The closest sagebrush ecosystem to Edmonds is in Central Washington. So why feature the Sage Thrasher in a column about Edmonds birds? Because three times in the last six years, one has arrived in Edmonds: May 15, 2013; May 9, 2015; and May 1, 2017. Presumably these three birds wandered off course in migration. The first two were at the marsh and the third appeared for two days in a yard near the waterfront.
There are eight species of thrasher in the contiguous U.S. Only the Sage and Brown Thrashes winter in southern states and then migrate further to the north for breeding. Because not all of the sagebrush ecosystems of Eastern Washington have been degraded or wiped out in favor of orchards and vineyards, Washington remains within the breeding range of the Sage Thrasher.
The Sage Thrasher eats mostly insects and berries. In summer it feeds primarily on true bugs, grasshoppers, beetles, wasps, caterpillars, and other insects. It forages on berries and wild fruits in winter. In any season this thrasher may feed on gooseberries, mistletoe berries, wild currants, and juniper berries. It mostly forages on the ground, running about in search of insects on open ground below the sagebrush. It perches in low trees and on shrubs when eating berries.
The male defends his breeding territory and attracts a mate with song. Courtship includes a flight display in which the bird sings whle flying in a low zigzag over brush. It then alights on brush, holding its raised wings and fluttering briefly. A pair builds its nest in sagebrush or other low bushes such as rabbitbrush, saltbush, or greasewood. The nest is a bulky cup of twigs that is lined with finer materials.
The adults share incubation of the 3-5 eggs for a period of 13-17 days. Sometimes a cowbird will lay eggs in the nest but the adult thrashers quickly reject them by tossing the eggs out of their nest. Both parents feed the nestlings. The young leave the nest about two weeks after hatching. There may be two broods a year.
The Sage Thrasher can mimic other birds as it sings. This led to its early name as a mountain mockingbird. Because of extreme temperature fluctuations in the high desert, this species will often orient its nest entrance eastward to maximize solar heat in the cold mornings and to shade its eggs in the afternoon heat. The Sage Thrasher has a reputation for being elusive because, when disturbed, it will frequently run on the ground instead of taking flight. Some genetic studies suggest that the Sage Thrasher is more closed related to mockingbirds than to the other thrashers.
The conservation status of the Sage Thrasher is of low concern, even though there was a 52% cumulative decline in the species between 1966 and 2014. There are still an estimated 5.9 million birds. Most sagebrush-dependent birds are not faring as well as is the Sage Thrasher, but it remains vulnerable to habitat loss due to heavy livestock grazing, residential development, agricultural conversion (which is still happening in Eastern Washington), herbicides and pesticides, and the spread of invasive grasses such as cheatgrass and wheatgrass to sagebrush communities.
Enjoy listening to the Sage Thrasher’s melodious song here: https://www.xeno-canto.
— By Carol Riddell
Carol Riddell manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.