Bean Goose Salton Sea Part 2

Best left as unidentified?

Hard to imagine a better photos of a Bean Goose! It’s an education for sure. Thanks to Paul Lehman,  Ken Kurland and Tom Blackman,  another set of photos of the Californian Bean Goose, and to Chris Batty for instructive rossicus shot. Have to say my pendulum has swung back a bit towards the Thick-billed Goose-ssp. serrirostris. In flight the neck still looks doesn’t look long enough for Middendorff’s and bill profile has me thinking Tundra- type again.

I am confused and stuck! Much more helpful though a detailed comment from Nial Moores in Republic of Korea (South Korea) where LOADS of both types winter! For his fascinating assessment, read on :

I have also pulled out an  excellent comment by Mike Kilburn on the 4 Hong Kong Bean Geese. Placed at the bottom here.

Bean Goose, Salton Sea, California. 21st November 2010. Tom Blackman

Bean Goose, Salton Sea, California, November 2010. Ken Kurland

and by way of comparison:

Presumed pair of Tundra Bean Geese (ssp rossicus), Lancashire, December 2010. videograb – Chris Batty.  Presumable the larger gander on the right. Quite a difference in bill size and even subtle difference in structure in presumably the same taxon ssp. rossicus.

Bean Goose, Salton Sea, California, November 2010. Ken Kurland

Nial Moores assessment of the Salton Sea Bean Goose.

Thanks very much Nial!

“First, as context and by way of apology over such an exciting record, I tend NOT to spend hours looking at geese these days, as main focus is on other species groups. All the same, I have fair experience of Eastern Beans, having lived in Korea for 12 years and in Japan for 8 before that. We have both taxa present here in the ROK, with probably between 6,000 – 10,000 middendorffi. overwintering and probably as many as 70,000+ serrirostros on migration, with perhaps 10,000- 20,000 overwintering (few people make the effort or are confident enough to separate them when surveying waterbirds).

Most winters, I get to encounter flocks of eastern Beans perhaps dozens of times, often in direct comparison with Greater White-fronts (vast majority are clearly “Asian frontalis“, though with very much smaller numbers of perhaps much more western albifrons?).

While I certainly am not a goose specialist (and would recommend you to make contact with the Japanese geese specialists like Kurechi Masayuki), I personally would not identify the California Bean Gooseas either Midd. or Serri.

I would be rather more tempted to wonder if this was e.g. a more western type Taiga (e.g. disputed johanseni?).

First, the majority of our Midd. are very much more ecologically dependent on shallow freshwater lakes or vegetated intertidal wetland (ranging from brackish to salt) for feeding and roosting. They dig the roots and tubers of aquatic emergent vegetation up out of the mud somewhat similarly to Swan Goose A. cygnoides or by up-ending. When such a food option is available for them they only rarely move into rice-fields, and very rarely graze when there (preferring damper areas than used by serri).

Even more importantly perhaps, “typical midd.” (best seen on a couple of lakes and reservoirs in the southeast, as the image at

http://www.birdskorea.org/Birds/Birdnews/BK-BN-birdnews-2008-02.shtml) look massive in direct comparision with frontalis Greater White-front, very much longer-necked and longer-billed.

The immediate and lasting impression of the California bird (to me at least) is that it is too small, too short-necked and not quite long-billed and snouty enough (for at least typical midd.) – esp. in direct comparison with frontalis.

As I wrote to Richard Millington when they were preparing the Bean Goose paper for Birding World, we however do seem to have at least two main “types” of midd. here. The latter type, rather more wary, appears to be somewhat smaller – but still obviously bigger than frontalis in direct comparison.

These latter midd. can look rather closer in size and bulk to big-end serri., and the easiest ways to separate them remain the calls (Midd. often give much deeper and more “ang”-filled vocalisations than serri.), details of bill and head shape – not always easy on individual birds – and habitat preference.

Typically serri. are more or less confined here to grazing in cut rice-fields, and roosting on large freshwater bodies. In this respect, ecologically they are much closer to the frontalis that we have here, and they very often form mixed flocks (the reason we have so few photos of this taxon in our gallery – as hard to find species-pure flocks).

Almost all serri. look comparatively short-necked and usually thick-necked, very deep-billed (obviously bulbous, not so long), snub-faced with a somewhat indignant expression (not at all regal unlike most midd), a little darker and oilier looking overall than Midd, with dark head and neck (whereas darkest parts on Midd tend to be the head and flank bars / axillaries).  They tend to show a little more variation in bill patterning than midd., though this is still very slight and of no use in id (have e.g. seen just two all-orange-looking billed serri in 20 years)

Finally on this goose, from other emails, I am a tad surprised to hear that people assume that Midd. is the most likely Taiga to turn up in California?  My sense of them here is that they are comparatively short-range migrants – with most eastern Midd. migrating to Kamchatka to moult and then down to Japan, while more western birds likely move to Korea.

Hope the above helps?

With best wishes,

Nial

Bean Goose, Salton Sea, California, November 2010. Ken Kurland

Bean Goose, Salton Sea, with juvenile Pacific White-fronted Goose. California, November 2010. Ken Kurland

Bean Goose, Salton Sea, with juvenile Pacific White-fronted Goose. California, November 2010. Ken Kurland

Bean Goose, Salton Sea, California, November 2010. Ken Kurland

Comment from Mike Kilburn on Hong Kong Beans

http://www.hkbws.org.hk/BBS/redirect…tpost#lastpost

“I should like to clarify the situation with the birds in Hong Kong.

We are confident that two of the birds are middendorffi and that the smaller of the other two is serrirostris, but have no conclusion on the large, thick-necked, deep-billed fourth bird.

My personal hunch (NB mostly based on ignorance and a desire for tidiness) was that this fourth bird was also a serrirostris, albeit a very large one. We are interested that the middendorffi are still present while the other two departed together, and its tempting to suggest that feeding ecology was the driver – our middendorffi feed quite happily on submerged tubers etc (see this video:
http://www.youtube.com/watch?v=rh0sN6qGiUc) while serrirostris is noted to be a grain feeder, with no suitable food available in Hong Kong, or at least at Mai Po. As a birder who will never look at anything’s mitochondrial DNA I love the idea of the feeding requirements being a specific determinant which can be determined by field observation, but I’m aware that this is probably wishful thinking!

The Salton Sea bird is another atypical individual, which appears to me to have a head shape tending towards middendorffi, but a thicker, shorter neck, suggesting serrirostris. we’re not sure there is a sound final answer for the for the HK bird, and the minefield of hybridisation aside, it looks like that may be the case here – albeit with a different set of conflicting features.

I wonder if the feeding habits of this goose may provide an indication of its species?

Cheers
Mike Kilburn (Hong Kong)”

Comments from Bob Millar at Salton Sea

Hi Martin,

By the fact that the Salton Sea Bean Goose happens to be in my “backyard” I have had the opportunity to see it quite frequently! It is only ten minutes drive from home so I was able to be there most every morning. Have been following your posts in awe. Your post of the comment from Mike Kilburn has prompted me to offer a few observations.

Mike’s comment that “our middendorffi feed quite happily on submerged tubers etc” seems to be very much NOT this birds preferred habitat or at least where it has spent most of its time that I have observed.  In fact the only habitat of that type at this location would be the shallow ponds with cattails being about the sole vegetation in them. The bird only seems to go to the ponds about mid morning and late afternoon to drink and bathe. Hmmm, and to charge after its companion Greater White-fronted Geese on several occasions as it does appear to be the dominant one of the group!  The field they were feeding in the first few days was very newly emerged grass. Possibly Rye grass, not sure, but a thin, tall leafed winter type grass.  Since those first few days they now spend most of their time in a more well established field that most would probably describe as a pasture. Larry Sansone and Ken Kurland’s photographs show it well.  They seem to graze continuously except that the Bean Goose has its head up much more often than the others which helps very much in locating them when they move off to the far sides of the field.

Another interesting note is that it has not been the same three individual Greater White-fronted Geese with this bird since its discovery but it has always been three birds with it!?  The mix of ages, of the accompanying birds has changed several times but for the last few days it now seems to be two imm. and one adult.  Yet I have seen no other GWFG away from this group except for the second or third day. Am wondering if the others have continued south and if the remaining three head off is our surprise visitor going to be off with them!

See ya at the sea……….

HAPPY BIRDING

BOB MILLER

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About Martin Garner

I am a Free Spirit
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4 Responses to Bean Goose Salton Sea Part 2

  1. Oscar Johnson says:

    Thanks for the analysis. This is certainly very helpful. If it helps at all an observer (Al Demartini) heard the bird call a few days ago and described it as “a low ‘runk’ amid the higher Snow/Ross’ chatter.”

    • Martin Garner says:

      Hi Oscar

      If its still around, ideally if someone could record the call, could be very useful piece of data

      Martin

  2. Pingback: Bean Geese & Witchcraft! | binocularface

  3. Pingback: Big Bean Goose | Birding Frontiers

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