Streaked Horned Lark Inventory, Nesting Success and Habitat Selection in the Puget Lowlands of Washington

In the spring and summer of 2004 we conducted research on Streaked Horned Lark at two research sites and inventoried all appropriate habitat on Ft. Lewis Washington for breeding Streaked Horned Larks. The objectives were to describe breeding phenology and clutch size; conduct an inventory of all potential streaked horned lark habitat and map breeding territories on Ft. Lewis; assess reproductive success at Gray Army Airfield and 13th Division Prairie; identify habitat features important to breeding; use herbicide to create potential lark breeding habitat; and assess lark flush distances. In the four sites used in 2002, combined nest success was 28%. In the two sites used in 2003, combined nest success was 21%. Predation was the primary source of nest failure along with abandonment and human activities. Territorial Streaked Horned Larks selected habitats that were sparsely vegetated by relatively short annual grasses and with a relatively high percent of bare ground (particularly associated with gravel and cobbles).