What is the Northern Leopard Frog's call?

A rattling snore of at least 3 seconds is the call of the Northern Leopard Frog (Rana pipiens,Lithobates pipiens).

Specifically, the voice of the Northern Leopard Frog begins quite softly, builds to a level of loudness and trails off. The call is heard during the warmer weather in late winter and early spring. Breeding may last as short as a week or as long as a month or more.
A rattling snore of at least 3 seconds is the call of the Northern Leopard Frog (Rana pipiens,Lithobates pipiens).

Specifically, the voice of the Northern Leopard Frog begins quite softly, builds to a level of loudness and trails off. The call is heard during the warmer weather in late winter and early spring. Breeding may last as short as a week or as long as a month or more.