The Merlin (falco columbarius) is a small falcon, 10-13 inches, formerly called Pigeon Hawk. It hunts with a lightening burst of speed, as it chases flocks of small birds.
Migrant Merlins arrive here in September, and spring migrants depart by May. There are two identifiable races, or subspecies, of Merlins in the Pacific NW. The "Black Merlin" (f.c. suckleyi) is very dark on the underparts and is most abundant along the coast. The normally-colored blue-gray nominate form (f.c. columbarius) is found more often inland. [Peterson's Western Field Guide places the wrong subspecies labels on his illustrations.]
Merlins eat small birds they catch by flying low over the ground and snatching surprised birds as they burst into flight. Alternatively, they may perch high in a dead snag and may make short hunting flights at tree-top level. One favorite bird in the NW is Pine Siskins (winter visitor at KOP). When the siskin population erupts, from time to time, we see many more Merlins. Merlins may take prey as large, or larger, than themselves. These could include teal, quail, and pigeons. Of course, as most raptors, squirrels, mice, snakes, grasshoppers, and other small animals are included in their diet.
The voice, rarely heard away from the nesting area, is a shrill cry: "ki-ki-ki-ki-kee."
Male Merlins are blue-gray above, white below with streaked breasts. The tail is barred. Females and immatures are brownish above, but otherwise similar. The coastal form is especially dark and heavily streaked. Merlins lack the heavy mustache mark present in many other falcons.
Several other hawks and falcons may be mistaken for Merlins. These include Peregrine Falcon, American Kestrel, and even Sharp-shinned and Cooper's Hawk.
Merlins, as falcons, have sharply pointed wings, unlike the broad rounded wings of Cooper's and Sharp-shinned Hawks.
American Kestrels have a rusty back and tail. They also have a bold whisker mark, and a second mark down from they ear. Merlins are more uniform in coloration - either dark blue-gray or dark brown. They are much more heavily streaked on the underparts. Merlins have only a faint whisker mark. Merlins do not hover as kestrels.
It's always difficult deciding on the size of a lone bird flying in the sky. Thus, Merlins may easily be confused with the larger Peregrine Falcon. Peregrines also have races which mimic the coloration of Merlins - especially the dark coastal races. Peregrines show a strong solid helmet which comes down to form a pointed cheek patch. Merlins have 3 or 4 wide dark bands across the tail. Peregrine Falcons have more and thinner barring, making the tail less conspicuously banded. (text by by G. Gillson)