Pomarine jaeger Stercorarius pomarinus

Identification Tips:

• Sexes similar
• Large jaeger, heavyset, thick-necked with broad-based wings
• Thick, heavy bill with prominent gonydeal angle
• Sometimes chases other birds to steal their food
• Powerful, yet agile, flight
• Juveniles take several years to reach adult plumage
• Light and dark color morphs
• Mainly pelagic but occasionally seen inland

Adult light morph:

• Central tail feathers elongated and spatulate
• Heavy pale-based bill
• Black cap covers eye and crosses chin
• Yellow area below cap
• White nape and chin
• Very dark upperparts
• White underparts with dark mottled breastband, flanks, and undertail coverts
• White patch at base of primaries; diffuse on underside and along the shafts from the upperside

Adult dark morph:

• Central tail feathers elongated and spatulate
• Heavy pale-based bill
• Entirely dark plumage except for white bases of primaries

Juvenile:

• Rounded, central tail feathers barely project beyond rest of tail
• Upperparts dark with pale edgings
• Primaries dark with pale shaft streaks on outer 5-7 primaries
• Head, body, and wing linings barred-belly may be pale
• Uppertail coverts barred black and white

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 Pomarine 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 similar as well but are bulkier, thicker-necked, with much more prominent wing patches. Jaegers look most similar to each other. Size and shape often isthe best way to distinguish the three species: note the Pomarine's larger size, heavyset body, broad-based wings, and thick, angular bill. Adult Pomarines can be safely identified by either their long, spoon-shaped central tail feathers or their mottled breast band. The light phase has a heavier breast band than the Parasitic Jaeger. Juvenile jaegers are very difficult to tell apart but the tail feather shape is still diagnostic though subtle and the uppertail covert pattern is useful as well. Long-tailed Jaeger is very small and dainty and should rarely be confused with Pomarine.