- Length: Male 9-11”, Female 11-12”
- Wingspan: Male 21-23”, Female 24-27”
- Weight: Male 150-210g., Female 189-255g.
Slightly larger and denser than the kestrel, the Taiga Merlin is a small, but powerfully built bird with the typical falcon shape. The head is large in relationship to the body, with large, dark eyes, and a small, hooked beak. The wings are long and pointed, and on perched birds, do not reach the tail tip. The cere, eye ring, and legs are yellow. The adult male is slate blue above, with a buffy eye line and cheek patch, and a faint mustachial mark. The whitish underparts have reddish to dark brown streaking. The tail is dark gray with three thin, bluish bands, and a wide white terminal band. The head of the adult female is similar to that of the adult male, but the upperparts are brownish, sometimes with a grayish cast, and the upper tail coverts have a definite grayish appearance. The brownish tail has three to four buffy bands, and a wide white terminal band. The creamy underparts are heavily streaked with dark brown. The immature Merlin is similar to the adult female, but lacks the grayish cast on the back and upper tail coverts.