The largest of the four ponds at Lightwood reservoir has consistently held the highest numbers of spawning frogs and toads in the last few springs. Yet once the tadpoles are metamorphosed, they are obliged to leave the water or drown, and their exodus is thus as urgent as it is challenging.
Last week I estimated that the whole migration involved tens of thousands. There were particular bottlenecks where dozens of them were gathered briefly in confusion. Everywhere along the path encircling the pond – and even in any grass patch that I bothered to scrutinise – were amphibians measuring about 1cm each.
