Copyright Chris Gomersall, RSPBHabitat & Behaviour:

Our smallest bird of prey, a male Merlin is no bigger than a Mistle Thrush. They are extremely fast and agile and hunt small birds such as Meadow Pipits over moorland and rough grassland.

Identification & Voice:

These small falcons are an attractive blue grey above with a rusty toned breast and belly.  They have short, broad-based, pointed wings and a shorter tail than a kestrel. Females are larger than the males and browner in colour.  Merlins can be very hard to observe due to their small size and low, dashing flight, with the best indication that they are about is their high pitched call. Merlins sometimes adopt a disguise whilst hunting by imitating the undulating flight of a thrush to avoid detection as a bird of prey.   They are usually silent, but near a nest a shrill ' kek-kek-kek-kek' may be heard when the bird is chasing off intruders.

RSPB video footage of a Merlin:

Listen to the Merlin: