What can I do about sparrows or other birds nesting on my house?
House Sparrows and European Starlings are non-native species, introduced from Europe, that have adapted to nesting on homes and other buildings since the beginnings of the Agricultural Revolution more than 10,000 years ago. They build their homes in gutters, vents, or other openings in buildings. Sparrows can gain entrance to holes as small as 1 1/4 inch diameter, while the larger starlings need holes at least 1 5/8 inch diameter.
The best way to stop these birds from nesting on your house is to block any and all possible nest holes with boards, bird netting, or any physical barrier that might be cosmetically and structurally appropriate. Birds can nest in gutter downspouts if there is a horizontal section of pipe near the entrance at the top, so avoid this gutter design. While native bird nests, eggs, and babies are protected by law and cannot be moved or destroyed, Starlings and House Sparrows are not protected and you may legally remove them from your home or building.
For native birds such as House Finches (often nesting in hanging plants), Mourning Doves and American Robins (nesting on ledges), Carolina Wrens (nesting in buckets, shoes, or mailboxes), or Barn Swallows (nesting over doors or on porches) it is best to discourage them before they start nesting by eliminating or blocking access to potential sites. If you want to encourage these birds to nest on your home, you can build ledges or provide nesting boxes to attract them. Since these native birds are protected and beneficial, once they are nesting they should be left alone and given as much space as possible. Their eggs are only in the nest for two weeks before they hatch, and then the young are only in the nest for two more weeks after that. Be sure to remove the nest and clean the area with a strong disinfectant after the birds are gone.