An Avian Murder Case on a Quiet Back Porch

I open the pantry door and the eastern phoebe flies off the nest. Her cup-shaped home is made of mud, covered in moss and cantilevered over a glass light fixture — an avian Fallingwater. Her nest placement makes sense. Before eastern phoebes lived so close to humans, they built their nests on cliffs. Every year for 35 years, we’ve had an eastern phoebe nest under the eaves of our back porch. Without her, it would not be spring.

Eastern phoebes are in the flycatcher family and consume not just flies, but also wasps, grasshoppers and even ticks — great news to those of us who can’t walk in the woods without getting bitten. Native to North America, they also eat small berries from our native plants such as Virginia creeper. Its call is like its name: an onomatopoeic “fee bee.”

I puzzled at first if the bird might be an eastern wood-pewee, another grayish white flycatcher with a short bill, but the giveaway was the way the eastern phoebe wags her tail when she flies off the nest and lands on the lilac bush by the stream.

Eastern phoebes have the distinction of being the first bird ever banded, in 1804 by John James Audubon himself. He, too, watched an eastern phoebe nest at his farm in Mill Grove, Pa., about 200 miles east of here as the flycatcher flies. One autumn day, the story goes, he tied silver threads onto the legs of five nestlings before they migrated south and reported that two of the marked birds returned the next spring.

On our farm, eastern phoebes are among the first birds to return from the southern United States or Mexico, and the female at my back door was sitting on her first clutch of eggs by mid-April. Females lay two to six white eggs, maybe with dots of red and brown, usually two clutches a year. Every day I watch her from my perch, a kitchen table that doubles as a desk.

But this year I’m worried. One day last spring when I went to check on her, I found three raw and naked eastern phoebe nestlings tossed onto the porch floor. At first, I suspected brown-headed cowbirds, famous as they are for raiding nests. But I’d observed house sparrows divebombing the back door, which I’d never seen before, and then learned that while brown-headed cowbirds often remove eggs to make room for their own, they don’t dump out nestlings.

Which meant a nonnative bird was killing our native birds. House sparrows, originally from Europe and Asia, were brought to Brooklyn in the 1850s to control caterpillars. By 1870, their introduction had incited a “Sparrow War” between two ornithologists who disagreed on whether it was a good idea. Though house sparrow numbers in the United States are down — to 80 million today, from 400 million in 1966 — they are still one of our most common birds, and we’ve had an explosion of them on the farm. They nest in gutters and hanging lanterns and are aggressive when competing for nesting space.

According to the Cornell Lab of Ornithology, house sparrows have been known to attack many bird species, including bluebirds, purple martins and tree swallows. The situation is so bad for eastern bluebirds that the North American Bluebird Society recommends removing and destroying house sparrow eggs from bluebird boxes and trapping adult house sparrows. (Be sure house sparrows are the culprits, they advise, because native species are strictly protected under the Migratory Bird Treaty Act.)

Kill house sparrows? Smash their eggs? Isn’t there anything less lethal I can do in my own sparrow war?

“Yes, there is,” said Robert Mulvihill, an ornithologist at the National Aviary in Pittsburgh. “I know my position is at odds with some of my colleagues, but I don’t blame the house sparrow,” he said. “Introduced or not, they are now a fully naturalized wild North American species, and I don’t think any wild bird should be labeled the bad guy just for doing what it naturally does to survive.”

Mulvihill said he was surprised that a century and a half of nest competition hadn’t resulted in more defensive behavior in bluebirds. They just need to adapt, he suggested. Still, he told me, we can help bluebirds by putting bluebird boxes only where they belong: not near houses, barns or bird feeders, but in open meadows, which house sparrows would never call home.

“Eastern phoebes have to regroup and find safer nesting sites,” Mulvihill said, “preferably forested settings near streams, where they breed naturally.”

Eastern phoebes are an early nesting species and may have traditionally had their first brood before competition from later-nesting house sparrows, he explained. “But warmer spring weather induces house sparrows to nest earlier in some areas, and eastern phoebes may have lost their usual seasonal head start,” he said.

To Mulvihill, killing house sparrows is an all-too-typical human response. “Let’s be honest,” he said. “If bluebirds and eastern phoebes have an enemy, it is we humans, not the house sparrows we brought here.”

First, Mulvihill pointed out, we wanted the sparrows to control pest insects. “They did that, and made themselves at home.” he said. “Now, we don’t want them because they are too good at competing with other birds we want around. This is a lesson why you never want to introduce an adaptable species into a new environment because it will inevitably upset the ecological balance and create problems.”

“It rarely ends well,” Mulvihill added.

This human may be part of the problem. I could stop feeding the birds by February, which might cause year-round residents like house sparrows to disperse. I could avoid inexpensive bird food mixes that contain cracked corn, milo, wheat and rye, preferred by house sparrows, and instead use more expensive seed that contains black-oil sunflower seeds, safflower seeds and white millet. And I could change from a platform feeder to a tubular one that house sparrows can’t dominate as easily.

Still, as the climate changes and species relocate, we may all have to get used to seeing birds compete for nesting space in our own backyards. The problem, Mulvihill predicted, is “going to snowball.”

I’ve broken up rooster fights, but it seems there’s little I can do on a large scale about competition between wild birds. Even if I tried to kill all the house sparrows at my house, Mulvihill said, “you’d be doing that year in and year out.”

Still, I’m on the lookout this spring for nest-raiding house sparrows. I will watch whatever scene plays out at my own back door, witnessing the results of human interaction in the bird world: a mother bird simply trying to raise her young, dealing as best she can with what we humans have thrown at her.

Daryln Brewer Hoffstot’s book “A Farm Life: Observations From Fields and Forests” was just published by Stackpole Books.