Large swathes of the land is seasonally flooded, and areas of the reserve are therefore not accessible to visitors year-round.

Over a thousand wigeon and teal have been recorded, while birds of prey such as merlins and peregrines are regularly seen.

Large areas of Otmoor have benefited from extensive agriculture using traditional methods, resulting in good numbers of songbirds that are otherwise declining in the UK, including bullfinch, skylark, reed bunting, grasshopper warbler and European turtle dove.

The butterflies include three species of hairstreak: the black, brown and White-letter in the hedgerows, and in the meadows there are populations of marbled white and orange tip.

Mammals living on the reserve include the brown hare, European badger and Reeves's muntjac.