Day 161: Black-billed Cuckoo

Another bird we really wanted to see in western Maryland was a Black-billed Cuckoo. These are shy birds, so they can be hard to spot, even though they are fairly large. We heard several (they have loud calls), but were also lucky to get a decent look at one. It can be easy to confuse the Black-billed Cuckoo with the more common Yellow-billed Cuckoo, which I will blog about another time. The Black-billed Cuckoo has a more northerly range, and they prefer more densely wooded areas.
 

Adults have a long brown tail and a black bill. The head and upper parts are brown and the underparts are white. They also have a red ring around the eye.

I found some interesting facts about the Black-billed Cuckoo. Evidently, they are a huge consumer of caterpillars (particularly poisonous species), and have been observed to eat 10-15 caterpillars per minute. Stomach contents of individual cuckoos may contain more than 100 large caterpillars or several hundred of the smaller species. The bristly spines of hairy caterpillars pierce the cuckoo’s stomach lining giving it a furry coating. When the mass obstructs digestion, the entire stomach lining is sloughed off and is regurgitated as a pellet. Kind of gross, but also fascinating! It is speculated that the decline of Black-billed Cuckoo populations is due, in part, to the use of pesticides to kill caterpillars.