Tree swallows are in decline in Quebec. (Photo credit: Gabriel Pigeon, Université de Sherbrooke)
A new study shows that tree swallows between Montreal and Sherbrooke became fewer (-19% population decline) and smaller (-8% weight loss) from 2005-2011, especially the females.
Insect-eating birds are in decline all across northeastern North America, and pesticide use is a suspected culprit, but the authors did not find a link between weight loss and intensive agriculture in their study. They conclude that more needs to be known about the winter habitat of tree swallows in the southern US and Central America; it could be that they arrive in Quebec already in bad shape from their migration.
Original research paper published in the the Proceedings of the Royal Society B on May 20, 2014.
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