The goose is a water bird, noted for its foolishness and credulity; oddly, it was also a symbol of vigilance, due to the legend of the Capitoline geese saving Rome. It’s a period charge, found in the canting coats of Barnak (“barnacle geese”) c.1410 [TJ 1312] and of von Ganse (German Gans), 1605 [Siebmacher 182].
The goose is close by default, as in the illustration. When blazoned “enraged”, its wings are elevated and addorsed, its head is extended for a hiss: functionally equivalent to rising.
The “duck”, a smaller relative of the goose, is also found in period armory: the canting arms (Italian anatra) of di Anedre, mid-15th C. [Triv 50]. It shares the same defaults as the goose. For related charges, see swan.
The Baron of An Dubhaigeainn bears: Azure, a duck naiant to sinister argent, billed, within a laurel wreath Or.
Mathilde Meyer bears: Per pale azure and argent, two geese respectant enraged counterchanged.
Emma of Wolvercote bears: Argent, three geese naiant azure.