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Dear Dot,
Google advises that I kill the nest of house sparrows that is full of babies on my porch because they’re “invasive.” Seriously?
– Jessie
Dear Jessie,
Your question ruffled some feathers among Bluedot staffers now squawking about the ethics of a sparrowcide. Surely not! We love birds, don’t we? All birds? Even gray catbirds which, Dot recently learned, knock eggs out of nests in order to lay their own, leaving confused mother birds to feed odd-looking, often larger babies as their own.
Dot, as many of you know, is a devoted Merlin user. (Merlin is the app that helps us identify birdsong and educates us about our winged, feathered friends.) It’s is the brainchild (birdbrain?) of the world renowned Cornell Lab of Ornithology., which also spearheads the NestWatch project, a citizen science initiative whereby we birdwatchers share our nest observances in real time.
Yes, I know it is taking me a long time to explain how I got to the advice I’m about to share. And that is because …
Murder, my fellow bird-loving friends, is indeed on the table.
Why such a drastic response?
“House Sparrows are indeed invasive in North America, and will outcompete native birds for nesting space, including bluebirds and other cavity-nesting songbirds,” explains Holly Grant, Project Manager with NestWatch. “They will kill chicks and adults of other birds that are already nesting to then take over that same nesting space for themselves.” But … murder? Aren’t there laws against this? Turns out … not so much. While most native bird species are indeed protected under the Migratory Bird Treaty Act of 1918, house sparrows and European starlings — both invasive species — are fair game.
For this reason, many nest monitors choose to manage their nests to deter or discourage nesting by invasive species. Our website has an article that describes their behavior and multiple legal management techniques. The page includes both passive and active actions; one “active” option is indeed to trap and kill the sparrow. The Cornell Lab doesn’t recommend any one particular method; we understand not everyone may be comfortable with these techniques, but as an educational institution, we aim to educate folks that are interested in doing so. Management of invasive species is not a requirement of the general public (and likely doesn’t put any real dents in the overall population of House Sparrows anyway), but some monitors that do so may reduce the number of House Sparrows nesting in their own backyard. Whether they simply move on to nest in another area is not easy to know. That said, personally, I think the method of controlling the nest when it’s still in the egg stage – by oiling the eggs so that the House Sparrow sits on the nest for longer than normal and is distracted away from destroying another bird’s nest – is low effort and effective.
In any case, this question is a bit tricky. I would say that this person doesn’t need to kill the chicks in their nest if they’re not comfortable doing so, but they should remove the nest when the birds are done with it, and if they notice a new nest being built, to remove nesting materials as soon as they are added and/or block off the area to deter nesting. It’s tricky though, because deterring them from the porch might encourage them to take over the nest of a native bird elsewhere. If the question-asker leaves the nest, but finds more eggs are laid, then employing one of the management techniques in the article above is a good next step.
Gray Catbirds aren’t brood parasites; they are often victims of this behavior.