Big Butterfly Count: People asked to join in to help address extinction

People are being encouraged to count the number of butterflies they see over the next three weeks - as part of efforts to protect them from extinction.

Butterfly Conservation says two-fifths of British butterflies are under threat.

The charity encourages spending 15 minutes outside counting the number and type of butterflies and moths spotted.

Data collected will help assess the effect of climate change and pollution.

The annual Big Butterfly Count is backed by naturalist Sir David Attenborough - the charity's president - as well as actress Joanna Lumley and gardener Alan Titchmarsh.

The event will help scientists understand how environmental changes are affecting insects, and gather data from areas that would otherwise be unrecorded, experts said.

It is not just rare species that are at risk of extinction, but normal butterflies too - common species such as the small tortoiseshell have fallen by 79% since 1976.

Last year, people across the UK submitted 150,000 sets of results to the count, more than ever before, but it also saw the lowest average number of butterflies logged since the scheme began 13 years ago.

Those taking part included royalty - with Princess Charlotte photographed with a Red Admiral butterfly she found near her family's home in Norfolk.

Dr Zoe Randle, senior surveys officer at Butterfly Conservation, said: "Thanks to the wonderful British public, the Big Butterfly Count is the largest natural history citizen science project involving insects in the world and provides us with a valuable snapshot of what is happening for butterflies.

"It can act as an early-warning system, letting us know how various environmental changes are impacting insects, and allows us to gather vital data from places that would otherwise be totally unrecorded."

Ambassador Dr Amir Khan added: "Spending time in nature is hugely beneficial to our mental health and can help us feel happier and more energised.

"It is good for you as well as benefiting butterflies by helping Butterfly Conservation gather the important data they need to understand how to better protect these special insects. It is truly a win-win situation for all of us."

This year's count runs from 15 July 15 to 7 August - with a special website and app for people to send their findings.