Dark-bellied Brent Goose x Pale-bellied Brent Goose

juvenile Dark-bellied Brent Goose x Pale-bellied Brent Goose hybrids (with Dark-bellied Brent Geese), Salthouse (Norfolk, UK), 18th December 2014 - copyright Dave Appleton

(photo ID: 1700)

In the winter of 2013/14 a family part of Brent Geese spent most of the winter at Cley/Salthouse.  The adults were one each Dark and Pale-bellied Brent Geese and the young were presumed to be their offspring.  Despite several attempts I never managed to catch up with these but the following winter I got another chance.  It took me a few goes again but I did eventually manage to see them.  

It seems to be surprisingly rare for these two closely-related taxa to produce hybird young.  One of Norfolk's finest goose-watchers told me he'd never seen a mixed family party like this before, athough I think he and I have both seen one or two adult birds that we have suspected as being hybrids.

juvenile Dark-bellied Brent Goose x Pale-bellied Brent Goose hybrids (with Pale-bellied Brent Goose parent and Dark-bellied Brent Geese, same as birds in photo ID 1700 above), Salthouse (Norfolk, UK), 18th December 2014 - copyright Dave Appleton

(photo IDs: 1696-1699)

The following birds are presumably the same family - at least an adult Pale-bellied Brent Goose accompanied by three youngsters of which at least a couple looked distinctly pale-bellied.  Cley is adjacent to Salthouse and birds commute between the two sites a lot.
 

juvenile Dark-bellied Brent Goose x Pale-bellied Brent Goose hybrids (with Pale-bellied Brent Goose parent and Dark-bellied Brent Geese), Cley (Norfolk, UK), 14th February 2015 - copyright Dave Appleton

(photo IDs: 1905-1908)

This bird flew off with the family and I was pretty sure this was one of the hybrid young.  It's presumably the darker of the three and there's just a chance it was a juvenile Dark-bellied Brent Goose that got mixed up with them.

probable Dark-bellied Brent Goose x Pale-bellied Brent Goose hybrid (but possibly just an interloping Dark-bellied Brent Goose), Cley (Norfolk, UK), 14th February 2015 - copyright Dave Appleton

(photo IDs: 1909-1911)

In April 2017 I discovered the following bird which stood out from the accompanying Dark-bellied Brent Goose in having a more conspicous pale flank patch.  Usually that is a pointer to Black Brant hybrids, but this bird showed no other features of Black Brant hybrid - the upperparts and belly were no darker than the other Brent Geese - a fraction paler and browner if anything - and the neck collar was not larger (at times it looked smaller, at least not extending so far round to the front, which is often a feature of Pale-bellied Brent Goose).  It reminded me more of Pale-bellied Brent Goose and supporting the idea that this taxa was involved was the way that the pale flanks extended downwards further into the belly.  The bottom of the belly was dark, including between the legs, ruling out pure Pale-bellied.  I found the bird again a few days later and took the following photos.

Interestingly this bird seemed to be paired to a colour-ringed Dark-bellied Brent Goose, a bird ringed in Taimyr in July 2008 and reported a number of times since here in Norfolk, in Netherlands, in Germany and in France.  So far I have not been able to establish if the hybrid was accompanying this bird on any of the previous occasions it was seen.

presumed Dark-bellied Brent Goose x Pale-bellied Brent Goose hybrid (with Dark-bellied Brent Goose), Burnham Overy (Norfolk, UK), 2nd May 2017 - copyright Dave Appleton

(photo IDs: 3226-3227)

Dark-bellied Brent Goose Branta (bernicla) bernicla
Pale-bellied Brent Goose Branta (bernicla) hrota