The screech owl is a familiar presence in North American forests and suburbs, yet its name often causes confusion about its actual vocalizations. The term “screech owl” refers primarily to the Eastern and Western species, both of which possess distinctive calls far more complex than a simple shriek. Listeners often expect a harsh sound, but the characteristic noises of these nocturnal birds are surprisingly varied and melodic.
The Defining Sounds of Screech Owls
The name “screech owl” is misleading because the birds rarely produce a high-pitched screech, a sound more commonly associated with the Barn Owl. The Eastern Screech Owl (Megascops asio) is known for two primary calls. The first is a high-pitched, descending whinny, a tremolo call often compared to the sound of a miniature horse. This whinny typically lasts between 0.5 and 2 seconds and is used as a loud warning to other owls encroaching on its territory.
The second call is an even-pitched, purring trill, also known as a tremolo. This soft, monotone sound is sustained for three to five seconds, containing around 35 notes, and is used for intimate communication. This rhythmic trill serves as a contact call, allowing mated pairs or family members to keep track of each other while hunting or throughout the night. The Western Screech Owl (Megascops kennicottii) has a distinctly different signature call: a series of short, whistled hoots.
This Western vocalization starts slowly and then accelerates into a rapid burst, creating a pattern often described as a “bouncing ball” or Morse code. The number of hoots ranges from five to fifteen, and the accelerating rhythm is the key identifying feature. Both species employ these unique sounds as their main form of long-distance communication, making them the most likely vocalizations a person will hear.
Why Screech Owls Vocalize
The distinct calls of screech owls serve multiple functions essential to their survival in their nocturnal environment. One primary purpose of the whinny and the bouncing ball hoots is territorial defense, signaling to rivals that an area is occupied. Male owls use these loud, species-specific calls to advertise and mark the boundaries of their hunting and nesting grounds, especially during the breeding season.
Vocalizations are also integral to pair bonding and courtship rituals. During this period, which often intensifies in early spring, pairs frequently engage in duets, particularly using the Eastern Screech Owl’s purring trill. The male approaches the female, often emitting soft vocalizations, which leads to synchronized trilling that reinforces the bond.
These calls also function as general contact and location signals for family members. The softer trill maintains communication between a mated pair or with young owlets. Calls are typically heard most often at dusk and dawn, the periods of peak activity.
Differentiating Other Screech Owl Noises
Beyond the primary territorial and contact calls, screech owls possess a repertoire of secondary noises used in close-range situations. When an owl is threatened, distressed, or actively defending its nest or young, it may emit sharp alarm calls. These sounds are often described as barks, squeals, or, in rare instances, a true piercing screech.
Owlets, or baby owls, have a specialized vocalization known as a begging call. These are soft, repetitive squeaks and chirps used to solicit food from their parents. These sounds are typically heard only by those in close proximity to a nest cavity.
Screech owls also produce non-vocal sounds that are mechanical, serving as a physical threat or warning. The most common is bill snapping, where the owl rapidly claps its mandibles together. This sharp, clicking noise is not produced by the vocal cords but is an aggressive display used in territorial disputes or when the owl is cornered.