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.
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).
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.
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:
- 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).
- 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.
- 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!
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!