Hi. Like a lot of people, House Sparrows are taking over my bird houses rather than swallows or other birds. Next year, I have a plan: let the sparrows build their nests, but remove and dispose of their eggs before they're hatched. Is this an effective strategy for decreasing the population in my neighborhood?
Preventing opportunities (food, nesting, access to shelters) is a big part of reducing the impact of house sparrows on our native birds. At the nest box scale, we can pay attention to the size of the opening, make sure there's no perch on the front of the box, site the box well, and create devices such as "sparrow spookers" (See some designs here http://www.sialis.org/sparrowspooker.htm and here http://michiganbluebirds.org/problem-solving#House%20Sparrows ) Actively removing house sparrow nests and "addling" eggs is another level of management that some folks are willing and able to implement. Sparrows really favor the "filler" seeds (e.g., milo, millet, cracked corn) that are frequently included in prepackaged wild bird seed mixes. Feeding high quality seed such as black oil sunflower seeds helps attract and sustain native birds while also being less attractive to house sparrows. Finally, house sparrows are aptly named-They thrive in our human-built environment, so making sure that eaves, ledges, little hidey-holes in outbuildings, etc., are blocked or unavailable as nesting and winter roosting areas can help.