With distant, often brief views, the ‘jizz’ of birds of prey is an important consideration in ID. And a key part of this is flight style. A smallish raptor hovering by a motorway will probably be a Kestrel, a much larger one a Buzzard. Some birds of prey, notably harriers, have a slow, low hunting flight, often gliding with wings held in a shallow V. Buzzards also glide with their wings held in a shallow V, while Honey Buzzards very rarely will, preferring to keep the plane of their wings below the line of the body. Kites (as well as Honey Buzzards, which are closely related) use their long tails as a ‘rudder’, constantly twisting and adjusting. Sparrowhawks have distinctive direct flight consisting of rapid flaps interspersed with glides (a style which Peregrines may also use). Merlins are dashing, very agile speedy birds, and long-winged, swift-like Hobbies are able to turn on a sixpence and fly at incredible speeds. Ospreys can look like giant gulls!
From Top to bottom: Peregrine, Merlin, Red Kite, Marsh Harrier