Hybrid geese (captivity) (1 Viewer)

[JobSt]

Would anyone here be good at identifying the parentage of these this pair of adult geese, living at the dutch city zoo that I work at? We recently received them as Bean Geese (Anser fabalis) which they are obviously not. I am guessing Canada Goose (Branta canadensis) x Domestic Swan Goose (Anser cygnoides). The male seems to have a high forehead, pointing towards cygnoides. Their sound is harsh, high-pitched and (only just) two-toned. Any help is greatly appreciated!

http://www.flickr.com/photos/jobst/2183937088/ (bird to the right is domesticated A. cygnoides)
http://www.flickr.com/photos/jobst/2183937110/
http://www.flickr.com/photos/jobst/2183937106/
http://www.flickr.com/photos/jobst/2183937096/

 

[Joern Lehmhus]

dear JobSt,

from my experience with hybrid geese I´d say you have already solved this by yourself_ your identification is correct.

 

[KnockerNorton]

Is there enough black on the neck for Canada x though? I can't see any ghost of the canada face pattern, which i would have thought likely. But I can't think of what else would give the darker neck marking present. It isn't Barnacle, or Brent. This sounds crazy, but if I can see a ghost of any head pattern, it is Nene! Surely more likely to be Canada though...?

 

[nickderry]

Beofre reading the end of Poecile's post, I thought that Nene would perhaps give that neck pattern. In captivity I'd imagine that anything is possible to create. (?)

 

[JobSt]

Yes, Nene has crossed my mind, too...although I would find it difficult to imagine a swan goose mating with a Nene (purely size-wise). Nene x Canada Goose would not explain the large forehead of the male...
I don't find it very likely that they would be hybrids of more than 2 species, as they are so much alike...I would imagine that hybrid siblings of more than two parent species would look more diverse. I might be wrong though.
Here's a few more pictures.

 

[nickderry]

Compared to the swan goose that is with them, these ones seem a lot smaller (or at least the smaller one does). I'm not really convinced that there is any swan goose in them. My best guess would be Greylag (domestic perhaps) x Nene.

 

[nickderry]

http://www.birdforum.net/showthread.php?t=8174

A good discussion on hybrid geese is here (well above!)

 

[JobSt]

Compared to the swan goose that is with them, these ones seem a lot smaller (or at least the smaller one does). I'm not really convinced that there is any swan goose in them. My best guess would be Greylag (domestic perhaps) x Nene.

They are quite a bit smaller than the swan goose, indeed. You may well be right saying they are nene x greylag. A white domestic greylag might explain the white on their heads.
I think I wil never know for sure though (unless someone can show me a picture of a known hybrid that looks a lot like these) Thanks!

 

[Joern Lehmhus]

I still believe Canada x domestic swan goose is the most likely explanation. please see in the link below that the pattern of your hybrids can indeed occur in this hybrid combination.

here are a canada and a wildtype swan goose with their ofspring:


http://www.artportalen.se/artportalen/gallery/Image.aspx?rappsyst=0&obsID=10731601&imageID=57319

that link was found by LM Nielsen some time ago; many thanks again for sending me the link, Lars Michael!


There are also some photos of domestic swan goose x canada goose on the web with this neck pattern, which are even closer to your birds...but I didn't save the links...

The other extreme in this hybrid combination Swan Goose x Canada goose is in the attached picture I took some years ago in Bonn, Germany (Swan goose parent was very likely the domestic variant Chinese goose)


best regards, Jörn

 

[JobSt]

I still believe Canada x domestic swan goose is the most likely explanation. please see in the link below that the pattern of your hybrids can indeed occur in this hybrid combination.

here are a canada and a wildtype swan goose with their ofspring:


http://www.artportalen.se/artportalen/gallery/Image.aspx?rappsyst=0&obsID=10731601&imageID=57319

that link was found by LM Nielsen some time ago; many thanks again for sending me the link, Lars Michael!


There are also some photos of domestic swan goose x canada goose on the web with this neck pattern, which are even closer to your birds...but I didn't save the links...

The other extreme in this hybrid combination Swan Goose x Canada goose is in the attached picture I took some years ago in Bonn, Germany (Swan goose parent was very likely the domestic variant Chinese goose)


best regards, Jörn

Thanks! The ones in the swedish picture are quite similar indeed.

 

[Joern Lehmhus]

Dear JobST;

these might also interest you (In both links the same hybrids; In the second link you have to scroll down a bit):


http://users.utu.fi/hlehto/photo/hybrid/braxans2.shtml

http://pposblog.blogspot.com/

I think the hybrids in these links are resulting froma cross between a Canada and a domestic goose ( which was a cross of domestic greylag x Chinese goose( domestic swan goose)).

One of the hybrids shows a neck pattern close to your birds; the others are more like the photo I posted. However, most of them , if not all, do not show a black beak, therefoe the domestic goose can not be a pure domestic swan goose; but must also have some domestic greylag goose genes.


Further thoughts concerning your geese: I can not exclude the possibility of a domestic swan goose x Hawaiian goose; as I have no experience with that hybrid. I think what is clear from the all black bill is that the Anser parent very likely must have had swan goose genes (The leg colour says one parent must have been an Anser!) Most tail feathers are fully dark-that can only happen if one parent was genus Branta.

Therefore it is absolutely clear your birds are Anser x Branta.

hybrids of hawaiian goose with other geese seem to be very rare (I only have seen two such hybrids, which were probably siblings).

However the size difference between Hawaiian goose and domestic swan goose wouldn´t be a problem; I have seen hybrids of domestic greylag x Barnacle goose where the parents had similar size differences.

Hybrids of canada goose x domestic swan goose are on the other hand not a rare hybrid; and the pattern and coloration of your birds fits certainly to that combination.


However the structure of the feathers on the neck sides seems to be very strong in your geese- this is the only feature I see that might point to hawaiian goose.

The hawaiian goose hybrids I mentioned above, seemed to have only slightly reduced webbing on the feet... So also hawaiian goose has a very pronounced reduction in webbing this might not be a good indicator in hybrids to find out if there is hawaiian goose ancestry?

However...I´d stick to the commoner hybrid canada x domestic swan goose as most likely explanation. Concerning the size difference to the unrelated swan goose on the first photo; I think as domestic swan geese can vary markedly in size; the parent of the hybrids might have been a smaller sized bird.

 

[JobSt]

Thanks a lot for your comment! I will stick with your modt likely ID: Canada x (domestic) Swan Goose. It totally makes sense.

 

[Joern Lehmhus]

Thanks a lot for your comment! I will stick with your modt likely ID: Canada x (domestic) Swan Goose. It totally makes sense.

Dear JobST, due to the marked structure of neck feathers I was still not fully happy with my own explanation
and have compared the sturcture of the neck feathers of your hybrids with hybrids Canada x Domestic swan goose and also for good measure, with Hawaii goose ...

Interesting result, see this:

So I am not sure--that structure is really extreme in your hybrids-and would fit well to Hawaiian goose...

I guess we need some dna-testing...

 

[JobSt]

Dear JobST, due to the marked structure of neck feathers I was still not fully happy with my own explanation
and have compared the sturcture of the neck feathers of your hybrids with hybrids Canada x Domestic swan goose and also for good measure, with Hawaii goose ...

Interesting result, see this:

So I am not sure--that structure is really extreme in your hybrids-and would fit well to Hawaiian goose...

I guess we need some dna-testing...

Thanks for doing that! Yes, DNA testing would be good If only there'd be funds and priority!
I agree with you that first sight, the neck feathers appear much more Hawaiian-like, but then the hybrids, just like the Hawaii goose, have light-coloured neck feathers which could contract with a darker feather base or even appear to have more 'structure' because of the shade than dark-coloured ones. What do you think?
Again, when a Hawaii goose is one parent, then the other may well be Domestic Anser anser!? Which could explain the amount of white on their heads.

 

[Joern Lehmhus]

Dear JobST
I think the white on the head is easily explained; it comes from the Anser parent; think of the white band at the base of the beak of swan goose; compare with the swan goose x canada goose hybrid head patterns (some are close) .

Together with the black beak of both hybrids this strongly points to domestic swan goose.

If a Greylag (Doestic or wild ) is hybridized with a Branta; the beak isn't black in general, but at least partly pinkish or grey (some hybrids domestic goose x canada show all black beaks, but where i have seen the parents in such cases, there the domestic parent seems to have also some domestic swan goose genes)

So I am fairly confident that the white comes from the Domestic swan goose.. which doesn´t help to clarify the Branta parent...

for the neck structure: in the examples of canada x swan goose I have seen a similar feather structure is there ; but if you compare with your birds, the structure is clearly finer than in your birds. (This applies also to birds with light coloured neck sides).

So the question is can canada x domestic swan goose ever show that structure like in your birds... I do not know that and therefore I think we can only narrow the Branta parent down to Either canada goose or Hawaiian Goose ... (Until we see some more canada x swan goose hybrids and some hawaiian goose hybrids for comparison)