Aegolius acadicus, better known as the northern saw-whet owl, is a small owl native to North America. Noted for its diminutive size, the northern saw-whet owl is also extremely well adapted to a variety of habitats, and can be found in deserts, boreal and subtropical forests, and even some urban areas. Habitat loss has lead to diminishing populations in some of the owl's large range, but it remains one of the most populous owls throughout North America.
Usually rising to a height of about eight inches (20.3 cm), the northern saw-whet owl has a similarly small wingspan, generally reaching about 20 inches (50.8 cm) from wingtip to wingtip; females tend to be slightly larger than males. Coloration is dark brown with patches of white, the better to blend into the coniferous forests that the owl prefers. Like many owls, the northern saw-whet owl has startlingly large and bright yellow eyes.
A nocturnal hunter, the owl feeds mostly on small rodents, insects, and birds. Some coastal populations have been observed dining on crustaceans and other seaside species. The owl uses a combination of the diminished light of evening and its camouflaged coloration to help sneak up on prey. Though predators to many smaller animals, the saw whet owls can also be prey themselves, particularly to large owl species such as the great horned and barred owls. Unfortunately for avid bird-watchers, the nocturnal habits of the owl make sightings rare, despite its extremely wide-spread range.
Mating among the saw-whet owls takes place in spring and early summer, though males may start displaying mating behavior throughout winter. Owls typically form a bonded pair, particularly in areas where food supply is scarce. Mother owls incubate the nest full-time, but leave the nest shortly after the chicks hatch. The father owl provides food throughout the incubation and hatching period, and continues to bring meals to the baby owls even after the mother has departed. Chicks reach sexual maturity in about one year.
The range of the northern saw-whet owl is quite staggering, especially for such a small animal. Breeding and permanent populations are found across the entire continent, reaching well into Canada and even south of the United States into central Mexico. The excellent camouflage and adaptable eating patterns of the owl, as well as its cooperative parenting structure, allow it to thrive in many different settings. Population estimates for the species suggest that somewhere between 300,000 and 600,000 individuals live in the wild, making the northern saw-whet owl one of North America's most common, if least seen, owl species.