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Ecological processes are changing in response to climatic warming. Birds, in particular, have been documented to arrive and breed earlier in spring and this has been attributed to elevated spring temperatures. It is not clear, however, how long-distance migratory birds that overwinter thousands of kilometers to the south in the tropics cue into changes in(More)
The date when a landbird migrant arrives on its breeding grounds may have reproductive consequences. Generally, early arriving individuals begin breeding earlier and consequently experience greater seasonal reproductive performance. Here, we describe relationships between arrival timing and seasonal reproductive performance in the American redstart(More)
How and when migrants integrate directional information from different sources may depend not only on the bird’s internal state, including fat stores, but also on the ecological context during passage. We designed experiments to (1) examine the influence of stored fat on the decision to migrate and on the choice of migratory direction and (2) investigate(More)
--The narrow woodlands and wooded barrier islands along the northern coast of the Gulf of Mexico provide the first available landfall for Neotropical andbird migrants after their spring trans-Gulf light. We studied the timing, volume, fat stores, length of stay, and fat deposition of thrushes (n = 1,903) during stopover at a coastal Louisiana woodland in(More)
West Nile virus is a pathogen of concern for both human and wildlife health. Although many aspects of the ecology of West Nile virus are well understood, the mechanisms by which this and similar mosquito-borne viruses overwinter and become reinitiated each spring in temperate regions is not known. A thorough understanding of this mechanism is crucial to(More)
Nocturnal passerinc migration typically commences within an hour of sunset (Drury and Nisbet 1964, Casement 1966, Cochran et al. 1967, Parslow 1968, Gauthreaux 1971, Hebrard 1971, •kesson et al. 1996), and the bulk of migrants depart before the end of nautical twilight (which ends when the sun is 12 ø below the horizon or almost an hour after sunset). This(More)
Migratory birds use multiple sources of compass information for orientation, including the geomagnetic field, the sun, skylight polarization patterns and star patterns. In this paper we review the results of cue-conflict experiments designed to determine the relative importance of the different compass mechanisms, and how directional information from these(More)
Migratory birds are exposed to a diverse pathogen fauna by virtue of their long-distance travels. Although the immune system is an organism’s primary defense against pathogenic microorganisms, few studies have investigated avian immune function during migration, much less shown seasonal differences in immune function. We describe the immunological condition(More)
Local concentrations of migrating, fat-depleted birds with similar diets can lead to increased competition for food at a time when energy demand is high. Results of a predator-exclosure experiment indicate that intercontinental passerine migrants depress food abundance during stopover following migration across the Gulf of Mexico. Moreover, migrants that(More)
Most of our understanding of habitat use by migrating land birds comes from studies conducted at single, small spatial scales, which may overemphasize the importance of intrinsic habitat factors, such as food availability, in shaping migrant distributions. We believe that a multi-scale approach is essential to assess the influence of factors that control en(More)