Spawning toads produce four million eggs in pond

AS a consequence of the generally chilly nights in the last week, relatively few amphibians ventured out.

Although this was predictable, nevertheless quite a few volunteers were present every night of the week to collect those amphibians that were on the move.

The warmest night of the week was Wednesday, February 28, when it also rained.

Conditions were thus favourable and as a consequence more than 700 amphibians were collected at the barriers on either side of the road.

Reasonable numbers of toads, frogs and newts were all still heading for their spawning pond but the majority of the toads — 500, in fact — were on their way back, having completed spawning.

Thus not only were toads heading in both directions, but so too were the volunteers, some taking toads to their spawning pond, whereas others were taking toads “home” to Oaken Grove. Currently, nearly 11,000 toads have now been taken to their spawning pond, together with more than 350 frogs and 175 common newts.

Of those nearly 11,000 migrating toads, more than 4,500 have already been carried back across the road and released into Oaken Grove.

Although migration to the spawning pond has slowed appreciably in the last two weeks, it is difficult to know when it will cease and how many more toads will arrive at the main barrier before it does. Usually spawning migration peaks around mid-March and finishes later that month or in early April.

But this year the spawning migration occurred much earlier than it has in past years, so perhaps it will end earlier, too.

The fact that so many toads have spawned already and left the pond perhaps suggest that amphibian migration to the spawning pond will cease reasonably soon.

However, there are still a lot of toads and frogs clearly visible in the pond. The male frogs can easily be heard each evening, as they make a lot of noise while in the pond, whereas toads are relatively quiet as they go about spawning.

There is now a lot of spawn, of both toads and frogs, in the pond. Each adult toad will, on average, release about 1,500 eggs. More male toads than female toads migrate to take part in spawning each year but nevertheless about 3,000 female toads have been taken to the spawning pond by volunteers this year.

Even allowing for some deaths due to predation by birds, pike living in the pond, and we think, an otter as well as other causes, there could soon be around four million or more toad eggs in the pond.

The spawn is not easy to see because, unlike frog spawn, which floats on the surface, toads wrap their spawn around vegetation below the surface of the water.

Hatchling tadpoles will emerge from the spawn 10 to 14 days after it has been laid. Shortly after doing so, on sunny days so-called “sheets” consisting of hundreds or thousands of jet black toad tadpoles should be visible as they sun themselves in the shallows.