First Fall Survey of Raptors in the Columbia Hills Important Bird Area

First Fall Survey of Raptors in the Columbia Hills Important Bird Area

by Stuart Johnston

In the ongoing effort to learn more about raptor presence, distribution and use of the Columbia Hills Important Bird Area, a fall season survey was initiated this year. Four surveys in early and late winter averaged 256 raptors over the past two winters. And the first spring raptor survey found 170 raptors of 10 species on 15 April 2000, as reported in the Aug-Sept issue of this newsletter. Thus a fall survey seemed the logical next step.

State hwy. 97 divides the Columbia Hills in half, roughly, east from west, and the crest of the hills separates the area into north and south slopes. These boundaries create four quadrants and eight observers, 2 per quadrant, drove the roads in their respective areas on 21 October, stopping frequently to scan for raptors, employing the same protocol used in earlier surveys. Seventy raptors of seven species were observed:

 
N. Harrier 4
Accipitre, sp. 1
Red-tailed Hawk 37
Rough-legged Hawk 3
Buteo, sp. 5
Golden Eagle 7
Am. Kestrel 7 
Prairie Falcon 1
and hawk/eagle, sp. 5.

The weather was cool, in the low 50s, sunny with clear skies but for a few scattered clouds in the morning. Brisk westerly winds blew 20-25 mph. Observations spanned the day from 08:00 to 18:15.

This first fall survey was organised quickly, spur-of-the-moment, so the level of participation was low. Jill Barker, Stewart Fletcher, Cathy Flick, Diane & Roger Gadway, Stuart Johnston, Bonnie & Dennis White, volunteers from the Cascadia chapter of HawkWatch International, Columbia Gorge Audubon Society and raptor enthusiasts at large.

By the time this survey was held, vultures, Ospreys and Swainson's Hawks had already departed for their wintering destinations. Rough-legged Hawks apparently were just beginning to arrive. Three quadrants each saw one and a 4th was seen 1.5 mi. n. of Centerville Hwy. along High Prairie Rd. (D&RG). Missed altogether were Bald Eagle and Merlin. A little too early for the former, although, before the month was out, two adults were noted along hwy. 14 between MP 80-81, just w. of Murdock, on 30 October (possibly a resident pair?).

Few harriers and falcons were detected. Kestrel numbers were surprisingly low. Merlins, scarce even in winter, are usually missed and may not have arrived yet. A pair of resident Peregrine Falcons were observed 22 October between Maryhill and John Day Dam, harassing a red-tail (CF,SF). Prairie Falcons must have been hugging the cliffs in out-of-the-wind spots, as flying birds were not picked up; the one noted was perched on grassland in the SE quadrant.

Golden Eagles were found in all but the NW quadrant: 1 ad., 5 subad./imm. & 1 unknown. Accipitres were hard to come by, but this survey methodology may not be ideal for these birds. The one seen was medium-sized, probably a Cooper's. Red-tails accounted for more than half the raptors counted, a situation that has not been found on any of the earlier surveys.

No owls and only one N. Shrike were censused.

Thank you for making space in your busy lives to squeeze in this last minute survey. Next fall we might try to conduct an earlier fall survey too, in September. And maybe a stationary count, from one of the high points in the hills, could be organised. Meanwhile, raptor enthusiasts, mark your calendars for the 9 December 2000 Early Winter Raptor Survey of the Columbia Hills Important Bird Area. And on 3 February 2001 the late winter survey will take place. Please plan to join us for one or both of these counts; your participation is greatly valued. Contact Stuart Johnston, (509)493-3363, . (2 more short paragraphs to follow)