Owls are a diverse and widespread group of raptors across Illinois, representing a variety of sizes and habits. The state provides suitable habitat for several species, which play an ecological role by controlling small mammal populations. These birds are generally nocturnal, making them elusive, but their presence is confirmed by distinctive calls and occasional daytime sightings. Understanding the different species helps observers appreciate the natural diversity present in Illinois woodlands, fields, and urban parks.
Illinois’ Year-Round Resident Owls
The state is home to three common owl species that maintain a year-round presence. The largest and most recognizable is the Great Horned Owl, a powerful predator measuring 18 to 25 inches long with a wingspan up to five feet. It is identified by its prominent feathered tufts (often mistakenly called “ears”) and its mottled brown and white plumage with striking yellow eyes. This adaptable species is found statewide in nearly all habitat types.
The Barred Owl is another common resident, slightly smaller than its horned relative, typically ranging from 18 to 22 inches in length. This species lacks the ear tufts, possessing a large, rounded head and distinctive dark brown eyes. Its name comes from the feather patterning: horizontal bars on the chest and vertical streaks on the belly. The Barred Owl is strongly associated with dense, mature forests, especially those near water sources like swamps and bottomlands.
The Eastern Screech Owl is the smallest permanent resident, averaging only seven to ten inches tall, roughly the size of a robin. This tiny owl possesses small ear tufts and occurs in two color phases: grayish-brown and a less common rufous or reddish-brown. The Eastern Screech Owl adapts well to human-modified landscapes and is common in wooded suburban areas, orchards, and city parks across the state.
Distinguishing Characteristics and Vocalizations
Differentiating between Illinois’ resident owls is achieved by observing the presence of ear tufts and the sound of their vocalizations. The Great Horned Owl and the Eastern Screech Owl both have feather tufts, while the Barred Owl has a round head.
The calls of these species are distinct and serve as the most reliable identification tool for nocturnal birds. The Great Horned Owl produces a deep, rhythmic four- or five-note hoot, often transcribed as “hoo-hoo-hoo-hoo-hoo.” The Barred Owl’s call is a complex series of eight hoots that phonetically sounds like, “Who cooks for you? Who cooks for you-all?”
The Eastern Screech Owl does not actually screech, despite its common name, but instead emits a tremulous, descending whistle that sounds much like a horse’s whinny. The Northern Saw-whet Owl, a smaller species that migrates through Illinois, is identified by its persistent, mechanical “too, too, too” whistle, repeated in a long, monotonous series.
Seasonal and Migratory Owl Species
Illinois hosts several owl species that are temporary visitors, primarily during the winter months. The Snowy Owl is the most famous of these visitors, arriving from the Arctic tundra in irruptive years when northern prey populations crash. These large owls are unmistakable with their mostly white plumage and are active during the day, contrasting with most other Illinois owls.
Two other migratory species are the Long-eared Owl and the Short-eared Owl, both primarily seen as winter residents in the upper two-thirds of the state. The Long-eared Owl is a slender, secretive bird with long, prominent ear tufts, often found roosting communally in dense conifer stands. The Short-eared Owl is a bird of open habitats, preferring prairies and marshes, and is one of the few species observed hunting at dawn and dusk.
The Northern Saw-whet Owl is a rare migrant and winter resident that lacks ear tufts and is secretive. This tiny raptor travels south from its northern breeding grounds, migrating through Illinois in late fall and departing in early spring. It is often found roosting low in the dense cover of cedar or pine trees.
Locating Owls: Habitats and Regional Presence
Locating owls in Illinois involves targeting specific habitat types throughout the state. Barred Owls are closely tied to mature, continuous woodlands and river corridors, a habitat abundant in Southern Illinois. Great Horned Owls are geographically flexible, thriving in fragmented woodlots, suburban parks, and small city green spaces throughout all regions.
The smaller Eastern Screech Owl is adaptable to urban environments, often nesting in tree cavities or man-made nest boxes within residential neighborhoods statewide. Open-country specialists, such as the Short-eared and Snowy Owls, are most reliably found in the large, flat expanses of northern and central Illinois, including restored prairies, wetlands, and agricultural fields.
Long-eared Owls and Northern Saw-whet Owls are typically found during winter in dense stands of conifers, such as pine plantations, which provide excellent daytime cover. Finding these shy, camouflaged winter visitors often requires searching for their droppings (whitewash) or regurgitated pellets beneath roosting trees. The rare Barn Owl, considered an endangered species in Illinois, is most often found in open fields and old farm structures of the southern counties.