Study: Raucous Jackdaws Achieve a 'Consensus' Before Flight

On chilly, gloomy winter mornings in the United Kingdom, little black crows known as jackdaws can be heard crying loudly to one another from their winter resting sites before taking off simultaneously at dawn.

Researchers who have observed their everyday activities in unprecedented detail found evidence that these groups of hundreds of people rely on a "democratic" decision-making process to cooperate with each other and take to the air all at once.

Jackdaws on their noises

(Photo : YURI KADOBNOV/AFP via Getty Images)

According to Alex Thornton of the University of Exeter, big animal groupings, like humans, may employ decision-making procedures to overcome individual differences and establish a form of "democratic" agreement, as per ScienceDaily.

Previous research has looked into consensus decision-making in tiny animal groups or groupings made up of family members, he noted.

The sheer magnitude of the jackdaw roosts impressed them.

Their groupings are not only enormous, but they also contain members of all ages, sexes, family groups, and colonies distributed over the treetops.

It's unlikely that all of those diverse people would naturally desire to leave at the same time.

Nonetheless, banding together provides advantages, such as lowering the danger of predation and providing people with knowledge about where to locate food from their peers.

The researchers sought to learn how birds know when it's time to leave.

Thornton and colleagues, including first author Alex Dibnah, spent hours recording audio and video of six separate jackdaw roosts in Cornwall, U.K., to get a better look during the course of the winter.

The roosts ranged in size from 160 to over 1,500 people.

They measured the strength of the birds' sounds before and after they lifted off in flight.

To confirm cause and effect, the researchers played sounds of conspecifics calling to see whether they could encourage the birds to take flight earlier than they would have otherwise. And they discovered that they could.

By including cries in the mix, the birds flew an average of 6.5 minutes early.

The researchers wrote that jackdaws' cries appear to successfully convey their readiness to leave, providing huge groups with a method of establishing consensus to undertake coherent, collective exits from the roost.

According to their observations, a consensus is reached when the intensity of calls reaches a degree that prompts people to act.

The playback trials aid in establishing a causal relationship between calling intensity and takeoff.

Also Read: Smart Bird and Face ID: Jackdaws Can Recognize Faces

What makes them fascinating?

These little crows are very bright and gregarious, and they readily learn new tricks and talents both in the wild and in captivity, as per Discover wildlife.

A tame jackdaw was once trained by some Italian burglars to steal money from ATMs, although it's more typical to see them figuring out how to get into bird feeders.

Jackdaws nest in colonies and will use anything from a hole in a tree to a chimney.

Furthermore, jackdaw nests are typically built using sticks for the exterior part and lined with wool or hair. Tawny owl boxes can be used to attract jackdaws to nest in your yard.

Jackdaws create strong pair connections with their companions and are known for their commitment to their relationship.

Even after a few years of failed breeding, they remain together, maybe because they have put so much time and energy into attempting to raise young together.

It's fairly uncommon for certain birds to begin greying in old age, although it's typically not obvious since greying is caused by changes in feather structure (so light is reflected differently) rather than a lack of pigment as in people.

Since jackdaws have primarily black plumage, greying is more visible in them than in most other bird species.