Solved, the riddle of starlings’ aerial ballet
THERE are few more mesmerising sights than thousands of starlings performing an acrobatic display in the evening sky.
But it is also one of the world’s most mysterious natural wonders. Called ‘murmuration’, the reason for the birds’ behaviour has always baffled experts.
Some have suggested it may be a way to stay warm on cold winter nights, while others believe it is how starlings socialise or exchange information.
But now scientists believe they may have finally solved the puzzle. A study has found that the phenomenon actually seems to be a form of self-defence to deter birds of prey.
Professor Anne Goodenough, an applied ecologist at the University of Gloucestershire who led the research, said: ‘It appears murmuration has become the norm – a general way for the starlings to
stay safe from predators.’ However, only certain types of predators seemed to trigger this shift in behaviour, with birds which hunt on the wing, such as sparrowhawks and peregrine falcons, sparking the biggest response, compared with larger hunters like buzzards. The research, which is published in the
journal Public Library of Science One, also found that predators seem to influence how a murmuration will end.
When birds of prey were present around a flock, the starlings tended to land all at once in a dramatic downwards movement, rather than slowly drift away.
On average, the murmurations lasted 26 minutes but some would twist and turn through the sky for up to 50 minutes, with up to 750,000 birds in a single mass.
The study was based on over 3,000 sightings over two years. Most were in the UK, but it also included some from as far away as Australia, Canada, the US and Jordan.
Starlings typically form murmurs during the autumn and winter months. But numbers have plummeted in recent decades, with populations in the UK falling by up to 80 per cent since the 1960s.
Scientists hope that understanding murmuration may help to prevent numbers falling further.