The Gardeners Friend




The not so common Frog.










When I first started planning our garden five years ago I only had two criteria: firstly that an area should be set aside for the patio and secondly the garden must have a wildlife pond in it.

Even before I'd finished digging the pond it had attracted a couple of frogs and I had to make sure that I didn't step on them. Now after four winters with the pond I've grown use to the annual cycle of mating calls in January followed by sightings of spawn in March and hundreds of tadpoles and tiny little froglets (the size of ten pence pieces) in early spring.

Last year I took part in the BBC Springwatch survey and my little red mark on the map of Britain was one of the first - mating started before the end of the previous year and the familiar sound of the bullfrog trying to attract a mate carried on throughout January. I even find it quite comforting in a strange way to lie in bed on a cold January evening with the rain pouring down and the sound of a baritone voice croaking "Ribbet" for an hour or so.

This croaking is also a warning to other males but it rarely works - frogs are really into group sex and the other males generally just form a line, or sometimes fight each other for the females attention. The males can be distinguished from the females by their slightly larger feet with horny pads, to help them grip the females.Each female will lay up to 2000 eggs, surrounded by a layer of jelly (known as frogspawn) in the water; after having been courted and embraced for quite a long period possibly for days or even weeks by the successful suitor, this to persuade her to lay the eggs, which he then fertilises immediately in the water. The jelly then swells and all the eggs rise to the surface encased in the jelly from which the eggs obtain nutrition. This produces that mass we have all seen so often. As several frogs will spawn in the same place it can be a very large mass indeed, containing anything up to 25,000 or more eggs of which about one in one thousand survive to become a mature adult!

They breathe oxygen from the water through a pair of gills (just like fish) one gill on each side of the body just behind the head, these gills remain external for about four weeks and are then absorbed. They feed on minute water plants.Within seven weeks they will have grown hind legs, and formed the front legs, which stay within the skin. These legs come through at about ten weeks and the tails begin to be absorbed and they develop lungs and by twelve weeks they are miniature replicas of their parents. At this stage they are ready to leave the water and now feed on insects, slugs and small worms! So please be very careful when mowing your lawn.

In winter frogs hibernate, some, mainly males, will bury themselves in the mud at the bottom of your pond and the rest including most of the females will go off to find a cosy, muddy ditch. Their metabolism slows in order to conserve energy, although the ones in your pond may pop up for a look around and a practice croak in milder weather! Then the cycle starts again with everyone returning to the pond. They are ready to breed round about their fifth spring!

Unfortunately there is a virus, if you wish to be scientific, it is thought to be an iridovirus probably Ranavirus which is affecting our frogs, it is commonly known as Red Leg. Typically, adult frogs are seen to be dying over several weeks, resulting in dozens, or even hundreds, of deaths and as the name suggests their limbs are red in colour, for more information about this disease and to report any deaths you may see visit Froglife

Unfortunately due to the vagaries of the last few British winters the number of taddies that actually survive has been dwindling - this has been due to the mild-cold snap-mild pattern of weather down here on the south coast which has resulted in large numbers being killed off by the cold.

The changes to our environment and loss of habitat (ponds have been filled in and hedges and ditches removed) the frog is becoming more and more rare. If you do have space in your garden for a small pond, please ensure that it is child friendly if you leave little ones unsupervised, then please consider one. Even an old washing-up bowl sunk in the ground will attract frogs, we did that whilst waiting for the pond to be finished and we had a couple of frogs in it within days. Another key decision I made when I started gardening was to be organic, our garden had been turf for fourteen years before I decided to give it a makeover so I knew nothing containing chemicals had been used on it. The use of insecticides dramatically reduces the food sources for the frogs.

My garden is slug free thanks to the presence of my pond. There are slugs in the ground but as soon as they come out after a downpour they are met by enthusiastic diners! The pond has also attracted toads, dragonflies, waterboatmen, and other assorted insects - the only thing I haven't attracted so far are newts.