One morning, a buzzard was soaring above the field behind my house, about 70 metres away. The birds in the garden didn’t give a monkey’s about her. They were safely out of range, and probably too big or too mobile to present an easy meal. However, the local rooks took a different view.

Initially, a pair of rooks went up to try to fly off the predator with a series of close passes. But, the buzzard persisted. One rook went in to attack while the other returned to its roost, probably to guard their nest.

The buzzard, a predator, has binocular vision, with two eyes facing forward. This leaves her with a blind spot above and behind. The rook flew round and above her, into the blind spot, and dived in to land upon her back. This manoeuvre was repeated several times. But, the buzzard continued to circle. This is risky. There are no hospitals for buzzards or rooks. The risk of injury in such a confrontation is usually enough to persuade the predator to move on. This time, the buzzard remained.

The rook broke off the attack and flew away, straight towards the big trees near the church, about 450 metres away where most of the crow people hang out.

Within a minute, a patrol of five large crows had appeared and perched on the power lines beside my house. At the same time, a pair of crows came from the direction of the church and went up to start circling the buzzard and escort her away from the village. They did not need to attack her, their looming presence was enough deterrent.

I lost sight of them at about 900 metres range, well away from the village and presumably off the crows’ claimed territory.

I am not going to claim any highly organised air defence system for my local crows. But, I cannot help noticing that their strategy and tactics for dealing with an interloper appeared near perfect:

 A reconnaissance sortie is launched at first alarm and goes to assess the intruder and make attempts to remove it, possibly as part of the assessment.

Requesting backup, two larger interceptors are launched, and a support  flight is moved to a forward base where it can monitor proceedings.

The interceptors escort the intruder to the edge of territorial airspace, and everyone goes back to eating dead things.

It’s also worth noting that the rooks are not the same species as the larger crows. That means the rook was able to communicate the nature and location of the threat, and the crows responded, indicating that they understood and empathised that the threat, while not direct for them, was significant for the smaller rook.