Thank you for your report of house sparrows and starlings, non-native birds that have proliferated at the expense of Oregon's native species. More aggressive by nature and present year round, starlings and house sparrows take over bird houses and natural nesting cavities used by woodpeckers and migratory songbirds including bluebirds and chickadees.

How can home gardeners help discourage these two "weed" birds? The Oregon State University Extension Service recommends the following procedures:

Block the entrances to bird houses until native species arrive.
Remove nesting materials starlings and house sparrows place inside bird houses, cavities or nest boxes. Block off entrance for a few days, then reopen when natives arrive.
Block off open eaves and place hardware cloth over known nesting sites for starlings and house sparrows.
Put up nest boxes with oval holes no larger than 1 1/8 inch in diameter, to favor native songbirds.
Discourage house sparrows by placing nesting boxes and bird houses within 4 feet of the ground, as they won't nest this low. However, be sure to shield these nesting boxes or bird houses from predator cats, raccoons and opossums by placing sheet metal around the supporting pole. Or post houses on metal rather than wood poles. Put a sheet metal collar around the upper portion of the support pole to keep marauders out.
Avoid feeding birds millet. Black oil sunflower seeds encourage native birds. Starlings and house sparrows like millet.
Hang suet, rather than post it. This keeps starlings from eating it, but still makes it available to native birds.

Lisa DeBruyckere
May 14, 2008, 9:32 a.m.