—Plasma lipid metabolites may be useful indicators of mass changes in migratory birds. To test utility of plasma metabolites in field studies, we examined effects of several extrinsic (bleed time, time of day, location) and intrinsic (body mass, sex, age, migratory state) factors on plasma concentrations of triglycerides (TRIG), glycerol (GLYC), and B-OHbutyrate (BUTY) in free-living Western Sa...

The migration phase of birds is divided into two main states: stopovers and actual migratory flights. For soaring birds, such as storks, nighttime especially important to conserve energy start the next day in favourable weather conditions. Although there a large number recent studies on white stork Ciconia ciconia , for example using advanced technologies GPS technology, nocturnal behaviour spe...

Long-distance migration in birds is relatively well studied in nature; however, one aspect of this phenomenon that remains poorly understood is the pattern of distribution presented by species during arrival to and establishment of wintering areas. Some studies suggest that the selection of areas in winter is somehow determined by climate, given its influence on both the distribution of bird sp...

The world's Arctic latitudes are some of the most recently colonized by birds, and an understanding of the migratory connectivity of circumpolar species offers insights into the mechanisms of range expansion and speciation. Migratory divides exist for many birds, however for many taxa it is unclear where such boundaries lie, and to what extent these affect the connectivity of species breeding a...

Individual wintering strategies and patterns of winter site fidelity in successive years are highly variable among seabird species. Yet, an understanding of consistency in timing of movements and the degree of site fidelity is essential for assessing how seabird populations might be influenced by, and respond to, changing conditions on wintering grounds. To explore annual variation in migratory...

Environmental conditions encountered by migratory seabirds in their wintering areas can shape their fitness. However, the underlying physiological mechanisms remain largely unknown as birds are relatively inaccessible during winter. To assess physiological condition during this period, we measured corticosterone concentrations in winter-grown primary feathers of female great skuas (Stercorarius...

Background The island of Puerto Rico supports a diverse assemblage of breeding birds, including 16 endemic species (Raffaele et al. 1998), and provides critical wintering habitat for many North American migratory birds (Wunderle and Waide 1994). Despite being a hotspot of avian biodiversity, spatially extensive data on the distribution and abundance of birds on the island are scarce. Breeding-b...

b ackground: cercarial dermatitis is known as an endemic parasitic disease in north of iran, a hy- persensitive skin reaction to the penetration of nonhuman schistosome larvae into human skin. in recent studies in this region, final and intermediate hosts were recognized and trichobilharzia was identified as the main causative agent of cercarial dermatitis in this region, but to date the parasi...