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Frog spp in Somerset?: |
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Jeff Member Joined: 19 May 2005 No. of posts: 10  View other posts by Jeff |
Posted: 27 Jul 2006 I've lived on the edge of the Somerset Levels for the past 15 years and every year, in spring and summer, I've heard very loud frog calls, almost a quacking sound, coming from several pool edges. These frogs spread from their original site, a pond on Shapwick Heath NNR, and have been readily heard on Ham Wall RSPB and adjacent Walton Heath Reserve for at least the past five years. Yesterday, July 26th, whilst searching for dragonflies along the shallow margin of Sharpham Pools, near Walton in Somerset, I heard the same loud calls and eventually located five or six small frogs lying in the shallows, one of which I managed to photograph (two images). In the past I've always been told that these are Marsh Frogs, but from my photos and a Google Image search I doubt this; it appears to more closely resemble the Edible Frog Rana kl. esculenta or Pool Frog R. lessonae. All the frogs that I saw were fairly small, about 5 or 6 cm long; presumably part grown? If you can, I would like a positive ID? Thanks, Jeff H.
Jeff |
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herpetologic2 Senior Member Joined: 15 Jun 2004 No. of posts: 1369  View other posts by herpetologic2 |
Posted: 27 Jul 2006
Hi Jeff I think that you are right that the frogs pictured are not Marsh Frogs - Pelophylax (used to be Rana ridibunda) ridibundus - though a positive ID will be difficult as there are several species of this frog and of course their hybrids like the edible frog also complicates matters. It would be good to hear a clear recording of their mating call - we can then tell if they are Pool or possibly Edible - to get the species a further analysis of the mating call would be needed - Dr Julia Wycherley is the person to send the recordings to and she would be able to tell you which species of European Green Frog these are. D'oh I should have looked at Julia's Brit Wildlife article - in there is says that Edible frogs have been identified but other species may also be present which makes sense as Edible Frogs usually have to mate with one of their parent species (Pool or Marsh) to provide viable offspring etc Jon Vice Chair of ARG UK - self employed consultant - visit ARG UK & Alresford Wildlife |
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Jeff Member Joined: 19 May 2005 No. of posts: 10 View other posts by Jeff |
Posted: 28 Jul 2006 Thanks, Jon, I'll try to get some sort of recording. If I'm successful, do you know if I can attach a recording made with Windows Sound Recorder to this thread or would I need to write it to CD and then mail it to whom? Jeff H. Jeff |
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Jeff Member Joined: 19 May 2005 No. of posts: 10 View other posts by Jeff |
Posted: 28 Jul 2006 Hi Jon, Talking of Edible Frogs breeding: from my search on the web I was led to believe that they have to interbreed with a parent species, but not so according to The Herpetoligical Conservation Trust on their website http://www.herpconstrust.org.uk/index.htm which says that it is clearly a species in its own right as it can breed true. Jeff |
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herpetologic2 Senior Member Joined: 15 Jun 2004 No. of posts: 1369 View other posts by herpetologic2 |
Posted: 28 Jul 2006
Hi Jeff Most edible frogs do have to breed with either of the parent species - it is not the case that it is a species in its own right - it is a hybrid but in some cases where animals have an extra set of chromosomes (the collection of DNA/genes in their cells) a term called 'triploidy' (I think) this allows edible frogs to breed successfully with other triploidy populations of Edible frogs. Most edible frog populations in the UK are normally mixed populations with Pool or Marsh and in some cases various other Green Frog species from different parts of Europe. Edible frog populations over the years have died out possibly due to no parent species being present.
Jon
Vice Chair of ARG UK - self employed consultant - visit ARG UK & Alresford Wildlife |
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Jeff Member Joined: 19 May 2005 No. of posts: 10 View other posts by Jeff |
Posted: 29 Jul 2006 Hi Jon, Thanks for your latest info. I've been back to the site and managed to get some sort of sound recording, made with my camcorder. I've built a small website which has a short sound file embedded in it. Unfortunately Freewebs limits the "for free" file size to 750KB which equates to just 4 secs of a Windows .wav extension file, also my camcorder is fairly old and the drum-motor noise picks-up on the sound track. Anyway, please have a listen and tell me what you think? http://www.freewebs.com/frogcalls/ Jeff |
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David Bird Forum Specialist Joined: 17 Feb 2003 No. of posts: 515 View other posts by David Bird |
Posted: 15 Aug 2006 Specimens of the Green Frogs were brought to the South West area meeting of the Herp Groups of Great Britain held at the Somerset environmental recording centre about 8 years ago together with some photos taken in the wild and a tape of the calls unfortunately recorded on a portable tape recorder with a failing battery. Thye frogs were not p.ridibundain my opinion. As to whether they were P.esculentaor P.lessonaewe couldn't really tell as we did not see the colour of the vocal sacs or examine the specimens that closely. We had not been told that they were going to be displayed as we would have probably taken down some identification material and slides of the species in their native range, the only identification page that had been used was the plate from the 1st edition of Arnold & Burton British Herpetological Society Librarian and member of B.H.S Conservation Committee. Self employed Herpetological Consultant and Field Worker. |
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Peter Sutton Member Joined: 30 Aug 2006 No. of posts: 22 View other posts by Peter Sutton |
Posted: 31 Aug 2006 As per my message on the 'naturalised species' area of the forum, I examined a large specimen of a Somerset 'Green Frog' and its heel clearly extended beyond the snout. General opinion states that these are not Marsh Frogs, and my initial id was that they looked like Edible or Pool Frogs. How reliable is the method of determining species using the length of the hind leg? If it is reliable, the Somerset Green Frogs appear to be Marsh Frogs, or at least, have Marsh Frogs among their number. (Photograph available) Peter Sutton |
- Frog spp in Somerset? |
