Frogspawn

Mid-Winter Has Passed And One Of The Early Moves Made By Nature Is For Frogs And Other Amphibians To Appear As If By Magic In Any Standing Water.

Frogs do not spend all year in ponds. Most of the year they are off chasing slugs and other food in damp sheltered places around gardens and woodland. They hibernate in cold, damp, safe spots like pond mud, log piles, compost heaps, or underground burrows.

By the end of January, if it is warm enough, they will wake up, the breeding hormones kick in and they will go in search of water. Yet again, our warming climate is seeing this happening earlier and earlier. The 18^th century naturalist Gilbert White only mentions frog spawn in late March. The Woodland Trust Nature’s Calendar project records show the first spawning, usually in Cornwall and then Devon, is about two weeks earlier than twenty five years ago.

It is said frogs will return to their natal pond, the place they were born, but if you dig a new pond in your garden it is likely that frogs will find it and settle despite it not being their birth home.

When they leave the pond for the first time, something will encourage the young froglets to travel in a particular direction, research suggests it can be a particular smells, even the moon and earth’s magnetic field. When it comes to breeding time they just turn round and reverse the journey but they can smell ponds from some way off and will stop at any new pond on their route.

Once male frogs find a suitable breeding pond they will begin calling and this will attract females. It has even been shown that some newts are attracted to the frog chorus telling them there is a pond in the locality.

Mating is rather rough and tumble. Males, smaller than the females, clamp themselves to a likely partner using two grip pads on the front limbs to hang on. Several males will sometimes create an unsightly ball. When the female lays her eggs at least one male will shed sperm to fertilise it. The eggs then swell up into the familiar spawn ball that is much larger than the female that laid the eggs.

I don’t have room here for the full story but the embryos in the spawn hatch after 2-4 weeks depending on conditions. The tadpoles take about 16 weeks to develop from truly aquatic creatures to amphibian froglets that can survive out of water. If they survive, the froglets will disperse and spend up to four years growing into adult frogs that will then be ready to breed. They can live to about ten years old if they are lucky.

If you are fortunate enough to have frogs breeding in your garden then the best thing to do is to watch but leave it to nature. It is not recommended that you move frogs, their spawn or tadpoles. There are a number of diseases and pests that are threatening amphibian populations across the world. If there is a problem in a pond the worst thing you can do is spread it to another pond.

You have to accept the uncomfortable fact that very few frog eggs will make a frog. UK common frogs can lay up to 4,000 eggs in a spawn mass. It is likely that only 2 or 3 of those will make it back to the pond in four years time as adult breeding frogs. The food supply in a pond will dictate how many tadpoles it can support. Trying to feed the tadpoles might lead to an excess and they will start to cannibalise their brothers and sisters.

There is plenty of reliable information and advice about frogs, plus newts, toads and reptiles on the Amphibian and Reptile Trust website https://www.arc-trust.org/.

Ed Dolphin

Image credits: Frog, Charles Sinclair