American Egret, Treganza Heron, and Ring-Billed Gull at Malheur Lake in Winter
American Egret, Treganza Heron, and Ring-billed Gull at Malheur Lake in Winter
On December 21, 1939, in the vicinity of Malheur Lake, Oregon, fourteen American Egrets (Casmerodium albus egretta), eight Treganza Herons (Ardea herodias treganzai) and one Ring-billed Gull (Larus delawarensis) were recorded along with other waterfowl. A number of the egrets were seen with large flocks of Whistling Swans feeding in the shallow waters near the southeastern shore of Malheur Lake. The egrets and herons appeared to be having a hard time keeping warm and did little flying or wading. Many of the herons were standing humped up on top of muskrat houses. The maximum temperature during the day was 40" F.; prior to December 21 the lowest maximum daily temperature recorded in the fall was 36” F. The minimum temperature prior to that date was 10” F. In general the weather had been mild. On the night of December 22 it became colder, and until December 26 the maximum daily temperatures remained freezing or below and the minimum temperature was 4” F. On December 27, in the course of a trip around the lake, no egrets were seen, and only one Treganza Heron was noted with the other waterfowl.
Several herons were observed on a number of occasions in the Blitzen Valley, which is part of the Malheur Refuge, in each of the succeeding winter months. The birds evidently wintered there fairly successfully.
The above records are interesting inasmuch as the latest date recorded for the American Egret in Oregon by Gabrielson and Jewett (Birds of Oregon, 1940: 107) is November 19. They list the Treganza Heron as wintering regularly in Deschutes, Malheur, Klamath, Wasco, and Umatilla counties, and they give casual winter records for Crook, Grant, Union, Baker, Wallowa, and Morrow counties. It may be that the Treganza Herons have wintered in the Blitzen Valley in the preceding mild winters. The Ring-billed Gull was probably a stray, as the gulls normally leave Malheur Lake much earlier in the season.
Clarence A. Sooter
Fish and Wildlife Service, Burns, Oregon, December 26, 1940
