Caterpillar Leaf Damage, and the Game of Hide-and-Seek with Birds

Abstract

In an aviary, field—captured Black—capped Chickadees, Parus atricapillus, learned to forage preferentially at trees with either artificially or caterpillar—damaged leaves. The birds also distinguished between species of broad—leaved trees. These individuals showed differences in foraging behavior, possibly related to previous conditioning in the field. When captured, two of the birds were already using leaf morphology (rolls and discoloration) to search for caterpillars. Two others initially disregarded leaf morphology and instead scanned for prey directly. However, when the potential prey was highly cryptic or hidden, the birds all learned to use both tree species and leaf damage simultaneously as cues in their searching effort for specific prey. Caterpillars that were palatable to the chickadees had feeding behaviors that tended to minimize their apparent feeding damage on leaves, while caterpillars that were not eaten did not have these behaviors.