4 BULLETIN 2 03, UNITED STATES NATIONAL MUSEUM 



In my paper published in 1911, after stating the different hypotheses proposed 

 in order to explain the relations existing among the Golden-winged, Blue-winged, 

 Brewster's, and Lawrence's Warblers I added, half in jest, that the only hypoth- 

 esis left for a new-comer in the field was this : that the Golden-winged and the 

 Blue-winged Warblers themselves were merely two forms of one species. 

 Curiously enough, not long after this I found that this very opinion had been 

 expressed, and in a most unexpected quarter : in a letter dated Edinburgh, Sept. 

 15, 1835, Audubon wrote to Bachman that he suspected the golden-winged 

 warbler and the blue-winged warbler were one species ! That Audubon at that 

 early date, ignorant (as he was assumed to be) of the existence of Brewster's 

 and Lawrence's warblers, and but superficially acquainted with the golden-wing, 

 should suspect that two birds so diverse as the blue-wing and the golden-wing 

 were one species seemed incomprehensible, and in the light of what we now 

 know about these birds, his surmise seemed to presuppose an almost superhuman 

 faculty of prevision. 



As a possible explanation of Audubon's letter I have only this to offer : in the 

 winter of 1876-77 Dr. Spencer Trotter discovered in the collection of the Academy 

 of Natural Sciences of Philadelphia a specimen of Brewster's warbler without a 

 label, the third specimen known up to that time ; on the bottom of the stand was 

 written in the autograph of John Cassin, "J. C, 20 October, 1862," and also a 

 badly blurred legend "Not [note?] from Bell." An appeal to J. G. Bell elicited 

 the response that he remembered shooting a peculiar warbler in Rockland Co., 

 N. T., about the year 1832— a warbler something like a golden-vsdng, but lacking, 

 although in high plumage, the black throat of that species ; a great many years 

 afterward, he sold this specimen in Philadelphia but knew nothing of its ultimate 

 fate. Dr. Trotter justly inferred that the Philadelphia Academy specimen was 

 in all probability the very bird shot by Bell. 



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 plum- 

 age 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 



