Learning where to store your food: microsite caching preferences of yearling and adult Florida Scrub-Jays

Florida Scrub-Jays (Aphelocoma coerulescens) survive winter periods of low food availability by harvesting and caching acorns for future consumption. Cached acorns can germinate, rot, be eaten by other acorn predators or be recovered by jays, thus choice of caching sites might be important. However, it is unclear whether site choice is innate or learned. I attempted to determine if caching sites were influenced by microhabitat type or by the social context (age and sex of jays observing). In addition, I asked if food caching site preferences differed relative to the availability of potential cache sites and if those preferences were different between inexperienced birds during their first caching season and experienced birds. I found that inexperienced and experienced jays exhibited significantly different preferences for caching microhabitats. Yearlings cached items exclusively in vegetated sites (p=.015, χ2=8.38); whereas, adult birds cached exclusively in open bare sand sites (p=.035, χ2=6.68). Soil moisture was significantly lower in the sites utilized by adult jays compared to soil moisture of yearling cache sites (p=.028). I also found that yearlings cached significantly farther when they were observed by a dominant bird (p=<.001) and were more likely to cache in a vegetated site rather than in the open. These results suggest inexperienced birds may cache in poorer quality sites than their experienced, and usually socially-dominant family members. Experienced birds, whether socially dominant or not, preferred to cache in dry, bare sand patches, suggesting they had changed their preferences.