Our research is at the interface between adaptive biology, physiology and ecology. Our projects are inspired by the energy challenges that birds face during critical life-history stages such as migration and breeding and by the constraints imposed by their environment, especially cold environments.
The projects cover several themes:
Winter energetics, individual performance and seasonal cycles in resident forest birds.
Non-migratory birds that spend the winter in Québec must face the harshness of the cold season. To do this, they developed a variety of physiological and behavioral adaptations. However, while cold acclimatization has been studied for decades, little is known about the trade-offs that birds must make to survive rapid changes in the winter environment. For example, how do they respond to the constraints associated with a cold spell or a warm-up period? What are the consequences on the condition of individuals and do these consequences have long-term effects? Do they have an impact on survival and reproductive success? Do some individuals adopt strategies that improve their fitness? Climate change is accompanied by an increase in the frequency and magnitude of winter climatic disturbances. A major objective of this research is therefore to determine how birds are responding to these disturbances.
The research began in the winter of 2009-2010 and takes place in the Forêt d'enseignement et de recherche Macpès (20 km from Rimouski). The main study species is the Black-capped Chickadee (Poecile atricapillus), but we are also interested in Boreal Chickadees (Poecile hudsonicus). The latter has undergone a steep decline in recent decades. Because of their small size, which greatly increases heat loss, these species are excellent models for this type of study. We are especially interested in the mechanisms that improve cold endurance in winter, such as adjustments of metabolic performance, changes in body composition and energy reserve management. We follow a population of about 400 birds marked with colored bands. This system allows for individual monitoring throughout the year through field observations and recaptures.
Reproductive effort, success and prey quality
Our team is also very interested in chickadee's reproductive effort. As breeding is considered one of the most energy demanding life-history stage for altricial bird species, we're particularly interested in finding out how this challenge compares with wintering in a cold environment such as Québec. At the Macpès forest we are following the breeding of 30-40 couples per year using nest boxes. The forest currently counts more than 1300 boxes! As natural nesting sites (dead trees, snags) are not lacking, this is the amount of boxes we need to follow enough nesting couples for our studies. Using these boxes allows for monitoring reproductive effort (e.g. chick provisioning rate) quite precisely and link this effort to daily chick growth rate, thermal environment, insect prey abundance and quality as well as physiological performance and behavioral traits of adults.
Experimental studies on phenotypic adjustments to the constraints of wintering and migration
Our lab at UQAR is equipped with facilities to conduct experimental studies with captive passerine birds. This includes temperature controlled rooms, outdoor aviaries and a complete respirometry laboratory. These infrastructures enable us to study, in controlled or semi-natural conditions, several mechanisms otherwise impossible or difficult to follow in the field. Our work touches several aspects of the birds physiology (e.g. cellular and hormonal regulation of heat production, body composition changes, basal and maximal metabolic rates, behaviour, energy reserve management, nutrition and condition). These infrastructures allow us to study the ability of birds to respond to experimental climatic disturbances (e.g. cold spells or sudden rises in winter temperature). Using domestic models, such as the zebra finch (Taeniopygia guttata), which easily breed in captivity, we can also study inter-seasonal effects resulting from specific constraints (e.g. effect of the cold environment on subsequent success of reproduction). So far we have used these facilities to work with chickadees, white throated sparrows (Zonotrichia albicollis), pine siskins (Spinus pinus) and snow buntings (Plectrophenax nivalis).
One important ongoing project investigates seasonal phenotypic changes in outdoor captive snow buntings. This species being a cold specialist, we are particularly interested in variation of body composition and metabolic performance happening during winter and spring migration. We are also beginning new projects to study heat tolerance in that species to determine whether the rapidly rising temperatures of their Arctic breeding grounds might lead to physiological constraints in the future.
Phenotypic transitions from migration to breeding in the High Arctic
From a physiological point of view, long-distance migration is an extraordinary phenomenon that requires a great deal of phenotypic flexibility. For example, several shorebirds travel thousands of kilometres without stopping each year during their migration between wintering and arctic breeding grounds. These migrations are associated with spectacular physiological transformations, such as the hypertrophy of flight muscles before departure and an atrophy of most internal organs during flight. On arrival, these organs must be quickly reconstructed, in parallel with the development of reproductive organs, for the birds to breed in the short amount of time available in summer. The transition between migration and breeding in the Arctic is therefore a crucial time, especially since it happens at a period where conditions can be quite harsh with a high potential for snow storms and a lack of food on arrival.
Snow buntings may not be endurance flyers but they nevertheless migrate through a winter landscape. They indeed leave their wintering grounds very early and arrive on their arctic breeding grounds well before the snow starts melting. Some males may even arrive up to a month before the females to secure their breeding territories. There is no doubt that these birds must undergo significant physiological transformations for migration, but they also have to maintain a wintering phenotype to be able to travel in the cold. The combination of challenges for migration and life in the cold is particularly interesting to us.
In recent years, in collaboration with Dr. T. Piersma (University of Groningen, The Netherlands) and R.I.G. Morrison (Environment Canada), we have been working on wintering energetics and post-migration recovery of shorebirds such as the Red Knot (Calidris canutus). We are now focusing our interest more precisely on the critical period of transition between migration and breeding in both shorebirds and snow buntings. This work takes place at the Canadian Forces Station Alert on Ellesmere Island, where we study metabolic performance and physiological changes in these birds in the spring.