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The Mexican Spotted Owl (Strix occidentalis lucida) is of particular interest to owl fans like us, as it is very close to becoming an endangered species. With a wild popularion of only 2,160 in the USA as at 1990, and a dangerously low number of birds in Mexico, the Mexican Spotted Owl is classed as "Threatened" under the Endangered Species Act, and "Near threatened" by the the International Union for Conservation of Nature.
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It is one of three different subspecies of spotted owl, the other two being the Northern Spotted Owl (trix occidentalis caurina) and the California Spotted Owl (Strix occidentalis occidentalis). The largest numbers of Mexican Spotted Owl live in the Gila Wilderness, a 558,014 acre expanse which is part of New Mexico's Gila National Forest. In the USA they can also be found in the canyons of Arizona, Colorado, Utah and New Mexico as well as in the far west of Texas. In Mexico where they get their name from, these birds can be found in Eastern Coahuila, Chihuahua, Sonora, ranging throuigh the Sierra Madrea and Nuevo Leon and going south as far as Michoacan.
Unlike most owls, the Mexican Spotted Owl has dark eyes rather than the yelow to orangey color that most owls have. With a height of 16 to 19 inches and a wingspan of 42 to 45 inches, they are among the largest owls in North America.
The main food sources of the Mexican Spotted Owl are Woodrats, White Footed Mice, Voles. Also rabbits, northern flying squirrels and every now and then bats form part of the birds' diet. .
They like to roost in various different habitats but seem to have a preference for mixed conifer or pine oak forests. Mostly they have a tendency to reside under relatively dense canopied forest areas, in older trees, often surrounded by a few logs and forest debris on the ground - they seem to go for an olde-worlde look for their surroundings! Some Mexican Spotted Owls decide to nest in steep-walled deep canyons and cliffs however.
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A typical home range for a Mexican Spotted Owl spans between 640 to 3,680 acres for a single bird. Females have a home range which spans a significantly wider area than males.
The population density of Mexican Spotted Owl varies depending on location and habitat. It has been found that in mixed coniferous forest there is an average of 1 owl in every 3.64 square kilometers, whereas in pine forests the density ddrops to 1 owl in every 12.5 square km and in the Sacramento Mountains of New Mexico the density in pinyon-juniper woodland is as low as 1 owl in every 45.45 square kilometers.
During the winter areas of mountain scrub are used by young owls who have just left the nest and this type of habitat is also thought to be used by migratory Mexican Spotted Owls also.
The actual migration of the Mexican Spotted Owl only occurs over a very small distance of about 50 kilometers (31 miles) or less. This is all they have to travel to get from their winter homes to their breeding grounds. They make the journey to the breeding grounds between february and the middle of April, then in the Autumn they return to their winter ranges in November to December.
It takes between 86 to 102 days for a fledgling to become fully independant. Less than one in 5 Mexican Spotted Owls survive their first year, but the survival rate increases to around 65% for these birds between the age of one and two years old. The main causes of death are starvation or being predated by other animals. Death from exposure is also a danger for young birds in particular. Once a bird reaches adulthood it can expect to live for around 16 to 17 years old.
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