Distribution and Seasonal Movements of Bendire's Thrasher in California
WESTERN BIRDS Volume 20, Number 3, 1989 DISTRIBUTION AND SEASONAL MOVEMENTS OF BENDIRE'S THRASHER IN CALIFORNIA A. SIDNEY ENGLAND, Departmentof Wildlifeand FisheriesBiology, University of California, Davis. California 95616 WILLIAM E LAUDENSLAYER,JR., U.S. D. A. ForestService, Forestry Sciences Laboratory,2081 E. SierraAvenue, Fresno, California 93710 The ecology and distribution of Bendire's Thrasher (Toxostorna bendirei)have been little studiedand are poorlyunderstood. Garrett and Dunn (1981:280) classifiedthe speciesas a "fairlycommon but very local summer resident on the Mojave Desert" in southern California. Californiabreeding populations are known primarily from the eastern Mojave Desert and scattered locations in and around Joshua Tree NationalMonument in the southernMojave Desert (Johnson et al. 1948, Miller and Stebbins1964, Garrett and Dunn 1981), areas frequently visitedby bird watchersand naturalists. However, recordsfrom other parts of the Mojave and Colorado deserts suggest that breeding populationsof Bendire'sThrasher may be more widely distributedthan currentlyrecognized. Also, the preferredbreeding habitat in Californiais relativelywidespread. This habitatis typicallydescribed as Mojavedesert scrubwith either JoshuaTrees (Yucca brevifolia), SpanishBayonet (Y. baccata), Mojave Yucca (Y. schidigera), cholla cactus (Opuntia acanthocarpa,O. echinocarpa,or O. rarnosissirna),or other succulents (Grinnelland Miller 1944, Bent 1948, Garrett and Dunn 1981). Remsen(1978) consideredthe total Californiabreeding population of Bendire'sThrasher to be under 200 pairs, and the specieshas been placedon the list of Bird Speciesof SpecialConcern by the California Departmentof Fishand Game (Remsen1978). It was placedon this list becausepopulations are smalland locallydistributed and believedto be threatenedby off-roadvehicle use, overgrazing,and harvestingof Joshua Treesand other speciesof yucca. In this paper, we report the resultsof a 2-year studyof the breeding- season distributionand movement patterns of Bendire's Thrasher in California.
[Show full text]