查看完整版本: Rufous-bellied/Fujian Niltava - ID Please

Rufous-bellied/Fujian Niltava - ID Please

King's Park 03/03/2013 .. thanks to simon for the location .. cheers

[[i] Last edited by wilsondring at 3/03/2013 23:02 [/i]]

Fujian Niltava

[quote]Original posted by [i]lchunfai[/i] at 3/03/2013 20:41 [url=http://www.hkbws.org.hk/BBS/redirect.php?goto=findpost&pid=56187&ptid=18552][img]http://www.hkbws.org.hk/BBS/images/common/back.gif[/img][/url]
Fujian Niltava [/quote]

i appreciate that the two look similar and there is a debt about the two species on a separate thread regarding the same bird at King's Park [url=http://www.hkbws.org.hk/BBS/viewthread.php?tid=18548]Click Here[/url], however, I stand by the fact that the white on the belly is not clear enough to be a Fujian, from all images, the rufous-orange looks uniform all the way down to the belly.

[[i] Last edited by wilsondring at 3/03/2013 20:51 [/i]]

These are difficult species. The photos of Rufous-bellied Niltava at OBC Images seem to indicate that on this species the orange underparts are uniform all the way down to the vent/undertail coverts. Fujian Niltava shows an obvious contrast between the richer orange breast and the paler vent. Perhaps the contrast between the vent and breast is more important in terms of ID than the breast/belly contrast.

The photos of the King's Park niltava - although they are variable because of exposure etc. - seem to show a contrast between the breast and vent, suggesting that this is more likely Fujian Niltava.

David

Also, Rufous-bellied has bright blue shoulder patches and the back of the crown is also more bright blue. I also think it is Fujian.

I do not understand why nobody take into
consideration the pale area at the base of lower mandible that almost all Fujian Niltava show ( at least on the all set of pics of this sp on OBI), where no one Rufous-bellied show it.
An other good feature to separate this two species is the proportion between head and body, Fujian to me show a small head compare to the size of the body given an impression of not well structured bird compare to Rufous-bellied that looks better proportioned.
The shoulder patch and the contrast between undertail coverts, vent,belly and breast seems to be very variable between each individuals.
To me this bird is a Rufous-bellied.

All the best,

Jonathan

The pale bill base may indicate that the bird is a first-winter. The fact that all male Fujian photos on OBI were taken in Hong Kong and are of the same 3 individuals suggests a sample bias - photos of adult males wintering in Indochina (and this individual in King's Park) show black bill base too, for example in this nice shot: [url]http://www.flickr.com/photos/paulocoteriano/5527877830/[/url]; also the Sha Tin Pass male by PWMK on OBI also shows a black bill base.

On the other hand for Rufous-bellied, it seems to me that the extent and saturation of solid rufous down to the vent, and the obvious full azure shining shoulder brand are more consistent diagnostic features.

[[i] Last edited by kkoel at 3/03/2013 23:29 [/i]]

In my mind, the pale lower mandible may indicate that is a first-winter male only.
Interestingly, all the photos on OBI (fujian niltava) are taken in HK.

the only reference i have used has been "a photographic guide to the birds of hong kong" and it doesn't exactly show good photos of either ..

since the debt is on-going a week or 10 days since the first photos were published here, .. here are a few more taken exactly 6 days after my first photos were taken ..

again, i support the notion of rufous-bellied over the fujian .. due to the uniform orange belly ..

My photos contribution to the subject for matter experts reference. Thanks for the ID.

From King's Park 2013.03.15:

[img]http://www.bluebirdservices.com/My%20Photos/cntlaw-2013/20130315-FujianNiltava-03.jpg[/img]

[img]http://www.bluebirdservices.com/My%20Photos/cntlaw-2013/20130315-FujianNiltava-04.jpg[/img]

[img]http://www.bluebirdservices.com/My%20Photos/cntlaw-2013/20130315-FujianNiltava-05.jpg[/img]

From Po Shan Road 2011.02.06:

[img]http://www.bluebirdservices.com/My%20Photos/cntlaw-2013/20110206-FujianNiltava-01.jpg[/img]

[img]http://www.bluebirdservices.com/My%20Photos/cntlaw-2013/20110206-FujianNiltava-03.jpg[/img]

[img]http://www.bluebirdservices.com/My%20Photos/cntlaw-2013/20110206-FujianNiltava-05.jpg[/img]

[img]http://www.bluebirdservices.com/My%20Photos/cntlaw-2013/20110206-FujianNiltava-09.jpg[/img]

[[i] Last edited by cntlaw at 16/03/2013 11:28 [/i]]

To me all the Hong Kong birds above in this thread are Fujian Niltava, and I think the excellent photos taken by Wilson and Cntlaw illustrate the diagnostic features of Fujian Niltava quite well:

1. Paler vent/belly than the breast - you can always see a lot of white on the belly, especially on Cntlaw's shots and Wilson's 3rd photo, where the even lighting shows up the white on lower belly pretty well on the King's Park Bird despite the presence of pale rufous vent.
2. Lack of extension of gloss down to the nape
3. Lack of well-defined shoulder gloss

Please compare with the photo of a true Rufous-bellied Niltava below:
1. Note rufous vent, belly and breast - which are of uniform colour.
2. The glossy forehead + crown extends into the nape, which contrasts well with dark ear coverts;
3. The shoulder patch is sharply bordered and contrasting, where is Fujian this has blurred border, varies with angle and is less contrasting.

[img]http://ibc.lynxeds.com/files/pictures/rniltawaforos.jpg[/img]
[url]http://ibc.lynxeds.com/photo/rufous-bellied-niltava-niltava-sundara/fabulous-species[/url]

Having said that, I draw my conclusions from field guide descriptions and photos online and I'm happy to be corrected. =)

[[i] Last edited by kkoel at 16/03/2013 13:44 [/i]]

i believe that it all comes down to the orange on the breast and belly .. and how prominent the white.

from the photos of the King's Park bird, all except for a few feathers around the legs are completely orange, whereas the fujian should have a much clearer white towards the belly.

i appreciate that the orange shown in the photo kkoel, is far more orange through out, this can be achieved by the photographer post-editing to make the photograph more appealing as oppose to reflecting the true color of the plumage.

I'm not sure that the subspecies wintering in Thailand is the one that could occur in HK in winter, so to me this comparaison is not the most appropriate. The subspecies denotata breeding in NW Hunan, seems to be much shorter tail than the one in Thailand.
I'm still pretty convinced that the King's Park bird is a Rufous-bellied Niltava.
- on structure, the bird looks very bulky with a large head
- the bill looks rather short
- the rufous on breast seems very deep, more solid and uniform than on Fujian
- entire black bill, I doubt that the pale area shown by Fujian Niltava at the base of the lower mandible disapear so quickly, after its 1st year, that sounds pretty odd to me, but I agree than in some birds it is'nt so obvious, so it is very likely that this paler area is reducing with the age, but on most birds I've seen including some adults, there was always something can be seen....

I found really difficult to appreciate the extent of the iridescence on crown, as well as the plumage color on upperparts, it vary a lot depending on light, pictures conditions, bird position....
To me the best way to sperate them in the field is on structure, but I'm also happy to be corrected and agree that sometime they are really difficult to tell appart.

All the best,

Jonathan