Monday, 17 February 2014

Swan Goose x Canada Goose

domestic Swan Goose x Canada Goose hybrid, Bonn (Germany), summer 2003 - copyright Joern Lehmhus
(photo ID: 0822)


Many domestic geese contain a mix of Swan Goose and Greylag Goose genes and when such mixed-species domestic geese hybridise with Canada Geese the offspring may resemble either Swan Goose x Canada Goose hybrids or Greylag Goose x Canada Goose hybrids - sometimes both in a single brood.  The birds in this thread resemble domestic Swan Goose x Canada Goose hybrids, but we cannot exclude the possibility that the domestic parent had a mix of Swan Goose and Greylag Goose genes.

domestic Swan Goose x Canada Goose hybrid, Bonn (Germany), summer 2003 - copyright Joern Lehmhus
(photo
ID: 0823)





domestic Swan Goose x Canada Goose hybrid, Bonn (Germany), winter 2003 - copyright Joern Lehmhus
(photo IDs: 0824-0827)







domestic Swan Goose x Canada Goose hybrid, Stadtgraben, Wolfenb├╝ttel (Germany), 2nd September 2012 - copyright Joern Lehmhus
(photo IDs: 0601-0606)


Note the bluish tinge to the wing-coverts, most evident on Photo ID 0603 - possibly this could be an indication of some Greylag Goose ancestry in the domestic goose parent?


Steve tells us that the next bird was larger than most of the Canada Geese and some Greylag x Canada hybrids.  It differed from the latter in structure and bill shape and colour.  It was also very bold and aggressive, grabbing food from humans.





domestic Swan Goose x Canada Goose hybrid, Peasholm Park, Scarborough (North Yorkshire, UK), 24th June 2013 - copyright Steve Graby
(photo IDs: 1998-2002)


The next bird resembles a domestic Swan Goose x Canada Goose hybrid but was with a second hybrid resembling a Greylag Goose (possibly domestic) x Canada Goose hybrid.  When I first reviewed the photos I summised that they were likely to be offspring of the same pairing, and concluded that the domestic parent must have both Swan Goose and Greylag Goose ancestry.  Reviewing the photos again a few years later I think that a more likely explanation was that the two hybrids were not siblings.  Thus while the parent may have had mixed ancestry there is no longer any reason to assume so.


domestic Swan Goose x Canada Goose hybrid, Grovelands Park, Southgate (London, UK), 27th March 2008 - copyright Katy M ("BlueBirdy")
(photo IDs: 2351-2352)


domestic Swan Goose x Canada Goose hybrid, Grovelands Park, Southgate (London, UK), 30th October 2008 - copyright Katy M ("BlueBirdy")
(photo ID: 2357)


domestic Swan Goose x Canada Goose hybrid, Grovelands Park, Southgate (London, UK), 13th June 2009 - copyright Katy M ("BlueBirdy")
(photo ID: 2358)



domestic Swan Goose x Canada Goose hybrids, Grovelands Park, Southgate (London, UK), 6th January 2010 - copyright Katy M ("BlueBirdy")
(photo IDs: 2359-2360)


The next photo was hastily snapped as the bird flew past me, in dull conditions so requiring a high ISO.

domestic Swan Goose x Canada Goose hybrid (with Greylag Goose), Santon Downham (Norfolk/Suffolk border, UK), 4th April 2015 - copyright Dave Appleton
(photo ID: 2165)



Swan Goose Anser cygnoides 
Greylag Goose Anser anser 
Canada Goose Branta canadensis

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