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Shelduck hybrid? (1 Viewer)

passavy

Active member
Hi everybody

I saw a strange duck in the PN of Aiguamolls dell Emporda, Spain. I suppose it is a kind of Shelduck because of its size, easily comparable to other Common Shelducks swimming around, and wing pattern : white under and upper wing coverts. After a look in HBW vol1, it looks like a female Australian Shelduck (!) because of white eye-ring, base of bill, and collar. But many differences remain : brown color of head, difference of color between belly and upper body, white line betwen undertail and belly, and rusty undertail. That is the reason why I am suspecting an hybrid between Australian Shelduck and an other Shelduck, maybe common or ruddy. Can anyone help me to "choose the right hybrid"? Is an hybridation possible between a Shelduck and other ducks?
Thanks a lot

Guillaume passavy
 

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Shelduck certainly can hybridise with other ducks though without hitting the books I can't, off the top of my head, remember what ... something Mallard-ish about your bird to my eye, particularly the shots on the water, possibly bill structure, neck-ring and pale ventral stripe
 
Thanks a lot for your answer, the white collar comes very likely from the mallard, instead of an australian Shelduck!! Shame on me...
I searched the web in order to find this kind of hybrid, but I could not find anything. Does anybody have a picture of a Mallard/Shelduck Hybrid?
Thanks a lot

Guillaume Passavy
 
the size could also be a teller but it could have hybridized with a farmyard duck that can be as big as shelducks i saw some on the river Severn and on radipole lake last year and it could have been a different colour variety do confusing or what!!!
 
Thanks for your answers, I definitely agree with Shelduck x mallard (although it remains an hybrid, so this is only the most probable)
 
hi,
You should take into account that hybrids of Common Shellduck x Ruddy Shellduck can look like a variant Australian Shellduck,showing a white eye-ring, a white base of bill, and sometimes even a white collar like a mallard .
The white eyering and base of bill seem to be a common feature of such hybrids T.tadorana x ferruginea.
However, several hybrids of this combination don´t show a collar,and only some of them, especially males, seem to have dark brownish or blackish heads.

There are some Photos of this hybrid combination in one of the Gillham books on hybrid ducks which might fit your description.

However, while hybrids Common Shellduck x Mallard are rare, they also occur (and can show the mallards neckring but don´t always do-again according to the Gillham books). Attached a photo from the web, showing a probable such hybrid from the Netherlands.

To decide which was your hybrid,it would be good to know if the main body coloration was greyish as in mallard or more reddish as in ruddy shellduck?
 

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Hi Joern and thanks for your interesting post.

I unfortunately don't have Gillham books ... (I even didn't know them!) Anyway, i didn't know that T.tadorna x ferruginea hybrids may have the same head pattern as the bird in question. Your picture of the probable mallard*shelduck hybrid fits well with the pattern of the bird I saw. Nevertheless, two points differ : the color of body, which was brown for the spanish bird (I compared it on the field with the body color of female Tufted duck), and the color of the tertials(?), that were rufous to white (pic1) on this bird and that are grey on the bird from netherlands. This would argue for a T.tadorna x ferruginea hybrid instead of a mallard*shelduck hybrid, or maybe also a T.ferruginea*mallard hybrid. Does Gillham books mention such an hybrid? How far might it look like the spanish bird? If it doesn't, the hybrid should probably be an Ruddy*Common Shelduck thanks to brown body color, right?
Regards

Guillaume
 
passavy said:
Nevertheless, two points differ : the color of body, which was brown for the spanish bird (I compared it on the field with the body color of female Tufted duck), and the color of the tertials(?), that were rufous to white (pic1) on this bird and that are grey on the bird from netherlands. This would argue for a T.tadorna x ferruginea hybrid instead of a mallard*shelduck hybrid, or maybe also a T.ferruginea*mallard hybrid. Does Gillham books mention such an hybrid? How far might it look like the spanish bird? If it doesn't, the hybrid should probably be an Ruddy*Common Shelduck thanks to brown body color, right?
Regards

Guillaume

Dear Guillaume,
The tertials you describe are like in the photos of Ruddy x Common Shellduck hybrids I have seen. Look at the attached photo from some other thread on BF, showing such a hybrid.
If I remember correctly, the female Ruddy x Common Shellduck hybrid in the Gillham book is much like your bird, whereas the male differs in having a dark head with much less pronounced eyering and bill base, but showing a pure white neck ring! The body colours and the tertials were similar in the male and female bird, only the colours of the male were slightly brighter.

I don´t know any picture of a Mallard x Ruddy Shellduck hybrid, sorry.

Best Regards, Jörn
 

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