The Eastern Screech Owl Otus asio By: Nick  Classification: Kingdom - Animalia Phylum - Chordata Class - Aves Order - Strigiformes Family - Strigidae Genus - Otus Species - asio

Natural History:

About two hundred million years ago, a small animal developed small flaps of skin to help it glide. Eventually giant winged reptiles evolved. But skin wings were not easy to fold up and if they became torn, the animal didn't have a good chance of ever flying again. So they developed feathers.

In 1861, the fossil remains of Archaeopteryx were discovered. It lived about 150 million years ago. It was the size of a crow and was thickly feathered. Archaeopteryx had teeth like a reptile and had wings and a tail. Unfortunately Archaeopteryx died off when the dinosaurs did. Then a huge increase in bird population followed. There are about 8500 species of birds in the sky today, and one of them is the Eastern screech owl.

The owl has been associated with witchcraft and evil. Sometimes in movies you will see owls in grave yards or hear their calls in the background. In early Indian folklore, owls represented wisdom and helpfulness, and had powers of prophecy. By the Middle Ages in Europe, the owl became the associate of witches and the inhabitant of the dark, lonely places, a foolish but feared thing. The appearance of an owl at night, when you can't see very well, links it with the unknown. Their calls were eerie and people thought that death and evil was at hand.

During the eighteenth century through observation of the owl we reduced the mystery surrounding the owl. Most of the superstitions about owls died out in the twentieth century, and now we know that owls are beautiful and interesting animals.

Physical description:

Eastern screech owls are small, nocturnal, carnivorous, vertebrates. They come in two different colors, rusty brown and gray. The rusty brown Eastern screech owls usually live in the southern states, and the gray owls usually live in the northern states. In both colors their eyes are yellow. They are streaked and barred with dark markings. Their beaks are usually pale. Their coloration helps them blend in almost perfectly with the bark of trees. The Eastern screech owls are around ten inches in length. Their wingspans range from 18 to 24 inches. They weigh from about 7 to 8 ounces.

Eastern screech owls are among the smallest of the birds of prey in North America. They are the only small owls with ear tufts. Their calls are also important because Eastern screech owls are more often heard than seen. They give weird trembling calls and hollow whistles that run up and down the musical scale. Superstitious people think that their calls mean death or disaster is near.

Present Status:    Maine- Species of concern     Federally- Species of concern

Diet And Feeding Habits:

The Eastern screech owl is a carnivore.  They are not scavengers, they are predators.  It feeds on large, active, evening insects like moths and katydids.  The Eastern screech owl's diet is very diverse.  It also eats amphibians, reptiles, small mammals like mice and tiny bats, small birds and small terrestrial invertebrates such as worms. Seven percent of an Eastern screech owl’s diet is other Eastern screech owls. When the Eastern screech owl hunts, it finds a low perch so it will have a clear path to its prey. It will capture its prey just after spotting them from these locations. They are known to capture fairly large prey for their size.

Eastern screech owls hunt normally in the first four hours of darkness. They hunt mainly in open woodland and along open fields or wetlands. When the owl sees its prey, it dives down quickly and seizes it with its talons. Eastern screech owls usually return to an area where they have had a successful hunt before, so habitat destruction greatly effects the Eastern screech owl. They have been watched fishing in holes in ice that fisherman left behind. Both males and females have similar hunting behavior.

Owl pellets are about 1.5 by 0.75 inches. They are dark gray ovals that contain fur, bones, feathers, and teeth. Two to four pellets are expelled per day.

Habitat:

Eastern screech owls are endemic to the United States east of the Rocky Mountains. They are found on wooded stream sides, orchards, and open woodlots. They usually live in the tops of trees.

They generally live in the hollowed out areas of the trees or in the old nests of other birds because they do not make nests of their own. They avoid dense forest because great horned owls use that habitat. They also avoid forests at high elevation.

Eastern screech owls normally roost in natural cavities in large trees, including cavities open to the sky during dry weather. In suburban areas, they roost behind loose boards in buildings and in boxcars.

Causes Of Endangerment:

Eastern screech owls have few enemies other than man. Sometimes they are harassed by crows. Some owls prey on other owls. Deaths also occur from collisions with utility wires and motor vehicles.

The Eastern screech owl is nowhere near extinction because throughout the United States, the Eastern Screech owl is listed as a species of concern. Great horned owls, long-eared owls, barred owls, great gray owls, short eared owls, snowy owls, mink, and weasels are all predators of Eastern screech owls.

Eastern screech owls also suffer from deforestation, although they can live in suburban areas. The use of nest boxes supports owl populations, as does planting trees in deforested areas. However, owls cannot live in the younger trees because they are too small.

In captivity, Eastern screech owls can live for more than 20 years, much longer than a wild one.

Personal Essay:

In this section I will address one of the guiding questions for our expedition, “What is the value of wilderness to modern society?"  I think that everyone should care about endangered species and the environment; it's a big thing.  If there isn't anyone to care about wilderness then future generations will not have the things that we have.  

Rainforests generate much of the world's oxygen, and 214,000 acres of rainforests are being destroyed every day.  Scientists estimate that 137 species of animal are driven into extinction each year.  Rainforests cover 2% of the Earth's surface, or 6% of its land mass, yet they house over half the plant and animal species on Earth. They originally covered at least twice that area.  We get many of our medications from plants and animals.  If those plants and animals become extinct then we may not have those types of medications anymore.   

There are probably hundreds of species of insects and animals that we haven't discovered yet.  There are plants that we could never find due to extinction that would produce cures for diseases.  If 137 species become extinct every year then we may never discover these new plants that produce cures, or animals that would better our knowledge of the world.  What does it take for people to learn that if things like this keep up that soon we will not have these things?  

Bibliography:

1. Eastern screech owls- Otus asio.    http://www.owlpages.com/species/otus/asio/default.htm.  (Febuary 27, 2003)

2. Eastern screech owl.   http://birds.cornell.edu/birdhouse/bird_bios/speciesaccounts  (Febuary 28, 2003)

3. Eastern screech owl.   http://birds.cornell.edu/BOW/EASCOW/  (Febuary 29, 2003)

4. Eastern screech owl.   http://www.ronausting.com/screech.htm  (Febuary 29, 2003)

5. Otus asio. April 21 1998.  http://animaldiversity.ummz.umich.edu/

6. Owls.   http://museum.nhm.uga.edu/gawildlife/birds/strigiforms/oasio.html   (March 3, 2003)

7. Owls.   http://www.vetmed.auburn.edu/raptor/what_are_raptors/owls.html  (March 5, 2003)

8. Knopf, Alfred A.  North American Birds Of Prey.  New York: Alfred A. Knopf, Inc.1994.

9. Ford, Norman L.  “Owls.”  World Book Encyclopedia.