
This is a juvenile Brown-headed Cowbird in our backyard. I first noticed him hanging out with our male Northern Cardinal, which I found odd. Then I learned that Cowbirds are famous for laying their eggs in the nests of other bird species instead of building their own. This is known as a brood parasite. Cowbirds do not raise their own chicks, but the unsuspecting birds who incubate the Cowbird’s eggs raise them instead.
Brown-headed Cowbird — Molothrus ater
SIZE:
- Male
- Length: 7.5-8.7 in (19-22 cm)
- Weight: 1.5-1.8 oz (42-50 g)
- Wingspan: 14.2 in (36 cm)
- Female
- Length: 6.3-7.9 in (16-20 cm)
- Weight: 1.3-1.6 oz (38-45 g)
- Wingspan: 12.6-15.0 in (32-38 cm)
LOCATION:

FOOD:
Cowbirds eat seeds from weeds and grasses and some grains. They live near cattle and bison and feed on Insects such as grasshoppers and beetles, that the large mammals stir into into motion.

This is our male Northern Cardinal named “Red” who is feeding the juvenile Brown-headed Cowbird.
Eventually, the juvenile Cowbirds leave their adoptive families and find other Cowbirds. Scientists are studying this phenomenon to figure out how they recognize their own species. Some think it’s through their sounds that they recognize other Cowbirds.
SOUNDS:
https://www.allaboutbirds.org/guide/Brown-headed_Cowbird/sounds

We have cowbirds as well, but only in the spring and early summer.
I’ve just noticed cowbirds this summer. I’ll see if they stay.
It seems wrong that the Cowbird uses other species like this. Odd! 😂
Not only does it seem wrong, sometimes the chicks that belong in the nest die because the cowbird fledgling is bigger, takes all the food or smothers them.
This reminds me of a piece of parenting advice I once heard, which goes, don’t wait so long to have children that your parents are too old to raise them.
True. The Cowbirds have no interest in raising the chicks. Only laying the eggs.
This doesn’t sound like a nice bird. 🙂 I’ve never heard of this species before, but it’s nice of Red to feed the young Cowbird.
I see them together every few evenings. The Cowbird stays outside our fence and Red visits the bird feeder and flies over to the Cowbird with birdseed.
I suspect we have them here, given the map in your post but I don’t think that I’ve seen one yet. Probably more likely out on our hikes than in the neighborhood. Very opportunistic birds for sure, but I guess that’s what evolution is all about.
I have only seen one or two this summer. I’m not sure if they are seasonal or not. The males are shiny black and the females brown.
Wonderful observation. I’ve read about cowbirds but never seen them. For that matter I’ve seen many cuckoos and many of their target species, but never observed this kind of parasitic behaviour.
It was so fascinating to see. But I’ve also read that the Cowbird fledglings can be bigger than the songbirds chicks that are hatching. The Cowbird is more aggressive getting food from the songbird parents and can also smother the other chicks. I find it fascinating that our Cardinals had three of their own fledglings this summer who flew the nest, and now they’re raising a Cowbird!
Are cowbirds and crows the same species?
No. Cowbirds are a type of Blackbird while Crows belong to a different family. The male Cowbirds are black with a brown head, females are all brown. Crows also build their own nests and raise their chicks.