3 September 2025

The breeding season is over for brown-headed cowbirds in Pittsburgh. The adults courted constantly while the females were fertile but egg-laying stopped in mid-July. By now all the youngsters have fledged and left their hosts to join flocks of cowbirds. These youngsters were raised by another species so how do they know what flocks to join? A new study found out their parents have nothing to do with it.

Parental neglect starts early. Female brown-headed cowbirds (Molothrus ater) are brood parasites that lay their eggs in the nests of smaller birds.  Each cowbird chick is raised, not by its own mother, but by foster parents of another species. Initially the cowbird female lurks near the foster nest to make sure her own egg survives and will sometimes destroy the host’s eggs if her own egg disappears. But after that she’s too busy laying up to 40 eggs per season.

If the biological parents don’t care for it, why doesn’t the young cowbird stay with its host species?

Unlike most birds, a young brood parasite doesn’t get attached to its host parents. You can see this if you rear cowbirds by hand, said Mark Hauber, a comparative psychologist at CUNY Graduate Center in New York: “They start hating you at some point.” If a cowbird imprinted on a family of yellow warblers, say, and sought out warblers’ company as an adult, it would never find a mate and reproduce.

— New York Times: How a Parasitic Bird With No Parents Learns What Species It Is

Early studies on how the youngsters discover their own species found that young cowbirds are attracted to the chattering calls of adult females, prefer to associate with birds whose plumage matches their own (immatures and females look similar), and many even hang out with their mothers.

However, the new study published in ScienceDirect in August conducted DNA tests on groups of immature cowbirds and adults captured together and found that the youngsters always hung out with females but they were never related to them.

Somehow, Chamberlain says, they bump into adult cowbirds and start hanging around them and learning how to behave. But the clock is ticking: By the end of the summer, the juveniles and adults will migrate south. “They have a short time period in which they need to learn these things,” Mr. Chamberlain said.”

— New York Times: How a Parasitic Bird With No Parents Learns What Species It Is

Groups of women teach the young. It takes a village to raise a cowbird.

29 August 2025

Though eastern kingbirds (Tyrannus tyrannus) are smaller than robins they’re called kings because they win so many battles.

Attacks by Eastern Kingbirds on nest predators such as corvids, raptors, and even large, nonpredatory birds are legendary. Aggressiveness increases the chances that an active nest will fledge young.

Unsuspecting Blue Jays have been knocked out of trees or driven to ground to seek shelter under bushes. Flying crows, all Buteo hawks, Northern Harrier and basically all raptors are attacked whenever they enter kingbird’s defended space.

— Birds of the World: Eastern Kingbird Behavior: Responses to predators

When an eastern kingbird is especially annoyed it displays the red crown that’s usually hidden under dark head feathers. This one is thinking about attacking someone maybe a predator, maybe another kingbird, or maybe any bird that dares to enter his territory.

[The kingbird] also uses a particularly startling display during vigorous attacks on humans and presumably other predators. While in steep dive toward predator’s head, an Eastern Kingbird may expose and raise red crown patch and open mouth wide to reveal red gape. The effect is dramatic and has caused at least one human to nearly lose his grip and fall from a tree (M.T.Murphy).

— Birds of the World: Eastern Kingbird Behavior: Responses to predators

That’s exactly what Ed McKaveney (@edtechfocus) saw when a kingbird attacked a raven on 10 August. What a great action shot!

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A post shared by Ed McKaveney (@edtechfocus)

18 June 2025

We tend to take gray catbirds for granted but here are some cool facts you might not know. For instance:

• Gray catbirds (Dumetella carolinensis) are monotypic, the only species in their genus. The catbird’s genus name Dumetella means “small thorny thicket” a reference to his habit of singing from inside thorny thickets instead of from a prominent perch.

• Yes they are gray but they have a splash of color under their tails: rufous undertail coverts.

• Males and females look alike except for these subtle differences.

Sexes show similar appearances in all plumages, although females average duller than males and average less-extensive rufous on longest undertail coverts.

— Birds of the World: Gray Catbird appearance

• Catbirds use their sense of smell to find their way on migration(!) as described in this vintage article: Sniffing Their Way North.

• They are present all year in some parts of the U.S. (purple areas below) but most of us see them only in the breeding season. In Pittsburgh they typically arrive in late April and leave in mid October.

• They nest in the middle of thickets and lay turquoise blue eggs.

• Catbirds are rarely parasitized by brown-headed cowbirds because they recognize cowbird eggs in their nests and kick them out. Note the color! described in this vintage article Cat Versus Cow.

• Male catbirds are jazzmen! Their song is an improvisation rather than a direct imitation. Read more at: Virtuoso

Here’s the catbird’s song:

(video from Wikimedia Commons)

And here’s his “meow.”

Enjoy his song this month. He’ll stop singing soon.