Long-term monitoring of the population cycles and breeding success of Arctic and red foxes on Bylot Island, Nunavut

We are monitoring the reproductive activity of arctic and red fox on a 600km2 study area located in the South plain of Bylot. We have mapped (GPS) all available dens (n = ca. 100) and are visiting them every year. Foxes rarely dig new dens so the monitoring of existing dens can be considered as an exhaustive survey of the local population. Den visits allow us to estimate the abundance of the reproductive population (both species), the phenology of reproduction, and reproductive success (litter size) over the study area. About 50-80% of the pups and reproducing adults are tagged every year. Upon capture, tissue samples are collected for genetic and stable isotope analysis. A sample of adult males and females are also equipped each year with Argos satellite transmitters to determine year around habitat use by foxes. Automatic cameras are installed at some dens to monitor fox activities and behaviour.