Marsh Frogs

Mike Brill

All through March while walking at night with my dog down the road beside my garden I could hear regularly Brrrrr, Brrrrr coming from my pond. It sounded like a frog but nothing like the normal croaking. Eventually one day while cleaning some overgrown plants I discovered a large brown frog with circular regular black spots about 4mm in diameter. The spots covered the body and legs. I presumed the frog croaking is a male in which case he is large – about the same size as a common toad.

As many will know I was asking at a recent meeting whether anyone could remember from the Amphibian talk which frog it might be. Well after a number of calls I managed to find out which frog it is. We have two species in Britain with black spots, the Marsh frog and the Edible frog. The Edible frog can be distinguished because it always has a green stripe in the body – no stripes on the Marsh frog. The Edible frog is roughly the same size as our common frog but the Marsh frog is big. Males are the same size as our female common toad and the females are a lot bigger at about 5” in body size. Mine is the Marsh frog. It has large vocal sacs and as a result can be very noisy.

The Marsh frog has been established in the Romney Marsh since the 1930’s. In recent years numbers in Romney Marsh have dwindled considerably. However reportings of Marsh frogs at the same time have occurred from further afield, with the first sighting in Essex in the 1990’s. I happened to be at a meeting at the end of April for Epping Forest Country Care liaison Committee. I reported the finding of the Marsh frog and was told it was the first reporting from the Epping Forest District.

I had frog spawn this year but which species laid it I do not know. The eggs of the Marsh frog are supposed to be slightly larger than those of the common frog but the difference is not enough to spot. I used to have large numbers of common frogs, Common toad, crested newts and common newts breeding regularly in my garden. Then 6 years ago a grass snake took up residence and bred twice. Most of the fogs and toads were eaten. Common newts were not affected. Crested Newts disappeared but they did also throughout the area unfortunately. Two years ago, the food gone, the snakes moved on. Last year there was no spawn but this year plenty of toad spawn and some frog spawn. I have rebuilt my small wild life pond hoping that the newts might come back.

Well I hope others who have seen unusual frogs can check whether there is a green stripe or not and how big they are.

Mike Brill