When birds flock together they are either going to roost, going to feed or avoiding predators. In fact just being in a flock confers some protection from predators. Lots of eyes and ears help to detect approaching danger that a single bird might miss and a quick alarm call will put up the whole flock and might deny a predator its meal. Once in the air, a big wheeling flock of birds can confuse a flying predator and it will not be able to single out a likely target.
A few weeks ago this principle was demonstrated over Rossie Spit where, at high tide, a large number of different waders were waiting for the receding tide to reveal their feeding grounds. The sight of all this potential food was too much for a passing Peregrine falcon who decided to try his luck for a quick "take away". He flew over the massed birds several times without managing to scare any into the air so resorted to a quick fake attack at high speed at a very steep angle. This tactic produced the desired result and birds exploded off the ground in all directions.
Several hundred Knot ( a small grey wader) took off in a closely packed flock and demonstrated their aerial ability by swerving about en masse with the Peregrine in close pursuit. After several circuits over the sailing club house, one Knot swerved left as the rest swerved right. The Peregrine was after the loner immediately. Separated from the flock, this bird was the sole focus of the speeding raptor and the Peregrine closed in quickly and stretched out its talons to grab its small grey prey. Swooping up in triumph - its claws clutched only fresh air! The Knot had, in desperation, crashed into the water at the very moment its attacker struck.
The dismayed Peregrine cruised off to the north and out of sight. The waders - Oystercatchers, Curlew, Dunlin, Godwits and Redshank - slowly settled back down onto Rossie Spit and, after some shuffling about to get the best place to stand, tucked heads under wings and snoozed once more.
Ten minutes later, like a laser guided missile, the Peregrine shot back into the roosting waders for another try! Amid a riot of alarms calls birds bounced skywards once again and the chase was on, but again no luck for the hungry falcon.
So, both times, being in a flock gave the birds that vital few seconds warning and time to form a flock and fly to safety. However, once isolated, a bird can still escape, like our Knot, but its chances of survival a very much lower.
The thrill of watching birds is not just witnessing these high speed chases, but seeing how birds of different species cope with their environment and its dangers. Even in your own garden these dramas are acted out each day by the Robins, Blackbirds and finches as they search for food. Keep your eyes open!