The Tree frog (Hyla arborea) is an excellent climber. With his Adhesive discs on finger and toe tips he climbs trees. But you have to look closely to discover this little "tree frog". In the green thicket he is with his light green body colour difficult to recognise. Only one dark strip stretches along the sides of his body from the nostril to the hip.

During the breeding season from April to July, the male sings in chorus with other tree frogs in ponds, pools and ditches. A tree frog concert can last from dusk until deep into the night on warm evenings.

This amphibian species is highly endangered in Austria and threatened with extinction in Tyrol. The largest population in Tyrol is found in the Tyrolean Lech Valley. Tree frogs like it warm. Therefore, they only colonise the lower, lower sections of the Lech between Reutte and Vils.