Spectacled Owl

The spectacled owl is a large tropical owl native to the neotropics, resident in forests from southern Mexico and Trinidad through Central America to southern Brazil, Paraguay and northwestern Argentina. It measures 41 to 52.3 cm, with blackish brown upperparts, head and upper breast, white facial markings and whitish to yellowish-ochre underparts. It is the only Pulsatrix owl with yellow eyes. It is mainly a bird of dense, old-growth tropical rainforest and is largely nocturnal and solitary. Hunting usually starts with a perch and a quick pounce, mostly on small mammals, with invertebrates such as caterpillars, crabs and snails eaten regularly. It nests in tree cavities and usually lays one or two eggs.

About the spectacled owl

The spectacled owl (Pulsatrix perspicillata) is a large tropical owl of the typical owl family, Strigidae, native to the forests of Central and South America. It is named for the bold white "spectacles" framing its yellow eyes, and it is usually the largest and most dominant owl in the rainforests where it lives.

It belongs to the genus Pulsatrix, alongside the band-bellied owl and the tawny-browed owl. Six subspecies are recognized, ranging from the very dark P. p. saturata of southern Mexico and northern Central America to the pale "short-browed owl" of southeastern Brazil, which some authorities treat as a separate species. One of the six, the Trinidad race, is now believed extinct.

This is a big owl, 41–52.3 cm (16.1–20.6 in) long. Females are larger than males: males weigh 453–1,075 g (1.0–2.37 lb) and females 680–1,250 g (1.5–2.76 lb). In one sample of the nominate subspecies, ten males averaged 767 g (1.69 lb) and eight females 908 g (2.0 lb). Animal Diversity Web gives a wingspan of about 0.76–0.91 m (2.5–3 ft).

Across most of its range the adult is unmistakable. The upperparts, head and upper breast are blackish brown, the facial markings white, and the underparts whitish to yellowish ochre, with a dark band across the chest. The eyes are yellow, the only Pulsatrix owl with that eye color, and the bill is pale.

The young look like a photographic negative of their parents. Juveniles are almost entirely white with a chocolate-brown facial disc, and it can take up to five years for a spectacled owl to reach full adult plumage. Birds sometimes breed while still in immature plumage.

Behavior and diet

The spectacled owl is largely nocturnal. It becomes active at the last light of dusk and is usually back on its roost by first light, though it has occasionally been seen hunting by day. It is solitary and unsocial, roosting alone and associating with others of its kind only to breed. Spectacled owls are not migratory, and they often hide in low-hanging foliage, where predators have trouble finding them.

Its voice is distinctive. The main song is a series of guttural knocking or tapping notes with a popping quality, written as "PUP-pup-pup-pup-po" or "BOO boo boo boo boo," each note weaker, lower and faster than the last. Animal Diversity Web compares it to a hammer hitting a hollow tree. Males sing from the upper third of a tall tree to claim territory, females answer with a higher-pitched version, and pairs duet on calm, moonlit nights. Females also give a drawn-out "ker-WHEEER" scream likened to a steam whistle.

The spectacled owl hunts from a perch, scanning the forest and then dropping on prey with a quick pounce. It eats almost any nocturnal mammal it can overpower. Rodents are often the main prey; in Oaxaca, Mexico, Peters's climbing rat topped the list, followed by mouse opossums. Bats are also taken, and smaller monkeys such as tamarins may be at risk. Some prey is heavier than the owl itself, including opossums, skunks and agoutis that may weigh 2–4 kg (4.4–8.8 lb). One spectacled owl was reported to have killed an adult three-toed sloth estimated at 3.5–4.5 kg (7.7–9.9 lb), more than four times its own weight.

Invertebrates rank second in importance, mainly caterpillars but also crabs, snails, large insects and spiders, sometimes gleaned straight from vegetation. Frogs are also eaten, and birds are taken from their night perches, mainly medium-sized species of about 100–500 g (3.5–17.6 oz) such as jays, oropendolas, motmots and pigeons.

Spectacled owls are monogamous. They nest in an unlined tree cavity, usually in rotting wood, or occasionally in the fork of a large tree, laying eggs on the bare surface. In Costa Rica eggs are laid in the dry season or at the start of the wet season. The female lays one or two eggs and does all or nearly all of the incubation, about five weeks. When two chicks hatch, often only one survives, the smaller one starving or being attacked by its sibling. Chicks leave the nest for nearby branches at five to six weeks, before they can fly well, and may be fed by their parents for up to a year, which can keep the pair from breeding the next year.

Range and habitat

The spectacled owl ranges from southern Mexico through Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama, and across South America in Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil, Paraguay and Argentina. It also occurs in Trinidad and Tobago.

It is primarily a bird of tropical rainforest, most common where dense old-growth forest is plentiful. It does venture into secondary habitats such as forest edges, especially to hunt, and is occasionally found in dry forest, treed savanna, plantations and semi-open country with trees. Animal Diversity Web notes it often lives near water. Although it is mainly a lowland bird, in Costa Rica it can reach montane cloud forest up to about 1,500 m (4,900 ft). The larger great horned owl rarely enters true rainforest, which leaves the spectacled owl as the top owl there.

Spectacled owl vs band-bellied owl

The spectacled owl is hard to confuse with anything except its Pulsatrix relatives. Its range overlaps or meets that of the band-bellied owl from Colombia to northern Bolivia, with the spectacled owl usually at lower elevations.

Conservation status

The spectacled owl is listed as Least Concern on the IUCN Red List because it occupies a very large range and remains resident across much of it. It is also listed on CITES Appendix II.

That rating doesn't mean it is common. As a large, slow-maturing, strongly territorial predator, it naturally lives at low densities. Where people hunt its prey and destroy or degrade forest, spectacled owls can decline, and that combination is the likely reason the Trinidad subspecies, P. p. trinitatis, disappeared. Spectacled owls are also killed by cars where roads are cut through forest. Animal Diversity Web warns the species could become seriously threatened if South American forests continue to be cleared for farming and logging.