Supervised by:

François Vézina (Regular Member (Co-researcher))

Research project description

The paradox of thermal insulation in resident forest birds

Introduction

For non-migratory birds, cold seasonal environments such as those in Quebec require considerable physiological changes. In small birds, plumage insulation is not considered to change between seasons. For non-migratory birds that molt once a year in autumn, good winter insulation is an asset, but summer performance may be limited if plumage is maintained. Indeed, it is considered that performance is limited by the ability to dissipate heat in endotherms. So there's a paradox when it comes to thermal insulation.

Objectives

Using the black-capped chickadee as a model, the overall aim of this project to compare thermal insulation in winter and summer is to determine the influence of plumage insulation on individual physiological performance at two critical life-history stages for non-migratory forest passerines living in Quebec. That is, in winter and during the nestling provisioning period in summer.

Study Sites

The study will take place at the Forêt d'enseignement et de recherche (FER) Macpès in Sainte-Blandine, near Rimouski. A network of artificial nest boxes has been used for several years to monitor the breeding of black-capped chickadees. Winter fieldwork is also carried out at this site.

Material and methods

In winter, the birds are captured in the field using Potter traps installed near feeders previously set up to attract the chickadees, while in summer, they are captured in their nesting boxes. They are then taken to the FER laboratory for the duration of the respirometry measurements before being released at their capture site. Respirometry is a standardized method based on the measurement of oxygen entering and leaving a metabolic chamber containing a bird. In summer, nests are monitored from laying to fledging in occupied nesting boxes.

Expected results

Our preliminary data collected at FER Macpès suggest that heat loss is higher in chickadees in summer, during nestling provisioning than in winter. We expect to confirm this difference between the seasons. We also expect to observe higher heat production in less well-insulated individuals, and that the nestling provisioning rate is higher in individuals with less insulating plumage.

Research Site Coordinates