Half of this 100 hectare site near Penarth has been designated a Site of Special Scientific Interest, no surprise given its wide range of wildlife.
A disused quarry, Cosmeston is a great habitat for waterfowl including mute swans, great crested grebe and coots.
Britain's rarest breeding duck, the scaup, is a resident, as are pochards, wigeon and tufted ducks.
The amazing, and highly camouflaged, bittern has also wintered here recently, but you're more likely to hear than see this shy bird.
Lakeside plants such as reed mace, yellow flag iris and the rare greater spearwort support populations of dragonflies and damselflies.
Meanwhile, the extensive woodland is home to foxes and bats.
Tick off what you've spotted with our handy wildlife spotter guides.
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