Diving birds copy their neighbors when fishing

European Shag. Photo by Mark Caunt/Shutterstock

Diving seabirds watch each other to decide when to dive for fish, new research shows. Scientists studied European Shags, cousins of North America’s cormorants, and found they were twice as likely to dive after seeing a fellow bird go underwater.

The study is the first to investigate why large groups (known as “rafts”) of shags dive together at sea. University of Exeter scientists filmed the birds off the Isles of Scilly to examine their behavior.

“Our results suggest these birds aren’t just reacting to underwater cues when deciding where and when to dive,” says Julian Evans, who led the study as part of his PhD at the University of Exeter. “They respond to social cues by watching their fellow birds and copying their behaviour.

Subscribe now and save on BirdWatching magazine!

“They’re essentially using other flock members as sources of information, helping them choose the best place to find fish.”

This behaviour might bring various benefits, and more research is needed to fully understand it. “Watching other birds could help shags save energy by reducing the need for uninformed sample dives,” Evans says.

“Diving in the same area as another bird might also be beneficial because the prey might be disorganized, pushed into certain areas or fatigued by previous divers.”

Evans said it was important to understand the behaviour of European Shags because they — like most seabird species — are under “great pressure” due to declining fish stocks, climate change, and habitat loss.

Thanks to the University of Exeter for providing this news.

Read our newsletter!

Sign up for our free e-newsletter to receive news, photos of birds, attracting and ID tips, and more delivered to your inbox.

Sign Up for Free