Quite a small chunky falcon, the Merlin always flies low to the ground, chasing its prey. It has a relatively long, square cut tail and rather broader based pointed wings, shorter than those of other falcons. It has a rapid wing beat with occasional glides, with the wings held close to the body. Its small size enables it to hover and hang in the breeze whilst it searches for food.

The male Merlin has a blue grey back, ranging from almost black to silver grey. Its underparts are buff to orange tinted and streaked with black to redish brown dashes. Its tail feathers are predominantly grey with black banding.

The female Merlins have a mud brown coloured back, with a cream coloured chest and breast with streaks. Its tail feathers differ to that of the male in that they are brown with cream coloured bands

They rely on speed and agility to hunt their prey, they hunt by flying fast and low, often no more than 1 metre above the ground, using trees and large shrubs as cover. They actually catch their prey in the air and can often be spotted tail chasing the startled bird.