A good post day. A little Jiffy bag: inside was all of Zambia. A single disc containing the sounds of 579 birds, many as familiar to me as the sound of the robin singing in my garden, and as important. There are the voices of 20 mammals, gloriously vivid: my younger boy has been a lion for some days now. And 32 frogs.

The recordings were made by my old friend Bob Stjernstedt; indeed, I was with him when he made some of them. It was a thank-you present from Wildsounds; we were both involved in a charity gig last month. A wonderful surprise.

Just think, though: 32 bloody frogs. Sound has a magic quality: it cuts straight to the unconscious mind. There is no need to worry about this species or that species, or even what the noise means or where it came from: the sound instantly transports you over vast swaths of time and distance.

And so I was back on the banks of the Luangwa River, listening to the chorus of the painted reed frogs. As I did so, I found myself hearing sounds no longer on the recording — the crickets, the scops owl, the barred owlet, the guffaw of hippo, the whoop of hyena, the distant crump of lion.

A triumph for Bob, to isolate those 32 species of frogs and toads, to capture all those 32 voices, tinkling, creaking, croaking, whistling, muttering; filling the Zambian night with their music, their passions, their life. The nostalgia invoked was almost alarming in its violence.

We don’t have enough frog-music in this country, that’s the problem. This is a group of seldom-seen animals that delight us whenever they are encountered: I remember the tree frogs that visited my bathroom — looking as if they had been carved from the soap — when I lived on an island near Hong Kong.

Frogs are amphibians; there are a little over 6,000 species of amphibians known in the world, and of these a third are endangered. About 120 species have gone extinct in the past quarter-century.

This includes the southern gastric-brooding frog of Australia: the females kept the young in their stomachs, which meant that they had to stop production of stomach acid and the performance of peristalsis, or stomach contractions. If we hadn’t lost them, we’d probably be able to solve the problems of peptic ulcers in human beings, but it’s no good worrying about that now.

It is hardly too much to say that the amphibians of the world are on the brink of crisis, if not already there. To say that we could lose the lot is not scaremongering. It is for this reason that a new international group, the Amphibian Survival Alliance, has been formed.

Its tasks are simple: to find out what’s wrong, work out how to put it right, and then do it. It is a horribly daunting prospect. To sum up: disease, habitat loss, climate change, introduced species, commercial exploitation and pollution are all aspects of a great and global predicament.

There is one problem that is specific to amphibians, however, and it is here that the potential disaster lies. And it is not something that is easy to get angry about, understand or stop. It is fungus. Fungus is killing our frogs.

The villain is chytrid fungus. This was something that once affected only invertebrates and plants, but in 1999 a new species was described that brings on a fatal disease in amphibians. It can be passed on by touch and can travel through water courses — and amphibians are watery creatures that cannot live away from dampness.

The problem exists in this country — it has been found on 19 sites — but so far without catastrophic effects. It is in the tropics and Spain that the great die-offs have occurred. There, the effects have been dramatic, with up to 50 per cent of the species and 80 per cent of the individuals lost inside a single year.

Many frog species live in isolated populations: the problem with this is that there is no such thing as a small disaster. A creature living in a single place is by its nature vulnerable: the introduction of the fungus is likely to be the end. It is also possible that all the other conservation problems have stressed populations almost beyond bearing, and that fungus just finishes them off.

New here is one of the great things about conservation and conservationists. True, it looks like calamity. It looks like the end of froggy life as we know it. But conservationists are used to working in situations that would cause despair in a less-robust group of people.

Life. That’s the thing to concentrate on. Life, as opposed to death. Some species — very few — seem to have a natural resistance to the fungus. The naturally occurring bacteria that impart this resistance can be investigated. The possibilities of anti-fungal drugs can be explored. The resistance to fungus can be examined in captive populations.

Then there is translocation: moving members of vulnerable species to safer places. Madagascar so far is free of the fungus; now to find out why and try to stop it getting there. That’s conservation for you — you’re in a situation that seems to contain nothing but despair, and you walk away having discovered nothing but hope.

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