Data for: Climate change alters tension of conflicting selection pressures on breeding date in a passerine bird by Moelling and Duckworth

Contains data and SAS code for performing an analysis of natural selection on breeding date in a population of western bluebirds as well as a historical trend analysis of April temperatures and cold snap occurrence in the area since 1948. Breeding data comes from a long-term study of a population of western bluebirds in western Montana. Climate data were taken from a local weather station approximately 10km from the site (Missoula International Airport, Station USW00024153) using Cornell’s single station data tool CLIMOD