All you need to know about Frog spawn

, 14 March 2022
All you need to know about Frog spawn
Frog spawn © Ross Hoddinott/2020VISION

By Charlotte Owen

WildCall Officer

Every year, WildCall gets lots of phone calls from people worried about the frog spawn and tadpoles in their ponds. Here are some of the most commonly asked questions.

1. What type of spawn do I have?

Frog spawn is always laid in big clumps, usually in shallow water. Toad spawn comes in long chains like a string of pearls and is usually laid in deeper water, draped over pond weed and submerged plants. Newts lay individual eggs on the leaves of pond plants.

2. I'm worried that I've got too much Frog spawn in my pond.

There really is no such thing as too much Frog spawn! Unfortunately it's a tough life for a tadpole: they have a lot of natural predators and are susceptible to various amphibian diseases, so female Frogs lay thousands of eggs each year with the expectation that only a tiny fraction will survive to adulthood.

3. My spawn hasn't developed properly.

This can be a tricky one. There are lots of factors that affect whether spawn develops: it may be to do with the Frogs or it may be to do with the pond. The most common cause of spawn failure is lack of light and late frosts. Frog spawn needs a lot of sunlight and a lot of warmth to develop properly, so shady ponds with deep water are not good for spawn.

4. Should I move the spawn into a separate pond?

We never recommend moving spawn or tadpoles between ponds as this can spread non-native plant species and amphibian diseases. There’s also a risk of moving spawn from the perfect Frog pond to one that is far less suitable. Ponds may contain a big black mass of writhing tadpoles but this is how it is meant to be. Just sit back and enjoy watching these amazing amphibians.

5. I've got lots of newts but no Frogs. Why?

Newts and Frogs are not mutually exclusive, but they do tend to have a bit of a boom-bust relationship. Newts eat Frog spawn and tadpoles, so a pond with a large population of newts will tend to have fewer Frogs. However, late-stage Frog tadpoles can eat newt tadpoles, so a pond with plenty of Frogs may not have many newts. They can co-exist if numbers are more balanced. It may be that your pond is just more suitable for newts than Frogs but this isn't a bad thing, and newt habitat is just as valuable as Frog habitat.

6. I’ve found Frog spawn in a puddle at risk of drying out – what should I do?

Frogs do often spawn in puddles and other temporary water bodies, which offer the ideal conditions of warm, shallow water. It can be a risky strategy but the hope is that the spawn and tadpoles will develop quickly enough to emerge as froglets before the puddle dries up.

We do not advise moving spawn or tadpoles between ponds due to the risk of transferring amphibian diseases, so it’s probably best to let nature take its course. If you want to give them a helping hand, you could rear some in a tank or bucket of rainwater, then release the froglets back where you found them. See our guide to rearing tadpoles for more information on how to look after them: https://sussexwildlifetrust.org.uk/news/rearing-tadpoles

7. I’ve found a Frog/spawn in a bucket/watering can/unusual location – what should I do?

Frogs do sometimes spawn in strange places, especially if there isn’t a suitable pond nearby. Adults can become trapped in steep-sided containers, so it’s best to lift them out gently and place them in a patch of long grass or dense vegetation, where they are sheltered from the sun and safe from predators. If you do have a pond, you can move the Frog and/or spawn into the water. If you don’t have a pond, consider creating one – and in the meantime you can rear the spawn in a bowl, bucket or shallow tray of rainwater, placed in a sunny, sheltered position. See our guide to rearing tadpoles for more information on how to look after them: https://sussexwildlifetrust.org.uk/news/rearing-tadpoles

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Comments

  • Phil Brooke:

    A trick I learned from a friend as a school pupil more than 50 years ago is that you can feed tadpoles through both the vegetarian and carnivorous stage (before they start taking live prey, but you need to release them before this stage) on wheatgerm. They will learn to feed upside down at the surface – the very small wheat embryos going straight inside the mouth. As a Biology teacher for 20 years we reared lots of frog and toad tadpoles this way. The daphnia which multiplied of the bacteria which grew from their faeces fed the newt tadpoles (and later stage frog tadpoles, though these need to be released by the four leg stage whilst they still have tails since they become very poor swimmers and suddenly nervous of people as soon as they absorb their tails).

    Wheatgerm a good solution for vegetarians who want to rescue spawn from a puddle, but also rather fun to watch their feeding habits.

    17 Mar 2022 12:05:00

  • Tina Litchfield:

    Thanks for this information. We have two big clumps of frog spawn in our garden pond. We’ll keep our fingers crossed that some of them manage to survive.

    17 Mar 2022 13:25:00

  • Brenda Kenward:

    Really interesting.

    17 Mar 2022 14:11:00

  • patricia Joan osbaldeston:

    This year there is a great clump where the dark bit is grey/ white rather than black and I’m wondering whether it was frost damaged? Also the weed seems to have suddenly reached the pond – should I remove it because its suffocating the other weed or leave it because the tadpoles seem to hisde in it.

    Answer: This can be a tricky one. There are lots of factors that affect whether spawn develops: it may be to do with the Frogs or it may be to do with the pond. The most common cause of spawn failure is lack of light and late frosts. Frog spawn needs a lot of sunlight and a lot of warmth to develop properly, so shady ponds with deep water are not good for spawn.

    17 Mar 2022 14:31:00

  • Philippa Hopkins:

    I have had a frog pond for many years which usually has a lot of spawn in it. Last year my frogs starting dying shortly after spawning and I kept finding dead and dying frogs in or near the pond. I was afraid I wouldn’t have any spawn this year but I seem to have had just as much. Could it have been mainly the males that were dying? It hasn’t happened before. When there was a frog plague in the area (East Grinstead) some years ago that killed a lot of frogs, my frogs survived without problems.

    Answer: Sadly, adult amphibian deaths can be caused by many things. In the spring, lots will be eaten or killed by predators like herons, rats, foxes, grass snakes and domestic cats, which make the most of lots of frogs gathering in one place to breed. Female frogs may die of exhaustion after spawning. Read more here

    17 Mar 2022 17:27:00

  • Heather:

    Have enjoyed reading your article – very helpful. Have had frog spawn in one of my ponds and look very healthy. Nevertheless, have noticed there is a newt lurking and will obviously eat lots of tadpoles. Hope one or two frogs will survive!

    17 Mar 2022 18:18:00

  • Clive Bach.:

    We have a good sized clump of frog spawn in our small pond
    When the spawn become tadpoles should I feed them and if so…. on what?

    ANSWER: If spawn is in a pond, then you shouldn't need to feed the tadpoles when they emerge. Just watch them develop.

    18 Mar 2022 07:12:00

  • Gordon Sharp:

    Thanks. Very useful & sensible advice. And…..isn’t nature extraordinary!

    18 Mar 2022 08:26:00

  • Margaret Nelson:

    Our mini pond, made from a plastic box , has a huge clump of frogspawn in it. I noticed that the black embryos seem to be going white, does this mean that they are not fertilised, and should I take them out of the pond at some point if they’re not?

    Answer: It could be that the spawn was not fertilised. This often results in the spawn turning cloudy in colour and sinking to the bottom of the pond. Or it could be down to the environment. The two things that all spawn desperately needs to develop properly are light and warmth. No need to remove it as other wildlife will consume it.

    18 Mar 2022 09:48:00

  • Ann:

    Wonderful tale about the wheatgerm, thank you! I have lots of spawn in my small pond… to protect the creatures i’ve used an old piece of trellis resting on stones etc around the edge of the pool so there’s a gap large enough between pond & stones for the froglets to climb in & out . I hope it’ll prevent Reynard & the cat from ‘fishing’. So far so good!

    18 Mar 2022 10:27:00

  • Heather:

    Have enjoyed reading your article – very helpful. Have had frog spawn in one of my ponds and look very healthy. Nevertheless, have noticed there is a newt lurking and will obviously eat lots of tadpoles. Hope one or two frogs will survive!

    18 Mar 2022 13:08:00

  • Jethro Busby:

    Very interesting article – Sadly there doesn’t seem to be any spawn in my pond this year, maybe there yet will be.

    18 Mar 2022 14:14:00

  • Sallie:

    Hi there,
    We have lots of very large spawn in our large pond but, I have noticed that the eggs are getting furry or are covered in algae. The pond has a good fresh circulation from a local culvert. Any clues?

    ANSWER: It sounds like it might be mould, this would indicate that unfortunately the eggs were unfertilized or have since died. Occasionally, the top layer of spawn can be caught in a frost and killed, although often the spawn under the water can still survive.

    18 Mar 2022 14:22:00

  • Paul Scott:

    Re tadpoles dying very quickly. This happened in my pond and I reckoned it was foul water. Every two years in late autumn clear out as much sludge from the bottom of the pond. If it smells like rotten eggs then the water is contaminated. I’d also recommend removing most of the water during a rainy spell. Carefully to keep any larvae safe.

    18 Mar 2022 17:27:00

  • Jay Cooper:

    I’ve had frogs and spawn in my small pond for many years, and I saw froglets in the garden last year. This year I’ve not seen or heard frogs though I heard croaking last Autumn. Now the pond and garden is empty of frogs and spawn. Has the local fox eaten them en route to my garden? Soo disappointing, especially for my small grandsons.

    ANSWER: Sorry to hear that your Frogs have not returned yet, this could be due to a number of factors - including the local environment, suitable overwintering sites etc. It is possible that they still might turn up. Predation can be a factor, but is unlikely to be the sole cause. Lots of animals and birds do eat Frogs, including Foxes but only as part of a varied diet, so I wouldn't think that is the likely cause in this case.

    18 Mar 2022 21:35:00

  • Thanks. Very useful & sensible advice. And…..isn’t nature extraordinary!

    20 Mar 2022 07:01:00

  • Jenny:

    I went walking up in Yorkshire and there was a shallow big very high up. Stupid question, how did the frog find its way up there to spawn?

    ANswer: Frogs can live in a wide range of habitats, as long as there is water, food and shelter. After the winter, male Frogs will start searching for ponds using predominantly visual cues; scent appear to be less important. Once at water bodies, males start calling for females and this will bring the female Frogs to the breeding pond.

    21 Mar 2022 07:57:00

  • John:

    Wonderful article. I made a small pond just last year and waS frequently visited by mature frogs within a couple of months. I’m delighted to see just this week a bunch of frogspawn in the pond. Looking forward to watching them develop,)))

    22 Mar 2022 17:45:00

  • Andrew Coleman:

    Thanks for the article. Our pond is in a shady spot at the moment so I’m going to transfer the spawn into a shallow bucket with pond water and put it in the sun until later in the year when the pond gets the sun. I bought some indigenous weed last year and snails have gone bonkers. Can you have too many snails?

    ANSWER There are several different species of pond snails but most are scavengers, feeding on algae, plants and detritus, so they help maintain a healthy pond ecosystem and are also food for frogs, birds and other wildlife. But as with all things, balance is key and too many snails may deplete the plant life in a small or sparsely-vegetated pond. You’ll usually find a natural balance is struck and, even though snails can reproduce quite rapidly, their numbers are ultimately limited by their food supply. If you haven’t noticed any particular problems, snail levels are probably fine.

    26 Mar 2022 16:32:00

  • Bill stothart:

    How can a frog lay so much frogspawn? My frogspawn clumps seem to be much larger than the frog they come from?.??

    ANSWER Freshly laid eggs are small and compact, like tiny beads, but as soon as they enter the pond they start soaking up water until they swell up to their full size.

    08 Apr 2022 20:02:00

  • Kath:
    What’s your news?

    22 Apr 2022 10:31:00