Posted by Tony Leukering (152.163.194.191) on October 15, 2001 at 15:19:58:
Hi all:
Chris Wood, Brian Gibbons, and I are staring at the picture and agree among each other that the bird is a second-year, light-morph, Long-tailed Jaeger. The bird has adult-type underparts (smoothly-colored belly and undertail coverts, white breast) and juvenile-type underwings (strongly marked with whitish on most all feathers). The central rects appear very pointed, but there is an obviously-rounded feather on the right side of the tail that is probably an incoming rectrix. The bird's shape looks very good for Long-tail as the wings look relatively longish and narrow, as does the body. The underwing pattern suggests that the bird is not a Parasitic, as that species USUALLY shows much more evenly-colored underwings, with the pale markings being buffy or rufescent vs. the whitish of Long-tail. However, the real clincher for the CORRECT identification is the pattern on P10. This feather on Long-tail has the inner margin dark, which creates an obvious, long intrusion of dark from the wingtip into the white flash of the hand. The other two jaeger species do not show this feature, which is illustrated quite well by Master Sibley.
While the tail tip might be hard to explain, I'll take a stab at it. Since this bird has retained those rects from the nest (I believe that, like other larids, jaegers do not molt any flight feathers in their First Pre-Basic molt), I would guess that the R1s are just incredibly worn with no barbs remaining on the feather tips, thus creating pointed R1s on a species that is supposed to have rounded R1s.
Enjoy,