Persistent species relationships characterize migrating bird communities across stopover sites and seasons.

Global migrations of diverse animal species often converge along the same routes, bringing together seasonal assemblages of animals that may compete, prey on each other, and share information or pathogens. These interspecific interactions, when energetic demands are high and the time to complete journeys is short, may influence survival, migratory success, stopover ecology, and migratory routes. Numerous accounts suggest that interspecific co-migrations are globally distributed in aerial, aquatic, and terrestrial systems, although the study of migration to date has rarely investigated species interactions among migrating animals.

Linking phenological events in migratory passerines with a changing climate: 50 years in the Laurel Highlands of Pennsylvania.

Advanced timing of both seasonal migration and reproduction in birds has been strongly associated with a warming climate for many bird species. Phenological responses to climate linking these stages may ultimately impact fitness. We analyzed five decades of banding data from 17 migratory bird species to investigate 1) how spring arrival related to timing of breeding, 2) if the interval between arrival and breeding has changed with increasing spring temperatures, and 3) whether arrival timing or breeding timing best predicted local productivity.

Long-term climate impacts on breeding bird phenology in Pennsylvania, USA.

Climate change is influencing bird phenology worldwide, but we still lack information on how many species are responding over long temporal periods. We assessed how climate affected passerine reproductive timing and productivity at a constant effort mist-netting station in western Pennsylvania using a model comparison approach. Several lines of evidence point to the sensitivity of 21 breeding passerines to climate change over five decades.

An improved method for quantifying hematozoa by digital microscopy.

Intensity of hematozoan infection is infrequently quantified because accurate calculations require visual counts of parasites relative to a large number of erythrocytes. Manual quantification of erythrocytes can be circumvented by using ImageJ software (developed by the National Institutes of Health) to count erythrocyte nuclei from digital images. Here we use the ratio of microscope erythrocyte counts to digital image erythrocyte counts (field:image ratio) to extrapolate erythrocyte counts from smaller digital images to the microscope's larger field of view.