The spectacled owl (Pulsatrix perspicillata) 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.
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 (P. p. perspicillata) were found to average while 8 females averaged .Burnie D and Wilson DE (Eds.), Animal: The Definitive Visual Guide to the World's Wildlife. DK Adult (2005), CRC Handbook of Avian Body Masses, 2nd Edition by John B. Dunning Jr. (Editor). CRC Press (2008), . It is unmistakable in most of its range (except with other Pulsatrix owls) 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.Owls of the World by Konig, Weick & Becking. Yale University Press (2009), Compared to the band-bellied owl (P. melanota), 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 (P. koeniswaldiana), 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 (Dendrocopos major). In Brazil, spectacled owls are known locally as "knocking owls".Owls of the World: A Photographic Guide by Mikkola, H. Firefly Books (2012),
Subspecies
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 Kelso, L. (1934). A key to the owls of the Genus Pulsatrix Kaup. The Auk, 234-236.Weick, F. (2007). Owls (Strigiformes): annotated and illustrated checklist. Springer. 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. The wing is , the tail is , and the bill from the cere is . A mean weight of was published.Stiles, F. G., & Skutch, A. F. (1989). Guide to the birds of Costa Rica. 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
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.De Silva, H. G., Pérez-Villafaña, M., & Santos-Moreno, J. A. (1997). Diet of the spectacled owl (Pulsatrix perspicillata) during the rainy season in Northern Oaxaca, Mexico. Journal of Raptor Research, 31(4), 385-387. Numerous bats, such as greater spear-nosed bats (Phyllostomus hastatus) and broad-eared bats (Nyctinomops laticaudatus), are also rather vulnerable apparently.Knörnschild, M., & Tschapka, M. (2012). Predator mobbing behaviour in the Greater Spear-Nosed Bat, Phyllostomus hastatus. Chiroptera Neotropical, 18(2), 1132-1135.Carvalho, L. F., Cunha, N. L., Fischer, E., & Santos, C. F. (2013). Predation on Broad-eared bat Nyctinomops laticaudatus by the Spectacled Owl Pulsatrix perspicillata in southwestern Brazil. Revista Brasileira de Ornitologia-Brazilian Journal of Ornithology, 19(45), 3. Smaller monkeys such as tamarins (Saguinus ssp.) may be vulnerable to predation.Suarez, S. 2007. Paternity, Relatedness, and Socio-Reproductive Behavior in a Population of Wild Red-Bellied Tamarins (Saguinus labiatus). Ann Arbor, Michigan: ProQuest Information and Learning Company. 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.Voirin, J. B., Kays, R., Lowman, M. D., & Wikelski, M. (2009). Evidence for Three-Toed Sloth (Bradypus variegatus) predation by spectacled owl (Pulsatrix perspicillata). Edentata, 8, 15-20. Invertebrates are eaten regularly as well, second only in importance to mammals, mainly caterpillars, but also crabs, snails, large insects, and spiders.Proudfoot, Glenn. (2011). Owls of the World, 2nd ed. — Claus König and Friedhelm Weick . 2009. Yale University Press, New Haven, Connecticut. 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.).Proudfoot, Glenn. (2011). Owls of the World, 2nd ed. — Claus König and Friedhelm Weick . 2009. Yale University Press, New Haven, Connecticut. 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.Enriquez, P. L., & Salazar, J. L. R. (1997). Intra-and Interspecific Calling in a Tropical Owl Community. UNITED STATES DEPARTMENT OF AGRICULTURE FOREST SERVICE GENERAL TECHNICAL REPORT NC, 525-532.
Reproduction