A PLAGUE of frogs rained down on the London Wetland Centre last week.

The sudden arrival of warm wet weather caused a mass night-time migration of frogs, newts and toads to deluge the centre in Barnes.

Thousands of amphibians have been on the move since Tuesday, March 16, when the weather provided ideal conditions for them to move from their winter hibernation quarters to ponds and pools to breed.

On March 17 wardens at the centre rescued more than 200 newts and several frogs and toads from just two small road drains (since covered up) - the amphibians having mistakenly entered the drains through roadside grids, attracted by the water below.

Ecologist, Dr Richard Bullock, says: "In the ten years that I have been studying the London Wetland Centre site, there has never been a migration like this one.

"On Tuesday night I was having to run up and down Queen Elizabeth Walk, rescuing dozens of toads as they attempted to cross the road to the centre to breed, to stop them being squashed by cars - the biggest hazard for amphibians at this time of year.

"The combination of a prolonged cold winter followed by a sudden, extremely warm, wet spell has led to many of these amphibians coming out of hibernation at exactly the same time - an amazing sight to see."

A spokesman for the Wetland Centre said there are already signs that this will be an excellent breeding year for amphibians with large clumps of frogspawn evident in shallow pools throughout the reserve.

The creation of special hibernacular (small hollow earth and stone mounds) where amphibians can safely hibernate and the profusion of small vegetated ponds ideal for breeding means that amphibian numbers at the London Wetland Centre are set to increase.

There are six native amphibian species in the UK, of which three occur at the London Wetland Centre - common toad (bufo bufo), common frog (rana temporaria) and smooth newt (triturus vulgaris). A fourth non-native species also breeds at the centre - the marsh frog (rana ridibunda).

Amphibian numbers have increased year on year at the London Wetland Centre since the different habitats were created from 1995 onwards.

In 1996 there were just four adult frogs recorded, but by 2000 this number had risen to 268.

Over the same period smooth newt numbers increased from 21 to 131 and common toads are now breeding whereas before only non-breeding adults were recorded.