Falco virgatus Temm., Pl. Col., i, pl. 109 (1822 ex Reinw. MS.).
The typical form diners from that found in India in being slightly smaller. Kirke-Swann separates Accipiter affinis as a full species on the grounds that A. virgatus has three bars on the tail whilst A. affinis has four. As a matter of fact A. v. besra seems always to have four, though Swann admits this to be merely a race of the Javan virgatus.
Key to Subspecies.
A.Smaller, wing, 182 to 189 mm.; above paler in both sexes at all stages………..A. v. besra, p. 159.
B.Larger, wing, 197 to 210 mm.; above darker……………..A. v. affinis, p. 161.