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Subject: date of appearance of Greylag Goose en Ferruginous Duck [Print This Page]

Author: Jonathmartinez Time: 25/08/2014 01:11 Subject: date of appearance of Greylag Goose en Ferruginous Duck

Just a thought concerning the two recent sightings of Greylag Goose and Ferruginous Duck recently.
Both of them are known to breed quite far away from Hong Kong and with a migration period starting much later in season than august. I guess that a post breeding dispersion would not bring these birds that far away from their breeding site that for both species may well be a few thousand kilometers away from HK. They may well find attractive site before they reach HK.

So that, I have another theory to expose concerning the date of appearance of these two birds and it seems to be the case as well for the previous sighting of Greylag Goose in HK : august coincide with the end of the post breeding moult wich is full indeed including all primaries. People who usually keep these kind of birds for ornaments in small pool and whom usually cut the primaries of their birds to avoid them to escape may easily loose some birds at this time of the year if they do not cut again the newly growth primaries before they're fully growth.... Then to me at this time of the year they're is greater chance that these birds have escape from a private pool not far from there instead of deciding to migrate a few months earlier than usual.
Birds keep in large enough pool may not show more damage than a bird living in the wild in my opinion and some birds may stay shy with human.

I suggest to try to feed them with bred, this is usually the good test in Europe...

Happy to hear comments of other concerning this theory...

All the best,

Jonathan

Author: wilsondring Time: 25/08/2014 09:58

very interesting theory .. I missed the Greylag Goose on Saturday but I did see the Ferruginous Duck on three separate days and spent a good few hours over the weekend.

the bird is clearly able to fly as he moved from pond to pond but only on two to three occasions over the entire two days (Twice on Saturday and Once yesterday afternoon). i also noticed that when he was bathing and cleaning his feathers, it looks as if he was not very balanced, .. ie his left side would not clear the water as much as the left.

i have deleted the frames for exactly this reason but i will recover them from my trash box and post here once home tonight ..

Author: lmichael Time: 25/08/2014 11:39

Good point Jonathan.

Note that the Ferruginous Duck is still growing its primaries (see photos with its wings spread), unlikely to have migrated far in that condition.

Also the Greylag Goose could be the returning probable ex-captive bird of 2011/12.

I certainly have reservations as to the origin of both birds.

Best regards

Mike Leven

Author: ajohn Time: 25/08/2014 12:17

Maybe I've missed something, but I don't see any evidence that the Ferruginous Duck is moulting. In fact, I think the the photos of spread wings show that the feathers are fully grown. The same is true of the Greylag Goose, which also shows fully grown wings with no moult or damage.

Having seen the goose on Saturday, the thing that really struck me was how cautious this bird was. Note that the good quality pictures make this bird seem much closer than was actually the case. It stayed about as far from land as possible, and was scared of everything - even flushed away by a Black Kite flying over. Even when near other birds (egrets) for security, it was constantly on the lookout because it was so nervous. I find it hard to imagine that this bird had spent any time in an enclosure, and it definitely looked wild. I have absolutely no doubt that it would have passed the 'bread test' Jonathan mentions (it would have flown away when you were several hundred metres away, let alone being close enough to throw any bread).

I admit that I had exactly the same thought as Jonathan when these two species turned up in 2012 (coinciding as well with the Oriental Stork...). They ought to be much further north than HK at this time of year. But now that it has happened again, with the same two species, I am siding with them being wild birds. If these are escapes from captivity, then why are the same two species involved both times and why have none of the four birds shown any evidence of captivity (e.g. no damage to plumage or bare parts, no leg rings). Maybe there is something about the weather conditions at this time of year which may force the birds to move - perhaps some of the breeding or moulting sites are drying out and birds are forced to travel to look for food. This has been suggested for potential vagrancy of Marbled Duck and White-headed Duck during July/August in Europe (wandering north as wetlands in Spain/Portugal dry out).

Author: jsk_ppp Time: 25/08/2014 22:19

I've got a few photos of the duck's speading wings.

[ Last edited by jsk_ppp at 26/08/2014 22:32 ]

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Author: Jonathmartinez Time: 26/08/2014 01:09

Concerning the Greylag Goose, another point that disturb me, is how rare they are in South East China. Having spend several winter watching geese at Dong Ting Lake, to memory I've only seen once a flock of 30 Greylag Goose in deep winter. It seems to be the same case for Poyang Lake...It is the very same case for Ferruginous Pochard, even more rare...

To me there is another option that would fit better these weird time of occurence of rare anatidaes in the region. It is recent chinese law enforcment concerning wild birds and various animals in market of big city in Guangdong province. Many markets has been recently dismantle with thousands of birds from various origin seized.
I mention of various origin because some of these birds were obviously coming from some western remote province, another obvious fact was the presence of a large variety of drake, including many species very rare in the region like Red-crested Pochard, Baikal Teal, Scaup...and Ferruginous Duck. Some of the shop were having hundreed of them for sales... It takes me a very long time until I found the evidence of the origin of these birds that were looking in too good condition to have been caught in the wild using trap or poison....In a market in Jiangmen city I came throught a cage full of hybride Pintail x Falcated Duck... I then understood that most of these drake were raised and then sold in the market under the label "wild" bird that definitly affect the final retail price....and none of these were wearing any rings as it will have increase their ressemblance with barnyard drake and affect the final selling price as mention before...

From this statement, then I will give two other theories :
1- recent report from Forestry dpt mentionned that during a recent campaign in 2013 they seized 57 000 wild birds...wich I suppose has been released and i suspect without paying to much attention if the place of release was within each species range...I will try to enquire concerning this... Then ironically, the possibility that hugge amount of these raised drakes finally become wild in Guangdong is a hight possibility...
2- the place were these drake were raised remain unclear, but it is very likely that some of these has been raised in Guangdong as it's where the main market stand and could have escape from such place after having moulted to finally ended at Mai Po...

For the Goose, I've seen only once geese in illegal market, a Lesser White-fronted Goose together with a Greater-fronted Goose wich both were looking in very bad condition and for wich the origin is very likely one of the Yangtse reservoir...But what I've seen is only the top of the iceberg of illegal trading of wild birds in Guangdong and the possibility that a Greylag Goose that would have been caught in western province and then released from one of these illegal market and never find the way back to its breeding region and finally ended roaming in Guangdong province is another hight possibility especially if it turn back every year at the same time at Mai Po...we could said that it has been "truck assisted"(I don't know wich category it implies)...and would explain why it is especially so shy, having allready escape to hotpot and other atrocities of chinese gastronomy...then I also can only agree that the bred test is useless for that one...

All the best,

Jonathan

Author: wilsondring Time: 26/08/2014 08:05

here are a couple with him tilting to one side ..

but please also note that i had plenty of shots which show both wings spread perfectly too

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Author: wgeoff Time: 26/08/2014 08:47

If you compare photos of the 2012 and 2014 Greylag Goose, they look quite different
Here the July 2012 bird

Here the August 2014 bird

Whether these differences over two years are significant or not, I'm not expert to tell.

The Ferruginous Duck can't be compared - the July 2012 bird was a first summer, the current bird is an adult.

Thanks to the photographers for these images. They have all previously been posted on the website.

[ Last edited by wgeoff at 26/08/2014 08:50 ]

Author: ajohn Time: 26/08/2014 08:56

Wilson, I think the 'tilting' you refer to is actually fairly normal for a bathing duck. I think they typically lower one side into the water so that the wing can flip water onto the back.

Jonathan, regarding your revised theory, a couple of questions for you to consider.
- If these are from a released of 57,000 ducks in 2013, why would they turn up here in the middle of 2014? They could have turned up at any time over the past few months, but there is no suggestion that they have done so.
- Having turned up at Mai Po, why did the goose leave so quickly - if it has been wandering Guangdong for some time looking for somewhere safe and undisturbed, Mai Po should be a good place to stop. The previous summer Greylag and Ferruginous also stayed for only 1-2 days.
- Why do we not see similar summer records with the other species you mention (Red-crested Pochard, Baikal Teal, Scaup)? Wouldn't obvious escapes also turn up at other times of year? And why do we not see hybrids of the type you mention (Pintail x Falcated)?
- Finally, why do these birds not show any sign of damage to plumage or bare parts? It was very obvious on the winter Greylag a couple of years ago (http://www.hkwildlife.net/viewth ... &extra=page%3D1 and http://www.hkbws.org.hk/BBS/view ... p;highlight=greyleg) and you mention that the geese you have previously seen in the market were in very bad condition. Your theory about recent wing moult may have some validity, but that doesn't explain the lack of damage elsewhere on the bird(s).

I agree that on the basis of range, wild Greylag Goose wouldn't be expected to turn up in HK in summer. But with two birds, neither showing no clear evidence of a captive history, maybe there is something about their migration we don't yet understand.

Author: lmichael Time: 26/08/2014 10:52

Several points to respond to, as follows:

Active wing moult of Ferruginous Duck: SY Chan's very nice photos clearly show P1 in pin; I agree no evidence of moult in the Greylag;

I agree with Geoff W that the Greylag Goose seems to be a different individual to the 2011/12 bird, bill structure definately seems to be different and this is unlikely to change over time once fully grown;

I chose my words carefully, I 'have reservations' regarding the origin of these birds, I did not state that I considered them to be ex-captive.

As John A suggests we need to consider what mechanism might have brought them here (other than the ex-captive option). One possibility is 'moult migration' which is a phenomenon known in Europe for (at least) Mute Swan, Canada Goose and Common Shelduck. Moult migration routes can be counter intuitive to us (e.g. large numbers of Canada Geese breeding in southern England fly several hundred kilometres north to winter in the Beauly Firth in northern Scotland in late summer); I will do a bit of research as to whether this is known for Greylags and Aythya ducks;

Conversely, I am not sure that we can assume that all ex-captive waterfowl will show (obvious) signs of cage damage. In Europe and North America this is rarely the case as the individuals are generally well cared for (hence the relevance of the bread test). I do not think it unreasonable to hypothesise that ,with increased wealth and education, captive waterfowl in collections in China might be well cared for too. We may have to abandon the assumption that ex-captive waterfowl in Hong Kong will show obvious signs of previous captivity.

Perhaps this is something that Forum members can help with - what do we know about waterfowl collections in China, in parks, zoos etc? It would be useful to hear what members have seen on visits to the mainland.

Mike Leven

Author: Jonathmartinez Time: 26/08/2014 12:14

Hi John,

I never mentionned 57 000 ducks, I written birds, of wich a part of them could be have been duck.
This was for a single campaign, but I know that the identification dpt from The South China Endangered Animals Institute is sollicitades regurarly to ID birds that has been seized indeed birds are seized and released all the year round.

"Why do we not see similar summer records with the other species you mention (Red-crested Pochard, Baikal Teal, Scaup)?"
1st HK Red-crested Pochard turn up in HK in march 2013, just after big campaign and market crack down in Guangdong following the story of the poisoned stork in Tianjin and various reportage concerning bird market around Guangzhou. We notice rare birds, but do not common species....Does necessary all of them ended at Mai Po.

What would be the behaviour of a Red-crested Pochard or a Ferruginous that has been raised since several generation and then released in the wild? My guess is that they would stay at a not too far distance from where they have been released.
Short distance movment of birds at this time of the year can be easily explained as they usually have stayed at a place to complete their mould with a period during wich they can't fly.We can easily imagine that some place they will have choosen for moult could have changed due to heavy rain...., then once moult is complete the bird has to moove to find more suitable habitat...

"Finally, why do these birds not show any sign of damage to plumage or bare parts?"
As said if raised in small pool then why should they show any more damage than a wild bird...Since these bird just complete a full body moult, it is very unlikely to find any feather damage...

To conclude, in my opinion all this recent event with illegal market and better law enforcement concerning poaching, as well as increase of demand concerning waterfowl for delicacies has a better chance to explain the occurence at various time of the year of different species known to breed at several thousand kilometer away of HK, rather than by an hypothetical unknown behavior. Even I agree that every hypothesis has to be kept in mind...

If you would see a Chinese Pangolin swimming accross Deep Bay, you would have immediatly the same reaction as I does for these birds...(just joking)...

All the best,

Jonathan

Author: wgeoff Time: 26/08/2014 16:37

There is no definitive answer to this question, except to say

'showed no signs of being ex-captive, although the possibility cannot be excluded' (2012 HK Bird Report page 35)

[ Last edited by wgeoff at 26/08/2014 17:24 ]

Author: ddavid Time: 26/08/2014 17:33

Presumably then, the 2012 Greylag Goose and Ferruginous Duck records have not been added to the number of officially accepted records of wild birds i.e there have still only been four tickable records of Greylag Goose in Hong Kong?

Author: wgeoff Time: 27/08/2014 07:25

The July 2012 Ferruginous Duck was accepted as wild and is included in the officially accepted records.

The position with the July 2012 Greylag Goose needs to be reviewed by the Records Committee, together with the August 2014 record. So for the moment, it will not be included.

[ Last edited by wgeoff at 27/08/2014 08:10 ]

Author: Jonathmartinez Time: 28/08/2014 18:36

Some friends just mentionned to me this park :
http://www.nanshabirdpark.com/birds.asp?cid=53

It is in Nansha, just along the pearl river near Guangzhou.
All the birds are raised in open ponds, most of them wearing no rings and it seems that they don't cut primaries according to the information I received, so that many birds fly freely in the park....

I will try to get the entire list of species they raised.

Hopefully the Black-crowned Cranes are ringed, it will avoid any discussion concerning their origin in case one turn up in HK:-)( just joking again)

And if I can one more, I go for Bar-headed Geese for the next addition to HK list:-)

All the best,

Jonathan

Author: Paux Time: 28/08/2014 21:10

Just searched the net & it's good to find that both Ferruginous Duck & Greylag Goose are not yet on the park's "Distribution list of bird species at the scenic spots". Maybe these two species are not good enough to attract visitors (they have Swan Goose on the list)!

"景区动物分布列表
雨林岛：
①古巴火烈鸟 ②红绿金刚鹦鹉 ③亚马逊鹦鹉 ④鸿雁 ⑤红腹锦鸡 ⑥白腹锦鸡 ⑦东非冠鹤 ⑧海鸥 ⑨蓝孔雀；
花树岛：
①疣鼻天鹅 ②黑天鹅 ③白孔雀 ④白冠长尾雉 ⑤红腹角雉 ⑥翘鼻麻鸭；
棕榈岛：
①非洲火烈鸟 ②西非冠鹤 ③赤麻鸭 ④白枕鹤 ⑤白鹈鹕 ⑥斑头雁 ⑦黑水鸡；
迷宫岛：
①鸳鸯 ②蓝、白孔雀 ③赤麻鸭 ④黑水鸡 ⑤黑天鹅 ⑥疣鼻天鹅 ⑦花面鸭；
金银岛：
①黑颈天鹅 ②红腹锦鸡 ③白鹇 ④蓝、白孔雀 ⑤非洲鸵鸟 ⑥澳洲鸸鹋 ⑦环颈雉；
千鹤洲：
①白鹳 ②黑鹳 ③蓑羽鹤 ④苍鹭 ⑤白鹭 ⑥美国石鸡 ⑦黑水鸡 ⑧白骨顶鸡 ⑨绿山鸡；"

[ Last edited by Paux at 28/08/2014 21:21 ]

Author: HFCheung Time: 17/09/2014 11:52

There is a research student in Xinjiang working on the distribution of Ferruginous Duck. He and Prof. Ma Ming noticed that Ferruginous Duck has become more common in S China. There are some in Yunnan in winter.

Greyleg Goose is also in Yunnan, and I noticed some captive birds in Kunming Zoo.

HF Cheung

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