Song Sparrow - Predators and Parasites

Predators and Parasites

Common predators of the Song Sparrow include cats, hawks, and owls. Snakes, dogs, and the American Kestrel are treated ambiguously, suggesting that they are less of a threat. The Song Sparrow recognizes enemies by both instinctual and learned patterns (including cultural learning), and adjusts its future behavior based on both its own experiences in encounters, and from watching other birds interact with the enemies. Comparisons of experiments on hand-raised birds to observation of birds in the wild suggest that the fear of owls and hawks is instinctual, but fear of cats is learned.

Song Sparrows' nests are parasitized by the Brown-headed Cowbird. The cowbirds' eggs closely resemble Song Sparrows' eggs, although the cowbirds' eggs are slightly larger. Song Sparrows recognize cowbirds as a threat and attack the cowbirds when they are near the nest. There is some evidence that this behavior is learned rather than instinctual. A more recent study found that the behavior of attacking female cowbirds near nests may actually attract cowbird parasitism because the female cowbirds use such behavior to identify female Song Sparrows that are more likely to successfully raise a cowbird chick. One study found that while cowbird parasitism did result in more nest failure, overall there were negligible effects on Song Sparrow populations when cowbirds were introduced to an island. The study pointed to a number of explanatory factors including Song Sparrows raising multiple broods, and Song Sparrows' abilities to raise cowbird chicks with their own.