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

Dark-bellied Brent Goose x Black Brant

Dark-bellied Brent Goose x Black Brant hybrid, Burnham Overy (Norfolk, UK), 9th May 2016 - copyright Dave Appleton

(photo ID: 2822)

Vagrant Black Brants from either North America or (probably more likely in the majority of cases) eastern Siberia regularly appear among wintering flocks of Dark-bellied Brent Geese in eastern and southern Britain, and many of these return for successive winters suggesting that they also spend the breeding season with the Dark-bellied Brents.  In view of this it is no surprise that hybrids occur frequently and several are now present in eastern and southern Britain every winter.

Some hybrids are relatively obvious given good views, being clearly intermediate between the two parents.  Others can be really tricky, with some birds very closely resembling pure Black Brant and may easily be identified as such especially if conditions and views are not perfect.  Variation in both parents makes identification of hybrids even harder and whilst backcrossed birds also occur, picking these out would is an unenviable task unless part of a clear family party.  Note that bright sunshine is the worst condition for watching Brent Geese as the plumage tones can be impossible to assess accurately.


Although all of the following three birds were darker than the accompanying Dark-bellied Brent Geese, none seemed quite dark enough to be pure Black Brant.  The neck collar was variable between the birds, but mostly smaller than on Black Brant.  The first and third birds showed a fairly good neck collar, though perhaps not quite so extensive as on pure Black Brant.  The middle one was closer to Dark-bellied Brent Goose but was noticeably darker on the back and belly, more evident in the field.

Dark-bellied Brent Goose x Black Brant hybrids (different individuals in each photo, with Dark-bellied Brent Geese), Wells (Norfolk, UK), 22nd November 2006 - copyright Dave Appleton

(photo IDs: 0221-0223)

This bird stood out from the Dark-bellied Brent Geese but none of the Black Brant features were quite strong enough for it to be a pure bird.

Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese), Wells (Norfolk, UK), 19th February 2007 - copyright Dave Appleton

(photo ID: 0224)

At some angles the next bird showed virtually no contrast at all between the black on the back and belly and the black of the neck and breast, but at other angles the back and belly looked so pale it was almost overlookable among the Dark-bellied Brent Geese.  Such is the problem with watching Brent Geese in bright sunshine!  The neck colllar on this bird was very good for Black Brant and although the flanks were nowhere near as clean and white as a classic "textbook" Black Brant, this feature appears to be more variable in pure Black Brant than the textbooks give credit for (judging from internet photos).  Whether this bird was a pure Black Brant or a hybrid is not entirely clear, to me at least.

possible Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese), Wells (Norfolk, UK), 6th December 2008 - copyright Dave Appleton

(photo IDs: 0225-0230)

The next bird was only seen in flight and in bright sunshine, so impossible to identify with certainty - it may have been a pure bird and not a hybrid despite the belly looking a bit pale in the sunlight.

possible Dark-bellied Brent Goose x Black Brant hybrid (centre, with Dark-bellied Brent Geese), Burnham Overy (Norfolk, UK), 31st January 2009 - copyright Dave Appleton

(photo ID: 0231)

A couple more birds here that were sometimes reported as pure Black Brants.  In dull light like this they should have looked more obvious had they been pure, I think.

Dark-bellied Brent Goose x Black Brant hybrids (different individuals in each photo, with Dark-bellied Brent Geese), Wells (Norfolk, UK), 22nd January 2010 - copyright Dave Appleton

(photo IDs: 0232-0233)

The next birds were also sometimes reported as pure Black Brants, and certainly stood out from the surrounding Dark-bellied Brent Geese.  The first four photos show a bird with a neck collar that is clearly broken at the front, wrong for pure Black Brant (although an otherwise perfect-looking bird with a broken neck collar appeared a few years ago and it was considered by some that it may have been a pure bird).  The bird in the other photos has a better neck collar but is not quite dark enough on the back and belly, as well as having rather heavily marked flanks.

Dark-bellied Brent Goose x Black Brant hybrids (first four photos show one bird, the rest show a second bird; with Dark-bellied Brent Geese), Holkham (Norfolk, UK), 13th February 2013 - copyright Dave Appleton

(photo IDs: 0234-0241)

An adult Black Brant in Norfolk in autumn 2004 was observed to be paired with a Dark-bellied Brent Goose and accompanying young birds presumed to be its offspring.

juvenile presumed Dark-bellied Brent Goose x Black Brant hybrids (with adult Black Brant and Dark-bellied Brent Geese), Wells (Norfolk, UK), 19th November 2004 - copyright Dave Appleton

(photo IDs: 0218-0220)

A very problematic bird had been at Burnham Overy during the winter of 2013/14 which I saw badly a few times.  Each time I thought it looked good for a pure Black Brant but I was never able to see it well enough and in suitable light to convince myself.  Having discussed the bird with other observers I believe it was another hybrid, but a very difficult bird that was easily identified as a Black Brant.  The following winter this hybrid was present - it looked much more obvious to me, but perhaps it was the same returning bird and I just got better views of it?  Even in these photos you can see in some it looks obviously a hybrid while in others (like the first) it is much more like Black Brant.

Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese), Burnham Overy (Norfolk, UK), 26th October 2014 - copyright Dave Appleton

(photo IDs: 1740-1743)

Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese, presumed same bird as in photo IDs 1740-1743 above), Burnham Overy (Norfolk, UK), 28th October 2014 - copyright Dave Appleton

(photo IDs: 1744-1746)

At the same site later in the winter I located the same or another hybrid.  This time I noticed that it was accompanying an adult Dark-bellied Brent Goose and three juvenile birds.  They were behaving like a family party so I presume the youngsters were backcrossed hybrids.

Dark-bellied Brent Goose x Black Brant hybrid with Dark-bellied Brent Geese and 3 presumed backcrossed young (Dark-bellied Brent Goose x Black Brant) x Dark-bellied Brent Goose hybrids, Burnham Overy (Norfolk, UK), 1st January 2015 - copyright Dave Appleton

(photo IDs: 1733-1739)

The next bird was more like Dark-bellied Brent Goose - easy enough to identify in dull conditions but when the sun came out it became very hard to pick out.

Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese), Burnham Overy (Norfolk, UK), 7th December 2015 - copyright Dave Appleton

(photo ID: 2383)

Another tricky individual was this bird from Spurn.  Apparently there had been two 'good' Black Brants in the area and one of those was in the same field as this bird.  This bird looked pretty impressive and has been reported as a pure bird, but Dean and some of the locals had reservations.  Dean obtained these photos on a dull day, conditions in which a pure Black Brant should really stand out - as the other bird in the field did.  But Dean notes: "The mantle was only a fraction darker than the Dark-bellied Brent Geese (bests evaluated in profile) with a subtle but definite grey cast which contrasted markedly from the black neck, the brown breast was also the same saturation as the Dark-bellied Brent Geese with a notable contrast from the black neck."  The buffy grey suffusion to the rear flanks doesn't help its case either, though I don't think that is out of range for pure Black Brant.  The neck collar looked pretty good, although perhaps not ideal was the fact that the top edge was broken at the front, visible when the head is stretched up.  I'm pretty sure that's in range for pure birds though - at least I have seen otherwise perfect-looking birds sharing this feature.

Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese), Spurn (Yorkshire, UK), 19th March 2016 - copyright Dean Nicholson

(photo IDs: 2762-2767)

Next up are some more photos of the regularly returning bird from Burnham Overy.  You can see how it morphs from looking pretty much like a Black Brant to being pretty much like a Dark-bellied Brent Goose just by a change of angle to the sun.

Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese; same bird as photo ID 2822 at the top of this page), Burnham Overy (Norfolk, UK), 9th May 2016 - copyright Dave Appleton

(photo IDs: 2823-2832)

Dark-bellied Brent Goose x Black Brant hybrid (with Dark-bellied Brent Geese), Burnham Overy (Norfolk, UK), 26th November 2016 - copyright Dave Appleton

(photo IDs: 2820-2821)

Dark-bellied Brent Goose Branta (bernicla) bernicla
Black Brant Branta (bernicla) orientalis (formerly nigricans) or Branta (nigricans) orientalis