The unexpectedly fascinating life of a pond
by Paul Cormacain 23/05/2003
FROGS spend most of their lives on dry land, even if we tend to associate
them with water.
From January to March they take to the water to perform their ritual breeding which results in frog spawn, tadpoles, and then young frogs.
It is during this time that we mostly see frogs. This is when they are in their high profile mode and may even take to the roads on wet nights, usually returning to the spot where they were born.
They tend to breed in the spot where they were born and lived their first few months. But they do not return until about five years later, when they have matured
After the breeding season adults are exhausted and frequently hide in deep water for several weeks before venturing forth. They go onto dry land and remain there till the next breeding season. It is during this time they are rarely seen.
So it was some surprise that we came across young frogs in a pond on the slopes of Colin last week. Why had they not left by now?
The months January to March mentioned in books as the frogs' breeding season perhaps need to be re-thought. We have seen these amphibians heading for the water in December in years past, and now we find young frogs still in the breeding area in May.
We looked some more in the pond. Then we saw tadpoles, and this in the middle of May. Perhaps the frogs have been sold a batch of inaccurate calendars.
Tadpoles are a very unloved lot. Or, on the contrary, lots of creatures love tadpoles. Ducks love tadpoles. Herons have been known to sample the odd one. In fact any bird or animal, or even insects, who are close to marshy land and come cross tadpoles, are going to have a feast. And when the tadpoles turn to small frogs they will be equally desirable.
Luckily, Nature steps in and helps. After its initial look at life, the tadpole quickly learns to dive deeper, and hide from potential predators. Even so, its life expectancy is low.
In this same pond, in Colin Glen Park, were also great diving beetles. These insects grow into large, fierce predators who spend most of their lives in fresh water. Even in the larval stage of their lives these insects are carnivores.
It is no co-incidence that the larvae love tadpoles and will attack them and eat them with enthusiasm. Great diving beetles know how to breed.
Then there were the pond skaters. These creatures are common enough on lakes, ponds and even slow-moving streams. They have this great ability to walk on water!
It has three pairs of legs, and on the underside of the feet of two of the pairs grow dense pads of hair. These pads trap air. They do not get wet. The skater walks on the water without breaking the surface film of the water.
If a dead or dying insect falls on to the surface of the water when there is a skater in the vicinity, the slight agitation alerts the skater. Fie heads towards the fallen creature, grasps it tightly, pierces the body with its proboscis. When the skin is pierced the proboscis is then used to suck out the body fluids from the dead or dying insect. If the insect was not already dead, it soon is dead when the skater gets near it.
Did you ever realise just how fascinating ponds can be?
Children and adults alike can enjoy, you just have to take a closer look at a pond near you.
Till 31 May - Family fun searching for safe places for birds to lay their eggs at Castle Espie, telephone 9187 4146
Thursday 29 May - Birdwatch Morning fit Castle Espie, 10.30, more from 9187 4146
Sunday 1 June - A sea trip around some cliffs at Islandmagee, at 11am, bound to he spectacular. Contact Andrew Upton, Wildlife Trust, 4483 0282.