Number of butterflies seen around Norfolk Broads drops

The Butterfly Conservation charity has declared a national "butterfly emergency" after the annual Big Butterfly Count recorded the lowest numbers ever.

The Broads Authority has echoed this by sharing that weekly counts at the How Hill and Wheatfen nature reserves in Norfolk have plummeted.

There are several possible explanations for the decline (Image: Broads Authority)

In July and August, when butterfly numbers peak, it is common for around 150 to be counted at How Hill - but in the summer of 2024, the most volunteers recorded was 46.

Experts believe the drop could be down to the wet winter, cold wet spring and early-summer weather which meant fewer caterpillars could survive in the Broads. 

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Climate change is also believed to be affecting the survival of milk parsley, which is a swallowtail butterfly's preferred food source and where it lays its larvae.

Corrective measures are being taken such as more butterfly-friendly habitats being created on land around the Broads.

An image of a swallowtail caterpillar (Image: @ollie_outdoors)

Wheatfen's warden, Will Fitch, said it could be dangerous if the numbers could not recover. 

"Numbers for all species are down compared to last year," he said.

"Although we will no doubt see all these species back on the wing next year, consecutive years of low numbers may lead to the eventual localised loss of certain species.” 

Broads Authority ecologist, Hannah Southon, added: “We are concerned by the reported decline in butterfly numbers and hope that conservation efforts with our partners will help them recover next year.

“While no one wants this year’s decline to indicate a long-term trend, it should raise alarm bells because swallowtails in particular are so sensitive to annual environmental changes and face multiple threats.”