Do birds track climate or weather?
Post-doc Brooke Bateman is taking a new approach to evaluating where birds like to hang out. Typically, when people are trying to predict where certain species occur, they will compare long-term climate data from sighting locations to get an idea of the range of conditions those birds prefer. This information can then be used to map out where suitable environmental conditions for the different species exist, and estimate where on the landscape we can expect to find them. However, the long-term climate data is typically produced by reducing climatic conditions over the past 30-60 years to a single value. Brooke had a hunch that examining weather patterns over a shorter time frame might provide a little more insight into where different species occur. In order to compare the predictive power of climate and weather, Brooke produced two sets of species distribution models; the first using climatic data (averaged over 60 years), and the second using weather data averaged over shorter temporal extents (either 6, 12, or 36 months). She examined a range of climatic variables over this period, including average temperature and precipitation, along with the seasonality and extremes of these two variables. She examined the response at the individual species level, while also looking at effects at the guild level by grouping the species by either feeding or migratory tendencies. While most of the data are freely and readily available, this approach of using a fine temporal resolution required a little additional legwork and a whole lot of extra processing horsepower. But in the end, it appeared to be worth it.