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Subject: [Geese] Bean Geese at Mai Po, 3 Nov 2010 [Print This Page]

Author: yyattung Time: 3/11/2010 18:54 Subject: Bean Geese at Mai Po, 3 Nov 2010

Four Bean Geese were present in front of tower hide, Mai Po till dusk. Photos of the bird would be posted later.

Koel: a good find! Thank you very much!

Author: kkoel Time: 3/11/2010 21:23 Subject: Bean Goose (record shots)

Bean Goose (record shots)

3/11/10
17:20 - 18:00
Tower Hide

Super surprised to see them - especially as the sun has begun to set!

Thanks to Tung for pointing out that the second bird from the left in the first photo might be of a distinct subspecies from the rest, with its smaller bill and slighter build in favour of Tundra Bean rather than Taiga Bean - I'll leave experts to decide whether we're really looking at 4 Taiga Bean Geese, 3 Taiga + 1 Tundra, or otherwise!

[ Last edited by kkoel at 3/11/2010 21:37 ]

Author: lchunfai Time: 3/11/2010 21:29

My dear Koel , once again , u found a big tick when I was in school

Owe me a lunch , haha

Author: kkoel Time: 3/11/2010 21:38

Following the Bean Geese' example, I would be owing you a vegetarian lunch XD

Author: wleepoin Time: 3/11/2010 21:43

Fantastic find !! Congratulations!
You are such a lucky guy but I'm not complaining.

Many thanks for the huge tick(s).

Here are some comparing shots taken on 4th Nov.

Shorter bill Goose could be Tundra Bean Goose and Longer bill could be Taiga Bean Goose:

Flight comparison shots:
Right hand 2 birds seem to have longer neck, longer wing-span and bigger slender body.

Would need to hear further comments from the experts!

Cheers
PWMK

[ Last edited by wleepoin at 4/11/2010 10:53 ]

Author: ddavid Time: 3/11/2010 21:54

An excellent record & excellent photos.

Just to point out that the IOC, which is the body that the HKBWS Records Committee has decided to follow, separates Bean Goose into two distinct species - Taiga Bean Goose & Tundra Bean Goose.

So potentially you (well, anyone who saw them!!) could be looking at two ticks here...

david

Author: twallace Time: 3/11/2010 22:26

Congratulations~~

Superb find & amazing photos!!

You're really luck guy.

Author: fatchun Time: 3/11/2010 22:36

Hope they will be there until this Sat

Author: kkitty Time: 3/11/2010 23:04

Congratulations!

Author: jacwu Time: 3/11/2010 23:11

Congratulations!

Author: iherman Time: 4/11/2010 00:11

Author: Andiona Time: 4/11/2010 01:10

Congratulations Koel

Author: subbuteo Time: 4/11/2010 08:12

Spectacular. I am deeply frustrated to be at work for the next two days!

Author: cchristina Time: 4/11/2010 08:17

congratulation, Koel!

Author: WWF Mai Po Time: 4/11/2010 08:29

This morning all 4 were on Pond #8a (in front of the Tower Hide), flushed by a Kite at about 07:30. They moved to Gei wai #4, then flew out to Deep Bay around 07:50.

Author: hkinni Time: 4/11/2010 09:11

3/11/2010 4:14 pm

Long Valley

Author: WWF Mai Po Time: 4/11/2010 09:21

Dear Koel, please see pm about usage of your photos for a possible press release.

Author: HKBWS Vicky Time: 4/11/2010 09:46

wow kinni!!! A very good record for LV although they just flew pass there.
Ha... I'm still wondering to add this record to the LV list but they're not using the farmland.

Author: John Holmes Time: 4/11/2010 13:03

Three more shots of these Bean Geese from the Tower Hide on Nov 4, 2010.

Image Attachment: BG05-01.jpg (4/11/2010 13:03, 74.95 KB) / Download count 532
http://hkbws.org.hk/BBS/attachment.php?aid=7415

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Author: ddavid Time: 4/11/2010 15:51

Based on the above photos, particularly the pattern and structure of the bills, and the text/plate in Birds of East Asia, it seems to me that we're looking at two Taiga Bean Geese Anser fabalis- presumably subspecies middendorffii and two Tundra Bean Geese Anser serrirostris - presumably the nominate race.

david

[ Last edited by ddavid at 4/11/2010 15:55 ]

Author: Tony Time: 4/11/2010 16:25

Photo taken at 8:35am this morning.
Mai Po Nature Reserve
4Nov2010

The flank of the two Bean Geese seems to be different as well. Taiga Bean has clear black and white bands on flank but it is not that case for Tundra Bean. Could it be a characteristics for seperating "two species" as well?

[ Last edited by Tony at 4/11/2010 16:39 ]

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Author: brendank Time: 4/11/2010 17:27

Great photos everyone! Hope these birds stick around until this weekend.

I am having a hard time being convinced that there are two species here. I think to say that there was mixed species flock here there would have to clear structural and plumage differences between birds. To be honest, I don't see any plumage differences between these birds. I would admit that two of the birds appear slightly larger and thicker necked but I think in most populations of geese there is some variability in structure and size and I suspect the difference seen in these birds is well within the with-in species range.

Author: ddavid Time: 4/11/2010 17:43

Regarding Tony's point about the flank-pattern, the rather plain flanks on one of the Tundra Bean Geese may indicate that it's a juvenile.

I think the difference between these two very similar "species" is well shown in the last of John Holmes's photo above. My understanding is that the bills are the crucial feature. If you look at the photo, the bill of the Tundra Bean Goose on the right has a different shape to the Taiga Bean Goose on the left. There is also a difference in the amount of orange on the bill and how far the orange extends towards the nostrils. Also, the line formed by the closed mandibles is pretty straight on the Taiga Bean Goose but is somewhat downturned on the Tundra Bean Goose, giving a characteristic grin-like expression. The latter feature is clearly visible in other photos and may well be diagnostic.

david

[ Last edited by ddavid at 4/11/2010 17:58 ]

Author: hmartin Time: 4/11/2010 18:35

Another record shot showing the differences in bill shape, head shape and flank pattern.

Image Attachment: _37E9285bean-goose.jpg (4/11/2010 18:35, 131.64 KB) / Download count 540
http://hkbws.org.hk/BBS/attachment.php?aid=7425

Author: fatchun Time: 4/11/2010 19:32

Thank you Sam, Cwchan and Kinni! Especially Cwchan's spotting scope and Sam's 600mm telephoto-lens!

Author: ajohn Time: 4/11/2010 20:06

There is an article in Birding World April 2010 about the ID and taxonomy of Bean Geese (thanks to Mike Leven for leaving this in our office!) which could be useful in determining ID of these birds. Much of the following is taken from that article.

There are four or five recognised taxa: serrirostris and rossicus (Tundra Bean Geese), and fabalis, johanseni and middendorffii (Taiga Bean Geese). Johanseni is often considered a hybrid of fabalis and middendorffii, while middendorffii is sometimes proposed as another split (Middendorff's Bean Goose). The most likely taxa in HK are serrirostris and middendorffii, which breed and winter in East Asia. All features used for ID could vary slightly due to age, sex and posture, so need to be used carefully. Of the Mai Po birds, I think one is a first-year and three are adults.

These two taxa differ significantly in size. Male serrirostris is quoted in Brazil as weighing 3.2kg, female middendorffii is almost 50% heavier at 4.6kg. As well as looking large, middendorffii should also look long-necked, whereas serrirostris should look short-necked.

Bill structure should also be useful for separation. Middendorffii should be very long and heavy billed, with a straight or slightly convex culmen; the bill should be approximately 50% of the total head and bill length. The cutting edge of the lower mandible should be strongly curved and the lower mandible should be slightly convex, bulging below the bill. Serrirostris should have a shorter, more conical bill, only 33-37% of the head and bill length. The cutting edge should also be curved. Both should have only a small amount of orange on the bill.

Plumage should be fairly similar between taxa. Middendorffii may show a ginger wash and possibly a more contrasting underwing.

So, applying this to the Mai Po birds. Although there does seem to be a slight difference in size, I am not sure that this is as much as expected for the difference between middendorffii and serrirostris. More troubling, the bird with the most serrirostris- like structure (i.e. short, thick bill and neck) does not appear to be the smallest. None of the birds show the short, conical bill I would expect of serrirostris. The rear bird on Martin's photo looks closest, but I think this is foreshortened slightly (and is still not as little as 37% of the head/bill). Koel's first photo shows the birds to all have a similar bill length. The 2 birds with the apparently very long bills may possibly the least like middendorffii in bill structure, with the bills not being particularly deep.

Overall, despite the apparent difference in structure and plumage, I am not sure whether the size and bill structure fit for the different bird being serrirostris. Perhaps this represents a different extreme of middendorffii, or perhaps there are elements of 'johanseni' in this bird. The other three birds may be more similar because they are related (parents with an offspring perhaps?). I am not a goose expert, though, so I would be interested to know what others think.

Author: ajohn Time: 4/11/2010 20:22

To illustrate some of the points I made see these:
Middendorffii: http://www.birdskorea.org/Galler ... Anser-fabalis.shtml
http://orientalbirdimages.org/se ... _ID=&pagesize=1
http://orientalbirdimages.org/se ... _Family_ID=&p=5

Serrirostris: http://www.birdskorea.org/Galler ... -serrirostris.shtml
http://orientalbirdimages.org/se ... _ID=&pagesize=1

Author: cwchan Time: 4/11/2010 20:55

4.11.2010

I attach here a set of mine for the reference of our experts.

Digiscopic shots.

A digiscopic video taken on the same day. 30X scope + Lumix Lx5.

[youtube]fW549Rezo3o&hd=1[/youtube]

[ Last edited by cwchan at 6/11/2010 08:16 ]

Author: brendank Time: 4/11/2010 21:52

Quote:

So, applying this to the Mai Po birds. Although there does seem to be a slight difference in size, I am not sure that this is as much as expected for the difference between middendorffii and serrirostris. More troubling, the bird with the most serrirostris- like structure (i.e. short, thick bill and neck) does not appear to be the smallest. None of the birds show the short, conical bill I would expect of serrirostris. The rear bird on Martin's photo looks closest, but I think this is foreshortened slightly (and is still not as little as 37% of the head/bill). Koel's first photo shows the birds to all have a similar bill length. The 2 birds with the apparently very long bills may possibly the least like middendorffii in bill structure, with the bills not being particularly deep.

I agree with John completely on this point. I think his response is very well stated indeed. I don't know that much about Eurasian Geese species. But I do find that in North American Geese species such as frontalis Greater White-fronted Geese and atlanticus Snow Goose that there can be quite striking variation in size, bill length, and neck length within species.

Furthermore, it is my understanding that in Europe Taiga and Tundra Bean Geese rarely mix even in wintering flocks so I find it unlikely that geese from two different distinct subspecies would mix and then become vagrants in HK.

Author: msamuel Time: 4/11/2010 22:26

Why I was in LV when they appeared in Mai Po?
Why when they were flying up above LV, I was looking down on the ground?
Thank you all for sharing the photos and making every effort to get two ticks.

Author: mchristine Time: 4/11/2010 22:34 Subject: 贈msamuel 興

Quote:

Original posted by msamuel at 4/11/2010 22:26
Why I was in LV when they appeared in Mai Po?
Why when they were flying up above LV, I was looking down on the ground?
Thank you all for sharing the photos and making every effort to get two ticks.

此鳥可待成追憶，只是當時已茫然

Author: kkoel Time: 4/11/2010 22:39

Thanks everyone for the messages, and congratulations to everyone who shared all these beautiful photos!

Thanks John too for digging up the literature for the puzzle between the two Bean Goose taxa. In our 2 problematic Geese, the "grin" as David mentioned is really reminiscent of serrirostris from John's links, while the thin neck and big size go for middendorffi, and the bill shape itself seems somewhat in between the two.

So I wonder whether serrirostris and middendorffi actually hybridize - and whether the distinction of "taiga" and "tundra" Bean Goose is based more on research on fabalis/rossicus in Western Europe, such that in Eastern Siberia middendorffi/serrirostris actually shows more interbreeding than is currently known?

I'm not familiar with Beans at all, just thought this might be some food for thought. Would be nice to hear more from Goose experts =)

Author: ckt1234 Time: 4/11/2010 23:30

04.11 8:30am mai po

[ Last edited by ckt1234 at 4/11/2010 23:47 ]

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Author: subbuteo Time: 5/11/2010 09:16

Still there this morning- at least until 7.15

Dylan

Author: HKBWS Vicky Time: 5/11/2010 09:56

Jin Pan, one of the LV management team member, just saw a Bean Goose in LV flying very high towards Sheung Shui direction about 15 mins ago.

Author: lkatherine Time: 5/11/2010 12:03

Looks like Taiwan birders have similar situation about separating the 2:
http://nc.kl.edu.tw/bbs/showthread.php?t=35245

Katherine

Author: cwchan Time: 5/11/2010 12:29

Thanks Katherine, a very informative thread.

Author: Beetle Time: 5/11/2010 22:39

the geese (all 4) were still in #8 until dusk. Great chance for everyone going there tomorrow!

Author: pitarhk Time: 6/11/2010 06:50

6/11 06:38 Still here now!

Author: ajohn Time: 6/11/2010 08:22

The geese looked very at home feeding on the emergent grasses and sedges yesterday. I don't know how much can be read into it, but the Birding World article states that serrirostris tends to graze in drier habitats on open fields or crops, while middendorffii tends to favour wetland habitats and often feeds by upending or dabbling into mud.

Author: dick Time: 6/11/2010 16:04

2010/10/06 MP

Author: kyshum Time: 7/11/2010 15:09

7 Nov, Mai Po
.

.

[ Last edited by kyshum at 7/11/2010 23:41 ]

Author: kmike Time: 7/11/2010 20:30

It been a real pleasure to enjoy so many great photos of these fine birds. Thanks to all the photographers!

A big thanks and congratulations to Bena for creating a great new piece of habitat - well rewarded indeed!

Cheers
Mike

Author: dick Time: 7/11/2010 21:38

2010/11/06 MP#8
Beautiful habitat by iPhone

Author: tmichael Time: 7/11/2010 22:44

Newly "renovated" habitats like this are often VERY good for a certain period of time but then become less so over time, so let's hope we get two to three really productive years from this spot - Pond 20 was magical for a couple of winters or so it seems to me, about ten years ago, when first created.

Grey Lag Goose + a longer staying Sibe Crane than the last one and/or (no, AND!) Common Crane would do nicely please!

Mike Turnbull

Author: lpaul Time: 8/11/2010 17:15

Having finally gotten round to reading the Birding World Article that John mentions (I was waiting to do so before replying to John’s post) I have to say that I’m not that impressed by the article!  I think it is a bit misleading in that the paper does not describe what I would call ‘typical’ middendorffi and hugely overstates the bill structure differences between middendorffi and serrirostris.

I have also re-read Ruokonen et al. 2008 (Taxonomy of the bean goose – pink-footed goose) which is an excellent and helpful paper. That paper concludes that middendorffi is a valid species (Middendorff’s Goose) but fabalis, rossicus and serrirostris are subspecies of a second species – Bean Goose (note that they propose a treatment which is not biome related); they also fail to recognise johanseni.  If anyone would like a PDF of this paper, please send me a PM.

On the whole however, the two papers are in broad agreement - that ‘bean’ geese are usually separable as follows based on a combination of size, structure, and bill structure:
• middendorrfi
• serriostris/rossicus
• fabalis
Both conclude that on present knowledge not all individuals can be identified based on external morphology alone.
Applying this to the Mai Po birds I think three individuals are easy to identify, the two large birds with long slender necks and long sloping bills and gently sloping head profile (recalling Whooper Swan) – both these are to my eyes typical middendorffi – and the obviously smaller bird with the short thick neck, shorter looking  bill, obvious forecrown angle and rather angular head which is a typical serrirostris.
The fourth bird is far more problematic having the size of middendorffi but the proportions and neck length/thickness of serrirostris.  In the absence of any evidence that there is any marked size variation within serrirostris, I can only think this is an extreme middendorrfi.  Curiously, in the Birding World paper there are photos of a similar bird, and it seems that the paper uses this rather odd bird for the basis of the discussion on what middendorffi looks like.
I see no reason why both cannot occur together, other than mathematical likelihood!  I have seen both taxa in mixed flocks on migration in Xinjiang (in arable farmland for what it’s worth), and it has been known for a long time that fabalis and rossicus have overlapping wintering ranges.  Add to the fact that ‘only’ three bean geese were originally located, it seems likely that the serrirostris joined later.  I also noticed last week that one of the middendorffi  was regularly driving the serrirostris away when foraging.

Author: AC07 Time: 8/11/2010 20:22

08 Nov., 2010

Nikon D300 + AFS600 + 1.4x

Author: wkcheng Time: 14/11/2010 22:43

2 of them are still present today. Anyone know which species are they?

Author: fatchun Time: 14/11/2010 23:08

Probably they are both Taiga Bean geese. (Just take a look at my friends photo yesterday)

Author: wkcheng Time: 15/11/2010 23:46

Quote:

Original posted by fatchun at 14/11/2010 23:08
Probably they are both Taiga Bean geese. (Just take a look at my friends photo yesterday)

Thanks fatchun.

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