Using detailed computer simulations, Oxford University research has revealed why falcons dive at their prey using the same steering laws as man-made missiles.
Published today in PLOS Computational Biology, researchers from Oxford’s Department of Zoology use computer simulations of peregrine falcon attacks to show that the extreme speeds reached during dives from high altitudes enhance the raptors’ ability to execute manoeuvres needed to successfully attack agile prey that would otherwise escape.
Professor Graham Taylor and PhD student Robin Mills, alongside colleagues from the University of Groningen, built a physics-based computer simulation of bird flight that pits falcons against prey. The team had previously shown that falcons attack their prey using the same steering rules as man-made missiles.
The simulation incorporated the aerodynamics of bird flight, how birds flap and tuck their wings, how falcons perceive their prey and react to it with delay and how falcons target their prey like a missile. It showed that high-speed dives enable peregrines to manoeuvre faster, producing much higher aerodynamic forces, thereby maximising their chance of seizing agile prey.
In addition the simulation showed that high-speed dives require very precisely tuned steering for a falcon to attack successfully, revealing that the stoop is a highly specialist hunting technique. The research team found that optimal tuning of the mathematical laws that control steering in the simulation corresponded closely to measurements of steering for real falcons.
The team is now extending its simulation to explore other unique and specialised attack strategies as well as escape tactics employed by different raptor species.
‘Ultimately,’ says Mills, ‘we aim to understand the arms race between aerial predators and their prey that has led raptors to become some of the fastest and most agile animals on Earth.’
The image is a snapshot of the simulation in action. A stooping peregrine falcon (blue trajectory) is about to intercept a common starling (green trajectory) that manoeuvres erratically to evade them.