We analysed growth of nestling Chilean Swallows (Tachycineta meyeni) over four consecutive breeding seasons and determined the factors that explain variation in growth rate, asymptotic body mass and length of the nestling period. As the breeding season advanced nestlings grew more slowly and attained lower asymptotic mass, but the length of the nestling period and nestling survival did not show...

Testosterone has been suggested to be involved in the regulation of male territorial behavior. For example, seasonal peaks in testosterone typically coincide with periods of intense competition between males for territories and mating partners. However, some species also express territorial behavior outside a breeding context when testosterone levels are low and, thus, the degree to which testo...

Assessing the drivers of survival across the annual cycle is important for understanding when and how population limitation occurs in migratory animals. Density-dependent population regulation can occur during breeding and nonbreeding periods, and large-scale climate cycles can also affect survival throughout the annual cycle via their effects on local weather and vegetation productivity. Most ...

—Breeding seabirds have been well studied but seabird ecology during the nonbreeding season is poorly understood because many species disperse far from breeding colonies to molt at sea. We characterized the timing of prebasic molt and postbreeding dispersal, described postbreeding dispersal movements, and estimated changes in body mass during molt for Marbled Murrelets (Brachyramphus marmoratus...

Key findings There were a total of 98 individuals in pre-breeding and 240 individuals of lesser adjutant stork in post-breeding periods (94 chicks and 146 adults) in the study area. On average, there were 1.29 chicks per nest. Bombax ceiba and Adina cordifolia were found to be the most preferred nesting trees for lesser adjutant storks. Habitat preference of lesser adjutant storks revealed that...

—We studied the breeding biology of the Panamanian subspecies of the Yellow-crowned Parrot, Amazona ochrocephala panamensis, during 1997–1999 in the province of Chiriquı́, Panama, to provide basic information regarding the breeding behavior and reproductive success of these parrots in their natural habitat. We recorded parrot behaviors throughout the reproductive period, monitored nest success, ...

Understanding the mechanisms by which climate variation can drive population changes requires information linking climate, local conditions, trophic resources, behaviour and demography. Climate change alters the seasonal pattern of emergence and abundance of invertebrate populations, which may have important consequences for the breeding performance and population change of insectivorous birds....

The steroid hormone testosterone (T) influences a multitude of traits critical to reproduction in vertebrates. In birds, high male T supports territory establishment and mate attraction, but is thought to interfere with parental care. Interspecific comparisons indicate that migratory species with short, synchronous breeding seasons have the highest peak T, and that the seasonal profile of T exh...

Abstract A comparative study of some parameters nonspecific immunity in the Angelinskii rubella-resistant variant scaly and mirror groups carp prespawning late feeding periods was carried out. The level antimicrobial properties C -reactive protein, immune complexes blood serum, phagocytic activity neutrophils were studied. showed interbreed inter-seasonal differences indicators. It is concluded...