Why I Don't Like Cowbirds

It is the Sunday of Labor Day weekend and I am far from laboring. There is a large spider on one of the poles holding netting in front of the hummingbird feeder, taking in some sun. The squirrels don't seem as active in the trees. As usual, people are not rushing around in their cars or with their lawn mowers. There is the faintest tinge of red in the leaves of the dogwood, another signal that summer is ending, the days are getting shorter and soon I'll be closing up the garden and taking in plants for winter.

Male cowbird, Cape May, NJ (RE Berg-Andersson)

Birds should've ended their breeding and raising of young by now. Many birds are on the move southward, taking advantage of those recent cooler days when the wind comes from the north to give them a push along.

However, amid this sluggishness I hear a high-pitched chatter I recognize. Then I see them, the male cardinal flying across the yard with a begging, scolding, badgering cowbird chick close behind.

It has been some time since I've seen this. Cowbirds are a peculiar species, at least to me. The only way the species can continue is the female - a drag brown, easily overlooked or confused with something else - drops one of her eggs into another bird's nest. The egg hatches, usually ahead of the bird's own eggs, and the chick is usually bigger too. To make sure it gets fed, it can push the other eggs out of the nest, monopolizing the parents. This is what the cowbird chick in my yard was doing with the adult cardinal pair.

And yet, somehow when the chick grows to maturity it knows it is not a cardinal, a robin, a Carolina wren. It flies off and joins with other cowbirds in large flocks, frequently joining with even larger flocks of grackles, redwinged blackbirds and starlings in winter as a way of finding food and protection.

When the adults pair, they are not monogamous and the female can lay eggs from a number of mates in the nests of more than 220 species of birds, according to the Cornell Lab of Ornithology. (Yellow warblers have been known to recognize cowbird eggs and build a new nest and lay a new clutch of eggs over the old. Other birds toss the cowbird eggs out. Cowbird eggs placed in goldfinch nests don't survive because goldfinches eat only seed rather than the insects a cowbird needs.)

Male cowbird flock, Cape May, NJ (RE Berg-Andersson)

Some people find the male cowbird handsome but I do not. These birds were once found solely on farms, following cattle (hence their name). However, according to the bird people at Cornell, once the open grasslands became towns and suburban developments, the birds spread. Now you are as likely to see them at your feeders. I try to chase them off mine whenever possible.

I pity the cardinal. This species seems particularly vulnerable to the parasitizing of its nests. It does not see a cowbird when the bird begs to be fed, it sees young and must feed it. The adult bird is programmed to do that. It does not "see" that this is not a cardinal. In fact, both parents are "blind" to that fact. All they know is the bird must be raised to fledge and then fed until it can take care of itself so it can mate and continue the species next year.

Luckily, cardinals, unlike several other types of birds whose numbers are down because of the cowbird as well as habitat destruction, are far from endangered. They will have several broods a year. There are many cardinals. They will come to my feeder and I will keep it filled for them. 

Unfortunately, cowbirds aren't endangered either. For now, I will have to put up with hearing the continual, annoying, badgering, high-pitched begging whine until something in the cowbird's mind tells it it's time to go find more of its own kind.