Daniel Brittle's picture

Marsh Frog - Allhallows Marshes

Observed: 11th May 2010 By: Daniel BrittleDaniel Brittle’s reputation in Amphibians and ReptilesDaniel Brittle’s reputation in Amphibians and Reptiles
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Description:

Marsh frog i think

Identifications
Species interactions

No interactions present.

Comments

the naturalist man's picture

Green frog

There are three 'green frogs' found in Britian, all introduced (except for a possible native colony of pool frogs). These are
marsh frog (Pelophylax ridibundus - formerly Rana ridibunda), edible frog (Pelophylax esculentus - formerly Rana esculenta) and pool frog (Pelophylax lessonae - formerly Rana lessonae). Unfortunately it is very difficult to tell them apart from photos alone, indeed some believe they are not strictly separate species at all as they can interbreed producing viable hybrids. They are easily distinguished from the common frog or toad as they have a frog shaped head and stance but warty skin like a toad.

Therefore, your two photos are of a 'green frog' but which one?

The usual way is to capture them and measure the hind leg. When at rest the marsh frog has the longest lower leg reaching beyond the knee, under the fore-arms and often as far as the chin. The pool frog has the shortest and the edible frog is in between. Again unfortunately, your photos do not show the hind legs. I can not even go by distribution as you are within, or close to, the range of all three.

Having said that adult pool frogs and edible frogs always have a pale stripe down their spine; only in the marsh frog can this be missing. In addition pool and edible frogs are almost always an obvious green as in the above picture. The marsh frog is more variable, ranging from the rich green of the above picture to a darker olive green as in your other photo.

http://www.ispot.org.uk/node/33092?nav=og_unread

Therefore, the weight of the evidence suggests you have marsh frogs.

Graham Banwell

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