A crescendo of calls from hundreds of noisy jackdaws can often be heard right before they take to the sky all at once, right around sunrise on cold winter mornings.
Now, scientists who studied their daily activities in detail say these small black crows rely on “democratic” decision-making to coordinate their actions for the collective good.
The findings were published Monday in Current Biology.
“By establishing consensus to leave the roost early and in large flocks, birds may reduce predation risk, facilitate access to useful foraging information” and increase access to mates, wrote the authors.
Jackdaws — which may get their name from their brief “Jack”-like squawk — are found across Europe, North Africa and Asia, and form large groups known as “clatterings.”
Prior research on consensus decision-making in animals had focused on small groups or members of a family.
Jackdaw roosts were interesting for size as well as diversity, comprising individuals of different ages, sexes, family groups and colonies spread across treetops.
It’s likely individuals would have varying preferences about when to take off. But sticking together offers advantages, such as lowered risk of being hunted by birds of prey or small mammals.