Being startled awake by an unfamiliar sound piercing the quiet of the night often leads to the question of what kind of bird is making the noise. While most bird species are active during the day (diurnal), a significant number thrive under the cover of darkness. These nocturnal birds use the night to hunt, defend territory, and communicate with mates when the environment is calmer and less competitive. Nighttime calls generally come from dedicated nocturnal hunters, repetitive insectivores, or daytime birds whose routines are disrupted.
The Primary Suspects (Owls)
Owls are the primary group of nighttime vocalists, using calls mainly for territorial defense and attracting a mate. Their specialized biology, including highly developed hearing and silent flight, suits them perfectly for nocturnal life. While the deep, resonant hoot is the classic sound associated with owls, their vocal repertoire is diverse.
The Great Horned Owl, a widespread nocturnal raptor, produces a deep, rhythmic series of hoots, often transcribed as “hoo-h’HOO-hoo.” During the breeding season, pairs engage in a vocal duet, with the male’s call being deeper than the female’s. The Barred Owl, common in eastern North America, is known for its distinct, eight-to-nine-note call that sounds like, “Who cooks for you? Who cooks for you-all?”.
Smaller owl species produce sounds often mistaken for non-bird noises. The Eastern Screech Owl, which comes in both gray and reddish-orange color variations, has two common vocalizations: a descending, mournful whinny and a sustained trill. The Northern Saw-whet Owl emits a series of monotonous, high-pitched toots, which some believe resemble the sound of a saw being sharpened. Barn Owls do not hoot; instead, they produce harsh, raspy screams and shrieks that can sound distinctly human or even banshee-like.
Nighttime Insectivores (Nightjars and Relatives)
Nightjars, members of the family Caprimulgidae, are another major group of dedicated nocturnal birds known for their distinctive, loud, and persistent calls. These insectivores hunt flying insects at night in open areas and clearings. Their repetitive calls serve to establish territory or signal to a mate.
The Eastern Whip-poor-will is named for its onomatopoeic three-syllable call, “whip-poor-will,” which it may repeat hundreds of times without pause. Because the first syllable can be faint, observers sometimes only hear the last two parts of the phrase. A close relative, the Chuck-will’s-widow, has a four-note call that also sounds like its name, “chuck-will’s-widow,” though the initial “chuck” note is often too quiet to be heard.
The Common Nighthawk is a type of nightjar often seen performing acrobatic flights at dusk and dawn. This species produces a sharp, nasal call, a single note described as a “peent,” which contrasts with the rhythmic calls of its relatives. During breeding display flights, males also create a non-vocal sound: a deep, resonating “boom” made by air rushing through their primary wing feathers as they dive. Their calls are often the only clue to their presence, making the quality and rhythm of the sound the primary identification tool.
Diurnal Birds Vocalizing After Dark
While owls and nightjars are predictably nocturnal, some diurnal species occasionally vocalize at night due to specific environmental factors or behavioral periods. The American Mockingbird often sings throughout the night, especially during the spring and early summer breeding season. Unpaired males sing for extended periods to attract a mate.
Artificial light pollution in urban and suburban areas can confuse the circadian rhythms of many diurnal songbirds, making them believe it is dawn or dusk. Species like the American Robin, which are highly sensitive to light, may continue to vocalize after sunset near streetlights or brightly lit buildings. Daytime noise pollution is another factor, forcing some birds to sing at night when the environment is quieter and their calls can travel farther, improving communication.
Migration sounds also contribute to the nighttime chorus, particularly during the spring and fall. Many species, including warblers, thrushes, and sparrows, migrate under the cover of darkness to avoid predators and take advantage of calmer air. As they fly overhead, these birds maintain contact by emitting small, high-pitched vocalizations known as nocturnal flight calls (NFCs). These irregular and brief calls sound like faint chirps or chip notes, distinct from sustained territorial songs.
How to Identify the Mystery Noise
Identifying a nighttime noise requires analyzing the sound’s quality and context. Note whether it is a deep, rhythmic hoot, a loud, repetitive chant, or a brief, high-pitched chip note. Rhythm and repetition are often the clearest indicators; nightjar calls are persistent, while owl hoots are usually more measured and spaced.
Consider the time of night and the time of year, as these factors narrow the possibilities. Calls heard consistently in the deep night are likely from dedicated nocturnal species like owls or nightjars. Calls heard just after dusk or before dawn might be diurnal birds affected by light pollution. Migration-related calls occur only in the spring and fall, and mockingbird songs peak in the late spring and summer. Finally, be mindful of non-bird sounds frequently mistaken for vocalizations, such as the chirps of insects, the croaking of frogs, or noises made by small mammals.