Sunday 3 January 2016

Brent Goose x Barnacle Goose

Brent Goose x Barnacle Goose hybrid, Île de France (France), 2014-2015 - copyright Joern Lehmhus
(illus. ID: 2436)

Joern's illustration is based on 5 photos taken from the web, mainly from the French region of Île de France and probably in 2014-15 (not all websites gave details). Two of the photos can currently be found here and here.  He writes the following about it:
This drawing is a reconstruction from different photos of differing quality.  The photos may well be different birds of the same cross or a single individual looking slightly different throughout the course of the year or with age.  The drawing presents an average appearance from the photos.

The hybrid has much longer undertail and uppertail coverts than Barnacle goose and most other geese, but they are shorter than those very long coverts in Brent goose.  This is something you find also in other Brent goose hybrids ( with Greater Whitefront, with Canada or Cackling Goose and with Snow Goose).  We can therefore assume that this is a general characteristic of Brent Goose hybrids with other geese.

Also the head pattern is unique and not found in any other known Barnacle goose cross.  The overall body coloration is similar to, but much less contrasty than in Barnacle goose.  Especially the contrast between flanks and mantle/scapulars is relatively weak and the black markings of the Barnacle goose mantle and scapular feathers are only greyish in the hybrid.

A variant of the cross Barnacle x Redbreasted goose is often mistaken for a hybrid Barnacle x Brent Goose, but this bird here is clearly something different and most likely the real hybrid Barnacle x Brent goose.
I am not currently clear which form of Brent Goose is involved - Pale-bellied or Dark-bellied - the general pallor of the underparts may suggest Pale-bellied hrota though perhaps it is a little too dusky on the rear belly indicating Dark-bellied bernicla?  I am not sure!

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

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