On the last day of March, the sun makes a slow descent behind the dark hedgerow and April emerges under a blue sky. On the downs, ravens and buzzards are mobbed by nesting carrion crows. Chiffchaffs, finches and buntings are calling from the trees. Bumblebees work the willow catkins in the evening sun and appear to roost on the lichen-covered tree trunks. The first butterflies, brimstone, peacock and small tortoiseshell, are on the wing. The flowering blackthorn attracts large numbers of solitary mining bees that create small volcanoes of dug earth on the bare ground. Spring emerges in fits of southern warmth and starts of cold northerlies.