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Description


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Description: A relatively small screech owl with short ear tufts that are raised mostly during daytime. There are grey-brown, brown and rufous morphs, with intermediates. Most are of the grey-brown morph. This owl has a yellow iris and a light gray facial disk, with a prominent black border; underparts white with a herring-bone pattern where each feather has black shaft streaks throughout. Crown and upperparts heavily streaked dark; tail and flight-feathers are barred with brown and light buff, the scapulars have a dark-edged pale spots, what give them a white line along each side above the wing. The bill is greenish-gray, feathered tarsus, toes are bare and feet are grey-brown.

Size: Length 20-24 cm (8-9.5"). Wing 14.6-18.0 cm (5.75-7"). Tail 8.6-10.4 cm (3.4-4"). Weight 96-160 g (3.4 -5.6 oz).

Voice: Its main call is a brief trill followed by two louder toots, "gurrrrrrku-kúk". When excited, with a playback for example, the ending notes can be more numerous,"gurrrrrrku-kúk-kúk-kúk-kúk". The second song is a bubbling "bububububububub" normally used during courtship. When alarmed or surprised emits a laughing "hahahahahaha" or "kiah". Because they are nocturnal, these owls are mostly heard than seen.

Breeding: These owls lay eggs in January - July in Northern Hemisphere; in Southern Hemisphere, the egg laying was recorded in September-October. But males normally sing on August, initiating the courtship period, when both sexes are vocally active. These owls nest in cavities, as natural or old woodpecker holes in trees, but also in termite mounts and nest boxes. Usually about 1-4 white eggs, averaging 34.3 x 29.3mm, are laid on the bottom of cavity without any protection. Incubation is provided by female. In Misiones (Argentina) a male was reported carrying food to the nest. The nestlings are brooded for about a month when the young owls fledge.

Hunting & Food: Food habits are poorly known. Few samples of pellets and field observations suggest a mostly insectivorous diet, including crickets, katydids, beetles, ants, spiders and scorpions. Preys are mostly nocturnal and live on the ground. Insects can be captured on wing or on the ground. There are observations of individuals catching insects in flight, particularly in the vicinity of artificial light sources, suggesting a learning process. Small vertebrates are also consumed as rodents, opossums, anurans and snakes, but in small proportions. However, in terms of estimated prey biomass consumption, these vertebrates can support 1/3 to 1/2 of the diet.

Habitat: This species is found in a wide variety of habitats. However, Tropical Screech owls occur mostly in semi-open habitats, like timbered savannah, semi-open areas with scattered trees, forest edges, second-growth forests, plantations, and also town parks. In a gradient of physiognomies from open to woody areas, as the Brazilian savannah, this owl seems to avoid pure grasslands or grassland savannahs with shrubs, preferring patches with at last some trees to woody savannahs. Generally they occur in areas from sea level to 1500m, but they have also been recorded at 3000m. This raptor is almost strictly nocturnal, initiating its activities at dusk. During daytime this owl roosts in dense foliage trees, probably close to the trunks like other Megascops.

Distribution: The Tropical Screech owl is distributed on most of South America east of the Andes from Costa Rica to northern Argentina, east of Ecuador, Colombia, Peru and Bolivia, and all over Venezuela, Guyana, Suriname, French Guiana, Brazil, Paraguay and Uruguay. It was also reported in Trinidad . These owls are probably resident, but little is know about their movements.


Distribution of Megascops choliba

Status: No globally threatened. Widely distributed and rather frequent to common, but its ecology and population numbers are poorly known. As a mostly insectivorous owl it is probably affected by the use of pesticides. Road mortality has been observed, since this species not infrequently hunts on roadsides and on the ground below lampposts making it vulnerable to traffic. The loss of natural habitat, mainly trees with adequate trunk diameters for nest cavities, is also a threat for its survival.

Original Description: Vieillot, Louis Jean Pierre. 1817. Nouveau Dictionnaire d'Histoire Naturelle appliquée Aux Arts; 1816-17 (nouv. ed.), 7, p. 39.

Subspecies: M. c. choliba, M. c. crucigerus, M. c. decussatus, M. c. duidae, M. c. luctisomus, M. c. margaritae, M. c. surutus, M. c. uruguaiensis, M. c. wetmorei

http://www.owlpages.com/owls.php?genus=Megascops&species=choliba


Tropical Screech Owl
Otus choliba


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As of February 2005.

Description

Small owl with short ear tufts and yellow eyes. Grey (Gray), brown and red colour morphs occur with intermediates. Light grey (gray), black edged facial disk. Heavily streaked upper-parts and under-parts marked with herring bone pattern.













Size

20-24cm, 95-160g













Range

From Costa Rica to N Argentina East of the Andes.













Habitat

Savannah, open forest, plantations, parks, clearings.













Food

Mainly insects and other invertebrates, occasionally snakes and small mammals.













Breeding

January - July N. of equator and September - October south of it. 1-4 eggs in tree cavity. Little else is known about its breeding habits.













Call

Purring, short trill, followed by 2 toots.













Status

Not thought to be threatened, although exact status is unknown.













Comments

Often hunts on roadsides, and as a result roadside casualties are common.













http://www.owls.org/Species/otus/tropical_screech_owl.htm

The Tropical Screech-Owl is distinctive with its boldly black outlined facial disk. Like most screech owls, positive identification is best done by their calls.  Here you can find photos and information to help identify and enjoy this beautiful owl. The Field Notes section includes a Central American range map and information on nesting, habitat, description and identification.  To jump immediately to any of these sections use the Page Jump Links below.

 
The Tropical Screech-Owl is a strictly nocturnal owl and is not active until well after dark. Occurs in grey-brown, brown, and very rare rufous morphs. Facial disk light grey or tan with prominant black border. Crown and upperparts are heavily dark or black streaked. Underparts have prominate dark or black vertical streaks with fine cross streaks. Tarsis (leg above feet) is feathered; iris yellow, bill is greenish grey with yellow tip. It is a medium size screech-owl that is about the same size as the Vermiculated Screech-Owls (7.8 - 9.5 inches in length). There is some overlap in range with Vermiculated and maybe Pacific Screech-Owls but the black borders around the facial disc of the Tropical Screech-Owl readily separate it from these other species.

The Tropical Screech-Owl can be found in open woodland, second growth, forest clearings and edge, streamside groves, coffee plantations, forest clearings, semi-open or suburban areas with trees, and town parks. Generally it t ranges from 1300 ft to 500ft in Central America but can be much higher in South America (almost 9,000 ft).

It feeds mostly on large insects such as grasshoppers, crickets, bumblebees, spiders, scorpions, and moths. Ocassionally it will take snakes and small mammals such as rats and bats. Usually it pearches on low branches and pounces on prey but will also take insects in flight often at electric lights.

Nests in tree cavity, woodpecker hole, knothole, or old nest box. Usually lays 1-4 eggs from Februrary to April. The incubation is done by the female and the young leave the nest at 30 days old. Young with whitish down.



Little is known about its population although it is not considered globally threatened and may be the most common screech-owl of Costa Rica and Panama. Only one race is reconized in Central America with an additional eight reconized from South America. Several others have been described although further research is required.
http://www.owling.com/Tropical_Screech.htm


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