Why 15 minutes on a Cornish hedgerow matters this summer

Somewhere along the South West Coast Path, a speckled wood is doing laps of a sunlit gap in the hedge. It has no idea it is about to become a data point.

The Big Butterfly Count returns from 17 July to 9 August, and it asks very little of anyone taking part. Pick a spot. Watch for 15 minutes. Write down what you see.

A warning that cannot be ignored

Butterflies are beautiful, but they are also working parts of the ecosystem, and they are under threat. Numbers of butterflies and moths in the UK have decreased significantly since the 1970s. It is a warning that cannot be ignored.

That is the point of the count. It is a nationwide citizen science survey designed to take the pulse of nature, launched in 2010 and now the world’s biggest survey of butterflies.

How to take part

There is no specialist knowledge required and no equipment beyond your eyes.

Choose a place to spot butterflies and moths, ideally in bright weather. Watch for 15 minutes. Record which species you see and submit them through the Big Butterfly Count website or the free app, which is available for iOS and Android and lets you carry out and submit a count in one go while you are out walking.

If you are not confident telling one white butterfly from another, there is a downloadable butterfly ID chart to take with you. You can do as many counts as you like, in as many places as you like, and every submission feeds an interactive map showing how the data is being used.

The one to look for

The speckled wood is a good starting point. It has a habit of settling in dappled sunlight, which makes it easier to spot than most, and it turns up in the hedgerows along the South West Coast Path.

Fifteen minutes on a Cornish hedge is a low price for a national picture of how nature is doing.