Tundra/Taiga Bean Goose, Portugal (1 Viewer)

[PedroNicolau]

Hey everyone,

Currently there is a bit of a lack of understanding about which taxa have occurred in Portugal, and I would like to hear some opinions on one of the birds which has occurred in the past.

I attach the best pictures of the bird taken by Pedro Marques.

Video:
https://www.youtube.com/watch?v=chT84xS7C0g

Other photos can be found here:
https://ebird.org/checklist/S32332091 (flight silhouette comparison with Greylags)
https://ebird.org/checklist/S32379166 (feeding with greylags)

This bird appears to be rather controversial. Any opinions?

 

[CARERY]

Despite a fairly small area of orangey bill markings the bill shape, long neck and overall large size compared to the Greylags this is a rather straightforward fabalis for me.

 

[lupokatja]

I disagree, I can't see anything but a (young) Tundra Bean in these images. Bill may appear a bit on the long side in the video, but it looks rather short and triangular-shaped in most of the pictures. The head is rather small and rounded, and the neck looks shortish to me. It also lacks the strong muscular breast that Taiga Beans tend to have and is considerably smaller than the Greylags, although I guess that doesn’t rule out a young female. Lone birds can be difficult, and some young Taiga Beans may look surprisingly similar to Tundra Beans, but Taiga Bean Goose must be an exceptional rare bird in Portugal (nowadays at least). Are there any recent pictures of bean geese that turned out to be Taiga Beans from Spain or Portugal?

Lützen Portengen

 

[gerdwichers8]

Lutzen, you see Tundra in just any Beangoose. What's up?

 

[lupokatja]

Lutzen, you see Tundra in just any Beangoose. What's up?

Are you really that surprised that I think most birds that are offered for identification here on Birdforum, which tend to be from areas where Taiga Bean Geese are really rare and Tundra Bean Geese are much more common, turn out to be Tundra Bean Geese? However, and perhaps more importantly, what makes you think this is a Taiga Bean Goose (if that is what you think)?

Lützen Portengen

 

[PedroNicolau]

Hi all,

Thanks for the input so far. I guess this is a rather tricky bird...

I have to say that I leaned towards Tundra here because in the field the bird appeared really small and elegant, it was rather straightforward to pick it out in the middle of the greylags in flight because of the obvious smaller size. But I have no experience with either taxa and because the PRC only moved to IOC last year, this is a rather new discussion for us.

To put into perspective, there is no accepted record of Tundra Bean Goose in Portugal(!). This is in part because the taxon(a) has become extremely rare in the past decade decade, without any observation between 2002-2016! There are just 5 Taiga Bean Geese accepted between 1997-2002 (perhaps involving the same bird(s)).

I wonder how viable is this split, considering two people can consider the same bird obviously two polar opposites. What are the most essential criteria for the separation, if I may ask?

This year there are two new birds in the area, one which has been identified as Tundra, the other which again appears to be controversial... Which sparked the conversation yet again.

Nonetheless, either Tundra or Taiga, these taxa are decidedly rare in Portugal.

 

[lupokatja]

I am not sure I can really answer your first question about the viability of the split, but I find even small (family) groups of Taiga Bean Geese not so difficult to identify with confidence because there are often a few birds present that are rather obvious (large with a heavy breast and long dark necks and long orange bills). The local wintering population (very small and not present for the last 2 winters) also shows quite different behavior from the much larger number of Tundra Bean Geese that are present in the same general area. They tend to stick to different fields and only occasionally mix with the Tundra Bean Geese or Greater White-Fronted Geese. Whether that is significant given that all geese species tend to stick to their own family/wintering groups? The situation may be somewhat reminiscent to that of Canada Geese in the US.

With regard to the situation in Portugal I would be very surprised if Taiga Bean Geese turned out to be the more common of the two. There are a little under 300.000 Tundra Bean Geese wintering in the Netherlands and no or at most a few tens of Taiga Bean Geese. Taiga Bean Geese only come this far south if there is (too much) snow on their usual wintering grounds in north Denmark or south Sweden, which is usually not before the second half of December (and often much later). I realise these things may not be so important in the context of a vagrant bird, but the odds seem very much against your bird being a Taiga Bean Goose.
People unfamiliar with both species tend to attach too much importance to bill color, which in my experience is next to useless as every large(r) group of Tundra Bean Geese will include a few individuals with mostly orange bills (e.g. here https://oudeversie.waarneming.nl/waarneming/view/110612115). Are there any pictures of the other supposed Taiga Bean Geese? [I had a quick look on Ebird, and at least the bird from 12-2016 near Coimbra is an obvious Tundra Bean as well].

Sincerely,

Lützen

 

[PedroNicolau]

I am not sure I can really answer your first question about the viability of the split, but I find even small (family) groups of Taiga Bean Geese not so difficult to identify with confidence because there are often a few birds present that are rather obvious (large with a heavy breast and long dark necks and long orange bills). The local wintering population (very small and not present for the last 2 winters) also shows quite different behavior from the much larger number of Tundra Bean Geese that are present in the same general area. They tend to stick to different fields and only occasionally mix with the Tundra Bean Geese or Greater White-Fronted Geese. Whether that is significant given that all geese species tend to stick to their own family/wintering groups? The situation may be somewhat reminiscent to that of Canada Geese in the US.

With regard to the situation in Portugal I would be very surprised if Taiga Bean Geese turned out to be the more common of the two. There are a little under 300.000 Tundra Bean Geese wintering in the Netherlands and no or at most a few tens of Taiga Bean Geese. Taiga Bean Geese only come this far south if there is (too much) snow on their usual wintering grounds in north Denmark or south Sweden, which is usually not before the second half of December (and often much later). I realise these things may not be so important in the context of a vagrant bird, but the odds seem very much against your bird being a Taiga Bean Goose.
People unfamiliar with both species tend to attach too much importance to bill color, which in my experience is next to useless as every large(r) group of Tundra Bean Geese will include a few individuals with mostly orange bills (e.g. here https://oudeversie.waarneming.nl/waarneming/view/110612115). Are there any pictures of the other supposed Taiga Bean Geese? [I had a quick look on Ebird, and at least the bird from 12-2016 near Coimbra is an obvious Tundra Bean as well].

Sincerely,

Lützen

Thank you, Lützen

The bigger problem here is that, as I said, before going IOC in 2018, the Portuguese Rarity Committee was following AERC which didn't consider the split. So for most Portuguese birders any Bean Goose was a fabalis. Hence both birds having been submitted to eBird as such, not much thought went into it, and the PRC hasn't pronounced themselves regarding to the subspecies (now species).

The two current birds are:
https://ebird.org/checklist/S61525156 (supposed fabalis, albeit being contested by at least one observer)
http://aves.forumeiros.com/t29663-anser-serrirostris (supposed serrirostris).

Cheers,
Pedro

 

[lupokatja]

Thank you, Lützen

The bigger problem here is that, as I said, before going IOC in 2018, the Portuguese Rarity Committee was following AERC which didn't consider the split. So for most Portuguese birders any Bean Goose was a fabalis. Hence both birds having been submitted to eBird as such, not much thought went into it, and the PRC hasn't pronounced themselves regarding to the subspecies (now species).

The two current birds are:
https://ebird.org/checklist/S61525156 (supposed fabalis, albeit being contested by at least one observer)
http://aves.forumeiros.com/t29663-anser-serrirostris (supposed serrirostris).

Cheers,
Pedro

I did realize that Pedro, but it does show that rossicus is not as rare as the lack of accepted records would suggest. The older records might well have been fabalis, as that used to be the more common species in the Netherlands too.

I am pretty sure (>98%) the 2 current birds are rossicus also (sorry Gerd), the one that is supposed to be a fabalis looks like it might be a male. The white rim above the bill is another feature that is often quoted, but that I found to be pretty much completely useless. Perhaps your rarities committee might seek some input from Thomas Heinicke, a German ornithologist (see here https://riista.fi/wp-content/uploads/2013/11/AEWA_TaigaBG_Overview_Heinicke.pdf). I never met him, but he is supposed to have extenstive experience with (at least) the European bean goose taxa. He is also the guy that pointed out to us Dutch guys that we were messing up big time with the identification of these two species, so it seems he is willing to share some of that knowledge.

Cheers,

Lützen

 

[lupokatja]

I just checked the available pictures (rich media) from all bean geese sp. on Ebird from the Iberian peninsula.There are about 8 or 9 of them (some are returning individuals) and they are all currently listed as Taiga Bean Goose. For obvious reasons these were all birds from the last 5-10 years or so and I have little doubt that all of them were Tundra Bean Geese.

I guess that if you say that there were just "5 Taiga Bean Geese accepted between 1997-2002" you mean that they were accepted as Bean Goose at that time only and that the PRC has not yet decided what they were?

Lützen Portengen

 

[PedroNicolau]

I guess that if you say that there were just "5 Taiga Bean Geese accepted between 1997-2002" you mean that they were accepted as Bean Goose at that time only and that the PRC has not yet decided what they were?

Lützen Portengen

I mean that they all were accepted as subspecies fabalis!:eek!:
The good news is... The new PRC is essentially going to dig up the old records, and will reassess hopefully. So this may take a while, but I hope by next year we will have some answers.

Regarding the Spanish ones, I can only tell you that the Spanish eBird reviewers seem to be generally less strict, so it's easier for weird things to pop up (eBird is very recent in Spain).

The suggestion to contact Thomas is a really nice one, I've passed it on.

 

[Maffong]

I haven't seen any Taiga Bean Goose yet, but I've had my fair share of Tundras and thought I had found the real deal once or twice (but hadn't) and I must agree with Lützen on the ID of the historical records. All pictures I saw on ebird show Tundras. The current bird looks more promising, though the small size and figure aren't helpful IMHO. Nevertheless, I'd also call it a Tundra.
In the pictures I've seen of Taiga Bean Geese they are somewhat reminiscent of Swan Geese or even small Swans. The neck is elongated and the beak very triangular, often directly attached to the "crown" rather than to the forehead. Another important feature is the grin patch, which should be rudimentary in Taiga and rather obvious in Tundra.
Just as Lützen I've come to notice that bill markings are fairly useless.

Here are a few pics of Bean Geese from Germany
Taiga Bean Geese
Tundra Bean Geese

Maffong

 

[lupokatja]

I mean that they all were accepted as subspecies fabalis!:eek!:

As you can see in figure 1 (second panel) in the linked publication (Dutch trends in Bean Geese numbers) Taiga Bean Geese numbers had already declined quite strongly by that time (i.e. after 1997).

Here are a few pics of Bean Geese from Germany
Taiga Bean Geese

I am not really convinced that the first set of pictures in that link (from 30-03-2018) actually shows any Taiga Bean Geese. I found this picture (from the same link) instructive:
Mixed flock

It shows 8 Taiga Bean Geese swimming in front of some Tundra Bean Geese. The slightly drooping bill is a feature that can sometimes be helpful. I have seen quite a few Taiga Bean Geese that were less obvious then this though and I find the Tundra Bean Geese in this picture to be all of the rather “easy” type with fairly short, triangular bills.

In my experience there is considerable variation within Tundra Bean Geese (at least that is what I call them), where some family(?) groups seem to show consistent differences in bill coloration and also bill shape (longer, thinner). I find the analogy with the Canada Geese complex in the US (which someone once suggested to me) appealing. It would be unwise to equate “looks different” with “must be the other (rarer) species”, especially when also considering the possibility of hybrids with other geese species (hybrids between Tundra Bean Geese and Greater White-Fronted Geese occur quite frequent).

Cheers,

Lützen

 

[Maffong]

I am not really convinced that the first set of pictures in that link (from 30-03-2018) actually shows any Taiga Bean Geese.
Cheers,

Lützen

You're right, the ID of that particular bird was questioned and in the comments you'll find a query to change it towards Tundra, which unfortunately didn't happen

Maffong