Breeding birds: 900-1,500 pairs
Family: Falcons And Caracaras
Adult male merlins have blue-grey upperparts, and dark grey tails with a black terminal bar. On the underparts, the breast, belly, and undertail are pale buff to rust with white streaks. They have dark flight feathers on the upper wings and barred dark grey and white underwings.
On the head, the crown is blue-grey with a white stripe above the eye. The cheeks and nape are pale buff, and the chin and throat are white. The hooked bill is grey with a yellow cere, the eyes are dark brown with a thin yellow eye-ring, and the legs and feet are yellow.
Female merlins are larger than the males. The upperparts are browner with a grey lower back, rump, and upper tail. The upper wings are more spotted than the males and the head is brown rather than grey.
Juvenile merlins look similar to adult females but have darker brown upper parts, grey-brown eyes, and greenish legs and feet.
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Merlins breed between May and June. They are solitary nesters and typically monogamous and produce one brood per season. If clutches are lost, they will often lay a replacement. Usually, merlins nest in trees in the old stick nests of corvid, but will also use cavities in trees, and cliff ledges.
However, in the UK most merlins nest on the ground, which is unique to the UK population, although since the 1970s they have started to nest in conifer trees. The female builds the nest which is a shallow scrape in the ground lined with twigs, heather, and other plant matter.
Merlins lay 3-6 white or pale buff eggs marked with reddish-brown spots which are incubated for 28-32 days mainly by the female. She also defends the nest, while the male brings her food. Chicks are covered in brown and white down and are fed by both parents. They fledge at 28-32 days but if hatched on the ground will leave the nest earlier at about 18-20 days and hide in nearby undergrowth away from predators.
At this stage they can catch insects but rely on their parents for food for another 5 weeks. Female merlins reach sexual maturity at a year, and males at 2 years.
Merlins are predators of birds including sparrows, thrushes, warblers and small to medium-sized songbirds. They will also eat small mammals such as bats, squirrels, mice and voles as well as reptiles and amphibians.
Merlins can be seen in the UK all year round. In breeding season they can be found in the uplands of Scotland, Wales, and northern England on moorland but also in conifer plantations. In winter they are joined by birds from Northern Europe and move to lowland areas as far as south-west England. Look out for them in reedbeds, boggy areas, salt marshes, farmland, and heathland.
In North America merlins used to be known as ‘pigeon hawks’, not because they prey on pigeons, but because in flight they look somewhat pigeon-like. Their species name, columbarius, is also a reference to pigeons.
