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Subject: 1st year / female Paradise Flycatcher 壽帶鳥 (第一年或雌性) [Print This Page]
Author: HFCheung    Time: 12/09/2008 22:02     Subject: 1st year / female Paradise Flycatcher 壽帶鳥 (第一年或雌性)

1st year / female Paradise Flycatcher are tricky.  Here is a bird that birdwatchers have not come to a single conclusion yet.  This bird is trapped in Mai Po on 7 Sept 2008.



Any suggestion?
HF Cheung

[ Last edited by BWA at 19/10/2008 11:31 ]

Image Attachment: [Front view, the darker throat and paler breast show well] IMG_6767P.jpg (12/09/2008 22:02, 48.21 KB) / Download count 655
http://hkbws.org.hk/BBS/attachment.php?aid=2099



Image Attachment: [Side view, shinny crown show very well] IMG_6777P.jpg (12/09/2008 22:02, 50.05 KB) / Download count 1542
http://hkbws.org.hk/BBS/attachment.php?aid=2100



Image Attachment: [Back view, shinny crown not shown well] IMG_6757P.jpg (12/09/2008 22:02, 55.12 KB) / Download count 683
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Author: fkm    Time: 13/09/2008 09:00

I am wondering, after they trapped and have the bird in hand, they still do not know if it is a female or not?

I hope the bird did not get hurt and released properly thereafter.
Author: kmatthew    Time: 13/09/2008 17:13

Quote:
Original posted by fkm at 13/09/2008 09:00
I am wondering, after they trapped and have the bird in hand, they still do not know if it is a female or not?

I hope the bird did not get hurt and released properly thereafter.
fkm, I think you can trust the experts on that. You need to get a licence to trap birds for scientific research and all of these people are well trained to handle these birds. Also, there are species of birds which are really hard to identify even when hand held. There is a story in the UK where an expert trapped a warbler and said it was a willow, right after he released it the warbler flew on top of the tree and sang "chiff-chaff, chiff-chaff".
Author: HFCheung    Time: 13/09/2008 17:33

Yes, the bird was released unhurt.  Thanks for concern.
There were different opinions on the identity, and I am sure each side thought that they are right.  This kind of situation often happens in science.  With frank discussion, progress can be made.

HF Cheung
Author: fkm    Time: 14/09/2008 01:53

Quote:
Original posted by kmatthew at 13/09/2008 17:13


fkm, I think you can trust the experts on that. You need to get a licence to trap birds for scientific research and all of these people are well trained to handle these birds.
Dear Matthew,

Of course you know more than I do. But some time ago I have read elsewhere some "professional research" has caused casualties in birds, and another time that some research are totally unnecessary.

I think I have seen enough to conclude in many professions, there are well-trained professionals as well as mediocre and lousy ones. I do not take it for granted that any professionals can be trusted at the same level. But if you know them and trust them, I think I could too!

Thanks.

fkm
Author: 深藍-Owen    Time: 14/09/2008 02:15

so whats yr point fkm? are those "professional research" case u read apply to here? if not why u raise it here?

although bird ringing is a well known activites to most HKBWS members but seems some newbie like u not so sure what it is and dunno who is the host of this activities which held every weekend in the very early morning in Mai Po by some HKBWS volunteer for many years.

try to wake up early on Sat and go Mai Po Education centre before sun riase, spent some times with the profesional there like our Chiarman HF Chueng or if you see nobody there you may still read the poster on the small hut next to the EC and I think should enough to make you understand more .

lets back to the Flycatcher, u got any idea which species it is?

OC
Author: fkm    Time: 14/09/2008 03:33

What is your point in questioning my raising the question then, OC? Or if this is an ethnic in this society that any junior member should never question another senior member? To answer your question, my point is very simple: I would like to know! You know it well for many years does not mean another member will automatically know about it. So, I thank you for your explanation.

On the other hand, your explanation seems to imply that our chairman is hosting these bird trapping activities (correct me if I am wrong), so if he is offended by my question, he is the one who should let me know unless you speak for him.

Now, really back to the APF, the humble reference book I have always been relying on says "未成年雌鳥沒有冠羽". Hence, according to the book, this must be a juvenile male. But if the scientists got the bird in hand and still cannot make any conclusion, can the book be trusted?
Author: kmatthew    Time: 14/09/2008 05:14

fkm, I can trust the volunteers and experts in HKBWS because I know they have the experience and knowledge to handle these trapped birds. I don't know about other part of the world but I am sure you still need a license to do the same??

There is nothing wrong with wanting to know, but I think next time you can use a more forgiving use of words...it just sounds like you think all the researches are wrong.

It is not easy to identify some birds even on hand, some birds are just so tricky to identify. As I say, even experienced birders can get it wrong sometimes. Books are just for reference, there are bound to be some mistakes in them. If you look at older birdguides, I am sure you will find mistakes in them. There are so many things still unknown to us in this natural world, this is why researches are so important.
Author: 深藍-Owen    Time: 14/09/2008 09:03

fkm you are welcome, no need to say Thank you for me to spending time explain to you. I would like to share some knowledge to the newbie like you.

and people who know HF will understanding for the offended like this (if it is) really mean nothing to him.
Author: HFCheung    Time: 14/09/2008 17:51

The discussion is more heated than I wanted.  I do not felt really offended in the discussion, and I understand that some explanation is often necessary in a lot of situations.

Again go back to the question.  I really think that sometimes there are good reasons to doubt a book.  The case with Asian and Japanese Paradise Flycatcher is particular difficult.  I think the best reference book is Robson's "Bird of South-east asia".  The key id features are:
1. Glossy blue crown points to Asian
2. Colour contrast between throat and breast (or between crown and face in the illustration) points to Asian
3. The sharp change of the colour from the breast to the belly points to Japanese
4. Brownish tinted breast points to Japanese
5. Pale bill points to immature or 1st year

I believe the similarity and difference between Asian and 1st year Japanese is not well discussed in the reference books.  I think 1st year Japanese is very similar to the Asian.  I have the following comment and suggestions.
1. The colour of the upperparts (back and tail) is not a good feature at all for 1st year Japanese.  The colour is surprisingly difficulty to separate in the field and also in photo, due to the highly varying light conditions.
2. The glossy blue on crown seem to be convincing for Asian.
3. Tbe contrast of the throat to breast does point to Asian, even for the supspecies that we have in HK.  However, a few Japanese can show very similar constrast.  So this feature is not safe.  However, I think any brownish on the breast definitely points to Japanese.
4. Robson's illustration for Asian is good for wintering Asian, when the birds have new crown feathers and warn feathers on the rest of the head.
5. I have a lot of doubt on using pale bill/bill-base as a feathers for 1st year Asian or Japanese.

After all, I believe that the bird in hand is an Asian Paradise Flycatcher, and it could be an adult female.

HF Cheung
Author: fkm    Time: 17/09/2008 00:49

Dear Chairman,

Perhaps you are disappointed most of the heat is not on the identification of the bird...

Thank you for sharing your knowledge. Without being a researcher in this field, my only source of information is the books. It never occurred to me that this is an adult bird because the book I have been referring to says "兩種壽帶的咀和眼圈均藍色 (shown in illustrations too)"! I guess I cannot rely on this book anymore when the APF is concerned then. I also noticed descriptions in some other books are actually only referring to the saturatior sub-species but not others. I believe I once even read something like "the AFC will turn white after fully grown" (sort of). If the white morph is rare in Hong Kong, I suppose such description does not apply to our birds then. (We should be having the incei sub-species mostly, right?)

I am particular interested in the identification of this bird because I pictured one that appeared with the same configurations (I don't know if this is a proper term for birders though...) like that you trapped and examined. ( http://www.dchome.net/viewthread.php?tid=559874 ) However, these birds mainly stay in the shade of branches and leaves, any color shown in the photographs may just be the result of white balance setting and boosting by Photoshop. I have only considered it as a juvenile male until you provided your insights.

There is another bird that I thought was an adult male Japanese PF ( http://www.dchome.net/viewthread.php?tid=496438 ) but then there is no sharp distinction from breast to belly!

Anyway, I hope some distinctive features could be discovered in future researches.

Best wishes,
fkm
Author: HKBWS Vicky    Time: 17/09/2008 10:15

Glad to have discussion on bird identification again in this forum.
fkm, for the photos that you've taken, there is no doubt that the first one is APF and the 2nd one is JPF. It's difficult to distinguish between female and juvenile. Since i'm not an expert, i am not going to say anything about this. However, for the "sharp distinction from breast to belly", indeed the bird guide states "Dark ashy-grey breast forms a fairly sharp pectoral band...". Birders usually say "sharp distinction" when compare between JPF and APF, this is actually a comparative term which means "relatively sharp distinction" rather than sharp like putting a white paper on a blackboard. Actually #2 of your JPF series already showed this characteristic. You can compare #3 of your APF and #2 of JPF, you can see the difference of "diffused" (in APF) and "sharp distinction" (in JPF).
I hope you understand my explanation.
May experts please correct me if I am wrong, thanks!
Author: ajohn    Time: 17/09/2008 14:17

Adult males of these two species are easy to separate - JPF is rather dark overall on the upperparts (as shown on fkm's excellent photos), whereas APF is chestnut-brown above.

The confusion lies in the ID of 1st year birds and females. There seems to be a certain amount of disagreement in separating the species in these plumages. Unfortunately the subspecies passing through HK seem to be more similar than in other parts of the species range.

In my opinion, the photos posted by fkm show a 1st winter APF, with entirely chestnut upperparts. Aging as a 1st winter is based on the contrast within the greater coverts - some have been moulted, while others are retained.

Ho-fai's (trapped) bird is less obvious. I would consider this to be JPF based upon the maroon colours on the mantle - this is clearly different from fkm's bird.  The tail and tertials are more chestnut than I would usually expect for JPF, however.

I find the contrast between throat and breast (and between breast and belly) to be difficult to judge and rather subjective. This feature seems to be strongly affected by light conditions. Gloss on the crown will also be affected by light, and probably also by the age of the bird.

Other features may be useful in separation of the two, and may be less subjective.  Looking at photos, there may be some difference in the patterning of the tertials/coverts, and the undertail coverts may be slightly chestnut on APF (compared to pure white on JPF). It would be great if some of the HK photographers could get more good photos of these species in HK to help resolve this ID problem. The photos linked by fkm are very good, and are useful in ID.

I would be interested to know how the MP bird was aged/sexed as an adult female - I have little experience of handling these species and do not know which features are reliable for aging. I would have depended on bill colour (pale, plain) and lack of eye-ring as suggestive of a 1st-winter bird, but as Ho-fai suggests these features may not be reliable at this time of year.
Author: 18134567    Time: 19/10/2008 09:11

This is 寿带?



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