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How Common are Red frogs in England? |
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Cavy
Member Joined: 22 Apr 2006 Location: United Kingdom Status: Offline Points: 5 |
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Posted: 13 Jul 2006 at 1:05pm |
Sorry if this has been covered (did try to search, but was surprised I came up with nothing).
We have a very red frog in our pond. She has been like this for months, although I think she may be getting darker red (since I first noticed her a few months ago). I don't think it's Red Leg (a bacterial infection, apparently), because she's red all over & seems ok other than being dark brick red, and none of their other frogs have been found dead (or red). How uncommon is this? She (or he) is a full adult. We live in north Norfolk. |
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Jimpklop
Senior Member Joined: 23 May 2006 Location: United Kingdom Status: Offline Points: 208 |
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Hi Cavy Frogs aren't a strong point of mine I'm trying hard to learn about these aspects. What size is the Housing? How many frogs are housed there? Could you get a picture? Thanks James |
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Im Craving Adder's(www.jimpklop.moonfruit.com)
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administrator
Admin Group Joined: 01 Jan 2007 Status: Offline Points: 10 |
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Well Cavy, reports of oddly coloured common frogs (red/black/yellow/orange etc) are now fairly common particularly in urban areas. Piccy would be interesting to see. |
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Cavy
Member Joined: 22 Apr 2006 Location: United Kingdom Status: Offline Points: 5 |
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Sorry everyone, I'm so bad at this I can't even figure out how to add a new reply to this thread, but it seems I can edit this post? So I've now got a picture uploaded. Big Update is that the frog has died, so maybe she was poorly with something (it looked like she had a fungus or rot on her bottom, as you can almost see in this pic). So maybe she was poorly. But she was quite mature (not a subadult for sure). But rest of frogs still seem ok (if suffering from pond shrinkage in this heat wave). Pond size: it's a half-circle shape with radius of about 1.5m, so not small. We live on the edge of a market town. We live right in front (downwind) from a field growing barley that has been sprayed -- could chemicals cause the frog to be so red? Edited by Cavy |
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mynewt
Member Joined: 18 Jul 2006 Status: Offline Points: 12 |
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Hi Gemma and other Raukers
After having followed the various threads for a while on the site I thought it was time to take the plunge myself.. This is about the apparent increase in oddly coloured (common) frogs, especially in gardens. Apart from simple observer bias, I wonder if this has little to do with inbreeding and genetic drift (if so, wouldn't most of the frogs around one breeding site be expected to show the same 'odd' colour ?) and more to do with increased survival of odd coloured frogs in the benign environment of the garden. Most, if not all, of these odd coloured frogs are being observed as adults / subadults. Maybe it's just that the same fraction of odd coloured froglets metamorphose in the wild and in suburbia, but the higher survival rate for odd coloured frogs can be greater in gardens due to a lack of predation - especially by colour sensitive predators like herons (which do visit garden ponds, I know, but can't be as significant in this environment than in the 'wild'). To test this idea, it would be necessary to count the proportion of odd coloured froglets at metamorphosis in wild and garden populations, and see if there were differences in a) the proportions of odd coloured froglets in the 2 kinds of habitat and b) whether survival rates of odd coloured frogs were different post-metamorphosis in the 2 areas. Has anyone done any work to test this ? Any thoughts welcome. I'll try to post a pic of a lovely near-black common frog from a site in Islington, north London, which I saw last week - as well as a similarly coloured crested newt from a few years back, to show that the same odd colours can happen in suburban GCN too.. Cheers Mynewt |
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administrator
Admin Group Joined: 01 Jan 2007 Status: Offline Points: 10 |
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Hi Mynewt, I've seen near black frogs in Haringey. One interesting obs I made was when clearing an isolated courtyard population at an inner London school. Firstly, the pond had to go because of insurance reasons. The population could be assumed to be 100% isolated. The interesting bit was that all the youngest frogs looked 'normal' only as you have stated, the sub-adult and adult frogs showed colour aberration and rounded snouts. So counting odd froglets may not provide any information as it appears the symptoms occur in later life. There is no doubt in my mind that these odd frogs are mostly centered around garden populations, perhaps pointing to genetic factors, however I have also observed the occasional odd frogs in the wider countryside in the last couple of years showing similar characteristics. (colour aberration, rounded snouts, unusual gait, generally odd looking). Certainly common frogs visiting our garden pond from the wild look like the ones I remember from childhood, quite different to the distinctly odd ones I see on call outs in more suburban gardens. I wonder if it would be worth close observation of the development of frogs from these populations? Certainly something is not right but it appears mostly there is little interest in the issue. PS Cavy, you can upload images directly to the forum using the button, if all else fails just email me the piccy at admin and I'll post it up. |
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mynewt
Member Joined: 18 Jul 2006 Status: Offline Points: 12 |
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Thanks for the reply Gemma. Your point about the froglets not yet showing their 'true colours' is a good one.
I guess what I meant was that odd frogs - colour, shape etc - perhaps even the odd extra leg ! - might be no more common to start off with in gardens than in the wild, but that relaxed selection in gardens might allow them to persist for longer than in the 'tangled bank' of Darwinian realities out in the wild. As a result, alleles which could be maladaptive in the wild are not ruthlessly selected against and become more prevalent in the garden habitats. This is a separate although not mutually exclusive explanation from that offered by Trevor Beebee in which genetic drift (ie neutral selection) is held responsible for odd colours being more commonly observed in suburban than wild frog populations. Mynewt PS In my limited experience, 'round nosed' common frogs are very often older ones, and I would agree that this often correlates with odd colours and patterns - perhaps some frogs get more striking patterns as they age ? |
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mynewt
Member Joined: 18 Jul 2006 Status: Offline Points: 12 |
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Here are the odd frog and GCN from London; apologies for the low quality of images, especially the GCN which is a photo of a photo.. I thought the frog had a particularly black slimy mud on it when first seen but in fact that black colour is the frog's own Mynewt |
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mynewt
Member Joined: 18 Jul 2006 Status: Offline Points: 12 |
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Nice to see this illustration of at least one 'odd' / bright female common frog going back to the turn of the last century, from Boulanger's book
Mynewt |
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administrator
Admin Group Joined: 01 Jan 2007 Status: Offline Points: 10 |
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The rounded snouts I've seen on 'odd' frogs have included sub-adult individuals, perhaps not a clear description, though I am not confusing it with the usual appearance of adult female common frogs. There are other symptoms also including the look of the membranes surrounding the eye that mark some of the colour abarrent frogs apart in my mind to 'normal' frogs. The Trevor Beebee theory has a lot of merit, I wonder if counting odd coloured juveniles is not going to work, what other options are there to carry out field work to investigate this? |
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