ML47823161

Age

Not specified

Sex

Not specified

Media notes

Observer's sketch of the bird. From Brinkley E and Byrne A. A White-Tailed Eagle at Derby Hill, New York. North American Birds: Vol 66, No. 4: pp 613-631

Observation details

See published paper: Brinkley E and Byrne A. A White-Tailed Eagle at Derby Hill, New York. North American Birds: Vol 66, No. 4: pp 613-631 At 10:40 EDT on 24 April 1993, a sea-eagle (Haliaeetus sp.) passed the hawkwatch area at Derby Hill Bird Observatory, near Mexico, Oswego County, New York, seen by over 150 observers and photographed by Jean Litzenberger (frontispiece). The bird’s plumage and structure immediately indicated to the numerous experienced observers present that the bird was clearly a species of Haliaeetus but certainly not a Bald Eagle (H. leucocephalus). At the time of the observation, which lasted for about three minutes at ranges varying from about 50 m to 225 m, no one was able to identify the bird. Many observers immediately committed details of the bird’s plumage and structure to field notebooks, and some made sketches, admittedly rather rough ones (Figures 1-3). The observers’ unanimous impression was of a very large eagle, almost uniformly brown in wings and body plumage, with a large yellow bill, yellow feet, and spade-shaped tail (Figures 1-3, frontispiece). Brinkley, using a Kowa TSN-2 spotting scope with 30x-wide eyepiece, was able to see eye color (“brandy brown”) well and some detail in the visible rectrices, some of which had whitish interior portions but were otherwise edged dark brown. Another observer, farther from the bird and using a Celestron C90 scope, also detected white in the tail. No one reported seeing molt limits or heavy wear in the plumage, and the overall impression was of a bird in relatively fresh, even plumage. The bird appeared very large in its dimensions and also very stable in flight, more so than Bald Eagle. Within seconds of the bird’s appearance to the west-northwest of the Observatory, Gerry Smith, the hawkwatch director and counter, and Brinkley had alerted all observers within shouting distance that this bird was neither a Bald nor a Golden Eagle and that it should be observed and documented carefully. After circling and gaining altitude in soar, in company with a Red-tailed Hawk (Buteo jamaicensis) and several Broad-winged Hawks (B. platypterus), the eagle “broke” the soar and glided eastward, passing to the east of the Observatory grounds. Jean Litzenberger then photographed the bird, as other observers began to compose field notes, recording the following aspects of plumage and structure: 1) A very wide-winged eagle, rich brown in color overall, with no white feathers visible in the head, body, or wings, either above or below; 2) Width of wing uniform throughout the length of the wing, that is, leading and trailing edge of wings parallel, reminding some observers of an Old World vulture (Gyps) (cf. Figures 5-9, 13a, 13b); 3) White in the plumage limited to the spade- or wedge-shaped tail, which was not fanned during the bird’s passage but which appeared to have white restricted to the central portions (possibly inner webs) of some rectrices; basal portions of rectrices apparently covered by dark undertail coverts, making rectrix patterns difficult to see; 4) Very broad outer portion of the wing (“hand”) with strikingly long, distinct “fingers,” that is, distinctly segregated outer primaries; seven distinct outer primaries were counted; these long primaries, along with the “barn door,” square-handed wings and wedge-shaped tail, made for an appearance utterly unlike Bald Eagle, again recalling instead an Old World vulture (Clark and Wheeler [1987] emphasize that Bald Eagle has only six emarginate or distinct primaries, White-tailed seven; multiple observers present were aware of this and thus counted); and 5) A very large yellow bill, with no hint of dusky tones in the maxilla. Lifer sighting. Seen by 150+ observers during a massive raptor migration event.

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