Decline of the Rufous-Sided Towhee in the Eastern United States

Abstract

ABSTRAcr.-The Rufous-sided Towhee (Pipilo erythrophthalmus) is a forest-generalist species that migrates short distances, with most of its range confined to the contiguous United States. Using migration count data from the northeastern United States, national Breeding Bird Survey data, and regional Christmas Bird Count data, I show that the towhee is making one of the most dramatic declines of a non-endangered species yet reported in the United States. Breeding Bird Survey data from New England states show that the towhee has been declining monotonically at about 8 to 10% per year. Populations in the Northeast are now at levels only about 13% of what they were when the Breeding Bird Survey began in 1966. Christmas Bird Count data from the southeastern United States also showed a decline in towhees, whereas Breeding Bird Survey data from the same region showed smaller declines, or no declines. This suggests that declines in wintering migratory towhees from the Northeast might explain most of the declines found in the Southeast using Christmas Bird Count data. The most likely explanation for this long-term, chronic decline in New England towhees is a gradual reversion of southern New England from a landscape with much early-successional habitat to a more forested landscape. Natural forest succession, following human-induced forest changes earlier in this century, may explain the current declines in towhees. Received 2 March 1992, accepted 25 November 1992.