查看完整版本: Changes to the HK List (25th June 2009)

cgeoff 25/06/2009 19:13

Changes to the HK List (25th June 2009)

At the recent meeting of the Records Committee, the following changes were made to the HK List.

[u]Additions to Category A[/u]
[b]Slaty-backed Flycatcher[/b] [i]Ficedula hodgsonii[/i]
A first-winter at Tso Kung Tam, Tsuen Wan from at least 10th February to 2nd March 2008 (based on postings on the HKBWS website).

[b]Steppe Eagle[/b] [i]Aquila nipalensis[/i]
A juvenile was at Mai Po NR on 22nd and 25th December 2008. It was subsequently reported again from 28th March into April 2009.

[b]Blue-winged Pitta[/b] [i]Pitta moluccensis[/i]
In light of further records of this species on Po Toi and Fu Tian in spring 2008 and 2009, this species is now moved to Category A.

The HK List now stands at 491 species in Categories A-D.

[u]Additions to Category E[/u]
[b]Red-headed Bunting[/b] [i]Emberiza bruniceps[/i]
One was seen along the access road to Mai Po on 10th January 2008. However, as it showed signs of feather damage caused by captivity, it has been added to Category E.

With reference to a recent website posting, the RC also examined photographs of the recent Hawfinches at Airfield Road and Ping Che. The latter bird showed signs of having been kept in captivity. Consequently, it was decided to retain it in Category E. Such species as this (others comprise Ruddy Sparrow, and Rustic, Yellow-browed, Yellow-throated and Meadow Buntings) are particularly problematic for the RC, as it is quite possible that both wild and ex-captive birds occur.

In addition, in response to a suggestion elsewhere on this Forum, the following species have been removed from Category F: Red-throated Loon, Greater White-fronted Goose, Amur Falcon, Eurasian Oystercatcher, Drongo Cuckoo, Pygmy Wren Babbler and Sulphur-breasted Warbler.

An updated HK List will be posted as soon as possible.

Also at the meeting the RC considered the recent spate of records of small, all-dark shearwaters in spring. The fact that both Short-tailed and Sooty Shearwaters are common in the western Pacific in the northern summer means the RC will be very cautious in assessing records of these birds; this was highlighted by the recent claim of Sooty Shearwater in HK. We cannot assume that all small, dark shearwaters are Short-tailed, though, admittedly, it is likely that most are. Observers are encouraged to provide detailed notes and as many photos as possible when submitting records of these birds.

Geoff Carey
RC Chairman

[[i] Last edited by cgeoff at 26/06/2009 12:37 [/i]]

kmike 26/06/2009 10:39

Thaks to the Records Committee for their continuous, largely thankless, but highly important work in keeping Hong Kong's list and records as one of the most up to date and well managed anywhere in the world.

After reading the changes to the list The issue that fgures large in increasing numbers of records is that of cage damage.  It would be interesting to have more discussion about the issue of cage damage.

I regularly see birds with damaged feathers, and indeed birds moult their feathers because they do suffer wear and tear, including broken or missing flight and tail feathers.

I am also aware of the study that over 90 % of birds in the bird market showed signs of damage to feathers and bare parts.  

But just because most escaped birds are likely to have suffered cage damage does not mean that all birds with damaged feathers are cagebirds.

I fully appreciate that the Records committee has a duty to keen the list as "clean " as possible, but I wonder if the insistence on undamaged plumage, especially for migrant passerines,  is keeping good records off the list.  

I would be very interested to hear the views of others.

Mike K

cgeoff 26/06/2009 12:00

The RC plans to publish in the next HKBR an article on cage damage in birds, how it manifests itself and provide photographic examples.

I don't think there's an 'insistence' on perfect plumage, but, it is something we must take account of, especially given the unfortunately large number of birds traded through HK. To take the Red-headed Bunting as an example, if the sole HK record of a species constitutes a bird with plumage damage, there would have to be very strong other reasons for including it in Category A.

As always, comments are very welcome. Feel free to place them here, or email me direct.


[[i] Last edited by cgeoff at 26/06/2009 12:03 [/i]]

ajohn 27/06/2009 16:25

I think the issue of cage damage may appear to be increasing mostly because of the high quality of photographs now provided of most HK rarities. This allows a level of scrutiny of plumage that was not previously possible. The RC, of course, considers carefully each individual, and whether the pattern of feather damage is more likely to relate to cage damage, or if it can be accounted for by normal wear. I agree with their decision that if the first record of a species involves an individual showing unusual feather wear, it is better to retain the species in Category E rather than rush into Category A. The situation can be reviewed for each species at a later date if necessary, especially if further records support a possible wild origin (Blue-winged Pitta is an example of this re-assessment, I believe other species are being considered for upgrading from Cat. E).

I know some of the RC were initially of the opinion that the Red-headed Bunting and Hawfinch were probably wild, so I'm sure the decision has not been taken lightly. Although some 'good' species may slip through, I think it is also important to strike a balance against letting 'bad' species onto the list. I think for the balance is generally correct at the moment.

cywong 27/06/2009 21:40

Many thanks to the Records Committee for keeping the Hong Kong's list and records up to date; and thanks for raising the issue on feather damage for discussion. This is a really long-awaited discussion topic, as we often find birds that have damaged feathers.

Here are 2 examples:

This female Green-backed Flycatcher, which stayed at Po Toi from March to April09, had damaged tail feahters. Is it considered as a Cat. A bird ?

Po Toi, 29/03/09


This female Narcissus Flycatcher, which was found on 31Mar by Brenda and Lam, had no tail. Is it considered as a  wild bird?

Po Toi, 31/03/09

Looking forward to opinions of expert bird watchers.

lpaul 29/06/2009 18:12

The decision regarding category is often the most complicated part of the work of the Records Committee.  Whilst we sometimes struggle with problematic identifications, much more time is spent considering the status of potential additions to the Hong Kong list and upgrades in Category status.

However, I think there are already some rather subtle issues being raised which are worthy of discussion.

Firstly, the question regarding the status of the two flycatchers mentioned by cywong, whilst interesting and of concern for those who saw the birds, is unlikely to affect the position of the two species on the HK list.  Both species exhibit a pattern of records typical of a spring passage migrant and the bulk of the records concern individuals with no apparent cage damage.

This is not the case with Red-headed Bunting and Hawfinch.  The former has only one record, so the assessment of that individual has a direct bearing on the HK list; if it is deemed to have occurred naturally, or probably so, the HK List (or the categories that most people take seriously, A to D) increases by one species.  I believe this to be a highly likely addition to the HK List; however, the bird showed signs of cage damage, and is known to be traded.  However, were we to get another in spring or autumn, in excellent condition we would be faced with (another) difficult decision.

Hawfinch is more complicated, with a body of records which show something of a pattern but which includes birds with apparent cage damage.  Had the Ping Che bird referred to above not shown cage damage then the species could well have been upgraded from Cat E.  Certainly some records of this species do look like they refer to wild birds.  However, there is another important point to consider which makes the category assessment process so difficult; that ex-captive birds do not always show obvious cage damage.  Such an example would be Bearded Reedling, several of which were trapped at Mai Po a few winters ago and upon examination were in excellent condition; however, being a largely resident species breeding about 1500 km from HK, they were extremely unlikely to have made it to Mai Po naturally.

This leads us on to what cage damage actually looks like.  To appreciate this, one first has to understand what natural wear looks like and how moult functions.  I don’t propose to go into these in detail here.  However, there are one or two important rules that all birders should understand.  One rule is that moult is typically symmetrical in that the same feathers in both wings, and on both sides of the tail are replaced at the same time.  As such, a bird with a big gap in the primaries on only one wing or with the outer tail feathers missing on one side only is not in moult; this is the result of some sort of damage.  

It is also helpful if birders understand the timing of moult, although this varies according to species and is something that has to be slowly learnt (for example most adult buntings have a post breeding moult, except for adult Black- and Red-headed Buntings which moult in winter; hence a worn Black-headed Bunting in autumn is normal, but only if it's an adult).  Taking finches as an example, all individuals should be in fresh plumage in early winter as adults moult after breeding and first-winter birds have fledged a few months earlier; limited wear to the outer primaries and tail tips would not normally be apparent until the early spring. Natural wear would affect the plumage of a bird slowly and would not normally be apparent on a typical passerine until the feathers were many months old.  

Cage damage affects both feathers and the bare parts (bill and feet/claws).  Damaged feathers are eventually replaced (so this only a short term clue) whereas damage to the claws and especially the bill can be permanent (I recall catching a male White-tailed Robin at KFBG years ago which had immaculate plumage and terribly damaged feet and bill, and so it must have escaped sometime prior to being trapped ‘in the wild’).  

The base of the bill is often the first place where damage occurs (with abrasions to the base of the upper mandible and loss of forecrown feathering typical) as birds repeatedly poke their heads through the wire of the cage.  Other areas susceptible to damage are tail and primaries, with damage ranging from the feather tips being broken to entire feathers being lost.  Damage to the body feathers can also occur as birds hit the sides of the cage in panic (this sort of damage is especially unusual in the wild).  

Tail feathers are replaced quite quickly (on a short-tailed passerine in about two weeks) so a cage bird might lose part of its tail but subsequently regrow those feathers.  However, many passerines have different tail feather shapes according to age.  Thus a first-winter thrush will have narrower and more pointed feathers than an adult.  On both the Red-headed Bunting and the Ping Che Hawfinch two ages of tail feathers were apparent from the photos, which indicated that at some time in the previous six months (approx) tail feathers had been lost in some sort of an accident.

Ultimately, being able to differentiate between natural moult and wear and damage (whatever the cause) forms an essential part of the assessment process.

Getting back to cywongs two flycatchers, one shows a damaged tail feather and dishevelled plumage, the other is missing a tail.  However neither show ‘classic’ cage damage (tips to the tail, primaries and bare parts are in good condition), both occurred at a time of year that fits the known pattern of occurrence, and, as I mentioned above, both species have a history of good records.  There are, of course, potentially other reasons why one bird lost its tail (one of the Po Toi cats springs to mind!).  As such I would give them both the benefit of the doubt.  However, had one been a stunning male Kashmir Flycatcher without a tail, I would be a lot more reluctant to do this!

Please note that these comments are my personal views and not necessarily those of the Records Committee. However, both I and the rest of the RC welcome comments.

[[i] Last edited by lpaul at 30/06/2009 11:35 [/i]]

cywong 30/06/2009 22:13

Many thanks to Paul for the detailed explanation and sharing of his expert knowledge on this subject.
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查看完整版本: Changes to the HK List (25th June 2009)