Thursday 6 March 2014

Barnacle Goose x Canada Goose

Barnacle Goose x Canada Goose hybrid (with Canada Goose), Center Parcs, Elveden Forest (Suffolk, UK), 28th June 2008 - copyright Katy M ("BlueyBirdy")
(photo ID: 2356)


Barnacle and Canada Geese frequently hybridise where both species occur ferally, and the hybrids are fertile.  They may also occur in the wild in north-west Europe where vagrant Canada/Cackling Geese appear among Barnacle Goose flocks - there have been records of both F1 hybrids and backcrossed hybrids in north-west Scotland, for example.  Backcrossed hybrids can be difficult to determine and on our current knowledge it is not always clear whether browner-than-normal Barnacle Geese are so because they have Canada (or Cackling) Goose genes or for some other reason.  Certainly worn pure Barnacle Geese can appear browner than usual but the extent to which relatively fresh brown plumage is a certain indicator of hybridisation or not is yet to be clearly established.

Separation of Barnacle Goose x Canada Goose hybrids from Barnacle Goose x Cackling Goose hybrids can be very tricky.  Some birds may be obvious on size and/or structure (such as the bird above) but many may be best left undetermined.

Barnacle Goose x Canada Goose hybrid, Abberton Reservoir (Essex, UK), 20th December 2015 - copyright Adrian Kettle
(photo ID: 2414)


Barnacle Goose x Canada Goose hybrid (with Barnacle Goose), Sweden, June or July 2002 -
copyright Carl Gunnar Gustavsson
(photo ID: 1105)


The next bird, a male, is large for a Barnacle Goose and was accompanying a female Barnacle Goose and four offspring which resembled Barnacle Geese.  Possibly it is a backcrossed Barnacle Goose x (Barnacle Goose x Canada Goose) hybrid?


possible Barnacle Goose x (Barnacle Goose x Canada Goose) backcrossed hybrid, Malmoe (Sweden), 11th August 2008 - copyright Carl Gunnar Gustavsson
(photo IDs: 1058-1059)


possible Barnacle Goose x (Barnacle Goose x Canada Goose) backcrossed hybrid, Malmoe (Sweden), 1st July 2008 - copyright Carl Gunnar Gustavsson
(photo ID: 1057)


possible Barnacle Goose x (Barnacle Goose x Canada Goose) backcrossed hybrid, Malmoe (Sweden), 23rd July 2008 - copyright Carl Gunnar Gustavsson
(photo ID: 1037)


Here is a hybrid with one of its backcrossed offspring:

probable Barnacle Goose x Canada Goose hybrid (behind) with offspring backcrossed with Barnacle Goose (front), Sweden, June or July 2002) - copyright Carl Gunnar Gustavsson
(photo ID: 1109)


Here is another shot of one of the backcrossed young - Carl Gunnar tells us that two of the three offspring looked like this while the third resembled a typical Barnacle Goose.

Barnacle Goose x (probable Barnacle Goose x Canada Goose hybrid) backcross, Sweden, June or July 2002) - copyright Carl Gunnar Gustavsson
(photo ID: 1107)


Here is another feral bird from the UK:

Barnacle Goose x Canada Goose, Baffins Pond, Portsmouth (Hampshire, UK), 8th April 2015 - copyright  Eric Eddles
(photo ID: 2166)


Henry has a great series of photos.  To my eyes the bird looks a bit short-billed and short-necked compared with many Barnacled Goose x Canada Goose hybrids, and in some shots also quite square-headed.  So I wonder if one of the smaller forms of Canada Goose (or Cackling Goose) was involved.  The bird appears to be larger than the accompanying Barnacle Geese, so presumably not one of the smallest forms of Cackling Goose.  Henry points out that this bird has a stripe in its throat, a hard-to-see feature that is present in some Cackling Geese (but I'm not sure if it can also appear in Canada Geese?).







Barnacle Goose x Canada (or Cackling?) Goose (with Barnacle Geese), Turku (Finland), 18th October 2008 - copyright  Henry Lehto
(photo IDs: 2516-2522)



Barnacle Goose x Canada (or Cackling?) Goose (same bird as in photo IDs 2516-2522 above), Turku (Finland), 27th September 2008 - copyright  Henry Lehto
(photo IDs: 2523-2524)


Barnacle Goose x Canada (or Cackling?) Goose (with Barnacle Geese; same bird as in photo IDs 2516-2524 above), Turku (Finland), 5th October 2008 - copyright  Henry Lehto
(photo ID: 2525)


Barnacle Goose x Canada (or Cackling?) Goose (with Barnacle Geese; same bird as in photo IDs 2516-2525 above), Turku (Finland), 12th October 2008 - copyright  Henry Lehto
(photo ID: 2526)


The next bird was distant; although not obvious in the photos it was larger than the accompanying Barnacle Geese.



Barnacle Goose x Canada Goose hybrid (with Barnacle Goose), Hickling (Norfolk, UK), 10th August 2009 - copyright Dave Appleton
(photo IDs: 0192-0194)


(See also: Barnacle Goose x Cackling Goose)


Barnacle Goose Branta leucopsis
Canada Goose Branta canadensis

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