Foraging and Roosting Habitat Use of Nesting Bank Swallows in Sackville, NB

Abstract

Habitat loss and degradation caused by agricultural intensification is considered to play a leading role in the declines of aerial insectivores, making the understanding of habitat dynamics critical for protection of this bird guild. Of all aerial insectivores, Bank Swallows are declining at the fastest rate and little is known about their foraging and roosting habitat requirements on the breeding ground. Therefore, the goal of my thesis was to identify the foraging and roosting habitat of breeding Bank Swallows and to determine how both intrinsic and extrinsic factors affect this species’ habitat use. Using automated and manual radio telemetry I tracked the movements of 68 breeding Bank Swallows from three colonies in Sackville, NB. Foraging was concentrated near the colony and in salt marshes and foraging distance increased with chick age, was greater in birds with inactive nests and increased in cold and humid weather. Furthermore, the likelihood of Bank Swallows roosting communally in distant cattail wetlands was higher in males than in females and when chicks were young and decreased with relative humidity and ambient light. Moreover, Bank Swallows left the colony to roost earlier as chicks aged, when ambient light was low and when they traveled to further roosts and returned later as their chicks aged, when temperature and wind speeds were low and when they used distant roosts. Finally, the likelihood of roosting at the major roost site was higher when chicks aged, relative humidity was high and ambient light was low. These findings on Bank Swallow foraging and roosting habitat use can aid in the identification of critical habitat for this declining species.