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Bird Foraging on Incense-cedar and Incense-cedar Scale During Winter in California

Michael L. Morrison

出版	U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station, 1989
URL	http://books.google.com.hk/books?id=zvLgFgBIH0IC&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋

Seasonal differences in use of food and habitat have been shown for numerous bird species. Especially during winter, when insect food is often at its lowest availability, birds may be unable to secure enough food for survival. In earlier work in the mixed-conifer zone of the western Sierra Nevada (Blodgett Forest, El Dorado County), observers found that many birds significantly increased their relative use of incense-cedar (Calocedrus decurrens [Torr.] Florin.) for foraging in winter as compared to summer. Preliminary examination of cedar showed the presence of one predominant arthropod species: the incense-cedar scale (Xylococculus rnacrocarpae Coleman). Scales were abundant under the loose, flaky bark of small (