Why months matter

Though largely disliked by the general public, moths provide valuable ecological services – which makes the sharp decline in their British numbers all the move worrying

- James Lowen

In his book The Moth Snowstorm, journalist Michael McCarthy recalls childhood nights when the airspace above British roads was so congested with flying moths that drivers had to stop regularly to clear windscreens of their splattered forms.

Now but a distant memory, insect blizzards were already petering out when the Rothamsted Insect Survey began recording moths nationwide in the 1960s. In March, that initiative – complemented by tens of millions of observations gathered by thousands of citizen scientists through the National Moth Recording Scheme – generated several stark revelations: that Britain has one-third fewer larger moths today than five decades ago; that four times more species are declining than are increasing; and that nearly one in five British moths is in real or potential risk of national extinction.

The worrisome findings were announced by wildlife charity Butterfly Conservation, Rothamsted Research and the UK Centre for Ecology and Hydrology. Updating assessments from 2006 and 2013, The State of Britain’s Larger Moths 2021 report strengthens growing evidence that insects are vanishing across swathes of the world. “Though no bolt from the blue – we’ve been raising the alarm about moth declines since the early 2000s – this decline is very worrying,” says lead author Richard Fox.