140 bird species have been recorded at the Muir of Dinnet, 13 of which are United Kingdom Biodiversity Action Plan (UKBAP) species. The lochs of the reserve are of international importance for wintering wildfowl including whooper swans, goldeneye, wigeon, teal, mallard and tufted duck. Large numbers of Icelandic greylag geese also historically overwintered at Muir of Dinnet, however since 2000 a trend for milder winters has led to these birds no longer travelling as far south, and numbers have declined dramatically whilst numbers at more northerly locations have increased. Of the over-wintering species, mallards, teals, tufted ducks, wigeons, greylag geese, mute swans and goldeneyes remain at Muir of Dinnet to breed, being joined by other breeding species such as moorhen, water rail, sedge warbler and reed bunting. There are also summer migrants, with redstart, willow warblers and tree pipits nesting and feeding in the woods, and curlew, skylark and meadow pipit found on the heaths.