The range and population of the Trumpeter Swan (Cygnus buccinator) in the United States and Canada have been greatly reduced because of a number of factors. The major nesting areas today are in Alaska where the population is increasing; there are only remnant nesting populations elsewhere (Banko 1960, Hansen et al. 1971, Palmer 1976). The Trumpeter Swan's status in Oregon in the late 1970's was listed as occasional in the coastal areas and in the high desert east of the Cascade Mountains (Eltzroth and Ramsey 1979). The only breeding records in Oregon are from the Malheur National Wildlife Refuge (NWR) where transplanted birds from Red Rock Lakes NWR in Montana established a small breeding population in 1958 (Cornely et al. 1985). Gabrielson and Jewett (1940) listed about 12 sources for sight records in Oregon from 1806 to 1940, including several from the Willamette Valley. They considered this species near extirpation and reported no sight records in Oregon after 1929. The scarcity of Trumpeter Swans in western Oregon was reflected by (1) unsubstantiated reports of wintering birds on the Columbia River (Marshall 1969), (2) no verified observations from 1929 to the late 1950's (Banko 1960), and (3) suspected, but unverified, wintering in Oregon and as far south as the Sacramento Valley in California (Hansen et al. 1971). Other than the transplanted birds and their progeny at Malheur NWR (first transplanted in 1939), only two specimens of Trumpeter Swans are known for Oregon. One specimen (current location unknown) was reportedly collected at Malheur Lake (now Malheur NWR) in 1877 and one was taken in April 1881 on the Columbia River about 5 km west of Portland (Gabrielson and Jewett 1940). In this paper, we describe the first Trumpeter Swan specimen from the Willamette Valley. Also, we list post-1974 winter sight records that were obtained from American Birds; Oregon Birds; newsletters from bird clubs and Oregon Audubon chapters including Warbler, Sandpiper, Corvallis Chat, Grapeleaf, and Quail; and R. L. Jarvis (pers. comm.). We acquired a juvenile male Trumpeter Swan from the Oregon Department of Fish and Wildlife on 9 April 1986. The swan was found freshly dead on a road shoulder near Airlie (Polk County) on 6 March 1986; it was then stored in a freezer. After the bird thawed for 2 days at room temperature, weights and measurements were taken, the liver and kidneys were removed for contaminants analysis, and the gizzard was opened and inspected. Gross examination revealed no signs of disease; a good supply of body fat was present. We found an apparently lethal wound from a bullet that penetrated one wing and the breast. The plumage was gray except for white on the tail and underside of the body. A small penis was present. The mandibles were black except for a small area that was dark pink. The legs and feet were dark gray and splotched with orange-yellow. The huge gizzard (120 x 76 mm) contained mostly sand with a little grit and plant material. No lead or steel shot was detected in the gizzard contents. Weights (g) were: whole body-11,890, liver-138.6, kidneys54.4, and heart (approximately 160.5). Measurements in cm (following procedures of Baldwin et al. [1931]) were: bursa depth-4.2, body with feathers-159.0, wing chord-63.4, tail-17.8, tarsus13.8, middle toe with claw-17.8, and exposed culmen-10.7. Body weight and measurements were within the range listed for Trumpeter Swans, but most were much larger than those of Tundra Swans (Palmer 1976). A flock of 16 Trumpeter Swans was sighted near Airlie on 17 January 1986. This is the same area where our specimen was found in March. The swan was donated to the Department of Fisheries and Wildlife, Oregon State University (Specimen #FW 5152). Recent sight records by experienced birdwatchers indicate that the Trumpeter Swan is an uncommon winter resident in the Willamette Valley (Table 1). Although Trumpeter Swans are frequently confused with Tundra Swans (Cygnus columbianus) that commonly spend the winter there (Eltzroth and Ramsey 1979) the two species usually form segregated flocks in Oregon. These sightings indicate that wintering Trumpeter Swans may be increasing in the Willamette Valley.
Read full abstract