Forest Cover Correlation with Population Trends of the Eastern Towhee in the Mid-Eastern U.S.

The Eastern Towhee (Pipilo erythrophthalmus) is a large, ground-nesting sparrow-like bird in the Eastern United States that has shown dramatic population declines over the last 50 years. This species lives year-round in the southeastern U.S., but individuals from the northeastern U.S. migrate south in the winter and overlap with southeastern residents. The Eastern Towhee is one of the fastest-declining bird species in the eastern U.S. In this study, we compare Eastern Towhee population trends during the breeding season with winter population trends over the last three decades. Paradoxically, this species is significantly increasing in Maryland, West Virginia, New Jersey, Virginia, and Delaware during the winter, but decreasing during the summer. Using the national Breeding Bird Survey dataset, we show that the Eastern Towhee populations have been declining roughly at a rate of -11.58% in Maryland, -9.51% in West Virginia, -37.95% in New Jersey, -11.22% in Virginia, and -16.96% in Delaware per year from 1984-2015. But the populations have been increasing during winter roughly at a rate of 0.62% in Maryland, 0.05% in West Virginia, 0.33% in New Jersey, 0.08% in Virginia, and 0.51% in Delaware per year from 1984-2019, using the Christmas Bird Count. We explore a variety of hypotheses to explain this paradox, including a northward range shift in association with climate change, as well as changes in habitat availability. Our study documents how the natural world is changing in complex ways due to many stressors and will help understand how to conserve the Eastern Towhee.