Page 20

(n = 6,120 locations, range 6–488 locations/bird). Transmitters were removed in June 1996 from all birds except 3 that could not be recaptured because their transmitter batteries had failed. A single observer followed each radiotagged bird in daylight hours between roost emergence and roost entry for approximately 4 hours at intervals of 2–10 days. The observer used homing (Mech 1983) to move within 50 m and establish visual or aural contact without disturbing the bird, or alternatively to estimate the bird location to within approximately 15 m. The observer waited until the bird moved to another location, and then measured substrates used by the bird before resuming the follow. Observations were interrupted until the observer could re-establish contact if the bird was disturbed by the observer or flew far away. On each follow, the observer attempted to obtain data for at least 10 separate bird locations, which were classified as visual (bird observed), aural (bird heard), site (foraging site located), or radio (location only). Once contact was established, the time was recorded to the closest minute at the start and end of each activity or bird movement. If the bird was visible or activity could be determined using sound or site inspection, time was allocated to foraging, resting, interaction with other pileated woodpeckers (calling, drumming, courtship, juvenile and neighbour interactions, etc), and other (preening, flying, cavity excavation, nesting duties, roosting, etc). Foraging was classified as searching or gleaning on the wood surface, pecking or scaling bark, and excavating into sapwood. Tree species and type (live, snag (dead tree with intact trunk), stub (dead tree with broken trunk), stump (cut with saw), log) were determined for each used wood substrate. Diameter at breast height (dbh) was measured 1.3 m above the base for trees, snags, stubs and logs ≥1.3 m, and diameter was measured at the top for stumps, stubs, and logs <1.3 m tall. Height or length to the closest 0.1 m was estimated using a clinometer or measured with a tape measure for stubs, stumps, and logs. For dead wood types, bark cover: (1) <25%; (2) 26–50%; (3) 51–75%; and (4) >75%), and decay class: (1) recently dead, wet inner bark, sap and foliage often present; (2) dry stem and bark, fine branches present, bark present and firmly attached; (3) mostly sound stem, fine branches gone, main branches present, bark variable; (4) few or no branches, softening stem, variable bark; (5) no branches, stem soft, bark mostly gone; and (6) stem shape intact, no branches, bark gone, stem very rotten, were estimated. Decay classes were grouped into hard (decay classes 1–3) and soft (classes 4–6) categories. Presence and type of visible decay indicators were recorded for live trees. Fungal conks were considered to be conclusive decay evidence. Strong decay indicators were large dead branches or branch stubs, and trunk cracks, crooks, or swellings. Weak decay indicators were dead, forked or broken tops, and scars, galls, or injuries. Presence and position of previous pileated woodpecker excavation evidence was noted and classified as recent (within several days), fresh (within current season) or old based on the position of wood chips in relation to snow, rain, or litterfall, and wood weathering or sap extrusion at the excavation site. I recorded bird position as: (1) root; (2) base = ≤2 m from bottom; (3) top = ≤2 m from top; (4) trunk = >2 m from bottom or top; (5) branch; or (6) ground. The height of the bird above the substrate base was estimated to the closest 2 m. Foraging sites were inspected for visible food items: (1) carpenter ants; (2) thatching ants (Formica spp); (3) other ants (Formicidae); (4) other arthropods; and (5) unknown (no visible food items). Cavity Trees A cavity was defined as any opening excavated by pileated woodpeckers into a tree with entrance dimensions similar to those of completed nest cavities. Cavity trees were located by following unmarked and radio-tagged pileated woodpeckers, searching, listening for adult and nestling calls, and reports from the public. I attempted to locate all cavity trees within 14 territories by following radiotagged pileated woodpeckers and searching, with total effort equivalent to 2,022 8-hour person-days. Radiotagged birds often visited cavity trees during the day and always roosted in cavity trees at night. Searches for cavity trees in 1993, before birds were radiotagged, were conducted by walking parallel transects in a grid pattern, with systematic coverage of all areas searched. This method was inefficient, so in 1994–98 I used aerial photos and forest inventory information to identify stands in territories that were likely to contain large living or dead trembling aspen or balsam poplar trees and large conifer snags. These trees were identified as most likely to have pileated woodpecker cavities based on 1993 surveys. I was not able to search 10

Pwp 2001 04 rpt phdthesis pileatedwoodpeckerhabitatecologyinabfoothills  

http://foothillsri.ca/sites/default/files/null/PWP_2001_04_Rpt_PhDThesis_PileatedWoodpeckerHabitatEcologyinABFoothills.pdf