Another fairly common category of charge to be found in mediaeval Heraldry. the following are available:
The swan may be nageant, essorant, displayed or passant.
auk, bat, black bird, chough, crane, crane, crow, crow's head, dove, duck, falcon, martlett, owl, peacock, popinjay (parrot), quail, Pelican in her piety
There are several variants of the heraldic eagle, a conventional one, a double headed eagle, the immature eaglet oralerion;or, for a more life-like representation you can use natural eagle.
Wings and Feathers
In addition to complete birds, the following parts are also available: feather, ostrich feather, wing, a pair of wings (conjoined), a pair of wings (conjoined) in lure. The feather may be quilled of a different colour. Note that 2 wings argent gives you two separate white wings both in the same orientation, while 2 wings respecting each other argent gives you two white wings opposite each other with a gap. If you really want two wings together you must use one of the pair of wings variants.
Bird Features and Modifiers
The most common bird features (that can be given different colour) are beaked, legged. Some birds can also be shown displayed, that is with their wings open. The peacock is shown in his pride and the crane may be drawn holding a stone. The falcon may be hooded of a different tincture.
In addition, some birds can be modified to be in certain poses, including essorant, passant, displayed, volant.