Owl, Cactus Ferruginous Pygmy

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Owl, cactus ferruginous pygmy

Glaucidium brasilianum cactorum

phylum: Chordata

class: Aves

order: Strigiformes

family: Strigidae

status: Endangered, ESA

range: Mexico, USA (Arizona, Texas)

Description and biology

The cactus ferruginous pygmy owl, the most endangered species of owl in the world, is one of three subspecies of the ferruginous pygmy owl. As its name suggests, it is one of the smallest of the owl family, usually measuring less than 7 inches (17 centimeters) long. Males weigh about 2.2 ounces (62 grams), while females weigh more, at about 2.6 ounces (75 grams). The pygmy owl's feathers, or plumage, are usually a reddish-brown color, with a streaked beige belly and crown. The owl has no ear tufts, and on the back of its head there are two black spots outlined in white that look like eyes. The bird has yellow eyes and an unusually long tail for an owl.

The cactus ferruginous pygmy owl flies short distances directly from one perch to another. It will then sit in its perch

in a tree branch for hours. It is diurnal, or active during the day, and an avid hunter. Its diet is comprised of birds, lizards, insects, small mammals, frogs, and earthworms. It roosts at night in holes in trees or large cacti in dense desert scrub thickets. Its call is made up of a series of short, shrill notes. The small owl is nonmigratory—it does not travel seasonally to other habitats.

The cactus ferruginous pygmy owl begins its nesting activities in early spring. It usually nests in holes in trees or in cacti—most often in the large saguaro cactus in holes dug out by woodpeckers. The female lays between three and six eggs at a time. Incubation (sitting on the eggs to keep them warm until they hatch) lasts for about 28 days. Within another 28 days, the owlets will begin to fly.

Habitat and current distribution

The cactus ferruginous pygmy owl's range is from central Arizona south through western Mexico to the states of Colima and Michoacan, and from southern Texas south through the Mexican states of Tamaulipas and Nuevo Leon. The species is most likely to be found in desert oases or washes where there is moisture—along the banks of streams or other waterways—and where they can find a good variety of the animals they eat. They generally live at elevations below 4,000 feet (1,200 meters).

In 2002 a total of 18 cactus ferruginous pygmy owls were found in Arizona. Some of the pygmy owl's habitat is found in the fastest-growing areas of Tucson, where a few adult owls remain. There have also been a few sightings of these owls in Texas. The reported sightings in western Mexico are not complete enough to form population estimates, but the species is more common there.

History and conservation measures

At one time cactus ferruginous pygmy owls in Arizona ranged from an area north of Phoenix to the Mexican border. Due to habitat loss, however, the few remaining owls in the state are found only between Tucson and the Mexican border. The decline in population is due to the destruction of the pygmy owl's preferred environments: both riparian (on the banks of natural waterways) and desert habitats. The plight of the Arizona owls is dire. Housing developments, clearing for farming and logging, water diversion, livestock overgrazing, and many other symptoms of the ever-growing human population in the area have severely reduced the habitat of the species.

The U.S. Fish and Wildlife Service listed the Arizona population of pygmy owl as an endangered species in March 1997, designating 731,000 acres of protected critical habitat. Since that time there has been a battle between conservationists (people who work to protect and preserve the natural world) and the developers of urban sprawl—the people responsible for building housing, shopping malls, and related industry farther out into the desert, who stand to lose money if the land cannot be developed. In 1998, conservationists sued to stop a school from being built on the critical habitat of the pygmy owl. The courts ruled against them, allowing the school construction to continue. The National Association of Home Builders sued to have the cactus ferruginous pygmy owl removed from endangered status. The Southern Arizona Home Builders Association then fought to have the critical habitat designation removed from the area selected for the pygmy owl. In September 2001, a federal judge complied with their wishes, removing the critical habitat protection from the land until further studies could be accomplished. In 2003, a new proposal for critical habitat for the pygmy owl was issued. If enacted, it will encompass 1,208,001 acres (489,070 hectares), but there is very little time left for the cactus ferruginous pygmy owl. The species appears to be on the brink of extinction.