American Kestrels are smaller, more slender, and paler than Merlins. They have a strong face pattern with two bold “mustache” stripes that Merlns lack. Kestrels are much less heavily marked below and are warmer reddish-brown on the back than Merlins. Larger species such as Prairie Falcons and Peregrine Falcons are less compact than Merlins, with longer wings and slower wingbeats. They tend to have less heavily streaked underparts than Merlins, and their tails are not as prominently banded. Prairie Falcons have distinct dark “armpit” patches underneath the wings. Peregrine Falcons usually show a much bolder black “mustache” stripe that contrasts with its white throat. Sharp-shinned Hawks have similar coloration to Merlins but very different shape. They are accipiters: they have short, rounded wings and very long tails. In flight Sharp-shinned Hawks usually glide after every few strokes; Merlins flap almost continuously.
There are three subspecies of Merlins in North America: dark-plumaged “black” Merlins of the Pacific Northwest, pale “prairie” Merlins of northern prairies and aspen parklands, and “boreal” or “taiga” Merlins of northern forests, which have intermediate plumage. Six more subspecies live in Eurasia.
Find This Bird
Merlins are widespread, particularly in migration and winter, but seeing them is unpredictable. They have two modes: scanning open areas patiently from a treetop, and cruising at top speed in pursuit of small birds. If a flock of foraging birds (particularly shorebirds) suddenly bursts into flight, a Merlin or other falcon may be the cause. Be ready to look quickly—Merlins cover a lot of ground and can be out of range in just a few seconds. Scanning treetops and low perches at forest edges, grasslands, or saltmarshes can also turn up a perched Merlin and the opportunity for a longer view. Merlins are also increasingly common around towns, where there is a steady supply of House Sparrows.