‘Vital for looking after the soil’: fears as UK earthworm population declines

Keystone species has potentially enormous effects on above-ground wildlife and ecosystem functioning

• Invertebrate of the year 2024: all hail Earth's spineless heroes
• Nominate your UK invertebrate species of the year

In 2019, 15,000 children from primary schools across the UK went out to their local playing field. Instead of kicking a ball around, they dug up worms, looked out for birds, and counted them both.

The kids were just so enthusiastic about it. It was incredible," said Blaise Martay, lead researcher from the British Trust for Ornithology (BTO). Martay had worried about the data quality - she thought children's counting might vary with their enthusiasm. But the results showed exactly what we'd expect", she said: that more worms meant a greater number of blackbirds, robins and thrushes, the birds that rely on earthworms as a vital part of their diets. The data was consistent across school groups.

Welcome to the Guardian's UK invertebrate of the year competition. Every day between 2 April and 12 April we'll be profiling one of the incredible invertebrates that live in and around the UK. Let us know which invertebrates you think we should be including here. And at midnight on Friday 12 April, voting will open to decide which is our favourite invertebrate - for now - with the winner to be announced on Monday 15 April.

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