Species Spotlight: Merlin

Scientific Name:Falco columbarius

Size & Appearance:   Males are smaller than the females.  Males: overall length is 9 - 11 inches, with a wingspan of 21 - 23 inches; female: overall length is 11 - 12 inches, wingspan of 24 - 27 inches.  There are three subspecies, all with slightly different coloration, with the darker ones being found in more humid environments and the lighter ones in more arid climates.  Coloration is different between the sexes too.  The Boreal, or eastern subspecies, seems to be the one that occasionally strays into West Virginia and is the one discussed in this article.  Males have a dark blue-grey back with a dark tail that has alternating 2 to 3 slate blue-black bands visible from the top, the bottom of the tail is black with 3- 4 white bands when the tail is fanned out.  Chest is off-white with thin brown vertical streaks, eyebrow crest is light colored, vertical stripe below eye is less noticeable and thin. Females and juveniles are similarly patterned to the male, but have dark brown backs and tail, the tail has dark brown and tawny brown stripes instead of the male’s blue-grey and black ones.  

Range: Three of the Merlin’s nine subspecies occur in the US & Canada. The “Boreal” or columbarius breeds in northern Canadian boreal forests from Newfoundland to Alaska and winters in the Carribean and Central America;  the “Richardson’s” or richardsonii breeds and resides in prairies of south-central Canada and the upper Midwest of the United States with some moving south to New Mexico;  and the “Black” or suckleyi, is a resident in upper Pacific Coast forests from British Colombia to Alaska, occasionally straying to New Mexico in winter.

Food Preferences: Mostly songbirds and other small birds, will also supplement with mice.

Hunting Technique: Low, fast horizontal chasing flight.  Most often seen chasing prey or  perching watching for prey in their vicinity.  The majority of their hunting takes place at dusk and dawn, making this bird’s habits fall into the “crepuscular” category.

Breeding & Habitat: Bbreeds in open habitats, nests primarily in open woodland or grassy lightly wooded area, once in a while in cities.  Raises one brood per year, and are monogamous.  

Nesting & Eggs:  The nest is often the abandoned nest of crows, hawks or magpies, once in a while freshened up with feathers and twigs.  May also use a tree cavity, cliff or even a scrape on the ground in treeless country.  On average, 4- 5 white eggs are laid, some have reddish-brown markings, and are incubated mostly by the female, with some help from the male, who does all the hunting.  The chicks hatch out at 28-32 days, immobile, downy, & eyes closed.  They are fed by both parents until they fledge at 30 - 35 days old.  Yearlings, especially males, may return to the nesting area and help in territory defense.

NOTES: Outside of breeding season, these birds are usually solitary, found perching on any good vantage point such as a tower, utility line, tree branch, etc. watching for prey.  If conifer trees are available, merlins will shelter in them for the night or to avoid predators. Usually silent, they will vocalize to defend the nest area or when harassing larger raptors and birds.  Low altitude migration flight (right at tree top level, sometimes through the trees) can lead to lower individual counts during migration observations. They rarely soar on thermals. Frequently seen on migration during morning and late afternoon, some seasoned watchers call 4 pm during Fall migrations “merlin time”.