- A range of butterflies have been recorded in the area, including the Craig Cerrig Gleisiad & Fan Frynych National Nature Reserve.
- Here are photos of some butterflies seen in Senni Valley in 2005
Green-veined white butterfly, Pieris napi
Small white butterfly, Pieris rapae
Orange-tip butterflies, Anthocharis cardamines
Small heath butterfly, Coenonympha pamphilus
Small tortoiseshell butterfly, Aglais urticae