Thanks to volunteer Gary for this feature on the different geese that can be found at Pulborough Brooks
There often seems to be some confusion over the geese (and to a lesser degree the ducks) at Pulborough Brooks. The vast majority of geese here at Pulborough are feral Greylag Anser anser, which is Latin for – yep, you have to hand it to the scientists – Goose goose, and Canada Goose Branta canadensis meaning burnt goose from Canada! Both types here derive from either introduced, or in the case of the Greylag re-established populations. True migratory wild Greylag flocks can be seen in Scotland in the winter. Although there is always the chance that a truly rare bird may be present, many of the “odd” intergrades are frequently confused and reported as real species. It must be remembered that ducks and geese are genetically close, so are the most likely of the bird species to hybridise. They are the ancestors of domestic “farmyard” types, and are often kept unnaturally together in collections. Winter is the only time of year when genuine migrant species could be present.
The following are some of the confusion types.
Pure White Geese – Usually reported as Snow Anser caerulescens (bluish goose – no, me neither!) or Ross’s Goose Anser rossii, the usual culprit is an ex-farmyard Greylag type being all or nearly all white with a huge bill. The real things are white and have pure black wing tips, and the Snow Goose has a curious smile created by a black cutting edge to the bill. Ross’s goose is quite small, being only half the size of a Greylag.
Grey Geese – A fairly tricky group which could conceivably have some genuine wild birds. If there are, they will always look smaller and darker than the resident Greylag and will lack their huge orange bills. Always scrutinise the Greylag flocks for imposters such as White-fronted Anser albifrons (black bars on tummy and small white patch above bill), Pink-footed Anser brachyrhynchus (small and pinkish grey) and Tundra Bean Anser serrirostris (Dark neck and brownish). A domestic Chinese Swan-goose Anser cygnoides has recently been reported as a Bean Goose so have a long close look if you can.
Greylag goose - Stanley Porter (rspb-images.com)
White-fronted geese - Andy Hay (rspb-images.com)
Dark Geese – At Pulborough, the default dark goose is the Canada Goose, which was introduced to England in the 16th century and is now feral throughout most of the UK. Mating’s with other goose species (mostly Greylag, but sometimes another introduced species like the rather attractive Bar-headed) results in offspring with rather strange combinations of both parents. A frequent outcome is a white head or face which is similar in appearance to a Barnacle Goose Branta leucopsis. Barnacle Goose is a real possibility, but once again, it would look much smaller with the black neck extending to the breast and is frosty grey rather than brown. The other dark goose you are likely to encounter is the Brent Goose Branta bernicla. Brent Geese are normally coastal but do take a short cut across country, so may drop in from time to time. At a distance they look almost black and are similar in size to a mallard, so are unlikely to be confused with anything else.
Canada Goose - Andy Hay (rspb-images.com)
Barnacle goose - Andy Hay (rspb-images.com)
Brent Geese - Andy Hay (rspb-images.com)
Others – Although belonging to the Shelduck family, Egyptian Geese Alopochen aegyptiaca are becoming increasingly frequent at Pulborough Brooks. Once again, originating from collections and being particularly belligerent, they even look like it, having a large patch around the eye which I think looks as though they have got a black eye from a fight. In flight, large white wing panels are very obvious. Other non-native shelduck species have obviously taken a liking to Pulborough Brooks, as a growing number of reports have been made of Ruddy, Cape and Australian Shelduck. Confusingly I recently saw a Ruddy and Cape together and if they are a “pair” who knows what the outcome will be……..
All this just goes to show why lots of birders don’t bother and lump them all together as “plastic”, but there may, just may, be a rare bird lurking in there somewhere.