Black-tailed Gull (Larus crassirostris) in New York

Late in the afternoon on Sunday 31st January 1999, Andy Guthrie and I discovered an adult Black-tailed Gull (Larus crassirostris) roosting in a flock of Ring-billed Gulls (Larus delawarensis) near Parking Field #6 at Jones Beach on the south shore of Long Island, New York. To the best of our knowledge, this represents the first state record of this asiatic species.

Here is a series of photographs of this bird taken by Andy Guthrie in the rapidly fading light. The mantle appears much darker and the white primary tips less striking than in life.

Figure 1. We first spotted the bird as it stood with a group of roosting Ring-billed Gulls on the sand separating the parking field from the ocean. Although resembling a Lesser Black-backed Gull, the bird appeared only slightly larger than the surrounding Ring-billed Gulls.


Figure 2. The deep red orbital ring and bright yellow iris are clearly visible. The bill was yellow with a broad subterminal band crossing both mandibles. The bill was tipped with red and on the lower mandible there was a patch of red (gonyl spot) on the distal side of the black band. In life, the mantle was a uniform slate gray (lighter than in these photos) and without any hint of brown. Five white primary tips were visible on the folded wings. On the standing bird we counted three primary tips (P8-P10) beyond the end of the tail, with the next primary tip (P7) parallel with the tail tip. One additional primary (P6) carried a white tip. The white tips appeared larger and more striking in life than they do here.


Figure 3. Taking flight. The bold white rump (uppertail coverts) contrasted dramatically with the broad black subterminal band on the tail. This immaculate black band was approximately one bill length deep and stretched across all of the tail feathers except the outermost which appeared all white. The white terminal band was perhaps one third to one quarter the width of the black subterminal band. The yellow legs are clearly visible here. Note also the neat white trailing edge to the secondaries and inner primaries.


Figure 4. More detail of the tail. Notice how the black of the subterminal tail band extends along the outer webs of the tail feathers towards their base. The prominent white primary tips and the obvious contrast between the black outer primaries and gray inner primaries/secondaries/mantle are not evident in this exposure.


Figure 5. Closer view of the standing bird showing the diagnostic bill pattern, yellow iris, red orbital ring, yellow legs, subterminal black tail band and white primary tips.


Figure 6. Wings raised showing the dull gray undersides.


Figure 7. Detail of the subterminal black tail band as the standing bird raises its wings.


Figure 8. More detail of the tail. This time we can see the undersides of the tail feathers.


Exciting images of a 3rd basic Black-tailed Gull from Texas can be found here:
Martin Reid's site
Greg Lasley's site


All photographs are copyright of Andy Guthrie. Page layout and text is copyright of Angus Wilson. All rights reserved, 1999.
Comments or questions? Please e-mail Angus Wilson
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