Specieswatch: the bluffing peacock butterfly

Tis the season to be disturbing hibernating butterflies, and the naturalist Lucy Hodson recently posted a video of a memorable encounter with a peacock.

The butterfly was beneath a log and, its sleep interrupted, flashed its wings bearing vivid blue and maroon eyespots. Most strikingly, it also emitted a series of loud hisses that viewers judged like the rustling of petticoats or a whispered ‘pissaff’.

It may have been a fairy casting a spell but it was also a classic example of deimatic behaviour, a sudden bluff from a defenceless animal to momentarily unsettle a predator.

The peacock was also pictured upside down, which is exactly how most predators, from mice to birds, see it. From this angle, the blue eyespots on its hindwings combine with its beak-like abdomen to create a startling image of an owl’s face – from which a wood mouse would flee in terror.

Studies have found that a peacock’s hissing increases the likelihood of seeing off a mouse.

Enduring a British winter as an adult butterfly is a tough road that only five native species take (most hibernate as caterpillars). The wings that litter log-piles and sheds in spring are testimony to the peacocks whose smart defences aren’t quite bewitching enough.