Spectacled Owl

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Image:SpectacledOwl.jpg

Common Name: Spectacled Owl
Scientific Name: Pulsatrix perspicillata

Size: 16.1-20.6 inches (41-52.3 cm); Wingspan: 37.4-39.3 inches (95-100 cm)

Habitat: The Americas; a resident breeder in forests from southern Mexico and Trinidad, through Central America, south to southern Brazil, Paraguay and northwestern Argentina.

Primarily a bird of tropical rain forests, it is found mostly in areas where dense, old-growth forest is profuse. However, it may enter secondary habitats, such as forest edges, especially while hunting. On occasion, they have been found in dry forests, treed savanna plains, plantations and semi-open areas with trees. In areas such as Costa Rica, they may inhabit subtropical montane forests of up to 1,500 m (4,900 ft), although are generally associated with lowland forests.

Status: Least Concern to Extinct. Global population: 499,000- 4,999,999 adult individuals with a decreasing population trend. Being a large, slow-maturing bird of prey with a strong sense of territoriality, it as a rule occurs at low densities. In areas where prey populations are hunted by people and habitats are destroyed or compromised, they may decrease. This is the likely source of extinction for an entire race on Trinidad (P. p. trinitatis). It is estimated that there will be a 17.5 to 20.3% population decline over the next three generations.

Diet: A wide array of noctural mammals and invertebrates. Mammals such as Peter's climbing rat (Tylomys nudicaudus), the mouse opossum (Marmosa ssp.), the Greater spear-nosed bat (Phyllostomus hastatus) and broad-eared bats (Nyctinomops laticaudatus) are preferred prey. Smaller monkeys such as tamarins (Saguinus ssp.) may be vulnerable to predation. Invertebrates are eaten regularly as well, second only in importance to mammals, and may be comprised mainly by caterpillars, but also crabs, snails, large insects and spiders.

Nesting: Males and females are alike however females are larger and heavier than males. It is unmistakable in most of its range with blackish brown upper parts, head and upper breast, white facial markings and white to yellow-ochre underparts. The eyes are yellow and the beak is pale. The juvenile is even more distinctive than the adult, being completely white apart from a chocolate brown facial disc. The head is typically darker than the back and mantle but the shade of this area besides the composition of the breast band is the main distinguishing external feature of the subspecies.

This species is largely nocturnal, starting activity right around the time of last light at dusk and usually being back on their roosts for the day around first light. It is a solitary, unsocial bird, usually roosting singly each day and only peaceable while associating with others of their own species for reproductive purposes.

Eggs are laid variously in the dry season (November–May), or at the start of the wet season (June–July). This owl typically nests in an unlined tree cavity but may also use the crutch of a large tree. They do not build an actual nest; they simply lay their eggs on the bare surface of the tree cavities. Spectacled owls lay 1-2 eggs, which are incubated entirely or almost so by the female for about 5 weeks. If two eggs are hatched, often only one of the chicks will survive, the smaller chick usually perishing via starvation or by aggression from the larger nestling. Chicks leave the nest for surrounding branches at about 5–6 weeks but cannot usually fly well at this stage. However, they tend to depend on their parents for several months after leaving the nest and may be fed and cared for for up to a year once fledged, inhibiting the pair's ability to have young the following year. Spectacled owls may breed while still in immature plumage since it may take up to five years before full adult plumage is obtained.

Cool Facts: There are six subspecies. Each of the recognized species also has a distinct song.

  • P. p. Boliviana. First reported by Kelso in 1933. It is distributed in Bolivia. Most similar to P. p. chapmani, with slightly lighter color on mantle than that race and a lighter, more buff underside color. The feathers appear to be relatively long on this race especially on the flanks, probably due to the cooler climates it inhabits. Specimens have a single wing length of 335 to 366 mm (13.2 to 14.4 in) and a tail length of 205 mm (8.1 in).
  • P. P. chapmani. First reported by Griscom in 1932. It is found from eastern Costa Rica to northwestern Ecuador. A relatively dark hued subspecies, sooty black on the back and rich tawny-rufous below. The single wing length is 326 to 346 mm (12.8 to 13.6 in), tail is 183 to 193 mm (7.2 to 7.6 in), the bill from the cere is 29.5 mm (1.16 in). A mean weight of 750 g (1.65 lb) was published.
  • P. P. perspicillata. First reported by Latham in 1790. The nominate species has by far the largest distribution of the races. It is found from northwestern South America to as far south as central Brazil and Bolivia. The wing length is 305 to 355 mm (12.0 to 14.0 in), tail is from 133 to 196 mm (5.2 to 7.7 in) long, and bill from cere is 26.5 to 31.5 mm (1.04 to 1.24 in). P
  • P. p. pulsatrix. First reported by Wied-Neuwied in 1820. The "Short-browed Owl"; native to southeastern Brazil from about Bahia south to Rio Grande do Sul in the area of Aparados da Serra National Park and also bordering over into northeastern Argentina. This species has creamy-buff instead of white on the spectacles of the face. P. p. pulsatrix is lighter brown than in any other spectacled owl, with no contrasting darker plumage on the crown and nape as in other races. The breast band is brown and distinctly broken in the center. Main proposed difference (leading to it being considered a full species) is that territorial song is not as ascelerated as in other races. Apparently, where the ranges of more typical spectacled owls overlap with the short-browed types, they do not seem to hybridize. This is the largest variety of Spectacled Owl. The wing length is 363 to 384 mm (14.3 to 15.1 in) long and tail is 211 to 226 mm (8.3 to 8.9 in). The weight of a single male and single female was 1,050 g (2.31 lb) and 1,250 g (2.76 lb), coincidentally exactly the same of the maximum weight recorded for the nominate race of Spectacled Owl.
  • P. p. saturata. First reported by Ridgway in 1914. It is found from southern Mexico to northern Costa Rica. P. p. saturata differs from the typical spectacled owl only in that it is black on the head and the back, with black barring on the sides. It is one of the more distinct and widely described subspecies. The wing length is 314 to 370 mm (12.4 to 14.6 in) and tail is 182 to 204 mm (7.2 to 8.0 in) long. The bill from the cere is 27 to 32.5 mm (1.06 to 1.28 in). Weight is from 591 to 761 g (1.303 to 1.678 lb) in males and from 765 to 982 g (1.687 to 2.165 lb) in females.
  • P. p. trinitatis. First reported by Bangs & T. E. Penard in 1918. It is found on Trinidad and Tobago. This poorly-known race is sometimes treated as synonymous with the nominate by some authorities.Today, authorities believe that the race is extinct.


Found in Songbird ReMix Owls of the World Volume 2

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