Spectacled owl
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
[Image: Spectacled_Owl.png |left|thumb| Chan Chich Lodge area, Belize - flash photo]The spectacled owl is found in Mexico, Central America, Trinidad and Tobago, and South America. 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.
Description
The spectacled owl can range from in length. Mass in males can range from, whereas females can weigh from. 10 males from the nominate subspecies were found to average while 8 females averaged. It is unmistakable in most of its range with blackish brown upperparts, head and upper breast, white facial markings, and whitish to yellowish-ochre underparts. The eyes are yellow, the only Pulsatrix with this eye color, 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. Compared to the band-bellied owl, it is of similar or slightly larger size, but that species has dark eyes, white eyebrows, and a brown chest band broken by buffy-whitish barring the rest of broadly the underparts being whitish with reddish-brown barring. The spectacled owl is generally found at lower elevations than the band-bellied but their ranges overlap or abut from Colombia to northern Bolivia. The tawny-browed owl, found from northeastern Argentina to eastern Brazil, is fairly similar in appearance to the spectacled but is obviously smaller with ochraceous-tawny from the eyebrows down to the belly and dark chestnut eyes. Each of the three currently recognized species also has a distinct song.Vocal activity tends to be most prominent on calm, moonlit nights. The primary sound made by the spectacled owl consists of guttural knocking or tapping sounds with a popping effect: PUP-pup-pup-pup-po, POK pok pok bog bog bog bobobo or BOO Boo boo boo boo. Each progressive note becomes weaker and lower in pitch but faster in pace as the call continues. The male is the primary singer to proclaim a territory, often singing from the upper third of a tall tree. However, females also sing, uttering the same song but with a higher pitch. Duets between pairs have been heard on moonlit nights. Females also make a hawk-like scream with an emphasis on the drawn-out second syllable, ker-WHEEER, which has often been compared to a steam whistle. Young spectacled owls beg with a harsh, high-pitched call. In Colombia, an author noted that the song is similar to the tapping pattern of the great spotted woodpecker. In Brazil, spectacled owls are known locally as "knocking owls".
Subspecies
The following subspecies are currently recognized:Pulsatrix perspicillata boliviana Kelso, 1933Pulsatrix perspicillata chapmani Griscom, 1932Pulsatrix perspicillata perspicillata Pulsatrix perspicillata pulsatrix Pulsatrix perspicillata saturata Ridgway, 1914Pulsatrix perspicillata trinitatis Bangs & T. E. Penard, 1918Behaviour
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 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 followed by mouse opossums of unidentified species. Numerous bats, such as greater spear-nosed bats and broad-eared bats, are also rather vulnerable apparently. Smaller monkeys such as tamarins 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. Even the three-toed sloth 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, motmots, and pigeons, which are taken off of their nocturnal perches and perhaps smaller types of owl. 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.