Abstracts Category : Other

Behavioural Mechanisms of Protandrous Spring Migration in a Nearctic-Neotropical Songbird

by Jessica E Deakin

Most seasonally migrating songbirds have a protandrous migration pattern, meaning that males arrive to the breeding grounds before females. The proximate mechanisms that underlie this pattern are largely unknown for most species. In this thesis, I evaluate the behavioural mechanisms of protandry in the black-throated blue warbler (Setophaga caerulescens) using onset of migratory restlessness as a proxy for departure from the wintering grounds, migratory restlessness intensity as a proxy for motivation to fly, and stopover duration of radio-tagged birds. The onset of migratory restlessness and stopover duration was similar in both sexes. Males displayed higher intensity wing whirring than females, suggesting that protandry might be achieved through sex differences in nocturnal flight duration. Stopover duration was negatively correlated with migratory restlessness intensity on the last night the birds were in captivity, validating migratory restlessness as an accurate proxy for motivation to migrate at the individual level.