Marsh Frog (Pelophylax ridibunda)
Ever spotted one of these guys?! (The yellow stripe is variable and not always present). Yesterday at the London Wetland Centre we were drawn to them by sound rather than sight. A loud laughing croaking noise was coming from the margins of pool. It was so loud that at first I put it down to an abnormal bird call, but when no bird was present we looked closer and located several large Marsh Frogs. In the summer the adult males produce their loud “bre-ke-ke” call both day and night. Their call is given extra ‘umph’ through use of two dark grey vocal sacs, one on either side of the mouth.
This species is not native, it was first introduced to Walland Marsh in Kent in 1935, from Hungary. Today it is found mostly in south east England, with populations arising from either escaped pets, or frogs which have been brought in with fish stocks.
The Marsh Frog feeds predominantly on invertebrates, but sometimes eats other amphibians, fish and even young birds. Although not currently considered a serious threat in the UK, the species may prove to be a problem for native species through predation, competition or the transmission of disease, such as the chytrid fungus.