Effects of predator characteristics on hunting success on flocks of birds

Starlings (Sturnus vulgaris) can gather in enormous flocks composed of up to millions of birds. Avian predators such as the peregrine falcon (Falco peregrinus) are known to attack these flocks, employing a variety of hunting strategies. Because empirical data are difficult to gather on flocks of starlings and their interactions with falcons, models are used to gain further insight into the underlying mechanics. StarDisplay is a 3D model that uses a simplified version of fixed wing aerodynamics to simulate the flying and flocking behaviour of birds. In this bachelor project, StarDisplay was used to investigate several hunting strategies with different avian predator characteristics to determine what their effect is on predation in terms of success and efficiency per attack against both flocks of avian prey and solitary prey. Success was measured by recording how close the predator approached its prey during an attack, and efficiency was measured by the predator’s path length during the attack. Within the setting and limitations of the model, increasing the predator’s speed was shown to have a mostly detrimental effect on the success rate of attacks. Increasing the predator’s maximum roll rate did improve the predator’s performance against prey in many cases. The most successful hunting strategy was the repeated attacks sequence, in which the predator makes multiple attacks in rapid succession. However, this particular strategy was rather intensive in terms of energy expenditure. The posterior attack, in which the predator sneaks up behind a flock and makes a gradual approach to its target, was shown to provide a good trade-off between success rate and efficiency.