While walking in a fresh five inches of snow in my neighborhood, I watched two black-capped chickadees argue near an old snag with a cavity.
Yes, even though there are big piles of snow around, it’s time to make sure all of our nest boxes are ready for tenants. Chickadees and titmice are showing signs of territoriality, while bluebirds and tree swallows are working their way north to begin nesting in mid- to late March.
If you’ve ever maintained a bluebird trail, you know that invasive house sparrows are aggressive pests. They will stop at nothing to take over a nest box, including destroying an existing nest and eggs and even killing the adult birds. These exotic birds can be a frustrating problem.
House sparrows were brought over from Europe in the 1850s because people hoped they would aid in pest control in agricultural fields and also they were a reminder of home. When the house sparrows arrived, they preferred the city areas with ample amounts of horse droppings full of undigested grain to eat as well as all the nooks and crannies of buildings to use as nesting cavities. As humans spread, so did the house sparrow. They overwhelmed existing nesting areas and started competing with native cavity nesting species.
We’ll never be rid of the house sparrow in North America, but there are strategies people use to minimize house sparrow damage. For smaller birds like chickadees, make sure your bird house entryway is no larger than 1-1/8 inch – that’s just slightly too small to allow a house sparrow entry. For larger birds like Eastern bluebirds, it’s harder, but there’s a new endeavor underway to not only help but also contribute to research.
Sparrow Swap is a citizen science project brought to you by researchers and asks that you remove the house sparrow eggs, exchange them for “dummy eggs” and mail in the house sparrow eggs for study. They test the eggs to map out contaminants and study the geographic patterns of the species.
You can sign up for the project on Sparrow Swap’s Sci Starter page. After you sign up you can request the number of fake eggs you need. Then you will get instructions for removing the sparrow eggs, how to ship them, and data forms you’ll need to fill out. Though you have to pay the minimal cost for shipping the eggs, the project will send you decoy sparrow eggs for free.
The beauty of this project is that you contribute to science while preventing more house sparrows. Some people trap and dispose of house sparrows since that is legal with a non-native species. Some people remove the sparrow nests from the boxes, but this can sometimes result in retaliation by the surviving sparrows on their cavity-nesting neighbors. By giving them fake eggs, they leave other birds alone and waste time incubating eggs that will never hatch – simultaneously simple and scientific.