To catch that starling traveling in a straight path, the peregrine only needs to stoop at around 90 mph (~150 km/h). However, this advantage begins to disappear as the peregrine increases its speed by stooping.
Indeed, a starling can always escape a peregrine flying at the same speed. It turns out that starlings are quite good at outmaneuvering peregrine falcons if the peregrines are flying relatively slowly. Researchers at the University of Groningen in the Netherlands and at Oxford University used 3D computer simulations to analyze the hunting behaviors of peregrine falcons and the evasive maneuvers of starlings.
