Bird trends from long-term observation data at sites in the Hudson Bay Lowlands

Monitoring population trends for bird species in the Arctic and sub-Arctic can be difficult and cost prohibitive. Breeding populations of birds in these remote locations may be changing and have garnered much attention regarding their conservation. We analyzed data from bird lists (daily species observations) collected while conducting other targeted research to estimate trends in the probability of observing species at two sub-Arctic study sites. For Akimiski Island, Nunavut (52 species) we estimated positive trends with high confidence (95% credible limits do not include 0) for 14 species and negative trends with high confidence for 18. For Burntpoint Creek, Ontario (46 species) we estimated that 12 species had positive trends with high confidence and 12 had negative trends with high confidence. More than 60% of species at each site matched population trends for at least one of three larger geographic scales that we compared estimates with; regional, provincial and national. We hypothesized that trends may be due to climate change effects or because of effects related to intensive herbivory from nesting geese. Trends for most of the species where we made specific predictions from these hypotheses agreed with those predicted; however, well-designed experiments are needed to conclusively determine the driving mechanisms of these trends. Collecting bird list data while simultaneously conducting other research is not nearly as time consuming or expensive as targeted breeding bird surveys (e.g., point counts, call counts, nest searching, etc.). This analysis method may be of utility for other remote field study sites where gaps in trend data exist.