The unexpected sounds of birds piercing the quiet of night can be startling. While many associate bird calls with the daytime, various avian species are active and vocal after dark. These nocturnal vocalizations serve distinct purposes, from communication to territorial defense, offering a fascinating glimpse into the natural world.
Identifying the Nocturnal Screamers
Among the most prominent nocturnal vocalizers are owls, known for their diverse range of calls. Barred Owls, for instance, produce a distinctive eight-to-nine-note hooting call often described as “Who cooks for you? Who cooks for you-all?”. These calls can carry significant distances through wooded areas.
Great Horned Owls also hoot with a deep, low, and rhythmic “hoo-hoo hooooo hoo-hoo,” audible from great distances, with females having a noticeably higher pitch. Owls also emit screeches, barks, or gurgles, especially during courtship or when disturbed.
Nightjars are another group of birds frequently heard at night, named for their crepuscular or nocturnal activity. The Eastern Whip-poor-will is famous for its loud, repetitive “whip-poor-will” call, often chanted for extended periods on warm summer nights.
Common Nighthawks, though active at dusk and dawn, produce a sharp, nasal “peent” or “beernt” call while in flight. They also create a unique “boom” sound with air rushing through their wing feathers during courtship dives.
Herons can also contribute to the nighttime chorus, particularly in or near their nesting colonies. Species like the Great Blue Heron are known for harsh, croaking, or squawking sounds, especially when flying or disturbed. Black-crowned Night-Herons, true to their name, are active after dark and produce barking squawks when disturbed, or a raspy “woc-a-woc” call when bringing food to nests.
Understanding Why They Scream
Nocturnal bird vocalizations are not random; they serve specific biological and behavioral functions. Many birds use loud calls at night to establish and defend their territory, signaling their presence to other birds and preventing intrusions. This is evident during breeding seasons when boundaries are important for reproductive success. The stillness of the night allows these territorial declarations to travel farther, reinforcing claims more effectively than during the bustling daytime hours.
Attracting a mate is another primary reason for nighttime vocalizations. Male birds often sing loudly to advertise their availability and demonstrate their vitality to potential partners. The relative quiet of the night allows their calls to stand out, increasing the chances of being heard by females across greater distances. For example, unpaired male Northern Mockingbirds may sing continuously through the night to attract a mate.
Birds also use nocturnal calls for communication within their species, such as warning others of predators or perceived threats. Alarm calls can alert flock members to danger, even in low light conditions. Vocalizations also help maintain cohesion within a group, especially for species that move or forage at night, preventing isolation and identifying locations of other individuals. Calls can also occur if birds are startled or displaced from their roosts, leading to unexpected outbursts.
Deciphering the Sounds and Coexisting
Distinguishing between various nocturnal bird calls can be achieved by focusing on specific characteristics like pitch, rhythm, and overall quality. Owl hoots are deep and rhythmic, while nightjar calls are repetitive and can sound mechanical or like their names. Heron calls, by contrast, are harsher squawks or croaks.
Online resources and mobile applications can assist in identifying these sounds; several apps allow users to record sounds for identification or provide extensive databases for comparison. Merlin Bird ID, for instance, uses sound recordings to provide real-time suggestions for bird identification.
These nighttime sounds are natural behaviors and do not indicate distress or a need for intervention. Birds vocalize at night for their survival and reproduction. If the sounds are disruptive, simple measures such as closing windows or using white noise can help mitigate the disturbance. Understanding that these sounds are seasonal, particularly during breeding periods, can also provide perspective. It is best to appreciate these nocturnal choruses as part of the natural environment.