There is growing evidence in Europe and in North America that climate patterns affect the occurrence and migration of forest-dependent birds. In British Columbia, climate change effects will likely have profound implications for sustainable forest management. This project seeks to identify climate-change impacts on birds in British Columbia that will be critical to sustainable management strategies under a changing climate. Our specific objectives are to identify how climate has historically affected bird abundance, breeding, and distribution, and then project future abundance and distribution under likely climate change scenarios. We detected significant trends in the relative abundance of many avian species throughout British Columbia between the early 1970s and 2003, which may reflect changes in climate as well as changes in non-climatic factors, such as habitat quality and habitat availability. However, significant trends in the arrival and departure dates, as well as in the first date of egg laying and fledging, support the contention that at least some of the historical trends in population densities may be attributed to climate change. Our analyses to date have generated many significant relationships between climatic factors and the phenology and abundance of avian species. We found, for example, that several species increased in abundance (e.g., Winter Wren, Common Yellowthroat) or bred earlier (e.g., Common Loon) in warm or mild years. However, other species (e.g., Western Wood Pewee) declined in abundance with increasing temperatures. We also found that the effects of climate change were not consistent across the province. For example, unlike elsewhere in the province, many species in the Georgia Depression declined in abundance during warm years. This may be because warm years in most parts of the province were typically associated with wetter weather, but warm years in the Georgia Depression were often associated with lower precipitation. Although we found significant relationships between climate and abundance for many bird species, we were not able to detect any significant climate effects for the majority of cases. Our research is continuing to evaluate why this is the case.
Chan-McLeod, Ann. 2005. Effects of climate change on avian communities and implications for sustainable forest management. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report