HOARDING NUTHATCHES SPEND MORE TIME HIDING A HUSKED SEED THAN AN UNHUSKED SEED

We examine how time investment in handling food items of similar energ y content affects hoarding behaviour of wild Nuthatches Sitta europaea during autumn-winter in Central Spain. We test the possibility that N uthatches invest more time caching husked than unhusked seeds as they will obtain a benefit from the lower expenditure of energy and time du ring future consumption of prepared caches. Sunflower seeds were huske d in most of the observed caches (71.5%). In the study population indi viduals devoted over 27% of their hoarding time to handling the seed ( removing the sunflower shell), which means an important proportion of the time budget of hoarding Nuthatches. Hiding time, and time and dist ance flying from feeders to cache sites were longer when Nuthatches ho arded husked than unhusked seeds. These results are consistent with th e prediction that more valuable items will be spaced more widely toget her with more securely.