Birds make a variety of sounds that serve different purposes in their daily lives. The most recognizable bird sounds are bird songs, calls, and alarm calls. Birds primarily use vocalizations to communicate with other birds, but some species can mimic sounds they hear in their environment as well. Understanding the diversity of bird vocalizations provides insight into avian communication, behavior, and ecology.
What are the main types of bird sounds?
Birds make three main types of vocalizations:
Songs
Bird songs are often longer, more complex vocalizations used primarily by male birds to defend territories and attract mates. Songs tend to have multiple notes arranged in a sequence that is often repeated. Some well-known examples of bird songs include the northern cardinal’s “cheer cheer cheer” and the wood thrush’s flute-like song. Songs are produced primarily during the breeding season.
Calls
Bird calls are shorter, simpler vocalizations that serve a variety of purposes. Calls are used year-round by both sexes. For example, contact calls allow birds to locate each other, begging calls are made mainly by nestlings requesting food, and alarm calls alert other birds to danger. Some common bird calls include chickadees’ “chick-a-dee-dee” calls and crows’ “caw caw” contact calls.
Alarm calls
Alarm calls are specialized calls that warn other birds of potential predators and threats. They tend to be loud and high-pitched. A well-known example is the black-capped chickadee’s namesake “chick-a-dee-dee” alarm call sequence. Other small birds often recognize chickadee alarm calls and respond accordingly even though they make different vocalizations themselves.
Why do birds vocalize?
Birds vocalize for a variety of reasons. Some key functions of bird vocalizations include:
Defending territories
Songs proclaim ownership of territories and ward off rivals. For example, the song sparrow sings from prominent perches to defend its breeding territory.
Attracting mates
Bird songs indicate fitness to potential mates. The ability of male birds like lyrebirds and mockingbirds to accurately mimic sounds demonstrates vocal skill.
Strengthening social bonds
Vocalizations help maintain flocks and family groups. Greeting calls between parents and chicks or contact calls between mates serve social purposes.
Begging for food
Nestlings indicate hunger with loud begging calls. Adults may withhold food until they hear these vocalizations at close range.
Navigating
Birds may use contact calls to locate each other over long distances while flying or foraging. Flocking birds vocalize to maintain cohesion.
Coordinating mobbing
Alarm calls summon other birds to harass shared predators. For example, kingbirds and jays defend territories cooperatively when responding to each other’s alarm calls.
How do birds produce sound?
Birds lack vocal cords like humans. Instead, they produce sound via the avian syrinx, a specialized organ located at the junction of the two bronchi in their respiratory tract. The syrinx contains vibrating tissues called labia, which can be modified to produce diverse sounds.
The aerodynamics of the trachea, bronchi, and beak also influence the timbre and resonance of vocalizations. Some bird groups like parrots, hummingbirds, and doves use modified feathers around their syrinx to amplify or modulate sounds.
How do birds learn their songs and calls?
Birds learn vocalizations in different ways depending on the species. Three major types of vocal learning exist in birds:
Imprinting
Early auditory experience helps establish the basic structure of vocalizations in some species. Young birds may improvise on learned templates later in life. This is typical in non-songbirds like pigeons.
Innate
In some species like quails, vocalizations are entirely innate and require no learning. These birds can produce typical calls isolated from adult tutors, indicating their sounds are genetic.
Imitation
Oscine songbirds like sparrows learn most of their vocalizations through imitation. Young birds memorize and practice songs, gradually improving accuracy. Adults provide models and feedback on performance.
Some birds excel at imitating sounds beyond their species’ normal vocalizations. For example, lyrebirds, mockingbirds, and parrots incorporate other species’ calls, mechanical sounds, or even human speech into their repertoires.
How do bird calls and songs vary between species?
Bird vocalizations vary substantially between species due to anatomical differences in their vocal organs and diverse evolutionary pressures. Key features that vary include:
Frequency and pitch
Larger songbirds like crows tend to produce lower, deeper notes than smaller finches or wrens. Body size constrains vocal frequency.
Song complexity
Some birds produce simple, repetitive motifs while others have elaborate, lengthy melodies. Complex songs tend to be used for courtship rather than territorial defense. Nightingales are renowned for their complex, musical love songs.
Repertoire size
Northern mockingbirds can imitate over 200 distinct songs and calls, whereas chipping sparrows may only make 1-2 distinct chip notes. More versatile mimics have larger sound repertoires.
Regional dialects
Within a species, regional bird populations can develop different vocal dialects. White-crowned sparrows in California sound distinctly different than those in Washington state. Young birds learn the local dialect.
Mimicry
Some species readily incorporate non-native sounds from other species or their environment into their vocalizations. Lyrebirds are master mimics, replicating everything from camera shutters to chainsaws.
Examples of bird vocalizations
Here are some examples of common North American bird vocalizations:
Northern Cardinal
The northern cardinal’s loud, whistled song often sounds like “cheer cheer cheer” or “birdie birdie birdie.” It is used to defend territories. Cardinals also make short chip notes for staying in contact.
American Crow
American crows produce a familiar hoarse, creaking “caw caw” sound for communicating over long distances. They also make rattles, clicks, coos, and other calls in social interactions.
Black-capped Chickadee
The chickadee’s namesake call sounds like “chick-a-dee-dee.” The number of “dee” notes indicates the threat level perceived by the caller. Chickadees also make quieter contact calls like “hey-sweetie.”
Wood Thrush
The ethereal, flute-like song of the wood thrush contains melodic phrases that each begin with an upward sweep and descend in pitch at the end. Its call is a distinctive sharp “tuk.”
Eastern Bluebird
Both male and female eastern bluebirds sing, making a bright warbling song often written as “chur-lee chur-lee” or “tru-alley tru-alley.” They use distinct calls like “chir chirr” and soft whistles.
European Starling
Starlings are accomplished mimics. Their jumbled songs incorporate whistles, rattles, bell-like tones, and phrases from other birds. Calls include nasal whines, rasping squawks, and metallic clicks.
How can you identify birds by sound?
Identifying birds by ear takes practice but allows birdwatchers to detect hidden or hard-to-see species. Consider these tips for identifying birds by sound:
1. Focus on common vocal species
Learn the main calls and songs of common vocal yard and garden birds first like chickadees, titmice, cardinals, jays, wrens, etc.
2. Note song patterns
Pay attention to the pattern, pitch, notes, and rhythm of each bird’s distinct song or call. Visualize these patterns.
3. Use mnemonics
Use mnemonics like “teacher teacher teacher” for the oak titmouse or “drink your TEA” for the downy woodpecker to memorize songs.
4. Record and review
Use apps like Merlin Bird ID to record unknown bird sounds then review and compare them to sample recordings to ID them.
5. Learn bird language
Note how different species respond to each other’s calls and songs as these interactions provide more context for identifying species.
6. Focus your ears
Turn down background noise, position yourself downwind of vocalizing birds, and use acoustic aids to detect soft or distant bird sounds more easily.
How do other animals influence bird vocalizations?
Interactions with other species shape certain characteristics of avian vocalizations over evolutionary time through processes like acoustic niche partitioning. Some examples include:
Avoiding overlap
Birds minimize overlap in pitch and timing with other vocalizing birds sharing their habitat. This improves communication in noisy environments.
Predator deterrence
Birds may incorporate sounds made by larger, intimidating predators into their repertoire. For example, drongos copy alarm calls of mammals.
Mimicking prey
Species like cuckoos mimic the calls of their hosts’ chicks to deceive parents into feeding them. Predators use prey mimicry to attract targets.
Expanding niche space
Incorporating new sounds expands the acoustic niche a bird can occupy. Lyrebirds copy novel sounds from human activity expanding their mimicry repertoire.
How do birders record and analyze songs and calls?
Ornithologists record bird vocalizations to study avian communication and evolution. Sound analysis provides insights into bird behavior. Key techniques include:
Field recording gear
Specialist microphones, recorders, parabolic reflectors, and shotgun mics help produce clean recordings in the field.
Captive recordings
Researchers may temporarily and ethically house wild caught birds to elicit vocalizations under controlled conditions.
Sound editing software
Programs like Raven allow scientists to visualize and measure acoustic features like frequency, amplitude, and pitch.
Sonograms
Sonograms let researchers visualize bird vocalizations and compare characteristics between species or contexts.
Playback experiments
Ornithologists broadcast pre-recorded bird sounds to study behavioral responses to calls and explore their functions.
Statistical analysis
Statistics help analyze variation in large samples of bird sounds and relate this to variables like species, sex, location, or season.
Conclusion
Birds produce a remarkable diversity of songs, calls, and mimicry sounds using specialized anatomical adaptations like the syrinx. Variation in avian vocalizations provides insights into behavior, ecology, evolution, and communication. With practice, birders can also identify many species by sound. Continued research and careful listening provide deeper appreciation of the complex language of the birds sharing our world. Paying attention to the sounds outside your window can reveal a thriving community of vocalizing birds.