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

First, Mulvihill pointed out, we wanted sparrows to control pests. “They did and felt at home.” he said. “We don’t want them now because they’re too good at competing with other birds we want around. This is a lesson in 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 person may be part of the problem. I could stop feeding the birds by February, which could cause year-round residents like house sparrows to disperse. I could avoid the cheap bird feed mixes that contain ground corn, milo, wheat and rye that house sparrows prefer and instead use more expensive seeds that contain sunflower seeds, safflower and white millet. And I could change from a platform feeder to a tube feeder that house sparrows can’t dominate as easily.

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

I have discontinued cockfighting, but it seems that there is little I can do about competition between wild birds on a large scale. Even if I tried to kill all the sparrows in my house, Mulvihill said, “You’ll be doing it year after year.”

Still, I’m looking at house sparrows this spring. I will watch any scene that unfolds at my own back door and witness the results of human interaction in the bird world: a mother bird simply trying to raise her young and 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” has just been published by Stackpole Books.