Tadpoles not maturing

[CarolN]

We have hundreds of tadpoles in our pond but up to now only a few have developed any back legs and some look no bigger than they did at hatching. Some years ago I remember froglets hopping through the flower beds in mid-summer. The pond is crystal clear, has plenty of plants and small life but no fish. I have been in contact with some other sites on the web where there have been similar reports of tadpoles not maturing. Is this something anyone comes across regularly ? Our frog population has crashed in the past 6 years. I have a photo taken in 2002 of some 15 frogs all together by the pond (and there were as many dotted around) but this year we hardly see 2 together. I have only found 1 dead one and that was about 3 years ago. A bit worrying ! Any comments would be welcome.

[Dogghound]

Hi Carol and welcome. The first point i would like to make is tadpoles maturing slowly or not at all is a very common occurrence, as you say you have alot of tadpoles one explanation for your lack of development is the competition due to the numbers they slow their development as there is not enough food to go around. Another explanation is to do with the water quality or condition, they are highly sensitive so small changes may have occurred, another explanation is temperature cooler weather slows progress, another possibility is parental fitness were good genes passed down to the offspring, Or it could be a combination of these factors, it is highly common for this to occur in extremes such as uplands, the far north, nutrient poor ponds, new garden ponds etc, its likely that either some tadpoles will die due to competition, predation etc and some will grow naturally and leave the pond opening up space for others to develop and follow them out of the pond. Its not paticulaly a modern occurrence and has become a factor in frog reproduction, sometimes tadpoles will overwinter then develop the next year this is actually common in upland areas.
Regarding the adults the national population does seem to be on abit of a decline at the moment for various factors (disease, habitat loss etc), although local populations always fluctuate with good years and bad years, so it may just be a bad year. Have you altered your garden at all, started using chemicals etc? Hope this helps.

[CarolN]

Hi - thanks for that. I never use chemicals or poisons of any kind in the garden but alas we don't know what goes on in neighbouring gardens. One major factor was probably the development of land at the rear of our garden about 8 years ago. For a long time this was a derelict market garden, which was a haven for wildlife, including foxes, but three houses with fairly small gardens were crammed on to the plot. Although there is still considerable land involved in the adjoining gardens, this must have had a long term effect on the frogs. Thanks again

[dampflippers]

It may just be that there isn't enough food for them all. They will eat each other in this instance (that's why they lay so much spawn), and some may overwinter in the pond and metamorphose next spring.

You could try feeding with a single Rabbit food pellet or dog biscuit or fish food pellet to see if they like it. Or give them some boiled lettuce or spinach.
Or just leave them to it.

[newponder]

I was wondering exactly the same thing about my taddys as they dont seem to be moving on - i have noticed the bigger ones have a lighter colouring underneath but no sign of legs - my pond is 2 yrs old and its the first time ive had spawn (following a froggy orgy earlier this year) The pond is sunny for the middle of the day to early evening
but then in shade but gets alot more shade in winter. It is also a ballooning pond in that heavy rainfall drains beneath it (a flexi-liner) and pushes out the pond water although basket planting helps to keep some depth despite this!

Andrea

[Dillibags]

I'd also noticed this and was advised to feed them raw meat! I duly bought some cheap stewing stead, tied string round pieces of it and dangled them into the pond from rocks. Within minutes the pieces of meat were covered with tadpoles, they are really enjoying it!

The lengths we go to

[CarolN]

Thanks for all the responses. I have also read that dangling meat into the pond in some kind of string bag is a good idea. We are off to the supermarket tomorrow so I will get some, though I am not sure how 'im indoors will react to spending the shopping bill on the tads - I spend enough of it on the bird seed. I had another look in the pond today and several have quite developed back legs, while others look almost as they did at hatching. From what has been said, the little ones will possibly become food for the more developed.

[newponder]

I was advised to put in wtaercress to help with the pond-weed (??) and they love that!!

Will try the meat and see what happens!

[CarolN]

Oh wow! I was going to buy some meat but then we remembered that there was some cooked turkey meat in the freezer that was probably past its best. We defrosted a bit and I put this in a small string bag and suspended it in the water on a cane. After a few seconds one tadpole arrived, then a few more, then dozens and dozens. It was like something out of Jaws. It made me realise, firstly, just how many taddies were in the pond and, secondly, that quite a few did have fairly developed back legs. I will keep supplying them and see what happens.

[Adam Cheeseman]

Apart from delayed development, there is another reason why your tadpoles haven't started developing yet. They might be Marsh Frogs whose tadpoles only start to appear around July here in London. They are somewhat bigger than your average Common Frog 'pole though.

Cheers,

Adam

[Ellkebe]

I've just been reading through this thread as I'm monitoring my toadpoles' development at the moment. Only one looks like it's ready to leave the pond soon - proper little back and front legs and tail less than half its original length.
I've a couple of questions I'd love some help with. Do toadpoles have to have meat as they get their back legs? I've put some dried blood worm in as suggested in another thread but they seem to ignore that! Most of them, including ones with back legs, just seem to want to gorge themselves on watercress! Will they mature and leave each other alone if there is plenty of plant life for them, but no meat? And can they eat the various little dead insects that end up on the surface of the water?
Sorry - I know that's a lot of questions - more than a couple! Oh - one more though! - is the frog that's taken up residence likely to eat the toadpoles or even the little toadlets if they emerge this summer?
Many thanks for any advice.
Ellkebe

[vole-woman]

I was wondering whether there might be a biological reason for them maturing at different rates, to give them a better chance of survival because they're not all in competition with each other? All the spawn we had came within a week at the end of March, and the six baby tads I took in for my boys to watch matured into froglets within about 6 weeks.

But the ones that never left the pond are all different stages. Some have two legs and some four, and there are some very tiny brand new froglets which can't be the ones I released in May. It's as if their development's been staggered.

[Dogghound]

Originally Posted by Ellkebe

Do toadpoles have to have meat as they get their back legs? I've put some dried blood worm in as suggested in another thread but they seem to ignore that! Most of them, including ones with back legs, just seem to want to gorge themselves on watercress! Will they mature and leave each other alone if there is plenty of plant life for them, but no meat? And can they eat the various little dead insects that end up on the surface of the water?

The gaining of legs is just a rough estimate they should start feeding soon, blood worm may be eaten but they would prefer beef mince, but there should really be enough food in the pond without adding it. They will eat eachother regardless of the situation. They will eat the dead insects yes.

[Dogghound]

Originally Posted by vole-woman

I was wondering whether there might be a biological reason for them maturing at different rates, to give them a better chance of survival because they're not all in competition with each other? All the spawn we had came within a week at the end of March, and the six baby tads I took in for my boys to watch matured into froglets within about 6 weeks.

But the ones that never left the pond are all different stages. Some have two legs and some four, and there are some very tiny brand new froglets which can't be the ones I released in May. It's as if their development's been staggered.

The ones you brought in will have matured faster due to the warmer temperatures in your house. You always get groups that develop at different times, i personally think this is due to food availiability and certain individuals getting a better start and out competing the others resulting in them growing slower. In most wild situations they all emerge at the same time, i think this is due to the high numbers resulting in more getting away from predators. Although you do get genetically different sizes and growth speeds in all animals so it will play a part.

[vole-woman]

Thanks!

[Ellkebe]

Many thanks Dogghound - best brace myself for some losses then!

[newponder]

Update on my 'poles - have spotted some very tiny back legs on some this evening so i may yet get some leaving the pond? How long does it normally take from first signs of limbs ..... anyone?

[Dogghound]

It varies but if they have legs it is more than likely that they will emerge this year, if this warm weather keep up it wont be to long.

[newponder]

Thanks for the information

Andrea