Question: Have researched this question to no avail! We have tons of Brown headed Cowbirds this time of year on the feeders and on the ground. Often a male or two puffs himself up, tucks his head in, and naps on the ground under the largest feeder. Seems like a risk with all the birds of prey around. If you approach, they are not startled very easily. Never seen this before and is it normal? Thanks for any input! – Paula Adamson
Answer: This is not a behavior that I am familiar with, but we can always hypothesize. During the winter months, the Brown-headed Cowbird is a social bird hanging around with birds of a feather and other blackbirds. If multiple birds hang around together, every bird does not need to be watchful for predators. There needs to be some paying attention. Those birds sound the alarm and the quick reaction time for a bird would allow them to avoid predators.
If you had said that the birds fluffed themselves out, sat spread tail, and occasionally shook their head, I would have said the bird was anting. This common behavior lets ants roam over the birds body picking off parasites, but it usually does not look like sleeping.
About now, the Brown-headed Cowbird will start to pair up resulting in a whole host of displays, some to entice a mate others to define dominance. A bunch of males will go through an array of display postures which can be lifting their wings as they sing, fanning their tails, spreading their wings and bowing, or puffing up, arching their back and then move into a bow in an effort to entice a female. The male with the most moves will be the lucky one. Watch for some of these behaviors at your feeder.
While many birders revile the cowbird, they are a remarkable species. It is well known that these birds do not build their own nest, but lay their eggs in the nest of other birds who then raise their young. Scientist have documented 144 species that have raise cowbird eggs though they have seen cowbird eggs in the nests of over 220 species. Somehow once the baby is out of the nest, it recognizes that it is not the species of its adoptive parent. It then seeks out other cowbirds to hang out with at our feeders. Since we cannot do anything about their parasitic behavior, while we grumble about their abundance, maybe we should learn to watch and enjoy the uniqueness.
The Brown-headed Cowbird: An Abundant Brood Parasite (avibirds.com)
Behavior – Brown-headed Cowbird – Molothrus ater – Birds of the World
– Bob Mercer, SIB’s “Resident Naturalist”
Postscript comment from Paula: Thanks so much for your input. I was mostly concerned that the sleeping cowbirds looked like a perfect target for birds of prey, and I was right. Bob was watching with binoculars the other day and a sleeping Cowbird was scooped up by a red tailed hawk and taken away. Of course, part of normal nature, but the Cowbirds maybe aren’t too smart? Happy bird watching everyone!
Bob’s response: “Predators can most easily take the weak, sick, or aged prey. Your cowbird probably fell into one of those categories. It would explain the odd behavior that you first noticed.”