Habitat use and foraging behaviour of urban merlins(Falco columbarius)in winter

• Published in: Journal of Zoology
• Main Authors: Warkentin, I. G., Oliphant, L. W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1990
• Subjects: Canada; Bombycilla garrulus
• Online Access: http://dx.doi.org/10.1111/j.1469-7998.1990.tb04018.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1469-7998.1990.tb04018.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1990.tb04018.x; https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7998.1990.tb04018.x

Habitat use and foraging behaviour of resident merlins (Falco columbarius) wintering in Saskatoon, Canada, were studied over a five‐year period. Birds were trapped through the winter and selected individuals fitted with radio transmitters to monitor continously their location, movements and activities from roost departure until re‐entry. Merlins maintained individual home ranges in winter, with extensive overlap between neighbouring birds in some cases. Yearling home ranges were not significantly different in size from those of adults. The winter home ranges of adults were closely associated with their previous nest site. Both adults and yearlings made significantly greater use of Residential habitat in the city than expected based on the area available in their home ranges. However, while adults remained largely in the two oldest habitat types, yearlings were also found in more recently built areas of the city. Home ranges held within the city were sometimes combined with foraging areas in the adjacent countryside. The use of foraging areas in farmyards and cattle feedlots outside of the city was most notable in adults, although some yearlings apparently learned this strategy in their first year. Merlins also used Commercial‐Industrial habitat for hunting at levels much higher than expected from its availability in their home ranges. Diets in summer and winter had a high degree of overlap; house sparrows (Passer domesticus) and bohemian waxwings (Bombycilla garrulus) made up a large proportion of the diet during both seasons. Hunting activity peaked at 09:00 and 16:00 h, reflecting the replenishment of energy stores lost over‐night, and the storage of energy in preparation for the next over‐night fast.