Swarms of drones, David Hambling explains (in Swarm Troopers), might follow the model of pack-hunters like wolves:
Wolves are unusual among carnivores in that, in some areas, they prey largely on animals larger than themselves. Not only are moose and bison several times bigger than wolves, they are also faster. But a pack of wolves can bring down a large prey animal by working in a pack and using a set of heuristics — simple hunting tactics from a combination of instinct and experience.
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During the approach, each wolf moved towards the prey until it reached a certain distance; it then moved away from any other wolves that were the same distance. The net effect was that the wolf pack spread out and enveloped the prey. If the prey tries to circle around, the pack keeps homing on it, and in simulations the prey often ended up running towards one of the pursuers and was “ambushed” by it. Even though the prey may be faster than the wolves, it keeps turning to get away from the nearest wolf. This zig-zagging slows it down so that another member of the pack travelling in a straight line can catch it.
Harris hawks provide another model:
Harris hawks are medium-sized hawks native to the Americas, found from the southwestern US to Chile and Argentina, which use a variety of approaches to attack prey. They are among the few birds of prey that work cooperatively, often in family groups of four to six birds. The most common tactic is a simultaneous attack with multiple Harris hawks diving in from different directions; a rabbit or other prey may dodge the first hawk or two before getting picked up by the third or fourth.
When prey goes to ground, the hawks switch tactics. The birds perch around the cover where their target has hidden, surrounding the prey, and then take turns attempting to penetrate the cover. As soon as the prey is flushed out, the surrounding birds swoop in and take it.
Finally, Harris hawks also carry out “relay attacks” in which multiple birds swoop down one after the other, each chasing the prey for a short distance. As it escapes one hawk, the next one in the flock takes over. Researchers have recorded up to twenty swoops in one chase over half a mile before the exhausted prey was finally taken.