Systematics

Variation limited in widespread nominate A. f. flammeus . Other races differ from nominate in size, proportions, and plumage. Most are darker, especially with more limited pale markings dorsally and broader dark bands in remiges. Insular populations average smaller with relatively heavier bill and legs (Cramp 1985,). More migratory populations may have larger wing to tail ratio (Pyle 1997).

Ten subspecies recognized following Holt et al. (1999) and Dickinson (2003). Two occur in North America, one breeding and another only a visitor to s. Florida. Taxonomy and nomenclature in need of revision. May include more than one species as currently classified: for example, Antillean Short-eared Owl (domingensis along with portoricensis), Galapagos Short-eared Owl (galapagoensis) sometimes treated as specifically distinct (see Holt et al. 1999, Hoffman et al. 1999).

A. f. flammeus (Pontoppidan, 1763). Breeds across North America, Europe and n. Africa, and n. Asia. Compared to domingensis, wing longer (>300mm), tarsus shorter (<50mm), bill relatively smaller, upper back (between and anterior to scapulars) mostly tawny with dark brown central stripe, uppertail coverts tawny yellow, underparts less buffy (pale tawny to whitish) with streaking extending well down underparts, including on and around knee joints, toes densely feathered (Hoffman et al. 1999).

A. f. domingensis (Statius Müller, 1776). Hispaniola and Cuba, where known to breed only since 1981 (Garrido 1995); uncommon stray to s. Florida since about late 1970s (Hoffman et al. 1999). Differs from nominate flammeus in having wing shorter (<300mm), tarsus longer (>46mm), bill relatively larger, side of head just behind lateral edges of facial disk with dark brown patch (absent on flammeus), upper back mostly dark with tawny edges resulting in overall dark brown appearance, uppertail coverts dark brown, underparts more buff with only sparse streaking below breast and feathers around knee joints unstreaked, feathering on toes sparse (Hoffman et al. 1999).

A. f. portoricensis (Ridgway, 1882). Puerto Rico. Similar to domingensis . Hoffman et al. (1999) recommended only using the name domingensis for all Antillean Short-eared Owls, citing small sample sizes used by Wetmore (1928), who maintained portoricensis as subspecifically distinct from domingensis . Garrido (1995) also recommended merging portoricensis with domingensis . Some literature in the past used only portoricensis (e.g., Ridgway 1914), but see nomenclatural confusion discussed by Hoffman et al. (1999).

A. f. galapagoensis (Gould, 1837). Galapagos Is. Compared to nominate flammeus, legs heavily streaked with dark brown, underparts with distinct transverse markings, general coloration darker (Ridgway 1914).

A. f. bogotensis (Chapman, 1915). Found in nw. South America from Colombia to nw. Peru. Similar to nominate flammeus, but ochraceous markings on upperparts more restricted creating overall darker appearance; tarsi and toes less heavily feathered; size averages smaller but bill somewhat heavier and wholly black (characters based on Chapman’s description summarized in Cory 1918).

A. f. pallidicaudus (Friedmann, 1949) . Found at scattered localities in n. South America from Venezuela to Guyana.

A. f. suinda (Vieillot, 1817). Breeds in central and s. South America from s. Peru and s. Brazil south to Tierra del Fuego.

A. f. sanfordi (Bangs, 1919). Resident on Falkland Is.

A. f. sandwichensis (Bloxham, 1826). Resident on Hawaiian Is.

A. f. ponapensis (Mayr, 1933). Resident on islands of w. Pacific (Caroline Is. and Mariana Is.).

Species morphologically similar to congeneric Long-eared Owl, but multilocus protein electrophoresis indicates large genetic distance between the two species (Randi et al. 1991).