|The Question: I saw a songbird on my fencing out in a field that sang and sang. It was a little smaller than a robin. The body was black with a yellow/tan cap. Then there was a white vertical stripe down the back and a white fan on the tail. What was it?
Submitted by: Lisa, New York, USA
The Short Answer: That sounds like a bobolink (Dolichonyx oryzivorus) to me. They often sit on fenceposts at the edge of farm fields and sing. Here’s a link to a youtube video of a bobolink singing:
(Follow-up: The reader confirmed that this picture and song matched what she had seen, so I think we have a match.)
More Information: Bobolink populations have been shrinking in the northeastern U.S., probably due to habitat loss. Bobolinks are grassland birds and as open areas in the northeast are converted to housing developments and other uses, there is less habitat for bobolink and other grassland creatures. Farms and hayfields could provide some habitat for grassland animals like bobolink, but as ground nesters, bobolink have to contend with challenges such as agricultural chemicals, grazing by livestock, and harvesting of crops and hay. Any of these disruptions can lead to nest failure. Studies have shown, however, that with a little planning, we can have pastures and hay and bobolinks, too. For example, by waiting to mow hayfields until after the critical nesting period from mid-May to early July, nest success is greatly increased.
Carnivorous Cows: Some farm animals that we don’t think of as predators – cows, for example – will actually eat bobolink chicks out of a ground nest.
Sources: Perlut, N, & Strong, A. (2011). Grassland birds and rotational-grazing in the northeast: Breeding ecology, survival and management opportunities. Journal of Wildlife Management, 75(3), 715-720.
Ingold, D, Dooley, J, & Cavender, N. (2010). Nest-site fidelity in grassland birds on mowed versus unmowed areas on a reclaimed surface mine. Northeastern naturalist, 17(1), 125-134.
Kerns, C, Ryan, M, Murphy, R, et al. (2010). Factors affecting songbird nest survival in northern mixed-grass prairie. Journal of Wildlife Management, 74(2), 257-264.[cite]