Small birds make up the biggest part of the Merlin’s diet, with a variety of bird species targeted depending on regional availability (4) (8). Species including sandpipers and blackbirds are frequently taken, while in Britain, the meadow pipit (Anthus pratensis) forms the majority of the birds’s diet. During the breeding season in Shetland, the merlin is also particularly known to prey upon the northern wheatear (Oenanthe oenanthe) and skylark (Alauda arvensis) (11).
The birds often catches pigeons in urban areas, and in Canada it feeds mainly on house sparrows (Passer domesticus) (8). Dragonflies are also captured, and the merlin feeds on these during flight (4). In Alaska, it has been known to scavenge food, such as road-killed snowshoe hares (Lepus americanus) (12).
In Europe and Canada, the merlin prefers nesting in abandoned corvid nests (8) (13) (14), but if these are unavailable it may nest on cliff ledges or even on the ground (14). A clutch of 4 to 5 eggs is normally laid during May, and incubation lasts for 30 days (2) (14). The female performs the majority of the incubation, only briefly leaving the nest to feed (8) (14).
Like many other raptors, the male birds invests more energy in the offspring than the female (8). The nestling period lasts from 28 to 31 days (2), and during this stage, most of the nestling’s food is provided by the male (8) (14). After fledging, merlin chicks remain dependent on the adults for a few more weeks (14). The high energy cost of reproduction for male merlin’s is thought to explain why the male breeds from two years of age, whereas the female breeds from one year of age (8).