Family Typical Owls (Strigidae)

Least Concern

Magellanic Horned Owl (Bubo magellanicus)

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Taxonomy

French: Grand-duc de Magellanie German: Magellanuhu Spanish: Búho magallánico
Other common names: Lesser Horned Owl, Magellan Great Horned Owl
Taxonomy:

Strix magellanicus

Lesson

, 1828,

Straits of Magellan

.

Until recently included as a race of B. virginianus, but differs from the taxon in vocalizations#R and morphology, and also in DNA; in the past, occasionally even merged with B. v. nacurutu. Individuals from higher elevations in Andes have occasionally been separated as race andicolus. Authorship and dating of specific name rather complex: Lesson’s appears to be oldest available name, associated with description; but if homonyms of J. F. Gmelin (1788) and Suckow (1800) are to be considered merely varietal names, some other currently valid bird names, e.g. of Gmelin, might require similar rejection#R. Monotypic.

Distribution:

C Peru, Chile, W Bolivia and W Argentina S to Tierra del Fuego and Cape Horn.

Descriptive notes

c. 45 cm#R; 830 g (n = 1 male)#R. Very like B. virginianus; differs in smaller size (wing length 318–368 mm versus 297–390 mm in virginianus#R), smaller ear tufts, smaller bill, weaker talons, more prominent rim around facial disc, narrower and more closely spaced barring below; general coloration varies from grey-brown to darker brown. Irides bright yellow; cere and bill bluish-grey#R; claws dark horn with black tips#R. Juvenile much as B. virginianus.

Drawing by Tim Worfolk
Descriptive notes:

c. 45 cm#R; 830 g (n = 1 male)#R. Very like B. virginianus; differs in smaller size (wing length 318–368 mm versus 297–390 mm in virginianus#R), smaller ear tufts, smaller bill, weaker talons, more prominent rim around facial disc, narrower and more closely spaced barring below; general coloration varies from grey-brown to darker brown. Irides bright yellow; cere and bill bluish-grey#R; claws dark horn with black tips#R. Juvenile much as B. virginianus.

Voice

Male song 2 deep hoots, second one stressed, followed by low quiet purring sound, “huhOOh-urrrrrr”; female gives longer purr; duets in courtship.

Habitat

Rocky upland pasture, semi-open forest (especially Nothofagus), Patagonian steppe and semi-desert with scattered trees, bushy ravines and surrounding grassland; in S, also parks in areas of human settlement#R. In Andes mostly at 2500–4500 m; locally down to sea-level.

Food and feeding

Diet fairly well studied in Argentina#R#R#R#R and Chile#R#R#R. Mostly small mammals up to size of rabbits and hares; also birds (up to size of Chloephaga sp.#R and Vanellus chilensis#R), reptiles (lizards#R) and some invertebrates (insects, scorpions, spiders). A pellet analysis in C Chile revealed 69·3% rodents, 15·8% rabbits and 11·4% birds; in a study in S Chile, diet consisted solely of rodents, with Aulisco­mys micropus and Abrothrix longipillis together forming 60·4% of prey in terms of numbers captured and 74·4% of biomass consumed. In sample of 1532 prey items from three Andean locales in NW Argentina, diet dominated by rodents (92·8%), with remainder consisting of marsupials (1·6%), bats (0·1%), birds (0·3%) and invertebrates (5·2%)#R. Hunts mostly at dusk and dawn, sometimes nocturnally; also by day in S of range, where close to 24-hour daylight during summer. Foraging methods similar to those of B. virginianus; often uses rock as lookout perch.

Breeding

Poorly studied relative to diet. Season begins late winter. Nest in crevice or cavity on cliff or between rocks, or beneath rock overhang; sometimes depression on ground in forest. Clutch size 2–3 eggs; mean egg size 53·3 mm × 43·7 mm#R; incubation by female (as known for all owls studied), fed by male; young leave nest before able to fly, remain nearby. Apparently, no published information on length of incubation, nestling or post-fledging dependency periods#R.

Movements

Resident; some birds in extreme S move N in winter; juveniles sometimes wander longer distances in autumn#R.

Status and conservation

Not globally threatened (Least Concern). CITES II. Seems to be common in Chile and Patagonia. Numbers in C Chile increased after introduction of European rabbits (Oryctolagus cuniculus) in 1907. No information on global population size; numbers thought to be stable, but no hard data on population trends. Main threat appears to be human persecution, which locally quite severe; poisoned baits for foxes in Patagonia may be a potential threat, although no known deaths from such causes reported; road casualties also quite frequent.

Recommended citation

Holt, D.W., Berkley, R., Deppe, C., Enríquez Rocha, P., Petersen, J.L., Rangel Salazar, J.L., Segars, K.P., Wood, K.L. & Marks, J.S. (2019). Magellanic Horned Owl (Bubo magellanicus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/55007 on 26 June 2019).