In a development that will surprise no one who has ever been menaced by a spinning head with two large eyes, Cornish fishers have found that bird-shaped kites and a floating scarecrow can stop endangered seabirds from drowning in fishing nets.

Every year, an estimated 95,000 diving birds - including razorbills and guillemots - are accidentally caught in nets off European coasts. That's roughly the population of a small city, if that city were made entirely of confused seabirds.

But simple deterrents tested by Cornish fishers and devised by scientists and the RSPB have been shown to reduce the toll by about two-thirds. The scarecrow - or more properly a looming-eyes buoy (LEB) - has a spinning head with two large eyes that scare diving birds away from gillnets, walls of netting which hang vertically beneath the surface. The LEB was tested alongside a commercially available scarybird kite.

Ten Cornish fishers and Fishtek Marine, which created the LEB, fitted cameras to boats to monitor the effect of the devices on seabird behaviour. The results of the two-year trial, which was analysed by scientists from the University of Exeter and published in the journal Conservation Letters, showed that the chance of seabirds being caught in gillnets fell by 59% using LEBs and by 71% using kites.

The research revealed that in Cornwall most seabirds were caught in winter, which will help target the use of the devices by season - because apparently even seabirds have a busy season and a slow season.

Tom Horton, lead author of the University of Exeter research, said: “This study provides some of the strongest evidence to date that simple, practical deterrents can substantially reduce seabird bycatch in gillnet fisheries. By also identifying when and where bycatch risk is highest, we now have a clear opportunity to target mitigation measures where they can deliver the greatest conservation benefit for vulnerable seabird populations and encourage sustainable fishing practices.”

Yann Rouxel, bycatch programme manager at the RSPB, said: “After over a decade of research into gillnet bycatch and its solutions, it’s great to see this work moving towards real-world implementation. The performance of the LEB and kite, as evidenced in this study, is a major milestone in the effort to reduce seabird bycatch without impeding gillnet fishers while at sea.”

So there you have it: sometimes the answer to a complex conservation problem is just a floating scarecrow with googly eyes. Who knew?