the wintering area, itinerancy is apparently not an optimal strategy for the Common Redstart, possibly because of timing constraints. Alternatively, food availability may not be closely linked to vegetation greenness. | |
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