THE ADRENOCORTICAL RESPONSES TO STRESS IN SNOW BUNTINGS (PLECTROPHENAX-NIVALIS) AND LAPLAND LONGSPURS (CALCARIUS-LAPPONICUS) AT BARROW, ALASKA

Free-living snow buntings (Plectrophenax nivalis) and Lapland longspur s (Calcarius lapponicus) showed marked increases in circulating cortic osterone up to 1 hr post-capture, indicating that their hypothalamo-pi tuitary-adrenal axes responded to the acute stress of handling and res traint in a manner similar to that of other vertebrates, although the magnitude of these responses was generally less. In the snow bunting t here was no difference in the adrenocortical response to stress betwee n June (breeding) and September (just prior to autumn migration). Howe ver, individual variation in the maximum corticosterone level attained during the stressful period was significantly correlated with fat sco re in both species, Those with greater fat depots have reduced respons iveness to stress.