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San Clemente loggerhead shrike |
The San Clemente loggerhead shrike (Lanius ludovicianus mearnsi) is endemic to San Clemente Island off the coast of southern California. Its habitat has been degraded by sheep, pigs, mule deer and goats since the late 1880s [1]. The U.S. Navy took control of the island in 1934, began removing feral ungulates in 1973, and completed the task in 1993 [2]. Following the removal of goats, fire became a significant habitat destruction factor [1]. Predation by feral cats, island foxes, and ravens was responsible for 44% of nest failures in the late 1980s [1].
The shrike declined to about 20 birds in the early 1900s [7] and increased to about 50 in 1977 [3], before declining to a relatively stable population of 14-33 birds between 1982 and 1998 [3, 4, 5, 6]. Due to an active captive breeding and reintroduction program, the population began expanding in 1999, reaching a minimum of 135 captive and wild birds in 2004 [4]. [1] Yosef, R. 1996. Loggerhead Shrike (Lanius ludovicianus). In The Birds of North America, No. 231 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists’ Union, Washington, D.C. Roemer, G. W., and R. K. Wayne. 2003. Conservation in conflict: the tale of two endangered species. Conservation Biology 17:1251-1260. |
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