Project
Kluane red squirrels (Tamiasciurus hudsonicus) have several characteristics that make them ideal for studying ecological and evolutionary processes in the wild. Red squirrels are diurnal and actively defend exclusive, year-round territories so all individuals within a population can be censused with certainty. As a result, the fate of all individuals in a population can be followed from birth to death. We have used regular live trapping of marked individuals and complete enumeration of populations in spring and fall of each year to follow the fate of the roughly 5500 squirrels born in the Kluane populations since 1987. We have also developed reliable techniques to assess female reproduction and enumerate offspring within days of birth. Our ability to monitor the survival and reproduction of all individuals throughout their lifetime has allowed us to quantify female lifetime reproductive success, fitness and natural selection. Permanently marking offspring within their natal nest also means that all mother-offspring relationships are known with certainty. These maternal relationships comprise a pedigree of over 5000 individuals, which is one of the most extensive pedigrees for a wild mammal.

The Importance of Food Resources to Red Squirrels.
Kluane red squirrels feed almost exclusively on the seeds of white spruce cones (Picea glauca). White spruce exhibits 2-6 year masting cycles, where a year of superabundant cone production is followed by several years in which few cones are produced. We have quantified spruce cone production in our study area in each of the past 17 years. Red squirrels behaviorally mitigate this remarkable interannual variation in food abundance by storing cones for multiple years in central middens, but research on Kluane red squirrels over the past 17 years indicates that natural variation in food production still has important consequences for red squirrel population dynamics, behavior, life history and physiology.

Ecological Research
The ability to quantify resources available to individuals as well as their reproductive success has allowed us to determine how short- and long-term changes in resource availability affect life history traits, and population dynamics in this boreal mammal. The combination of long-term information on thousands of individuals and the ability to experimentally manipulate resources provides a powerful approach to understanding the causes and consequences of variation in individual reproductive success.

Energetics Research
We have recently developed protocols to measure resting and field metabolic rates of red squirrels during key periods including cone caching, winter, and peak lactation. In addition, focal behavior sampling during September and October allows us to estimate the number of cones cached by individual squirrels. We are now in the unique position of being able to measure the total food available on a red squirrel territory, how much is stored, and the associated activity levels, energy expenditure, life history traits, and lifetime fitness of individual squirrels

Evolutionary Research
Assessment of the reproductive success and fate of all females and the development of a substantial multigenerational pedigree has allowed us to document evolutionary changes in both the timing of spring breeding (i.e. parturition date) and juvenile growth rates over the past 15 years. Kluane red squirrels, therefore, represent one of the few wild populations for which evolutionary responses to contemporary episodes of natural selection can be quantified. However, what makes Kluane red squirrels truly unique is our ability to quantify and experimentally manipulate the key ecological resource shaping these contemporary adaptations.

Kluane Red Squirrel Experiment
The goal of this project is to experimentally test the importance of spruce cones to red squirrel ecology, energetics and evolution. In this collaborative project we will experimentally mimick high food conditions in replicate (3) populations of red squirrels in each of the next 5 years. We will do this by supplementing each individual with peanut butter in an elevated feeder (see photo at left) located near the ceneter of their territory. Measures of individual food availability, reproduction, energy expenditure, reproductive success and fitness will provide an integrated understanding of the importance of food resources to red squirrels. This ambitious experiment, together with 17 years of existing data will provide valuable insights into the relationships between ecology, energetics and evolutionary change in the wild.