Date of Award

10-17-2024

Publication Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

Keywords

Migratory pathways;Motus;Movement;Winter ecology

Supervisor

Oliver Love

Supervisor

Emily McKinnon

Abstract

The Snow Bunting (Plectrophenax nivalis) is an Arctic-breeding songbird facing population declines. The cause for these declines, however, is not well understood because of the difficulty of studying this species due to their remote breeding grounds in the Arctic and nomadic wintering movement. With climate change increasing ambient temperatures and affecting weather systems at a global scale, Snow Buntings will be affected at all life stages. To help fill in knowledge gaps for the wintering stage of this species, the goal of this research was to understand patterns of movements of Snow Buntings overwintering in Ontario, Canada. Specifically, we first investigated which environmental and intrinsic factors influenced space use during the wintering period, and used this as a basis to estimate spring migration initiation. To accomplish these goals, we spatially tracked birds using automated digitally-coded radiotelemetry (Motus Wildlife Tracking System) tags deployed on wintering birds in Southwestern Ontario. Additionally, while some individuals were banded, tagged, and released where they were caught, others were strategically displaced by several hundred kilometers to causally test their response to different environmental conditions. We found that surface pressure was an important extrinsic factor influencing movement decisions in wintering buntings. Further, surface pressure, precipitable water in the atmosphere, and wind speeds were important predictors of whether detections were associated with differentiating wintering or migration movements. However, we found no evidence to support the role of sex or body size influencing movement decisions in wintering or early-migration buntings. Finally, combining tracking and band-return data, we found support for a previously undescribed spring migratory pathway. Quantifying the movement ecology of Snow Buntings in Southwestern Ontario will help to determine whether they have the capacity to adapt to an increasingly changing landscape across multiple life stages.

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