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2. PILEATED WOODPECKER HABITAT USE AND SELECTION IN THE ALBERTA FOOTHILLS Pileated woodpeckers defend territories throughout the year against neighbouring pairs (Bull and Jackson 1995). Although widely distributed, the pileated woodpecker is never abundant, with individual home ranges of 257–1,464 ha (Renken and Wiggers 1989, Mellen et al. 1992, Bull and Holthausen 1993). Pileated woodpeckers are strongly linked to trees, especially dead trees, logs, stumps, and living trees with defects (Bull and Jackson 1995). Pileated woodpeckers nest and roost in cavities excavated in large trees (Hoyt 1957, McClelland 1977, Bull 1987, Bull et al. 1992a). They prey on wood-dwelling insects, especially carpenter ants (Camponotus spp), obtained mainly from dead wood (Conner 1981, Mannan 1984, Bull and Holthausen 1993), and use trees to escape avian predators (Lima 1993). The pileated woodpecker is a management indicator species for mature/old forest conditions in some U.S. National Forests (Bull and Holthausen 1993). In Canada, the pileated woodpecker is a species of special interest in many provinces (Kirk and Naylor 1996), primarily because of concerns about the effects of forest management, which may reduce availability of key structural components of pileated woodpecker habitat. Pileated woodpeckers occur across the southern belt of the North American boreal forest, but little is known about their habitat ecology in western boreal and cordilleran forests (Harestad and Keisker 1989, Millar 1992), which have generally smaller trees and longer winters with more snow cover compared to southern forests. I studied key aspects of pileated woodpecker habitat selection in the Alberta foothills at several scales to obtain ecological information needed to support forest management planning. I focussed on foraging ecology and cavity tree selection within pair territories, at the levels of third- and fourthorder selection (Johnson 1980). I defined selection at 5 scales: (1) within the territory of each bird or mated pair; (2) within stands in each territory; (3) at sites within stands; (4) at wood substrates used by birds; and (5) at the position used on the substrate. STUDY AREA The study area was the 26,000-km2 Foothills Model Forest in the Rocky Mountain and Foothills Natural Regions (Beckingham et al. 1996) of west central Alberta, Canada. Cavity tree information was also obtained on an opportunistic basis from forested areas of central Alberta and British Columbia. This area was roughly bounded on the west by Prince George, on the north by Fort McMurray, on the south by Red Deer, and on the east by the Alberta-Saskatchewan border. Most information was obtained within 14 territories of radiotagged pairs of pileated woodpeckers within approximately 50 km of Hinton, Alberta (127°46’N, 117°39’W). Forests above 1,150 m were dominated by lodgepole pine (Pinus contorta) and Engelmann spruce (Picea engelmannii). Below 1,150 m, mixed forests were codominated by lodgepole pine, trembling aspen, white spruce (P. glauca), and balsam poplar (Populus balsamifera; Beckingham et al. 1996). Other common tree species included black spruce (P. mariana), tamarack (Larix laricina), and subalpine fir (Abies lasiocarpa). Forest age composition was 12% <30 years, 30% 31–100 years, 52% 101–160 years, and 6% >160 years (Weldwood of Canada, unpublished data). METHODS Radiotelemetry I radiotagged and followed 32 adult pileated woodpeckers and 1 juvenile in 14 pair territories from June 1993–June 1996. Birds were initially captured in 1993 (n = 2), 1994 (n = 16), and 1995 (n = 15) at nest trees (n = 28) or roost trees (n = 4), using a hoop net or board trap (Bull and Pedersen 1978). Each bird was fitted with an 11-g, 2-stage transmitter attached with a backpack harness. Birds were recaptured to replace transmitters when batteries failed at 5–12 months. I radiotagged both pair members in 12 territories and 1 bird in 2 territories. When birds died, I radiotagged new birds that replaced them. Birds were followed for 3 years in 2 territories, 2 years in 12 territories, and 1 year in 2 territories. Individuals were followed over periods of 9–763 days 9

Pwp 2001 04 rpt phdthesis pileatedwoodpeckerhabitatecologyinabfoothills  

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