ML647543276

Beobachtungsdetails

At 41.9256893, -87.2344669, 11:20am. Juvenile. About 19.0 miles from shore. Flew in to the gulls behind the boat and attacked several in acrobatic fashion, typically approaching target birds by swooping up from below. Chased off by an Am. Herring Gull at 11:24am. Then several minutes later (11:28am), returned to vicinity of the boat, circling the boat closely two or three times. Departed at about 11:30am. Photos. Fast flying dark bird, decidedly smaller than the Am. Herring Gulls it approached. Overall chocolate brown appearance. Head fairly dark with modestly paler hind collar. Smallish and triangular head without notable forehead; dark-tipped bill with paler base occupying a bit more than half the length of the bill. Small thin pale area at the base of the upper bill. Upperparts chocolate brown with pale edges to most wing coverts and some scapulars. Outer five primaries with pale shafts. Messy white barring across uppertail coverts. Upper breast fairly dark without prominent pale markings. Lower breast and belly marbled dark and pale, vent area somewhat paler with some dark markings. Undertail coverts barred dark and pale. Tail dark with inner two rectrices pointed, extending shortly past end of otherwise even length tail. Underwing with dark and pale barring, especially prominent in the axillaries. Large rounded white patch in outer primaries beyond primary coverts.