ML646049402

观察细节

I initially entered this as Eagle sp but after reviewing photos and getting opinions from others I have concluded that it’s an adult or near adult Golden Eagle. A massive, medium dark raptor flew over low (maybe 20 m high) heading west and being mobbed by a half dozen western gulls. When I first saw the bird it was nearly directly overhead. It was a very large bird (roughly 1.5x the wingspread of the Western Gulls) with very long, broad wings, a medium-length tail. It lacked obvious structural marks like budging secondaries, wedge tail or weirdly large head or bill. The impression overhead was that it was an all-brown raptor that dwarfed the WEGUs in wingspread, wing width and length. The bird flapped and then settled briefly into a glide until it was attacked again by a WEGU. The wings were broad and long, with the distinctive plank shape of eagles and lacking a big secondary bulge. The tail was medium length. I didn't get a long enough look at the structure to be certain if this was a Bald or Golden Eagle at the time. For example, I don't remember the size of the head/neck extension nor the details of the underwing pattern except to say that neither were exceptional. It flew with ponderous wingbeats (like a GBHE or eagle). The undersides of the wings, body and tail were in distinctly patterned as shown in the photos. There were some paler/white spots but not forming an obvious pattern. The belly was not obviously paler or darker than the underwings, tail or flight feathers, and the wings didn't show the distinctive white central patches of imm Golden Eagle. In retrospect, I wonder if the impression of a pattern on the underwings was an artifact of the low light angle, exaggerating the contrast. My immediate impression was immature Bald Eagle given the massive size, proximity to the ocean and overall coloration. However, it lacked the high-contrast blackish/brown and white underside contrast I expect on an immature Bald Eagle. I grabbed my camera and got a few poor shots. These photos don't provide much useful detail on the pattern of the bird, other than showing massive size relative to WEGU, overall brown color, a mottled underwing (due to lighting?), yellow feet, large yellow bill, a uniformly brownish upperwing and tail. The photos do provide some information on the structure (long wings, long inner wing relative to the hand, etc.) and most importantly they show the size of the bird relative to a Western Gull that swooped in to attack it. The bird is roughly 1.3-1.4 times the wingspread of the Western Gull, (taking into consideration that the WEGU has its wings partly shorted by the view) which is consistent with my impression in the field. With western gulls being 58" wingspread (per Sibley) that would make an estimate of this bird's wingspread about 76" - 88'. Eagles, Turkey Vultures and not much else are in that size range. I considered Ferruginous Hawk, imm Bald Eagle, adult Golden Eagle, and Turkey Vulture. However, none of these species is an obvious fit. FEHA is perhaps a fit but this bird lacked pale in the tail and UTC and was also too big. Immature BAEA should show a bolder underwing pattern and imm has a dark bill. It is admittedly not perfect for Golden: GOEA adult would show pale carpal bar, hint of bars on tail. Turkey Vulture is too small and many plumage and structural features don't fit (e.g. large yellow bill).