Parasitic jaeger Stercorarius parasiticus


Identification Tips:

Adult light morph:

Adult dark morph:

Juvenile:

Subadult:

  • Variable; gradually acquires adult plumage
  • Occurs in both dark and light color morphs
  • Best identified by tail feather shape, size, and bill shape

    Similar species:

    Young Parasitic Jaegers look superficially like first-year Herring Gulls but have a more powerful, direct flight and white patches on the primaries visible from above and below the wing. Skuas are much bigger, heavier, thicker-necked, and have bolder white wing patches. Jaegers look most similar to each other. Adult Parasitics can be safely identified either by their long, pointed central tail feathers or smooth gray breast band. The adult Long-tailed Jaeger has longer pointed tail feathers, is pale gray above and lacks the breast band. Juvenile and subadult jaegers are very difficult to tell apart. All three jaegers differ in size and structure, but Parasitic is most difficult to identify since it can be confused with the larger Pomarine or smaller Long-tailed jaegers. Long-tailed is very tern-like and has a dainty bill which the gonys appears at or near the midpoint of the bill. Pomarine is much bigger and bulkier, almost skua-like, and has a thick bill with a prominent gonydeal angle. Juvenile Parasitics can have distinctive cinnamon tones to their plumage, usually have pale primary tips, and wavy uppertail covert bars which are diagnostic.

    Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.