Diurnal breeding bird data for unmanaged Douglas-fir forests in western Washington and Oregon: 1984-1986

This data publication contains bird count data from breeding bird surveys conducted between 1984 and 1986 in 151 natural fire-regenerated Douglas-fir stands within 3 provinces of Washington and Oregon: Southern Washington Cascade Range, Oregon Cascade Range, and the Oregon Coast Ranges. The sampling design incorporated an age gradient (young, mature, old-growth) and a moisture gradient (dry, mesic, wet). The moisture gradient was investigated only in old-growth stands (i.e., old-growth dry, old-growth mesic, and old-growth wet) and the age gradient was studied only in mesic stands (i.e., old-growth mesic, mature mesic, young mesic). In each stand, birds were sampled using the variable circular plot technique and, generally, early-morning surveys were conducted 6 times from mid-April to early July during 2 consecutive breeding seasons. Surveys were conducted in 48 Douglas-fir stands in the Southern Washington Cascades and a total of 71 bird species were detected; 56 stands were surveyed in the Oregon Cascades and 79 species were detected; and 47 stands were surveyed in the Oregon Coast Ranges and 85 species were detected. This publication also contains related stand data, including location, elevation, stand age, and moisture.
These data were collected as part of a larger USDA Forest Service research initiative identified as the Old-Growth Forest Wildlife Habitat Research and Development Program. This program was instituted to evaluate whether old-growth Douglas-fir forests in the Pacific Northwest provided significantly different wildlife habitat for birds, mammals, and amphibians than did younger forests. The objectives of the program were to (1) define old-growth Douglas-fir forests in the Pacific Northwest, (2) identify animal and plant species that were dependent or closely associated with these forests, (3) determine biological requirements and ecological relationships of closely associated species, and (4) evaluate old-growth management alternatives and determine economic aspects of old-growth forest ecosystems.
The research results of the breeding bird surveys conducted during the Old-Growth Forest Wildlife Habitat Research and Development Program are presented in a series of papers published in Ruggiero et al. (1991), including a regional analysis of the breeding bird communities across all 3 provinces (Huff and Raley [1991]). The data published here represent all of the bird data collected in all 3 provinces regardless of whether the data were used in final publications; for example, data sets used to calculate bird abundance in Huff and Raley (1991) were reduced to equalize sampling effort by dropping some survey days in some stands and only included birds detected within 50 meters [m] of the survey station.