LEARNING AND THE FORAGING PERSISTENCE OF WHITE-CROWNED SPARROWS ZONOTRICHIA LEUCOPHRYS

Ten White-crowned Sparrows Zonotrichia leucophrys took part in an experiment of 24 trials in which they foraged for food hidden in one of four blocks. Each block had six depressions covered with sunflower seed shells. On each trial three of the blocks were empty while one contained six sunflower seed particles. Initially the birds removed most of the covers from the empty blocks as well as from the baited blocks. However, as the experiment progressed, many of the birds learned to displace only a few covers from the empty blocks they encountered before leaving to search for the block with sunflower seeds. In other words, the sparrows proved capable of learning to adjust the time spent foraging in areas of identical appearance on the basis of the results of their initial “test” pecks. The ability to alter foraging persistence on the basis of test probes could contribute to the efficient exploitation of hidden food by bird predators.