Associations between sex, age and species-specific climate sensitivity in migration

Abstract

Weather often plays a key role in migration timing, and temporal shifts over the past century have been heavily researched and linked to climate change. Much research is however limited by the use of arbitrary time periods during which weather is thought to most influence migration. Here, we compare the classic fixed window method to a novel sliding window approach created to determine periods of temperature sensitivity among organisms, in this case on the migration phenology of nineteen passerine species banded at the McGill Bird Observatory in Montréal, Québec, from 2005 to 2015. We found overall shorter temperature sensitivity windows in the spring than the fall migration and deemed the nonarbitrarily chosen periods of temperature sensitivity to be more useful than the classic fixed window method when used with caution. We also found significant variation in migration timing of 11 species, as well as more cases of male birds arriving in spring prior to females than the reverse. More males departed in fall before females as well. Similarly, on average, older birds arrived in spring ahead of younger individuals and departed prior to younger in the fall.