Think about birds before spring mowing and pruning

Last Updated: 
April 2, 2007

CORVALLIS - For the birds' sake, home gardeners should be careful when mowing and pruning in the spring and early summer, according to Dan Edge, Tara and Doug Robinson, wildlife biologists at Oregon State University.

Trees, both dead and alive, shrubs, grass, riparian areas, bare ground and ground cover may all provide nesting habitats for wild birds in the late winter through early summer. Keep in mind bird nesting cycles when pruning and mowing in spring and summer.

Resident birds, such as owls start nesting in the late winter. Birds of prey begin nesting in winter and their young typically do not fledge, or leave the nest until mid- to late summer.

Migratory birds, including hummingbirds, start to come back from their winter holidays in February and usually begin nesting efforts in the early spring. Depending on the food supply, most songbirds will attempt to nest two, three or even more times during the nesting season. Some species can be nesting until mid- to late summer.

Here are some hints from OSU wildlife biologists to help home gardeners avoid destroying bird nests and nesting habitat during nesting season.

Wait until mid- to late summer or early fall to have trees limbed or trimmed, as dead or thick branches provide great nesting habitat.

Hold off major pruning of shrubs until nesting season is over, or at least carefully check for nests before pruning.

Leave tall grass in less traveled areas for ground nesting birds, such as juncos. Or before mowing, carefully check for well-hidden bird nests. Nests are often very well camouflaged. The best way to tell if there are any nests is to watch for birds that flush out of the tall grass or out of a shrub. Then check the place where the bird flew from - there may be a nest. Some birds nest in bare gravel on the ground, such as killdeer or nighthawks.

Consider postponing your mowing until nesting season is over if your property contains or is adjacent to large grassy, wetland, riparian or meadow areas. Grassland birds such as western meadowlarks, horned larks, grasshopper sparrows, vesper sparrows and common yellowthroats fledge their young in June and July. Waiting to mow until July or August is best.

If you have dead trees that don't pose an immediate safety hazard, you might want to leave these as snags or wildlife tress. Many cavity nesting birds including, hawks, owls, woodpeckers, nuthatches, bluebirds and swallows depend on snags for nest sites. Most of these species will fledge their young during July. Bluebirds may still be nesting until August.

If you find a bird nest, do not touch the nest, eggs or nestlings. If you find a bird on the ground, leave it alone. The parent birds know where it is and are feeding it.

Author: Carol Savonen
Source: Tara Robinson, Doug Robinson, Dan Edge