Date of Award

10-17-2024

Publication Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

Supervisor

Oliver Love

Abstract

The Arctic is experiencing rapid rates of climate change, where temperatures are increasing faster than the global average. Arctic-breeding birds that have adapted to harsh and cold conditions throughout their annual cycle may not be physiologically prepared for warming conditions, especially during the energetically demanding breeding period. Of specific concern within this group is the Snow Bunting (Plectrophenax nivalis), an Arctic-breeding songbird whose populations are declining without a clear mechanism. Due to high metabolic rates and correspondingly high body temperatures, effective heat dissipation during the demanding nestling provisioning stage is vital to reduce the risk of reaching lethal body temperatures. Thus, when operative temperatures exceed optimal levels, breeding birds must dissipate excess heat and adjust behaviourally by reducing investment in breeding behaviours. To determine whether and how buntings are responding to increasing temperatures during the breeding season, we tagged birds using Radio-Frequency Identification thermal tags which measure fine-scale body temperature and parental foraging responses. We found that low-Arctic breeding buntings at our site maintained physiological and behavioural diel patterns and exhibited sex specific differences in provisioning behaviours. Buntings did not appear to be physiologically responding to current operative temperatures and did not reach near lethal body temperatures during breeding. However, buntings do appear to behaviourally respond to diel temperature fluctuations. Temperatures within our site, did increase to above normal levels, thus, we believe that continuous and long-term exposure to high temperatures may drive both a physiological and behavioural response in breeding buntings. Understanding the conditions under which breeding buntings will need to respond through reproductive behaviours to avoid overheating when exposed to elevated temperatures will improve our understanding of Arctic songbirds’ responses to global warming.

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