Jackdaws, First Non-primates to Use Eyes To Communicate: Study [VIDEO]
Most species use either body language or vocalization to communicate. But for the Jackdaws, it's all in the eyes.
Humans using eyes to communicate has been well researched. But not much is known on how birds communicate with other members of the same species. In a new finding, researchers at the University of Cambridge and University of Exeter have discovered that jackdaws communicate through their eyes.
This is the only study that observed such a feature in a non-primate.
The study reveals that jackdaws, found mostly in Europe, North Africa and Western Asia, use their bright white eyes to keep off enemy Jackdaws and protect their nest boxes that are usually made in natural cavities of trees.
"Jackdaw eyes are very unusual. Unlike their close relatives, the rooks and crows - which have very dark eyes - jackdaw eyes are almost white and their striking pale irises are very conspicuous against their dark feathers," Gabrielle Davidson of the University of Cambridge, study lead said in a news statement.
Jackdaws (Corvus monedula) belong to the corvid family that includes birds like jays, crows and raven. They are known for their distinctive pale grey irises. They dwell in flocks and forage in open fields. They feed on tiny invertebrates and also practice active food sharing. These passerines (perching birds) are highly sociable as well.
Most of the birds in the avian world have either black or brown eyes, but nearly 10 percent of the perching birds have colored irises. Noticing the difference in the color of irises, researchers in the current study wanted to identify whether jackdaws use their bright eyes to communicate or send warning signals.
The scientists placed one of four different pictures in 100 jackdaw nest boxes on the outskirts of Cambridge. The pictures chosen were- black (control), a pair of jackdaw eyes, a pair of the jackdaw eyes in a jackdaw's face or a jackdaw's face with a pair of black rook eyes.
They then filmed the birdhouses to observe how each picture affected behavior of the bird. After analyzing 40 videos, it was seen that the birds avoided those nest boxes that had a picture of a jackdaw with bright eyes. Also the birds spent less time near those nest boxes.
The author continues to explain that the pale eyes of the jackdaw also enhance their ability to protect their nest and chicks from enemies.
The finding was documented in the journal Biology Letters.