Mostly, we used the term flock to describe a group of birds. But, especially when the flock consists of birds from the Order Galliformes, we talk about a covey. So we have coveys of francolins, partridges, spurfowl, guineafowl, quail and peafowl. A covey can be a group of birds on the ground, or in flight.
At a push, we can also describe a group of ducks, sandgrouse, bustards or korhaans as a covey.
The main purpose of a bird being part of a covey is that in decreases the risk of predation and increases foraging efficiency. The risk of predation is reduced because there are more pairs of eyes watching for danger; foraging efficiency is increased because each individual bird needs to spend less time being vigilant.
