[order] STRIGIFORMES | [family] Strigidae | [latin] Megascops asio | [authority] Linnaeus, 1758 | [UK] Eastern Screech Owl | [FR] Petit duc d’Amerique | [DE] Ost-Kreischeule | [ES] Autillo Yanqui | [NL] Schreeuwuil
The genus Megascops comprises 22 living species are known at present, but new ones are frequently recognized and unknown ones are still being discovered on a regular basis, especially in the Andes. For most of the 20th century, this genus was merged with the Old World scops-owls in Otus, but nowadays it is again considered separate based on a range of behavioral, biogeographical, morphological and DNA sequence data. Screech-owls are restricted to the Americas. Some species formerly placed with them are nowadays considered more distinct.
As usual for owls, female screech-owls are usually larger and fatter than the males of their species, with owls of both sexes being compact in size, shape, and height. The Eastern Screech-owl Megascops asio is one of the smallest species of owls in North America. All of the birds in this genus are small and agile. Screech-owls are generally colored in various brownish hues with usually a whitish, patterned underside, which helps to camouflage them against the bark of trees. Some are polymorphic, occurring in a grayish- and a reddish-brown morph.
Eastern screech-owls are small owls, from 16 to 25 cm in length. Females are generally larger than males, which is common in owls. Eastern screech-owls are dichromatic, they come in two distinct color morphs. They are either uniformly gray or uniformly rufous, with darker streaking on the body. Both color morphs make them very difficult to distinguish from surrounding tree bark. They have bold streaking on their breasts, yellow beaks and eyes, relatively large feet with feathered toes, and large “ear” tufts on either side of their head. Eastern screech-owls are distinguished from their close relative western screech-owls, by their yellow bill, descending trill call, and by the rufous coloration of some individuals.
Listen to the sound of Eastern Screech Owl
[audio:http://www.planetofbirds.com/MASTER/STRIGIFORMES/Strigidae/sounds/Eastern Screech Owl.mp3]
Copyright remark: Most sounds derived from xeno-canto
North America, Middle America : Southeast, Southcentral Canada to Northeast Mexico. Eastern screech-owls are found throughout much of eastern North America, from the Rocky Mountains in the West to the Atlantic coast and from Florida and southern Texas in the south as far north as southern Canada.
Eastern screech-owls have the broadest ecological niche of any North American owl. They are found in virtually all kinds of habitats below about 1500 meters elevation, from urbanized surroundings to boreal forests. They are generally found in wooded areas but do well in urban and suburban areas and acclimatize readily to human presence, often using bird boxes for nesting. These birds are cavity nesters and use natural cavities or those created by other animals
Most eastern screech-owls form pair bonds for life with individuals of the same age. Some mate switching occurs after unsuccessful nesting attempts and some males have been observed nesting simultaneously and sequentially with more than one female. Both males and females crouch and trill when their mate approaches. Eastern screech-owl females lay eggs over a period of days to more than a week and generally do not begin full-time incubation until the last egg is laid. As a result, eggs laid first also develop and hatch first. With larger broods, where newly hatched young may be developmentally up to 8 days behind their nestmates, younger nestlings tend to be killed accidentally or by their siblings. From 2 to 7 eggs, usually 3 or 4, are laid in a large nest cavity. They are incubated for 26 (eggs laid last) to 34 days (earlier eggs), with an average of 30 days of incubation. Eastern screech-owl females incubate the eggs and brood the young. Males feed females and guard nest cavities during incubation and brooding. The young leave the nest at about 28 days old and remain with the parents until they are 8 to 10 weeks old. Both parents feed the young during this period.
Eastern screech-owls eat the most varied diet of any North American owl. Their diet includes large evening active insects, like moths and katydids, crayfish, earthworms, amphibians, reptiles, small mammals, like mice and bats, and small birds. These owls have symmetrical ears, which suggests that they hunt primarily using their vision. They do, however, have excellent hearing as they often capture prey hidden by leaf litter. They hunt by sitting on a tree branch and waiting to see or hear prey. Eastern screech-owls cache prey in their nests for later consumption by adults or nestlings.
Video Eastern Screech Owl
copyright: Bill Wayman
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Eastern screech-owls may suffer as a result of deforestation and the loss of appropriate nesting cavities and prey populations. They are relatively common throughout their range, though, and are not currently threatened.