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Article Excerpt
An isolated race of the Loggerhead Shrike (Lanius ludovicianus anthonyi) was described as phenotypically distinct by Mearns (1898). The taxonomic identity of this subspecies has been studied using morphological, nuclear, and mitochondrial DNA analyses to show the anthonyi subspecies occurred historically on California's northern Channel Islands of Santa Cruz, Santa Rosa, Anacapa, San Miguel, Santa Barbara, and Santa Catalina (Mundy et al. 1997, Patten and Campbell 2000, Eggert et al. 2004). This subspecies mixes with the mearnsi and gambeli subspecies on Santa Catalina and San Clemente islands (Eggert et al. 2004). L. l. anthonyi is listed by the California Department of Fish and Game (2003) as a species of special concern.
Historical accounts of L. l. anthonyi provide insight into its relative abundance on Santa Cruz Island, but descriptions are limited and lack quantitative population estimates. Blake (1887:330) described shrikes on Santa Cruz Island as "extremely common." This race was considered a "fairly common resident" on some of the Channel Islands in the early 1900s (Willett 1912:92, Howell 1917). Grinnell and Miller (1944:382) described it as "fairly common on Santa Cruz Island; less numerous on other islands," with the "total population ... small by reason of limited range and normal spacing of individuals." Miller (1951:119) later described the status of this race on Santa Cruz Island as, "[shrikes occur] regularly on Santa Cruz, but one must search particular areas, chiefly about the ranches ... on my recent trip I saw none, although I took one in 1922." Collecting of island shrikes was not uncommon in the mid 1900s, with 42 anthonyi specimens collected between 1900 and 1949 (HSW, unpubl, data). These historical reports clearly indicate that shrike numbers were decreasing. Between 1900 and 1950,...
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