Monthly Archives: December 2016

Christmas fudge goose

By Yoav Perlman

Geese are fun, aren’t they? The perfect head-scratching activity for dark and cold winter days. In Norfolk, views are typically rubbish, which makes it even more fun. Hybrid geese have been discussed on Birding Frontiers before.

When geese turn up in funny places, things get really interesting. This intriguing goose was found at the spectacular KKL Agamon Hula in Israel on Christmas day by Hamudi Musa Heib, and was later photographed by Dror Galili. Dror kindly allowed me to use his images here. Shai Agmon sent me some more images and shared his field impressions with me. It was an overcast day (even in Israel…) so Dror’s images are rather dark and blue.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

First impression is Lesser White-fronted Goose (LWFG), isn’t it? The bold eyering shouts loud. But then a closer look does show some pointers to other or mixed identities. In images it looks quite a brute, compared to Wigeon. However, people who saw it in the field said that the field impression wasn’t that massive. The neck is thick but rather long. The bill is long and powerful, different from the cute mini-beak of LWFG, to my eyes closer to Eurasian White-fronted Goose (EWFG).

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

First, ageing this bird is important – this appears to be a 1cy (1st-winter; it will turn 2cy in five days). Check moult contrast in scapulars and flanks. It is probably moulting out of juvenile plumage.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Some context: 

This is a special goose year in Israel. All geese are rare in Israel. The only regularly occurring species in Israel is Eurasian White-fronted, with single birds seen almost every winter. Agamon Hula is a hotspot for them. This winter Israel is experiencing a goose influx, with several flocks of White-fronts around the country, several flocks of the rare Greylag, and even records of mega rarities – Taiga Bean Goose (5th record) and Lesser White-fronted (7th record). Check this article in Hebrew (sorry), Google Translate will make you chuckle I’m sure. So it is likely that this bird is of wild origin.

In Israel this bird was first broadcast as Lesser White-fronted Goose. Then talk started about hybrid options.  With Eurasian white-fronted Goose? Red-breasted Goose? Egyptian Goose? Ruddy Shelduck? Perhaps wildfowl collections can create unlikely love stories? I don’t know if that’s even possible. So many question marks in one post… So to make some sense I contacted Dave Appleton from the excellent Bird Hybrids. Dave sent me this most detailed reply:

“Firstly I think the reddish colour on the flank feathers is a red herring… I think it is dirt and not a real plumage feature.  I don’t think any hybrid combination would give rise to such a plumage mark and also I don’t think the pattern of it really fits any normal feather patterns – it seems to cross feathers in a weird way, not like a normal plumage feature.  For example in IMG1897 (the top image in this post – YP) the rearmost blotch of reddish brown along the rear flanks seems to cover the outer half of the tip of one feather and the outer ¾ of the base of the feather behind it – like a random spot of dirt rather than a normal plumage pattern.

The other issues would all be explained, I think, if there was (Greater/Eurasian) White-fronted Goose influence – a first-winter would show a dark nail to the bill and have a longer bill than Lesser White-front, it would be large and heavy and I think the head shape and colour are ok too.  So then my question becomes, is it a hybrid between White-fronted Goose and Lesser White-fronted Goose, or could it be just a pure White-fronted Goose?  The features you mention as making it superficially like Lesser White-fronted Goose are the eye-ring and the long primaries.  To me the feathers at the wing-tip look dishevelled – the tertials aren’t lying flat and the primaries seem to be pointing at a slightly odd angle.  I am not sure if it is damaged or has loose feathers, but whatever the cause I am not sure it is safe to judge the relative length of the primaries in this state. 

That leaves only the yellow eye-ring (or more correctly, orbital ring) to potentially indicate Lesser White-fronted Goose origin.  Of course White-fronted Goose can have a slightly yellowish orbital ring, it’s just that its usually so dull and inconspicuous that you don’t notice it.  It does vary though – e.g. the Reeber Wildfowl book says (under the description of adult Greater White-fronted Goose), “Brown iris with a usually inconspicuous orbital ring, which is sometimes yellow (most frequently in breeding males).”  I can’t find them now but I’m sure I’ve seen photos of apparently pure White-fronted Geese with yellow orbital rings that would make a Lesser White-front proud.  Of course your bird appears to be a first-winter, so that may be more unusual in a bird of that age, but I am not sure it is enough on its own to exclude a pure White-fronted Goose.  On the other hand they say that most captive Lesser White-fronts are not pure, having some White-front ancestry (which in my experience rings true – they often seem to have less white on the forehead than wild birds) and I guess the opposite might be true of captive White-fronts.  So if captive origin is likely then perhaps mixed ancestry might be the best way of explaining the yellow eye-ring, but if wild origin is more likely (and if recent events in England are anything to go by it must be a good winter to see White-fronts a bit outside their usual range) then I would tentatively suggest a pure first-winter White-fronted Goose would be the most likely identification.”

Many thanks to Dave for this interesting and eye-opening analysis.

I have some points to discuss though – open to debate:

  1. I think the red colouration on the flanks is genuine feather pattern, rather than red dirt. It seems to be symmetrical on both sides (check two top images).
  2. I agree that wingtip structure is not fully clear in relation to tertials, but the primaries do certainly project beyond tail. It is hard to judge exactly how much, but this is more than I would expect from a EWFG.
  3. I am not sure that the dark bill nail is not a result of the goose digging in the dark peat soil of the Hula Valley.

Would be interesting to hear more opinions on this bird!

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

I apologize for a certain back-log I have here on BF. I promise to address the grey chat (stejnegeri?) issue soon. I also have some interesting terns in the oven, and should also write about a certain house martin that I hope to see on Thursday when I arrive in Israel for a short visit…

So stay tuned for some more exciting stuff here on Birding Frontiers in 2017. I wish all of our followers and supporters a lovely and exciting 2017!

 

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Holboell’s Red-necked Grebe

by Guillermo Rodríguez

The American/East Asian subspecies of Red-necked Grebe, P g holboelliii, has been observed in the WP with accepted records in the UK (a bird shot in Wester Ross in September 1925 and subsequently identified based on measurements), Spain (two winter records from Galicia in 1984 and 1987, which were identified in the field, although these records will likely be reviewed again in the near future by the Spanish Records Committee), Iceland (at least five), and single accepted records in Sweden and Norway, in addition to several other reports. Since they are quite common as wintering birds along the American Atlantic coast (where, for instance, Pacific Diver is scarce/rare), they should be expected to reach Europe regularly. But do they?

holboellii is known to be larger and darker, and to have more yellow in the bill than the nominate grisegena. According to Pyle (2008), the differences in size are likely to be significant enough to clinch the ID. For example, the wing length is 180-212mm in holboellii versus 153-188mm in grisegena, showing that there is limited size overlap. However, these differences would obviously require in-hand measurements for identification. It’s my understanding that separation of holboellii from grisegena is currently considered to be impossible under field conditions, and the validity of the pattern of yellow in the bill has also been questioned (because a few grisegena show yellow bills similar to holboellii). However, the longest-billed holboellii show impressive harpoon-like bills which, in my opinion, are clearly outside the range of variation of grisegena.

Another identification feature that’s not usually mentioned in the literature is the general body structure; holboellii is considerably more powerful, with a longer neck, a longer and stronger bill and a flatter forehead. The head often looks square rather than rounded (although it’s also important to consider the age-related variation of the head shape, since first-winter birds tend to show rounder heads in general). As a useful comparison, holboellii somewhat resembles Great Crested Grebe. The main problem is that structure is subject to interpretation, and any identification solely based on the jizz is usually disputable. Variability in body shape is also quite extensive, and in particular many American holboellii may look as small and delicate as European grisegena. On the other hand, the largest-billed grisegena are at the same time the biggest individuals, with a more powerful structure than average birds, altogether favouring the holboellii impression.

Still, I do think that the largest and most striking holboellii could be definitively identified in the field if one turns up in Europe. For instance, check out two examples of such extremely large birds here and here.

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Red-necked Grebe ssp. holboellii, first-winter, February 2014. New Jersey. Picture by Sam Galick.

Many first-winter holboellii show a striking pale iris, which forms a contrasting ring around the dark eye that is very obvious with close views. I don’t know the variation in grisegena well (any feedback is welcome!), but my impression is that it isn’t always so obvious; perhaps the iris is on average paler in holboellii?.

The structural differences are easily noticeable even in distant birds at sea:

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Red-necked Grebe ssp. holboellii, December 2015. Massachusetts. Picture by Guillermo Rodríguez.

Sadly not all individuals are so distinctive; for instance the bird below – although it still looks large and long-billed – is probably still consistent with grisegena.

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Red-necked Grebe ssp. holboellii, adult, December 2015. Massachusetts. Picture by Jeremy Coleman.

And actually many holboelli look much smaller, more delicate and round-headed:

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Red-necked Grebe ssp holboellii, December 2005. Massachusetts. Picture by Tom Murray.

As a rough estimate, I would say that on the east coast of the United States the proportion of birds that are 1) markedly large and powerful, 2) intermediate 3) small, grisegena-like is somewhere between 20-40-40(%) and 10-30-60(%). My impression from a winter trip to Korea is that Asian holboellii on average are even more obvious, but at the time I didn’t pay enough attention (see some examples from Japan here).

Some birds, particularly adults, are remarkably dark, especially on the flanks; in addition, the facial dark mask sometimes extends towards the cheek.

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Red-necked Grebe ssp. holboellii, adult, November 2012, Massachusetts. Picture by Christopher N. Ciccone.

A couple of birds from Spain

One obvious problem with using structural features for identification is that they are strongly affected by the posture and activity of the birds. Take a look at this (presumed) grisegena from northern Spain photographed on two different days. I have the impression that birds at sea tend to look more like holboellii than birds on calmer waters, such as estuaries, where they tend to look more like grisegena. Presumably this is because the latter are more relaxed, but it’s difficult to say.

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Red-necked Grebe ssp grisegena, February 2016. Cantabria, N Spain. Picture by Lander Zurikarai.

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Red-necked Grebe ssp grisegena, February 2016. Cantabria, N Spain. Picture by Jesus Menéndez.

The amount of yellow on the bill of this bird is similar to that shown on all the holboellii in previous photos, extending over the entire lower mandible and reaching the upper mandible up to the nostrils.

In March 2015, an interesting Red-necked Grebe was found in Galicia, northwest Spain. The bird was remarkably dark on flanks and cheek and presented a substantially long neck, strong structure, and powerful bill, which accentuated its long-headed impression. This bird was probably within the size range of grisegena (at least it wasn’t one of the obvious and “identifiable” holboellii) and the reduced yellow in the bill was certainly against it being holboellii, but it still gave a Nearctic impression.

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Red-necked Grebe, first winter, March 2015. Galicia, N Spain. Picture by Jose Luis Lorenzo Garcia “Colon”.