|The Merlin is, in my opinion, among the most accomplished flying machines to have evolved in the avian kingdom. Smallest of the falcons most often used in the sport of falconry, the males are about the size of American Kestrels. What the merlin lacks in size it certainly makes up for in spirit. Ounce for ounce and inch for inch, it is the speediest, most maneuverable and the most dashing bird I have ever encountered. The females are somewhat larger. The species is rather circumpolar in breeding distribution, like the Gyrfalcon, but is highly migratory. For most of the year, it preys upon smaller birds. Three distinct races are generally recognized, ranging in color from very light to very dark.
All falcons are birds of the open country, and the Merlin is no exception, even though its primary breeding range in North America is within the boreal forest north to the tree line, occurring in Ohio as spring and fall migrants. They do not hunt in the forest itself, but around the edges and openings, and especially over and around the shorelines of the many lakes that abound there.
Merlins most often nest in trees throughout most of their range, and, like all falcons, do not build a nest of their own. Previous years' nests of magpies, ravens and other species are utilized. At northern range limits, nesting is accomplished right on the ground. The usual clutch of five eggs hatch some four weeks later and the young are ready to fly at four to five weeks.
Adult male Merlins acquire their beautiful blue-gray dorsal plumage, which is most striking among the lighter subspecies, during their second year. Females remain brown and look virtually identical to the young of the year. Several thin, whitish bars across the tail (in all plumages), which are most apparent from underneath, are good field marks.
Even though Merlins feed upon small birds throughout most of the year, during fall migration they pursue large dragonflies with great zest, capturing and devouring them on the wing in a couple of gulps. Such flights are not especially exciting to watch, but, when the Merlin is in pursuit of a small bird, it so outclasses its intended victim as to leave the observer feeling sorry for it.
Sometimes Merlins merely play with other birds, especially swallows, making a game of it, as if to show off their superior abilities. I saw my first one in Winton Woods near Cincinnati, Ohio in April 1, 1953 while on Ranger patrol. That falcon appeared to be after a tree swallow, until further observation revealed that the two were merely engaged in a playful game of tag. Swallows, of course, are no mean fliers themselves; the aerobatics performed by these two left me breathless. I have since, watched them playing with Tree Swallows on several occasions. They would take turns stooping at each other, describing giant Vs of a hundred feet or more, Merlin chasing Swallow for a few passes, then Swallow chasing Merlin, as if the rules of the game had already been set. They would suddenly switch roles; it seemed unnatural to see a swallow chase a merlin. A potentially dangerous game too, I thought, because the lesser bird might not know just when the falcon might decide to quit playing!
The American Merlin, known until recently as the pigeon hawk, is a close relative of the European form. It was a popular bird of the nobility when the sport of falconry reached its peak in medieval times. Being a true falcon, the merlin enjoyed the same noble status as the Peregrine and Gyrfalcon. In medieval Europe, the Merlin was the ladie's bird, so long as she happened to be a queen or princess. Its docile and unsuspicious nature allows for easy training. But it is also easily lost because of its strong inclination to carry its quarry over the hill and out of sight after the catch.
Length 10-13 inches