Now as Audubon was intimately associated with Bell, is it not possible that he had examined this example of Brewster’s warbler? In that case, seeing that this bird’s characters were in part those of the blue-wing, in part those of the golden-wing, he may have inferred the interbreeding of these two birds, and so (rather unwarrantably, it is true) their identity. If this be not the explanation of the passage in Audubon’s letter to Bachman I have no other to suggest.
When Audubon came to publish his account of the Golden-winged Warbler in 1839 (Ornithological Biography, 1839, 5, p. 154) he said not a word about its connection with the Blue-winged Warbler.
Recently Karl W. Haller (1940) described “a new wood warbler from West Virginia” from two specimens, male and female, which he collected on May 30 and June 1, 1939, respectively, at points 18 miles apart, and proposed for it the new name Dendroica potomac, Sutton’s warbler. These birds resemble the yellow-throated warbler in plumage but lack streaks on the sides. They also suggest the parula warbler in having a faint yellowish wash on the back and, in the male, “an almost imperceptible hint of raw sienna” on the upper breast. The male sang a song much like the parula’s, but doubled by repetition.
Two more Sutton’s warblers have been carefully observed in the field: one at the point where the type was collected on May 21, 1942, by Maurice Brooks and Bayard H. Christy (1942); the second about 18 miles to the westward on June 21, 1944, by George H. Breiding and Lawrence E. Hicks (1945). Another aberrant warbler has been described by Stanley G. Jewett (1944), who examined four specimens which show a curious intermingling of the plumage characters of the hermit and Townsend warblers.
[Author’s Note: Since the above was written, Kenneth C. Parkes (1951) has published a study of the genetics of the golden-winged—blue-winged warbler complex, to which the reader is referred.]
BLACK-AND-WHITE WARBLER
Contributed by Winsor Marrett Tyler