WatchList Species Account for Varied Thrush (Ixoreus naevius)

Qualifies for the list as a Declining Yellow List Species

 

Photo: USFWS
Photo: USFWS

Breeding in moist coniferous and mixed forest from Alaska and northwestern Canada south to the Pacific Northwest, the Varied Thrush winters along the coast of Alaska from Kodiak Island, south along the coast of British Columbia to California.

 

It is shy and retiring on its breeding grounds, where it feeds on ground-dwelling arthropods and later in the season on berries. In winter it is found in forest but also in parks and gardens, where it feeds principally on fruits, berries and acorns and also on earthworms, where it sometimes associates with American Robins.

 

Its nests are predated by red squirrels and Canada and Steller’s Jays, while feral cats may cause heavy mortality during the winter; severe weather during the winter is also a significant mortality factor, as are collisions with windows. In recent years it has declined significantly in the U.S. and trends are negative throughout its range.

 

Little research has been done on this species and more information on all aspects of its biology is needed. One aspect of interest is its degree of dependence on mature or old-growth forests and how sensitive it is to fragmentation of habitat. The bird may benefit from reserves established for the Northern Spotted Owl.