North American Owls

North American Owls

NORTH AMERICAN WILDLIFE OWLS (Strigiformes)
By George Constantourakis, Spetember 1998

The order of "Owls" (Strigiformes) is divided into two families: "Barn Owls" (Tytonidae) and "Typical Owls" (Strigidae). In the family of "Barn Owls" there are 11 species worldwide and 1 in North America, the "Common Barn-Owl" (Tyto alba). In the family of "Typical Owls" there are 135 species worldwide and 19 species in North America. These birds are primarily nocturnal raptors, with deeply hooked bills and sharp talons.

They have a large head that is compressed. The enormous frontally placed eyes are fixed in their sockets (viz. Eyes cannot move within the sockets). The eyes give owls a narrower field of vision. This construction creates the need for extensive flexible head rotation. An owl can turn its head through most of a circle and thus can see almost 360 degrees. An owl can even turn its head upside down for all-around vision. Figure 1 shows on the card at the bottom a red Eastern Screech-Owl rotating its head at almost 180 degrees .

Eastern Screech-Owl

Fig. 1. Eastern Screech-Owl, on stamp and upper left on card a Gray morph; and in middle & lower left on card a Red morph. Stamp issued on Mar. 13, 1998; for Bird Conservation. Card from a painting by J. J. Audubon, plate 97, National Gallery of Art, Washington, D.C. Color Postcard: Pub by Running Press Book Publishers, 1986. Cancel: Pictorial (triple), Dorval, QC, April 3, 1998. Realized by George Constantourakis.

Owls are often heard rather than seen because they are nocturnal. Most owls have specific calls, but some species have extensive and variable calls. Female owls are somewhat larger than males, but both sexes have similar plumage. The body feathers are very soft and the flight feathers are saw-toothed at the edges. This allows for a very silent flight in order to surprise its unaware prey. Their prey is caught with talons and generally swallowed whole. Owls regurgitate indigestible bones, feathers, and fur as pellets. Figure 7 shows on the stamp a Saw-Whet Owl in flight, and on the card the same owl landing with its prey in its mouth. Both stamp and the card show the flight feathers that are saw-toothed at the edges.

This article will deal with four different species, all of the "Typical Owls" (Strigidae) family.

EASTERN SCREECH-OWL (Otus asio)

This is the only small owl (7-10” or 18-25.5 cm.) in eastern North America with erectile ear tufts. This species is subdivided into two distinct color types (or color morphs), the Red and the Gray-brown color morph.

Red morph: the upperparts are cinnamon rufous, and the underparts are white streaked and barred with rufous. Figure 1 shows on the card two red Eastern Screech-Owls. On the owl in the middle one can see the upperparts of cinnamon rufous, and on the owl at the lower left one can see the underparts of white streaked and barred with rufous.

Grey morph: the upperparts are gray-brown streaked with brown, and the underparts are white heavily streaked with dark brown. Figure 1 shows on the stamp and on the card (upper left) a gray Eastern Screech-Owl.

Both morphs have yellow eyes, with white eyebrows and lores. The eyes are surrounded by facial discs, bordered by a broad black stripe, and continues on to the throat. Juveniles of both morphs are barred all over with brown and white. Figure 2 shows on the card seven juvenile Eastern Screech-Owls perched on a tree branch.

Juvenile Eastern Screech-Owls

Fig. 2. Juvenile Eastern Screech-Owls, on the card 7 juveniles perched on a branch. Stamp issued on Mar. 13, 1998; for Bird Conservation. Color Postcard: Pub. by New York Zoological Society, Nr. 652.B. Cancel: Pictorial (triple), Dorval, QC, April 3, 1998. Realized by George Constantourakis.

Its habitat is deciduous forests, open woodlands, and groves by the banks of rivers and lakes. Its range is from Minnesota south to the Gulf of Mexico; and from southeastern Canada south to Florida, including the Keys. Their voice is characterized by a long "whinny", beginning on a rising pitch and then descending with a pronounced waver. Similar species: Western Screech owl. The range of these two different species overlaps in a small zone in Texas, and are only distinguished by their voice.

Great Horned Owl

Fig. 3. Great Horned Owl. Stamp issued Aug. 26, 1978; for Wildlife Conservation. Card from a painting by J. J. Audubon, plate 61, Nat. Gallery of Art, Wash. D. C. Color Postcard: Pub. by Running Press Book Publishers, 1986. Cancel: Pictorial (triple), Binghamton, NY, Mar. 22, 1997. Realized by George Constantourakis.

GREAT HORNED OWL (Bubo virginanus)

This is a very large owl (18-25” or 45-63 cm) and has a prominent widely spaced ear tufts. Figure 3 shows, particularly on the card and on the pictorial cancellation, the very pronounced ear tufts. Its eyes are bright yellow. (See Figure 4 the owl on the card.) The wings are dark above, and the wing linings are buff. Overall color varies from nearly white in the Arctic (See Figure 4, the Canadian stamp and the card) to very dark in the Pacific Northwest (See Figure 3, the owls on the card).

Its habitat is equally in deep forests, open country, or city parks. The Great Horned Owl is the most powerful and aggressive of the North American Owls. Its diet includes animals as large as skunks, ducks, cats, fowls, opossums, hawks, and Great Blue Herons. Its range is from the northern limit of the tree line south throughout the lower 48 states, and also throughout Central and South America. It is nonmigratory, restricted to the Western Hemisphere, and also the most widespread owl. Its voice is characterized by a wide variety of sounds. Most frequent are deep low hoots: "hoo-hoo-hoo-hoo-hoo."

Similar species are: Barred, Spotted, Great Gray, and Snowy Owl, all without dear tufts. It is also related to the Long-eared Owl that is much smaller with ear tufts set closer together.

Great Horned Owl

Fig. 4. Great Horned Owl (From Canada, lighter in color). Stamp issued on Aug. 26, 1978; for Wildlife Conservation. Color Postcard: Pub. by Photo Décor Ltd., Nr. 731. Cancel: Montreal, QC, June 30, 1993. Realized by George Constantourakis.

BARRED OWL (Stix varia)

This is a large owl (17-24” or 43-61 cm) distinguished by its round head with no ear tufts. The body plumage is gray-brown, crossed by transverse bars on the neck and upper breast, and by vertical streaks on the lower breast and belly. Figures 5 & 6 show on each card and stamp, this sharp contrast of the transverse barring on the neck and upper breast, with the vertical streaks of the belly.

The Barred Owl has distinctive brown eyes. It has short broad wings and moves easily through the forest on slow wingbeats. Its habitat is in wooded swamps and deep forests. It is especially common along lake shores. It hunts small prey such as frogs, crayfish, small mammals, and birds, mainly screech-owls. Its range is in Canada from British Columbia to Nova Scotia, and in the U. S. in the eastern states including Florida and Texas. Its voice is characterized by a wide range of sounds, most frequently by nine hoots, not as low as the Great Horned Owl’s call. Similar species are: Great Gray Owl and Spotted Owl.

Barred Owl

Fig. 5. Barred Owl, in flight on stamp and perched on branch on card. Stamp issued on Aug. 26, 1978; for Wildlife Conservation. Color Postcard: Pub. by Wildlife Portraits, Maine, NR. WL-34. Cancel: Pictorial, Big Creek, WV, Oct. 5, 1995. Realized by Terry Watson.

SAW-WHET OWL (Aegolius acadicus)

This is the smallest of all eastern owls (7-10” or 18-25.5 cm). Its name comes from one of its calls which sounds like the filing of a saw. It is distinguished by its large round head, large yellow eyes set in facial discs that lack the black edge found in most owls. The body plumage is dark above flecked with white and buff, below streaked with brown. Its bill is dark.

Juveniles are colorful and unique. The are chocolate brown above with a cinnamon-buff belly and a white triangular patch on the forehead. Its habitat is the boreal and montane forests. It is strictly nocturnal and thus difficult to see. This is obvious on Figure 7, observe the background on the card. The owl’s range is in Canada from British Columbia to Nova Scotia, and in the U. S. from the Pacific Northwest, south to California, and east to New Mexico. It winters south of its breeding range.

Its voice is characterized by a very long series of “toots” or whistles, easily imitated. It can be whistled into view by imitating its call. It is very tame and will often allow itself to be picked from a tree and held with struggle. Similar species are: Elf and Flammulated Owls, Ferruginus, and Northern Pygmy Owls.

Barred Owl

Fig. 6. Barred Owl, in flight on stamp and perched on branch on card. Stamp issued Aug. 26, 1978; for Wildlife Conservation. Color Postcard: Pub. by Photo Décor Ltd., Nr. 696. Cancel: Pictorial, Louisville, CO, June 28, 1997. Realized by George Constantourakis.

George Constantourakis is the Secretary/Treasurer of MACSU and has exhibited worldwide, garnering many awards for his exhibits.

Saw-whet Owl

Fig. 7. Saw-whet Owl, in flight on stamp and landing on card. Stamp issued on Aug. 26, 1978; for Wildlife Conservation. Color Postcard: Pub. by National Museum of Natural Science. Cancel: Pictorial, Louisville, CO, June 28, 1997. Realized by George Constantourakis.

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Last Updating: Feb-06-1998