The great horned owl has dark gray and brown plumage and feathered tufts on both sides of its head. The animal's face is a lighter buff color with a black outline. The bird also has a white patch on its throat. The owl's eyes are large and yellow, and it has dark bars along its breast. The males and females look alike except the females are larger. Females can weigh up to 4.5 pounds while males are usually about 3 pounds but can be as small as 2.5 pounds. Great horned owls stand about 2 feet tall and have a wingspan of 4 to 5 feet.
Great horned owls are found throughout South, Central and North America. They live as far north as Alaska and as far south as the tip of South America. They easily adapt to a variety of habitats and are the most widely spread of any owl species in the New World. They thrive in deserts, woodlands, swamps, farmland, prairies and city parks. They can live on craggy cliff faces and coniferous and deciduous trees. They perch in trees or on rocks and hunt in open spaces.
The great horned owl is important to the variety of ecosystems it lives in because it provides effective pest control. In the wild, the owl preys upon more than 250 animal species. No other bird in North America has such a diverse diet. They are the only animals known to eat skunks. Great horned owls mainly eat rabbits and mice, but will also devour other birds, reptiles and insects. Many of the animals that owls eat are pests that destroy human property and food. Mice and rats can spread disease to humans, and they eat grain crops in fields and in storage. Rabbits are also notorious for snacking on garden produce. Owls hunt at night and use their strong sense of hearing to detect the smaller prey animals. They can hear the sound of a mouse from up to 900 feet away.
Great horned owls are also beneficial to the ecosystem as an indicator of the area's overall ecological health. The owl is at the top of the food chain, and its behavior can indicate if the species it preys upon are in decline or are flourishing. If owls start to leave an area, this indicates a lack of prey. If more owls migrate to a region and successfully produce many young that stay in the area, prey is plentiful. Using owls as an indicator species saves biologists from having to individually count and study each animal population in an ecosystem and enables them to quickly pinpoint species that may be in trouble. If certain species of animals die out in an area, it may indicate a shortage of food even lower in the food chain, a widespread disease or an environmental poison that is affecting the food or water supply. Ecosystem indicators like the great horned owl may alert scientists to environmental problems before they can affect humans or cause long-lasting damage to an ecosystem.