Although not much larger than a Kestrel, they weigh about twice as much, looking somewhat like a pigeon in flight, hence the former name Pigeon Hawk.
Their presence is often noted by shorebirds, that scatter in alarm before I can see the speck on the horizon that comes in on a gentle glide at great speed to easily overtake any small bird that it desires.
Yet Louise Lawrence found that small birds nested with impunity close to the nest that she studied at Rutherglen, where Merlins hunted at a distance from their nest, not molesting their neighbours.
This is a stout pigeon-sized falcon with barred tail and streaked breast, lacking the contrasting face pattern of the Kestrel.
Adult males have blue backs where the females and young are brown.
The yellow cere is often quite conspicuous.
Dr J Murray Speirs