Ross's Goose Anser rossii

Formerly Chen rossii. Ross's Geese are popular in captivity and escaped birds often turn up in the wild, sometimes breeding. However wild birds from North America also turn up here in the UK occasionally, although it has taken a few years for them to be formally recognised as doing so (added to Category A of the British list towards the end of 2021). Wild (or presumed wild) birds have turned up among Pink-footed Goose flocks most often but feral birds seem to prefer the company of Barnacle Geese with which they often hybridise.

Ross's Goose (with Pink-footed Geese), Burnham Overy (Norfolk, UK), 24th January 2009

presumed escaped or feral Ross's Geese, Snettisham (Norfolk, UK), 17th March 2009

presumed escaped or feral Ross's Goose (with Greylag Geese), Snettisham (Norfolk, UK), 22nd February 2008

feral Ross's Goose (with Barnacle Geese and a Ross's Goose x Barnacle Goose hybrid), Cley (Norfolk, UK), 3rd January 2011

I'm not quite sure if the dark secondaries (in this case two on one wing and three on the other) are signs of immaturity (making this a second-winter) or if it's a feature that crops up sometimes in adult birds. We can at least say that it's a feature that crops up from time to time in adult-like birds.

Ross's Goose (with Pink-footed Geese), Burnham Overy (Norfolk, UK), 24th January 2009

captive Ross's Goose, Blakeney Quay collection (Norfolk, UK), 23rd December 2015

captive Ross's Geese, Pensthorpe (Norfolk, UK), 9th March 2014

This is the larger of two unringed birds wintering in the county in 2003/04:

Ross's Goose (with Pink-footed Geese), Burnham Overy (Norfolk, UK), 14th December 2003

This is the smaller of two unringed birds wintering in the county in 2003/04:

Ross's Goose (with Pink-footed Geese), Burnham Overy (Norfolk, UK), 14th December 2003