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Volume 9, No. 1

Published January 1, 1978

Issue description

Volume 9, number 1 of Western Birds, published 1978

Articles

  1. ROOST CHARACTERISTICS AND BEHAVIORAL THERMOREGULATION IN THE SPOTTED OWL

    Previous studies on the Spotted Owl (Strix occidentalis) have established important parameters in habitat preference of this species. Old growth, multi-layered forests; water availability; and the presence of suitable nest sites are consistent characteristics of the habitats occupied (Gould 1974, 1977; Forsman 1976). These authors postulated heat intolerance as a possible factor in habitat selection. To further examine this hypothesis, we analyzed aspects of Spotted Owl habitat in preferred use areas, particularly at major roost sites, and related this information to behavioral adaptations of the owls.

    This preliminary investigation was aimed specifically at understanding features of the forest environment which determine roost site selection. Relating to these features, possible limitations imposed on the Spotted Owl by physiological tolerances to environmental extremes were also considered.

  2. BREEDING BIRD DENSITIES, SPECIES COMPOSITION, AND BIRD SPECIES DIVERSITY OF THE ALGODONES DUNES

    The Algodones Dunes, also known as the Imperial Sand Dunes, in Imperial County are considered to be the largest sand dune system in California and one of the largest in the United States (California Division of Mines 1952, Miller 1957). Within the Algodones Dunes are several different habitat types which contribute to the biological uniqueness of the area. Few data are available on the avian community of these dunes. The purpose of this investigation was to determine avian species composition, breeding bird densities, bird species diversity, and plant species diversity in the various habitats associated with the Algodones Dunes.

  3. COMMENTS ON THE STATUS AND DISTRIBUTION OF WESTERN AND MOUNTAIN BLUEBIRDS IN WASHINGTON

    Concern has been expressed for many years over the decrease in numbers of both Western Bluebirds (Sialia mexicana) and Mountain Bluebirds (S. currucoides) in Washington. One major problem in attempting to document this reported decline is the lack of comprehensive status and distribution data. Seasonal reports in American Birds provide summaries of observations but often these are not quantitative in nature. Recent breeding bird surveys conducted by the U.S. Fish and Wildlife Service (Robbins and Van Velzen 1969, Van Velzen and Robbins 1971) are quantitative but often provide only limited data on bluebirds. The purpose of this study is to supply quantitative information on the status and distribution of both bluebird species in Washington for the summer of 1974, to provide an analysis of Breeding Bird Survey (BBS) data for 1968 through 1976, and to evaluate population trends during the past 80 years.

  4. NOTES: FIRST RECORD OF THE LITTLE BLUE HERON FOR BRITISH COLUMBIA AND WASHINGTON

    In late October 1974, an immature Little Blue Heron (Florida caerulea) was reported by Bud Anderson from Judson Lake, a small lake (about 1.5 km long) lying astride the British Columbia–Washington boundary, about 7 km southwest of Abbotsford, British Columbia. Local residents later told us that the bird had been present since about 15 October. On 2 November 1974 Eugene Hunn visited the lake and confirmed Anderson’s identification. On 3 November the heron was studied by Wayne Weber and by many other experienced observers, and it was seen frequently until 10 November on both the Canadian and American sides of the lake. The only subsequent sighting was on 5 January 1975, when Ian D. MacDonald again saw the bird at the lake. During this two-month gap in records, the heron may possibly have visited other small lakes in the vicinity.

  5. NOTES: BALD EAGLE CONCENTRATIONS IN GLACIER NATIONAL PARK

    Bald Eagles (Haliaeetus leucocephalus) congregate in Glacier National Park, Montana, each autumn to feed upon spawning Kokanee Salmon (Oncorhynchus nerka). Systematic observations and censuses of these eagle concentrations were initiated in 1965. McClelland (Condor 75:121-123, 1973) reported the results of the censuses for 1965-1966 and 1968-1970. From September to early December during 1971 and 1972 I conducted a study of the eagles in the same area, with special emphasis on recommendations for management. The purpose of this note is to present findings supplemental to McClelland’s, including the results of my censuses during 1971 and 1972, and censuses conducted during 1973 through 1977 by Park personnel.

  6. NOTES: WHITE PELICANS NESTING AT HONEY LAKE, CALIFORNIA

    The breeding status of the White Pelican (Pelecanus erythrorhynchos) has been reviewed in papers by Thompson (1933), Lies and Behle (1966) and Sloan (1973). These papers show that, although the number of breeding birds may fluctuate considerably in any one colony from year to year, colonies tend to remain in ancestral locations. For example, it appears that the only new colony established west of the Rockies between 1965 and 1972 was at Crump Lake, Oregon.

    We were thus surprised to find a White Pelican nesting colony on Hartson Reservoir, adjacent to Honey Lake, Lassen County, California, in June 1976. Although pelicans reportedly laid eggs at Honey Lake in the early 1950s (A. M. Lapp pers. comm.), this appears to be the first record of a productive colony at this location.

  7. NOTES: PREDATION BY A RUBBER BOA ON CHESTNUT-BACKED CHICKADEES IN AN ARTIFICIAL NESTING SITE

    During the past 9 years, by use of artificial nest boxes, we have conducted studies on the life history of the Mountain (Parus gambeli) and Chestnut-backed (P. rufescens) chickadees and their impact on insect populations. Nine study plots consisting of 50 nesting boxes per plot at 100 m intervals (area of 50 ha) have been established in several montane regions of California (Dahlsten and Copper, unpublished manuscript).