Hybride Branta x Anser gans?!

Gestart door Jan Harteman, januari 15, 2008, 19:35:40 PM

Vorige topic - Volgende topic

Jan Harteman

CiteerOp de kinderboerderij waar ik werk werden onlangs twee rietganzen aangeboden, voor niks. 3 jaar oud en een koppel. Nou leuk, breng maar. Zie foto's...geen rietganzen dus, maar wat wel? Ik denk dat het een kruising-canadese gans is, maar wat is de andere helft dan, àls het al halve canadezen zijn? Ze zijn duidelijk kleiner dan boeren- en knobbelganzen en, denk ik, ongeveer even groot als een grote canadese gans. Hybrides met boerenganzen zien er doorgaans anders uit, daarvan hebben ze er in Engeland een hoop.
Het geluid dat eruit komt is tweetonig, enorm hard en schel (niet echt prettig om te horen, en dat was de reden dat we ze kregen!), en de gent schreeuwt zo'n beetje de hele dag.
Ik ben benieuwd naar jullie meningen!
Dank,
Job.


Even voorop stellen dat deze ganzen op een kinderboerderij lopen (dus NIET in het wild). Ik ben benieuwd welke soorten jullie hierin herkennen.
De vogel rechts is een Knobbelgans, het gaat dus om de twee linkerganzen.







Zelf vermoed ik dat er Hawaii gans in zit, maar sluit ook Zwaangans (of Knobbelgans) niet uit. Canadees is ook een mogelijkheid.

Wat denken jullie ervan?

Jan Harteman

Nog enkele foto's van dezelfde ganzen:






gjcaspers

Eén ouder is in in ieder geval een Knobbelgans. De andere ouder moet een Branta spec. zijn, vanwege de geheel zwarte snavel en de zwarte staart. De Branta-ouder zal ook de prominente halsgroeven in moeten brengen (want die heeft de Knobbelgans niet), dus dan blijft inderdaad alleen de Hawaiigans over. Ook lijken sporen van de dunne zwarte halsring van de Hawaiigans aanwezig.
Groet,
Gert-Jan Caspers

Jan Harteman

Maar hoe verklaar je dan het wit in de kop?
Dat ontbreekt bij de Hawaiigans en komt slechts zeer beperkt voor bij een Knobbelgans.
Ik ben nog niet zo heel zeker van Knobbelgans, al acht ik de kans wel groot.

tekenaar

#4
mijn eerste reactie was: hawaii x knobbelgans. Dat zou veel verklaren (geribde halsveren, donkere nekstreep, zwarte snavel, oranje-grijze poten, wat opgerichte houding) alleen niet de wittige kop. Bij een meerdere-generatie-kruising zou ik meer variatie tussen de exemplaren verwachten dus ik denk wel richting f1. Maar nu ik de foto's nog eens bekijk wordt ik alleen maar minder zeker...

Zou via de ringen de kweker te achterhalen zijn?
Paul Veenvliet
dieren en planten tekeningen: https://paulveenvliet.art/
excursies in Slovenie: https://www.slovenia-nature-guide.si/

Jan Harteman

#5
De vogels hebben geen vaste voetringen maar knijpringen (herkenbaar als AI gevaccineerd in 2005).
De vorige eigenaar heeft ze aan de kinderboerderij geschonken, maar die zei dat het Rietganzen zouden zijn... tjah, daar kun je dus niet van op aan.

De Knobbelgans op de eerste foto is dus sowieso geen verwant van de hybriden.

Alcedo atthis

#6
I have seen these birds already in another forum and believe them to be probably Canada x domestic swan goose.
I give my thoughts here again, because i think they look quite unusual.


General thoughts concerning these 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.


canada x swangoose (Domestic) 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/gall...1&imageID=57319

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)



The following hybrids might also interest you in this respect
(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/]

http://bp1.blogger.com/_-MgqO-m4WWI/RsDGx6...0-h/hybrid3.jpg

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.



Back to the hybrids posted here by jan:

In my experience 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.


To be sure what these birds are a genetical testing would be best!
greetings,
Jörn Lehmhus

Alcedo atthis

Further thoughts:

due to the marked structure of neck feathers I was still not fully happy with my own explanation

and Hawaiian goose as branta parent has also been proposed

So I have compared the sturcture of the neck feathers of these 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 these hybrids-and would fit well to Hawaiian goose...

Jan, you were concerned about the white feathers on part of the head, did I understand this correctly?
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) and think of wild greylag x canada hybrids which also can have some white at the base of the beak.
So I am fairly confident that the white comes from the Anser parent.(Domestic swan goose).. which doesn´t help to clarify the Branta parent...
greetings,
Jörn Lehmhus

Jan Harteman

So - if I do understand you right, you think it is a Domestic Swangoose (African) X Hawaiian? I think this makes sense yes :)  

Alcedo atthis

#9
Jan,

I think one parent is a domestic swan goose or so-called chinese goose; not nessecarily the extremely massive variant "African Goose".

The other one is a Branta species; in my opinion either Canada goose or Hawaiian goose.
Apart from the extremely strongly pronounced structure of the neck feathers (I have not seen this that strong in Canada x Swan goose before- but that doesn't mean it couldn't exist) , I see nothing nothing which would really exclude Canada goose as the Branta parent.

So I think we cannot say for sure for the Branta parent, which species it was, but it is narrowed down to these 2 Branta species.

We need more experience with Hawaiian goose hybrids to solve this  (or some DNA testing!)
greetings,
Jörn Lehmhus