Chambers’s Journal No. 581 107, col. 2: The male of the eatable frog is distinguished... by... a pouch... These pouches increase the volume of the croak, and render it so powerful that the possessors have, from the county in which they are particularly plentiful, received the nickname of Cambridgeshire nightingales [F&H].at Cambridgeshire nightingale (n.) under Cambridge, adj.