DECLINE OF THE RUFOUS-SIDED TOWHEE IN THE EASTERN UNITED-STATES

Authors
Citation
Jm. Hagan, DECLINE OF THE RUFOUS-SIDED TOWHEE IN THE EASTERN UNITED-STATES, The Auk, 110(4), 1993, pp. 863-874
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Ornithology
Journal title
ISSN journal
0004-8038
Volume
110
Issue
4
Year of publication
1993
Pages
863 - 874
Database
ISI
SICI code
0004-8038(1993)110:4<863:DOTRTI>2.0.ZU;2-4
Abstract
The Rufous-sided Towhee (Pipilo erythrophthalmus) is a forest-generali st species that migrates short distances, with most of its range confi ned to the contiguous United States. Using migration count data from t he 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 repo rted 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 19 66. Christmas Bird Count data from the southeastern United States also showed a decline in towhees, whereas Breeding Bird Survey data from t he 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 Bi rd 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 mo re forested landscape. Natural forest succession, following human-indu ced forest changes earlier in this century, may explain the current de clines in towhees.