'Frightening' Decline Of Small Tortoiseshell Butterfly

One of Britain's best-loved butterflies has suffered a "quite frightening" decline in numbers this summer.

The numbers of the small tortoiseshell - one of Britain's most recognisable and widespread - has fallen sharply.

It is partly down to the cool spring and slow start to the summer, which disrupted the butterfly's attempts to breed and feed.

Sightings of the butterfly are down across the UK, and now gardeners are being asked to take part in a nationwide garden butterfly survey to build a countrywide picture of what is happening.

Conservationists said the number of the butterflies has plummeted by 73% since the 1970s.

Numbers had bounced back in recent years, but this summer has been a major setback.

Dr Zoe Randle, surveys officer for Butterfly Conservation, told Sky News: "The decline in our common widespread species are really quite frightening and we need to take action."

The group's head of recording, Richard Fox, said that while weather conditions are partly to blame, there may be other factors involved.

He said: "We don't understand what is causing the drastic long-term decline of this familiar and much-loved butterfly.

"Theories involve climate change, pollution and parasitic flies that kill the butterfly's caterpillars, but we need more information."

Other factors include the urbanisation of gardens - with paved and decked areas becoming more common.

Gardeners are being encouraged to plant butterfly and pollinator-friendly plants and help record the butterflies they see.