Domestic goose and wild ancestor, the greylag goose (photos from Wikimedia Commons)
We’ve all seen one … an all-white goose hanging out with the mallards and Canada geese.
Even if we’re unfamiliar with barnyard geese it doesn’t take long to find out the white ones are escaped domestic waterfowl that naturally prefer the places where people feed ducks.
Their scientific name is Anser anser domesticus, the same genus and species as their wild ancestor the greylag goose (above right).
Greylag geese (Anser anser) are mottled gray-brown with paler breasts and bellies, orange bills, and pink legs. Native to Europe and Asia they were domesticated about 4,000 years ago for their meat and eggs. In addition to food, they’re useful as Watch Geese because they’re quick to sound the alarm and chase off intruders. How vigilant are they? It’s said they saved Rome by warning of a night attack by the Gauls.
Selective breeding has given domestic geese bulky bodies and big butts but they aren’t always white and that causes identification problems. Not only do some resemble their wild ancestors but geese freely hybridize. When a barnyard goose mates with a Canada goose they produce some really odd offspring. Click here for pictures of the many strange results.
If you find a gray-brown goose in western Pennsylvania your field guide will suggest the greater white-fronted goose but be careful before you decide that’s what you’ve found.
Greater white-fronted geese (detail from Crossley ID Guide Eastern Birds via Wikimedia Commons)
Greater white-fronted geese (Anser albifrons) breed in the arctic tundra and winter west of the Mississippi and in Mexico. They’re a rare bird in western Pennsylvania so check the field marks carefully. Greater white-fronted geese have a “white front” (white forehead and base of bill), lots of black mottling on the belly, a smaller bill and are much less bulky.
Here’s the “white front” that gave them their name. (I added the red arrow.)
Greater white-fronted goose (detail from the Crossley ID Guide Eastern Birds via Wikimedia Commons. Arrow added to indicate white front.)
Chances are the odd goose in Pittsburgh has domestic relatives but take a really good look at him. You never know …
(photos from Wikimedia Commons. Click on these links to see the originals: wild greylag goose, domestic goose, greater white-fronted geese from the Crossley ID Guide Eastern Birds)