Age differences in the response of California ground squirrels (Spermophilus beecheyi) to conspecific alarm calls

Juvenile California ground squirrel responses to adult alarm calls and juve nile alarm calling may be modified during development to achieve adult form . Adult conspecific chatter and whistle alarm calls were played back to juv enile and adult ground squirrels at an agricultural field site. In response to chatter playbacks, adults spent more time visually orienting to the env ironment and less time out of view and in covered habitats than juveniles; the converse was true in response to whistle playbacks. To test the evocati veness of juvenile calling, a subset of adult subjects received juvenile ch atter and whistle playbacks. Adults spent less time out of view to juvenile call types than to adult calls, and showed more similar responses to juven ile chatters and whistles than to adult chatters and whistles. Age differen ces in the ground squirrel's alarm call system may reflect adjustments to c hanging risks during development.