The Barred Owl (Strix varia) is a fascinating species of owl found across North America, inhabiting a variety of forest ecosystems. This guide provides an in-depth look at the life of the Barred Owl, covering its preferred habitats, diverse diet, intricate nesting behaviors, characteristic behaviors, and the conservation status of the species. Understanding these aspects is crucial for appreciating and protecting these magnificent nocturnal predators.
Habitat
Barred Owls are year-round residents of mixed forests characterized by large trees, with a particular preference for areas near water. They thrive in extensive, unfragmented tracts of mature woodland, which typically support a richer diversity of prey and offer ample large cavities suitable for nesting. Their habitat preferences are diverse, ranging from swamps and streambanks to uplands. These forests can be composed of various tree species, including hemlock, maple, oak, hickory, beech, aspen, white spruce, balsam poplar, Douglas-fir, lodgepole pine, or western larch. The presence of large, mature trees is a key factor in their habitat selection, providing both food sources and essential nesting sites.
Diet
The diet of the Barred Owl is varied, encompassing a wide array of small animals. Their prey includes mammals such as squirrels, chipmunks, mice, voles, and rabbits. They also hunt birds, which can be as large as grouse, as well as amphibians, reptiles, and invertebrates. Barred Owls are patient hunters, typically perching on an elevated spot to scan their surroundings with acute vision and hearing. They have been observed perching over water to deftly snatch fish or even wading into shallow waters to catch fish and crayfish. While they are most active hunters shortly after sunset and throughout the night, they may also forage during daylight hours. Prey is often temporarily stored in a nest, on a branch, or at the top of a dead tree (snag). Small prey items are swallowed whole, while larger prey is consumed in pieces, with the head typically being eaten first, followed by the body.
Nesting
Nest Placement
Barred Owls predominantly choose natural cavities in large trees for their nests, typically situated at heights of 20 to 40 feet. They are also known to utilize abandoned stick nests built by other animals, such as hawks, crows, ravens, and squirrels, and will readily use human-made nest boxes. Interestingly, Barred Owls may investigate potential nest sites as early as a year before occupying them. The exact process of site selection, whether by the male or female, remains unknown.
Nest Description
These owls generally do not significantly alter existing tree cavities or previously constructed platform nests. If using a stick nest, they might add lichen, fresh green conifer sprigs, or feathers. For squirrel nests, they may flatten or remove the top portion. The dimensions of these cavities typically range from 10 to 13 inches in width and 14 to 21 inches in depth, though some can be considerably deeper, with one recorded cavity extending nearly 8 feet.
Nesting Facts
- Clutch Size: 1-5 eggs
- Number of Broods: 1 brood per year
- Egg Length: 1.7-2.2 inches (4.3-5.6 cm)
- Egg Width: 1.5-1.8 inches (3.8-4.5 cm)
- Incubation Period: 28-33 days
- Nestling Period: 28-35 days
- Egg Description: Pure white with a rough surface.
- Condition at Hatching: Hatchlings are helpless, covered in white down, with their eyes closed.
Barred Owl Nest Cavity
Behavior
During daylight hours, Barred Owls rest on branches or within tree cavities, emerging at night to hunt. They maintain a territorial presence year-round, actively chasing away intruders with loud hooting calls. This territorial aggression intensifies during the nesting season, particularly from females, who may strike intruders with their talons. Pairs of Barred Owls are believed to mate for life, successfully raising one brood annually. Their nests are vulnerable to predation from other large owls and hawks, as well as mammals like weasels and raccoons. When humans approach a nest, the parent owl might flee, engage in a distracting display with quivering wings, or even attack. Other bird species recognize Barred Owls as predators, and small songbirds, crows, and woodpeckers may cooperate to mob them. The Great Horned Owl is considered their most formidable predator, preying on eggs, young birds, and sometimes adult Barred Owls.
Barred Owl in Flight
Conservation
The Barred Owl is currently considered a species of low conservation concern. Populations have been relatively stable, with an estimated global breeding population of 3.5 million individuals. According to the North American Breeding Bird Survey, their populations increased by approximately 1.1% per year between 1966 and 2019. Historically, Barred Owls were confined to the old-growth forests of eastern North America. However, factors such as fire suppression and extensive tree planting in the Great Plains have facilitated their northward and westward expansion over the past century. This expansion has led them to the West Coast, including California, where they have come into competition with the Spotted Owl. Barred Owls have been observed displacing the smaller, less aggressive Spotted Owls and even hybridizing with them, posing an additional threat to the already compromised Spotted Owl population. As forest-dependent birds that require large, mature trees for nesting, Barred Owls are sensitive to the impacts of logging. Consequently, they are often utilized as an indicator species for the management of old-growth forest ecosystems.
References
- Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.
- Mazur, Kurt M. and Paul C. James. (2000). Barred Owl (Strix varia), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
- Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.
- Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
- Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.
Learn more about Barred Owls at Birds of the World.
