Butterflywatch: mixed blessings of a long winter

Interrupted hibernation can play havoc with the caterpillar population with the consequences seen in butterfly numbers later in the year

A long, hard winter is no bad thing for butterflies. Researchers are discovering that milder winters wreak more havoc, disrupting the hibernation of many of our 59 native species, most of which endure the coldest months as caterpillars.

So this late spring may be a blessing in disguise, although erratic pulses of cold weather could spell disaster for some species. This March, I've only seen two small tortoiseshells - an unprecedentedly meagre return.