Photograph courtesy of John Wilkinson
Have you heard this call?
If you have please log your record at the Record Pool
How to identify marsh frogs
Behaviour
Behaviour
Marsh
frogs stay in or around water all year and tend to sunbathe on the sunny banks
of ponds or on submerged vegetation. The photos above and below are
classic marsh frog poses. This behaviour differs from native frogs and toads
that tend to leave ponds after spawning in February and March[1]. Therefore, if you see a frog behaving in this
way between April and September it is very likely to be a marsh frog or a close relative (see below in More about marsh frogs).
Photograph courtesy of John Wilkinson
Call
Male frogs have a very loud and distinctive call. It often consists of repeat bursts of five rapid quack-like sounds that have been compared to a laugh or cackle. Marsh frogs call both day and night from late spring sporadically throughout the summer.
Size
Marsh frogs can grow to 13 cm or more, much larger than native frogs and toads.
Skin
Their skin is warty, with folds of skin running from their eyes down either side of their back. This distinguishes marsh frogs from another non-native the North American Bullfrog (Lithobates catesbeianus).
Colour
This can vary between green, brown or grey, but marsh frogs are often more vivid green than native frogs and toads.
Vocal Sacs
Male marsh frogs have grey vocal sacs either side of their head that inflate when calling.
Please Remember
Unfortunately, section
14(1) of the Wildlife & Countryside Act 1981 makes it an offence for anyone
to release marsh frogs back into the wild once they have been captured; so
please only observe and listen to them.
[1] A native toad called the natterjack toad (Epidalea calamita) can spawn in ponds until July. However, natterjack toads are fairly rare, much smaller than marsh frogs and prefer shallow sandy bottomed ponds so they are unlikely to be mistaken for marsh frogs.
More about marsh frogs
Relatives of the marsh frog
The marsh
frog is part of a group of frogs called ‘green frogs’ or ‘water frogs’ and
other members of this group are present
in the UK e.g. pool frog (Pelophylax
lessonae) and the edible frog (Pelophylax
kl. esculentus). There are a few differences
between the species. Pool frogs are smaller, have white vocal sacs and a pale
dorsal stripe (marsh frogs do occasionally have a dorsal stripe). Edible frogs
are a hybrid cross between marsh frogs and pool frogs so tend to have features
that are a mix of the two parent species. For example they are between the two
in size and have light grey vocal sacs. Unfortunately you can only reliably
distinguish the different species by their call unless they are examined in the
hand.
Edible frogs are rarely
found without one of the parent species therefore it is only in areas where
pool frogs exist that the presence of marsh frogs could be misidentified. The pool frog was recently found to be native
to East Anglia but became extinct in the 1990s and is being reintroduced to
Norfolk. There have been unmanaged introductions of pool frogs around the
country and in Surrey you are more likely to find pool frogs or hybrid edible
frogs than marsh frogs.
History of the introduction
In 1935, 12
marsh frogs, thought originally to be from Hungary, were introduced into
gardens near Walland and Romney Marshes, Kent. Since then, the species has
become abundant in the low-lying wetlands of the south eastern counties. However,
there are also records of sightings in the Midlands, as well as a water frog
population in Yorkshire which may contain marsh frogs.
After their
introduction marsh frogs spread rapidly along watercourses but their dependence
on water has prevented natural colonisation of suitable habitat that is
geographically separated. Accidental or
deliberate translocations are likely to be the cause of the occurrence of a new
population. The map below shows the recorded distribution of marsh frogs
in Kent and Sussex and illustrates the characteristic pattern of dispersal
along rivers with smaller populations radiating from these. This is
particularly evident around the River Ouse in East Sussex.
Useful
Information
Useful links
Durrell
Institute of Conservation and Ecology – http://www.kent.ac.uk/dice/
References
Amphibian and Reptile Conservation. Alien Encounters Marsh frog
and relatives [Online]. Available from http://alienencounters.narrs.org.uk/marshfrog.html
[Accessed 19 Marsh 2013.
Beebee, T. J. (1980). Habitats of the British Amphibians (3): River Valley Marshes. Biological Conservation, 18, 281-287.
Beebee, T. J., & Griffiths, R. A. (2000). Amphibians and Reptiles: A Natural History of the British Herpetofauna. London: HarperCollins.
Brady, L. (2009). Further Thoughts on Common Frog Pond Occupancy. 18 October 2009. Lee Brady's Recording Blog Reptile and Amphibian Conservation [Online]. Available from: http://calumma.typepad.com/lee_bradys_recording_blog/2009/10/further-thoughts-on-common-frog-pond-occupancy.html [Accessed 29 August 2011].
Gregory, P. & Isaac, L. A. (2004). Food Habits of the Grass Snake in Southeastern England: Is Natrix natrix a Generalist Predator? Journal of Herpetology, 38, 88-95.
Innocenzi, P. (1995). The Ecology and Conservation of the Marsh Frog. Thesis submitted for the degree of M.Sc. in Conservation Biology. Durrell Institute of Conservation and Ecology, University of Kent at Canterbury.
Inns, H. (2009). Britain's reptiles and amphibians: a guide to the reptiles and amphibians of Great Britain, Ireland and the Channel Islands. Old Basing, Hants.: WILDGuides ltd.
Peter, A. K. H. (2001). Dispersal Rates and Distances in Adult Water Frogs, Rana lessonae, R. ridibunda, and Their Hybridogenetic Associate R. esculenta. Herpetologica, 57(4), 449-460.
Savage, M. R., (1961). The Ecology and Life history of the Common Frog. London: Pitman.
Wycherley, J., & Anstis, R. (2001). Amphibians and Reptiles of Surrey. Surrey: Surrey Wildlife Trust.
Zeisset, I., & Beebee, T. J. (2003). Population genetics of a successful invader: the marsh frog Rana ridibunda. Molecular Ecology, 12, 639-646.
Beebee, T. J. (1980). Habitats of the British Amphibians (3): River Valley Marshes. Biological Conservation, 18, 281-287.
Beebee, T. J., & Griffiths, R. A. (2000). Amphibians and Reptiles: A Natural History of the British Herpetofauna. London: HarperCollins.
Brady, L. (2009). Further Thoughts on Common Frog Pond Occupancy. 18 October 2009. Lee Brady's Recording Blog Reptile and Amphibian Conservation [Online]. Available from: http://calumma.typepad.com/lee_bradys_recording_blog/2009/10/further-thoughts-on-common-frog-pond-occupancy.html [Accessed 29 August 2011].
Gregory, P. & Isaac, L. A. (2004). Food Habits of the Grass Snake in Southeastern England: Is Natrix natrix a Generalist Predator? Journal of Herpetology, 38, 88-95.
Innocenzi, P. (1995). The Ecology and Conservation of the Marsh Frog. Thesis submitted for the degree of M.Sc. in Conservation Biology. Durrell Institute of Conservation and Ecology, University of Kent at Canterbury.
Inns, H. (2009). Britain's reptiles and amphibians: a guide to the reptiles and amphibians of Great Britain, Ireland and the Channel Islands. Old Basing, Hants.: WILDGuides ltd.
Peter, A. K. H. (2001). Dispersal Rates and Distances in Adult Water Frogs, Rana lessonae, R. ridibunda, and Their Hybridogenetic Associate R. esculenta. Herpetologica, 57(4), 449-460.
Savage, M. R., (1961). The Ecology and Life history of the Common Frog. London: Pitman.
Wycherley, J., & Anstis, R. (2001). Amphibians and Reptiles of Surrey. Surrey: Surrey Wildlife Trust.
Zeisset, I., & Beebee, T. J. (2003). Population genetics of a successful invader: the marsh frog Rana ridibunda. Molecular Ecology, 12, 639-646.
