ความคิดเห็นที่ 48
Oy,oy oy.... these Cyornis!!
Your latest picture is a perfect female Hill Blue. The brown on the side of the head does not much extend on to the sides of the throat and the demarcation between the orange and the brown on the sides of the breast is fairly sharp all the way down.
Hainan and Chinese Blue might be a bit problematical (and even David Wells has had problems here). The bird photographed by Chaiwat is definitely not a Hill Blue, as it has significant brown on the sides of the breast and some brown on the sides of the throat. I'd be pretty sure that this is hainanus, but I can't 100% rule out glaucicomans. If it was taken in forest, where hainanus occurs, the sensible thing to do would be to suppose it is hainanus unless you can prove otherewise.
I think glaucicomans and hainanus can be problematical. I think the best distinction is that hainanus, even though it has brown on the sides of the breast (it probably has more brown on the sides of the breast than glauciomans), still has a fairly broad, evenly tapering wedge of orange extending up the throat, rather more like Hill Blue. The demarcation on the lower breast, between the orange and the white, is sharper, more clear-cut in glaucicomans than in hainanus (which has a blurry demarcation, more like Hill Blue).
In addition, hainanus practically always calls with a tic, whereas to my ear the short call of all other small Cyornis spp. is a definite tac.
Will Duckworth says that hainanus occurs as a migrant around Vientiane, Lao PDR in winter, so we might even expect odd ones to how up around Bangkok. I believe I once trapped a migrant hainanus in mangroves at Samut Sakhon (way back in September 1988), but it is so ,long ago that I am not sure.
Your glaucicomans slide no 1, where the bird is front-on, shows how clearly the orange cuts in on the lower throat to just a narrow wedge.
The chances are that any Cyornis in scrub/mangrove in gardens in the Central Plains is going to be glaucicomans. However, I have caught 2-3 Hill Blue Flycatchers in mangrove scrub on autumn migration, and also one in parkland at Salaya in midwinter, so migrant Hill Blue can also turn up it seems. In addition, just to confuse things even further, the Himalayan/SW Chinese race magnirostris of Hill Blue Flycatcher has been recorded in the peninsula in winter, and could also well turn up. And interestingly, the new Indian Guide by Pam Rasmussen and John Anderton treats this as a full species. Magnirostris has a long primary projection (like glauciomans), a sharp throat demarcation (like Hill Blue), a longer bill, and, according to David Wells has "prominent pale purple on the base of the lower mandible."
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9 ต.ค. 48 23:01:51
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