Screech owls are small, nocturnal birds of prey found across North America. Their presence in an area is often first detected by sound rather than sight, as they are adept at camouflage and typically active after dusk. These owls produce a range of distinctive vocalizations, and exploring their unique calls helps in understanding these elusive creatures.
The Primary Calls
Screech owls are known for two primary and highly recognizable vocalizations. The first is often described as a “tremolo” or “trill,” an eerie, even-pitched sound lasting 3 to 6 seconds. This purring trill sometimes changes pitch and is used by mated pairs to maintain contact, often calling back and forth day and night. This call has been likened to a horse’s whinny or a mournful, quavering whistle.
The second signature call is the “bouncing ball” song, particularly associated with the Western Screech-Owl. This vocalization consists of a series of short, whistled hoots that begin slowly and then accelerate, much like a ball bouncing with increasing speed. The rhythm of these hoots is distinctive, often described as sounding like “too too tootootootootoo” as it speeds up. Both males and females vocalize, though males tend to be more vocal.
When and Why Screech Owls Vocalize
Screech owls primarily vocalize at dusk, throughout the night, and into dawn. While possible during the day, their most active calling periods occur after sunset. Their vocalizations are particularly prevalent during late winter and early spring, which marks their breeding season.
Calls serve several important purposes. Males use their songs for territorial and courtship advertising, often from potential nest sites, to attract mates. Mated pairs utilize calls like the tremolo to stay in touch and reinforce their pair bonds. Calls also play a role in territorial defense, with the whinny often used to defend territory from rivals. Additionally, vocalizations facilitate communication with offspring, including begging calls from owlets and alarm calls to signal danger.
Distinguishing Screech Owls from Other Species
Identifying screech owl calls can sometimes be challenging due to similar sounds made by other nocturnal animals. People occasionally confuse their calls with those of mourning doves, other small owl species like the Northern Saw-whet Owl, or even certain frogs and insects.
To differentiate, listen for the specific qualities of the calls: the Eastern Screech-Owl’s whinny-like descending tremolo and the Western Screech-Owl’s accelerating “bouncing ball” series of hoots. The tremolo is a sustained, quavering note, while the bouncing ball features distinct, quickening hoots. Online resources and birding applications with sound libraries can also be valuable tools for comparing and confirming identifications.