This entire series of photos (below) captures an immature (intermediate/dark) Parasitic Jaeger observed offshore Vermilion, Ohio (3.5 miles out) on the October 29th, 2011 Local Patch Birding pelagic tour. Photos by Laura Keene, Jerry Talkington and Karen Potts (noted before each set of photos). CLICK ON PHOTOS TO VIEW FULL SIZE.
Overall, this bird shows an even-weighted body (more slender than a Pomarine). The bill is more slender (longer-looking) than Pomarine, which would have a heavier, thicker, more blunt-looking bill. The pointed central tail feathers (rectrices) show well. Pomarine’s central rectrices barely stick out beyond the rest of the tail and are blunt.