Hawker hunters: Animal behaviour and missile design

Hawker hunted

Target acquired

Read my latest piece for The Economist and an exclusive from the University of Oxford in full below or by clicking here for the original.

FALCONRY is less fashionable now than it was in days of yore. But, over the past few years, sharp-eyed ramblers in south Wales may have witnessed an updated version of this ancient pastime.

Since 2012, in a project sponsored by the United States Air Force, Caroline Brighton and Graham Taylor of Oxford University have been flying peregrine falcons (see picture) and Harris’s hawks over the Black Mountains of Monmouthshire to study how these birds chase their prey. Ms Brighton hopes to gain a doctorate from the research. The USAF hopes the birds may be able to teach it a trick or two about intercepting targets, both in the air (the speciality of peregrines) and on the ground (the speciality of Harris’s hawks).

To carry out their research, Ms Brighton and Dr Taylor turned to the technology of wildlife documentaries. They attached miniature cameras and satellite trackers to harnesses worn by their birds. Then they put the birds through a series of tests. These included attacking a dead pheasant on the ground, chasing a dead chick that was dragged along the ground and through a series of tunnels by a winch and cable, and catching a dead chick dropped at altitude from a radio-controlled model aircraft. They fed the images they had recorded into a computer, which worked out the trajectory taken by the bird to intercept its prey.
Their first discovery was that, rather than hunting in the way previous research had suggested—namely, holding the prey at a constant angle while they moved in to intercept it—the birds followed a rule, known as proportional navigation, currently used by many missile-guidance systems. Unlike constant-angle tracking, this requires constant recalculation of speed and bearing, and is considered a hard trick.

What really intrigued the researchers’ air-force paymasters, though, was a peregrine’s responses if a live pheasant or duck turned up during a test. Then, the bird instantly lost interest in the lure and chased its new quarry using a tracking technique, dubbed optimal guidance, that is fitted only to the most advanced sorts of missiles. Optimal guidance employs optimal-control theory, a branch of maths also used in things like inventory control for manufacturing processes. That has led the air force’s experts to hope birds of prey may have other techniques to show off, perhaps including ones that human missile engineers have not yet thought of.

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