Hearing birds vocalize after sunset is common. While most birds are active during the day, some species are known for their distinct calls and songs that fill the night. This nocturnal activity often sparks curiosity about these unseen singers and their reasons for vocalizing.
Common Nighttime Singers
Several bird species are well-known for their nocturnal vocalizations, each with distinct sounds.
The Northern Mockingbird is a prolific nighttime singer, particularly unmated males during breeding season. Its song is a long series of varied phrases, often repeating each phrase two to six times. It can mimic many other birds, including artificial sounds like car alarms, with a repertoire of up to 200 different songs.
Another celebrated nocturnal vocalist, especially in Europe, is the Nightingale. Its powerful song features a rich array of whistles, trills, and gurgles, often performed loudly. Its song is notable for a loud whistling crescendo. Unlike the Mockingbird, the Nightingale’s song is primarily its own, rather than mimicry.
The Eastern Whip-poor-will, a nightjar, is named for its distinctive, chanted call: “whip-poor-will.” This repetitive call can continue for hours, especially on warm summer nights. Males use it to establish and defend territory and attract mates. These birds are primarily nocturnal, well-adapted to low-light conditions with large eyes.
While not “singers” in the traditional sense, various owl species are prominent nocturnal vocalists. Owls use hoots, screeches, and calls to communicate, establish territories, and attract mates. For example, the Barred Owl is recognized by its unique “who-cooks-for-you” hoot, which can devolve into a “raucous jumble of cackles, hoots, caws, and gurgles” during duets. Barn Owls, on the other hand, produce a raspy, drawn-out scream rather than a hoot.
Why Birds Sing After Dark
Birds vocalize at night for several interconnected reasons.
One primary reason is territorial defense. By singing after dark, birds assert their claim over a territory when fewer competitors are active, ensuring boundaries are recognized even in low light. This acoustic marking is important in dense habitats where visual cues are limited.
Attracting mates is another significant driver for nocturnal singing. During breeding season, particularly in spring, male birds may sing persistently into the night to signal their fitness and readiness to reproduce. The quieter nighttime environment allows their songs to travel further and be heard more clearly without daytime sounds.
Environmental factors also play a role in nocturnal vocalizations. Cooler nighttime temperatures and reduced predator activity can create a safer, more energetically favorable time for some species to be vocal. The absence of much daytime background noise, especially in urban areas, means sounds can propagate more effectively.
Artificial light, such as streetlights and building illumination, can confuse birds’ internal clocks, prompting some diurnal species to sing at night. This light pollution can disrupt their circadian rhythms, leading them to begin their dawn chorus prematurely. Some species are naturally nocturnal or crepuscular, meaning they are active during twilight hours, and their nighttime singing is part of their inherent biology.
Identifying Nighttime Bird Calls
Identifying birds by their calls at night can be an engaging activity, and several methods can enhance your ability to recognize these nocturnal vocalists.
The first step involves careful listening, paying close attention to the patterns, pitch, and repetition within the calls. Noticing if a sound is a continuous song, a series of distinct phrases, or a specific type of call can provide initial clues. Focusing on unique characteristics, such as mimicry or a distinct rhythm, helps narrow down possibilities.
Technology has significantly advanced bird identification, with smartphone applications becoming invaluable tools. Apps like Merlin Bird ID and BirdNET offer “Sound ID” features that analyze real-time audio recordings and provide suggestions for the bird species vocalizing. These applications use artificial intelligence trained on vast databases of bird sounds to identify species, often displaying results instantly, and can even distinguish multiple species within a single recording.
Beyond apps, numerous online resources provide extensive libraries of bird calls and songs. Websites such as the Cornell Lab of Ornithology’s All About Birds and the Macaulay Library offer recordings, often accompanied by sonograms that visually represent the sounds. These resources allow you to listen to known calls of nocturnal species and compare them to what you are hearing. When observing, patience is important, and minimizing disturbance to the birds and their environment ensures a more authentic listening experience.