The spectacled owl also called a Murucututu, is a large tropical owl native to the neotropics. It is a resident breeder in forests from southern Mexico and Trinidad, through Central America, south to southern Brazil, Paraguay, and northwestern Argentina. There are six subspecies. One is occasionally treated as a separate species called the short-browed or brown-spectacled owl but the consensus is that it is still merely a race until more detailed analysis can be done.
📌 Distribution and habitat
The spectacled owl is found in Mexico, Central America (Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama), Trinidad and Tobago, and South America (Colombia, Venezuela, Suriname, French Guiana, Guyana, Paraguay, Ecuador, Peru, Bolivia, Brazil, Argentina). The spectacled owl is primarily a bird of tropical rainforests, being 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 cloud forests of up to , although are generally associated with lowland forests.
📌 Subspecies
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The following subspecies are currently recognized:
* Pulsatrix perspicillata boliviana Kelso, 1933
:Distributed in Bolivia. Most similar to P. p. chapmani, with a slightly lighter color on that 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 had wings of and a tail length of
* Pulsatrix perspicillata chapmani Griscom, 1932
:Found from eastern Costa Rica to northwestern Ecuador. A relatively dark-hued subspecies, sooty black on the back and rich tawny-rufous below.
* Pulsatrix perspicillata perspicillata (Latham, 1790)
:By far the largest distribution of the races, found from northwestern South America to as far south as central Brazil and Bolivia. Nominate as described above. The wing is , the tail is from long, and the bill from cere is .
* Pulsatrix perspicillata pulsatrix (Wied-Neuwied, 1820)
:Or 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. The main proposed difference (leading to it being considered a full species) is that territorial song is not as accelerated 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 is long and the tail is . The weight of a single male and single female was and respectively, coincidentally exactly the same as the maximum weight recorded for the nominate race of Spectacled Owl.
* Pulsatrix perspicillata saturata Ridgway, 1914
: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 is and the tail is long. The bill from the cere is . The weight is from in males and from in females.
* Pulsatrix perspicillata trinitatis Bangs & T. E. Penard, 1918
: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.
📌 Behaviour
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This species is largely nocturnal, starting activity right around the time of the last light at dusk and usually being back on their roosts for the day around the first light. It is a solitary, unsocial bird, usually roosting singly each day and only peaceable associating with others of their own species for reproductive purposes.
The spectacled owl is typically the largest and most dominant owl in its range, with the larger great horned owl (Bubo virginianus) rarely venturing into true rainforest habitats. Most hunting starts with the owl perched on a branch and scanning the area, then dropping with a quick pounce when prey is located. It preys principally on a wide array of mammals, eating almost anything that is nocturnally active. Various rodents may be primary but virtually any type of small mammal in its habitat is vulnerable. The primary food by far in Oaxaca, Mexico was the Peters's climbing rat (Tylomys nudicaudus) followed by mouse opossums (Marmosa ssp.) of unidentified species. Numerous bats, such as greater spear-nosed bats (Phyllostomus hastatus) and broad-eared bats (Nyctinomops laticaudatus), are also rather vulnerable apparently. Smaller monkeys such as tamarins (Saguinus ssp.) may be vulnerable to predation. Prey species can be heavier than the preying owl, weigh over , possibly up to in Didelphis opossums, Mephitis skunks and agoutis (Dasyprocta ssp.). Even the three-toed sloth (Bradypus variegatus) has been reported to have been killed, specifically an adult female estimated at in weight or more than four times the weight of the owl itself. Invertebrates are eaten regularly as well, second only in importance to mammals, mainly caterpillars, but also crabs, snails, large insects, and spiders. Insects may be gleaned directly from foliage while the large owls actively forage. Frogs are also recorded amongst their prey. Birds are also taken, including mainly medium-sized species in the average weight range of , such as jays, oropendolas (Psarocolius ssp.), motmots (Momota ssp.), and pigeons (Patagioenas ssp.), which are taken off of their nocturnal perches and perhaps smaller types of owl (e.g. Megascops ssp.). Little is known about how spectacled owls interact with other owls but in a study where playback of a number of owl species was played in Costa Rica, spectacled owls appeared to be the least responsive, neither vocally stimulated by the calling of other owl species nor by playback of calls of their own species.
📌 Reproduction
In Costa Rica, 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. Like all owls, they do not build a nest so just lay their nest on the bare surface of the wood given, usually rotting wood in the case of 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 cared for and fed 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.
📌 Status
The spectacled owl occurs over a very large range and is still a resident in much of its range. Due to this, it is classified as Least Concern by the IUCN. However, 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).