Eavesdropping Helps Birds Survive

Your mother might have scolded you for eavesdropping and told you that it was rude, but for the scimitarbill, an African bird with a strongly curved beak that forages alone, it is the key to its survival. According to a recent study in the British Ecological Society’s Functional Ecology Journal, the lone scimitarbill eavesdrops on gregarious white and brown pied-babblers in the area to warn approaching predators.

“Eavesdropping is a much more efficient way of gaining important information than relying on your own senses the whole time,” explained lead author of the study, Dr. Amanda Ridley to PhysOrg.

Researchers from the University of Western Australia conducted the study in South Africa’s Kuruman River Reserve, a semi-arid dune country study site. They focused on 18 groups of pied babblers and more than 25 scimitarbill breeding pairs. 

Unlike the scimitarbill, pied babblers are very social, and have developed an effective warning system to alert them, and their flock-mates, of danger. One member, the sentinel, will perch above the rest of the group and keep an eye out while the rest will forage for food. If a predator approaches, the sentinel will sound the alarm. The alarm, unbeknownst to the pied-babbler, will also alert the scimitarbill nearby.

According to Ridley, scimitarbills have undergone significant behavioral changes in the presences of pied babblers in their habitat.

“They reduced their vigilance rate by over 60 percent,” Ridley said to Science Network, “Individuals were even able to expand their foraging niche, venturing out to forage in the open, something a solitary individual would not do because they are too exposed to predators.”

So for loner birds like the scimitarbill, eavesdropping on their noisy neighbors seems to test mom's advice.