Workers in Lozère are building nesting boxes for great tits to encourage them to nest and target the caterpillar, which can ravage pine trees.
The caterpillars, known for moving in long nose-to-tail lines, are covered in irritating hairs that cause severe rashes.
These hairs stop most birds attacking but the great tit, cuckoo and hoopoe are natural predators, along with solitary wasps and bats.
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