I’m here to study how red-winged blackbirds respond to the vocalizations that signal nearby nest parasites called brown-headed cowbirds. The cowbirds seek to lay their eggs in these other species’ nests and let the adoptive parents raise their young. But the host birds have evolved their own strategies for dealing with cowbirds. Yellow warblers, in particular, have evolved a special call, the “seet” call, that they use to warn each other that a cowbird is nearby. We think that red-winged blackbirds, who also get parasitized by cowbirds, might understand the meaning of this call, and actively eavesdrop on their yellow warbler neighbors to glean the information. My job is to study these interactions and measure the birds’ responses to the calls.
As I approach the nest, the blackbird parents begin making alarm calls and hopping between cattails around the nest. The male stares me down while flicking his tail and wings – a sign that I’m not welcome here. Red-winged blackbirds are among the most brash and vocal birds you’ll ever meet.
I find a suitable branch near the nest, unzip my pack and pull out a game call speaker to hang on the branch. I turn on the speaker, select a track and quickly hide nearby.