Mesilla Valley Audubon Society’s Bird of the Month: Mexican spotted owl

Gil Sorg (Mesilla Valley Audubon Society) | June, 2017 | Columns, Features


Mexican spotted owlBird of the Month: Mexican Spotted Owl (Strix occidentalis lucida)

The Mexican spotted owl (MSO) is found in mountainous areas such as New Mexico’s Gila and Sacramento Mountains, as well as Arizona and Mexico and is a threatened species. Historically sightings have been made in Colorado and Utah, but not recently.

MSOs are one of two owl species that can be identified by their black eyes. The other is the Barred owl. The MSO is a cousin to the Northern spotted owl found in the Northwest region of the country.

These owls have a range that encompasses large areas mostly in the 8,000 to 10,000 foot elevations, especially during the nesting season, from April to July. They mate for life, making a nest mostly in large Douglas fir or White Fur trees of old growth forests that have a parasitic fungus called a Witches Broom. Mountain sides that face north or northeast are where the nest trees grow. That is so the nest and owls are in the coolest part of the forest. They make a dense mat in the fur trees and nests are made on top of them. Other nesting sites can be used such as a hollow snag tree or cliff hole. Each female lays one to four eggs (although only one nest has been found to have four eggs that have survived to fledging). While the female sits on the nest and the eggs hatch, the male hunts for food for the female and the chicks. Once the chicks are a few days old, the female will forage also. Chicks will fledge at 32 to 36 days old. Most prey are small mammals, and wood rats are its favorite.

MSO prefer forests with cover to hide from predators. You will find a male roosting under a Rocky Mountain Maple tree as it has broad leaves and good cover. Several raptors have been known to predate MSO, hawks and eagles to name a couple.

Their call is a four-note hoot, although it can sometimes be a three note.

From the Defenders of Wildlife: “In the United States, there are an estimated 2,106 Mexican spotted owls. Numbers in Mexico are also dangerously low.” In the past six to eight years there have been several forest fires in MSO habitat. One would think that would destroy their habitat, but research has shown they are resilient. “We looked at spotted owl foraging behavior at multiple spatial extents and we found that whatever scale we used, the owls foraged in severely burned unlogged forests in proportion to their availability. In other words, they foraged in burned forest with the same likelihood as in unburned forest,” said Monica Bond, lead author of the study.



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