Posted by Greg Gillson (192.65.40.9) on October 11, 2001 at 12:38:14:
Gary Potter posted the correct ID: Parasitic Jaeger. I can be a bit more sure than Gary's >55% confidence. The barred underwings indicate an immature bird. The short, pointed central tail feathers belong only to Parasistic (tail points on immature Pomarine and Long-tailed are rounded). The base of the tail is white; this is only shown on immature an Parasitic Jaeger. The ratio of the hand length to arm length is about even, pointing to Parasitic (Pomarine has a shorter hand; Long-tailed has a shorter arm). The width of the based of the wings is about the same as the distance from the rear of the wing to the end of the tail (not counting the central tail points). This points to Parasitic, as well. Long-tailed have long tails--even without the central tail feathers. Pomarines have wide wings and a short tail. The general rusty coloration to the plumage and the lack of black-and-white undertail coverts (in immature plumage) both add credence to the identification as a Parasitic Jaeger.