PHENOLOGY OF SIX MIGRATORY COASTAL BIRDS IN RELATION TO CLIMATE CHANGE

The migration phenology of six species of coastal birds on Mustang Island, Texas, USA was examined for a 27-year period (1978-2005). First arrival date, last date of departure, and duration of stay were quantified for three winter and three summer residents. These three variables were analyzed for changes over time and correlation with local, regional, and global temperature indices. Mean local summer temperature increased 0.03 degrees C/year (0.74 degrees C overall), while mean local winter temperature increased 0.10 degrees C/year (2.76 degrees C overall). The three winter residents had a trend for increasingly later arrival, increasingly earlier departure, and decreased duration of stay over the 27-year period. These trends reflect a shortening of the winter season for these birds and are consistent with expected responses due to warming temperatures. The three terns representing summer residents had less homogeneity in temporal trends than the three winter residents. Correlations of local temperature with arrival and departure dates, and duration of stay yielded few significant results and no overall pattern. Only Double-crested Cormorant (Phalacrocorax auritus; a winter resident) and Least Tern (Sterna antillarum: a summer resident) had significant correlations between arrival date and arrival temperature. Received 27 March 2009. Accepted 3 September 2009.