Dawn M. O’Neal, Suzanne H. Austin, and Ellen D. Ketterson. 2024. Impact of climatic change on non-breeding distribution and abundance in a classic differential migrant. In review.
A recent Ketterson lab study (O'Neal et al. 2024 in review) using Christmas Bird Count data shows that the winter distribution of the dark-eyed junco has moved northward since 1960! Note that abundance varies by latitude and the distribution curve is bell-shaped, indicating that juncos are most abundant at middle latitudes and abundance declines to the north and south.