Spotted Owl

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Image:Spottedowl.JPG

Common Name: Spotted Owl
Scientific Name: Strix occidentalis

Size: 18 inches (46 cm); Wingspan: 42 inches (106 cm)

Habitat: North America; found from Canada to Mexico mostly in dense, dark, old-growth or mixed mature and old-growth coniferous forests. Forests are usually dominated by firs or Douglas-fir, but they also use mature hardwood forests of cottonwoods, alders, oak, and sycamore, especially along steep-walled river valleys. They prefer an uneven and multilayered canopy. They prefer shaded mountain slopes and canyons over flat plateau areas. S.o. lucida also occurs in heavily logged secondary pine-oak forest, warmer and drier conditions and even bare rocky canyons.

Status: Near Threatened to Critically Endangered. Global population: 15,000 with a decreasing trend. Degradation and fragmentation of its habitat through clear felling and selective logging is the primary threat to the species. This species require old-growth forests to survive. This has been compounded by the removal of a requirement that contractors assess the viability of wildlife on U.S. Department of Agriculture Forest Service lands. It faces strong competition from Barred Owl (Strix varia) which is gradually displacing Spotted Owls from much of the northern part of their range, out competing it for food and space and occasionally hybridizing. The extent to which Barred Owls have been responsible for recent continuing declines in Northern Spotted Owl populations remains uncertain.

Mexican populations may be stable because habitat tolerance is combined with forestry activities that typically modify rather than destroy habitat. Most other populations are declining and, in some, the decline is accelerating because of clear-felling and selective logging. The species is close to extinction in Canada.

They are protected under the Migratory Bird Treaty Act in Canada, the United States, and Mexico. They are also included in CITES Appendix II. The Northern and southern spotted owl populations are currently listed as threatened in the United States under the Endangered Species Act.

Diet: Spotted Owls feed mainly on flying squirrels and wood rats. These prey are necessary for successful breeding. Other major prey include gophers, rabbits and hares. Summer diets are more varied with deer mice and voles being important foods. They also eat small birds, snakes, crickets, beetles, and moths.

Hunting is done mainly at night, usually beginning just after sunset and ending a half hour before sunrise. Spotted Owls us a perch to "sit and wait" to dive down onto prey. They rarely forage in flight. Prey is sometimes cached for later use. Prey taken to the nest by the male is often decapitated first. During the day, a Spotted Owl may take the odd prey that passes by its day roost, fly to a food cache, or fly to a nearby stream to drink.

Nesting: Females are slightly larger. The breeding season is from March to September. Timing and success in producing offspring are strongly linked to the availability of prey, and not all pairs breed every year. Spotted owl pairs mate for life, but a new mate is readily taken if the other disappears. They probably begin breeding at two to three years of age.

Spotted Owls primarily nest in old growth forests. They.nest primarily in abandoned stick nests of Northern Goshawks, on clumps of mistletoe, in large tree cavities, on broken tops of large trees, on large branches, or cavities in banks and rock faces. Old nests are not repaired before eggs are laid, and tend to be reused year after year. Clutch size ranges from 2 to 4 eggs, but averages 2 to 3 eggs. Eggs are laid every 3 to 4 days, usually in April. The female does all incubation and the male delivers food to the nest. The incubation period is about 28 to 32 days. Unlike most other owls, Spotted Owls may not defend their eggs and young from predators, watching nearby as the nest is destroyed. Young are brooded constantly by the female for 2 weeks, then she begins to hunt as well. The male brings food to the nest and passes it to the female to feed to the young. Young start roaming from the nest onto nearby branches at about 5 weeks, but some flutter to the ground before climbing up into trees. They can fly weakly at about 6 weeks. At 9 to 10 weeks young can capture insect prey by themselves. Families remain loosely associated during summer before young disperse in the autumn. Adults tend to remain near their traditional nesting territories, while juveniles disperse widely, as much as 100 to 200 km (60 to 125 miles).

Juvenile Spotted Owls have an average survival rate of 11%, with an average birth rate of .58 owls per pair.

Cool Facts: The spotted has four subspecies: S.o. caurina has a minimum of 3,778 pairs and 1,001 territorial individuals from south-west British Columbia, Canada, to north California, USA; S.o. nominate has a minimum of 3,050 individuals in central and south California, USA, and (formerly) Baja California, Mexico; S.o. lucida has a minimum of 777-1,554 individuals from Utah and Colorado to Arizona, New Mexico and extreme west Texas, USA, and also occurs in Sonora, Chihuahua and Nuevo León to Jalisco, Durango, Michoacán and Guanajuanto, Mexico; and S.o. juanaphillipsae has been recently described from the State of México.

Spotted owls roost in deep shade during the day.


Found in Songbird ReMix Owls of the World Volume 1

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