Responses of Naive Temperate Birds to Warning Coloration

Eight house sparrows (Passer domesticus), seven blue jays (Cyanocitta cristata) and two red-winged blackbirds (Agelaius phoeniceus), hand-reared on moderately varied diets, were offered a series of colors and patterns painted on wooden dowel models. All three species attacked every color and pattern without measurable hesitation; this included two patterns avoided by similarly hand-reared neotropical omnivores. The temperate birds' attack on aposematic patterns and their tolerance of novelty suggest that there is no widespread mechanism allowing newly fledged birds to reject the first aposematically marked organisms they encounter. The blue jays and red-winged blackbirds attacked a coral snake pattern, even though individuals of both species migrate into coral snake range, and young coral snakes are both prey-sized and potentially lethal. The difference in behavior between these northern migrants and the neotropical omnivores studies earlier may be related to the age at which each can encounter its first coral snake.