Birds make a variety of sounds with their wings as they fly. The most common sound is a soft whooshing noise as their feathers cut through the air. This sound is caused by air rushing over the surface of the wings and feathers. The specifics of the sound depend on the size, shape and features of the wings and feathers. Small songbirds have a gentle fluttering sound from their small rounded wings beating rapidly. Larger birds like hawks and eagles have a deeper swooshing sound from their long broad wings. The features of the feathers, including the stiffness of the shafts and the shapes of the vanes, also affect the sound. So every bird species has a distinctive wing sound.
What causes the sounds birds’ wings make?
The sounds that birds’ wings make as they fly are caused by the interaction of air with the wing and feather structures. There are a few key factors that contribute to the sounds:
- Shape of the wing – Long, broad, rounded or pointed wing shapes disturb the air differently, creating variations in sound.
- Size of the wing – Larger wings move more air, creating louder swooshing sounds.
- Flapping speed – Faster flapping creates more turbulent airflow and often a higher pitch sound.
- Feather structure – The vanes and shafts of feathers slice into the air, causing sound.
- Feather overlap – Small gaps between feather vanes allow air to pass through, amplifying sound.
As the wings beat up and down, air flows over and underneath the wing surface. The wings push the air downwards as they flap, which generates lift. The motion of the wings disturbs and slices through the air, creating small turbulences and eddies. These rapid disturbances in the airflow cause variations in air pressure that our ears perceive as sound.
What features of wings and feathers affect the sound?
Birds have evolved specialized feather structures and wing shapes that help minimize noise while flying. But subtle differences in wing and feather features produce the unique sounds we hear.
Wing Shape
The shape of a bird’s wing affects the pattern of airflow over the wing, altering the sound it generates. Long, broad, rounded or pointed wing tips will disturb the air differently. Rounded wing tips create smoother, quieter airflow while pointed tips generate more turbulent vortices.
Wing Size
Birds with larger wings, like eagles, buzzards and hawks, must displace more air with each flap. This creates a loud swooshing or whooshing sound. Small birds with shorter wings produce a softer fluttering sound.
Flapping Speed
Faster flapping speeds displace air more rapidly, creating a characteristic pitch to the sound. Hummingbirds beat their wings up to 80 times per second, producing a high-pitched hum. Larger birds flap more slowly, creating a lower pitch.
Feather Structure
The vanes and shafts of feathers are designed to maximize lift while minimizing noise. As air flows over and between feathers, the vanes create small turbulences. The thin, flexible trailing vanes flutter in the breeze, amplifying sounds.
Feather Overlap
When perched, birds’ feathers overlap neatly to form a smooth surface. During flight, gaps open between the feathers, allowing air to flow through. This circulation amplifies the sounds created by each feather structure.
Do other wing features affect sound?
In addition to basic wing shape and feather structure, some other wing features can influence the sounds produced during flight:
- Wing slots – Gaps between wing feathers at the wingtips called alula slots allow air to flow through, potentially increasing noise.
- Leading edge fringes – Owl wings have soft, pliant fringes on the leading edges to dampen turbulence and reduce sound.
- Trailing edge fringe – The ragged trailing edge of owl wings helps break up wingtip vortices, muffling noise.
- Vane asymmetry – Asymmetrical vanes on owl feathers reduce noise by avoiding parallel surfaces that amplify sound.
- Covert feathers – Small flexible feathers covering the wings can dampen air disturbances, reducing sound.
Raptors like owls and hawks have specialized feather structures that maximize silent flight. Their wings make less noise compared to other birds.
How does wing loading affect sound?
Wing loading refers to the ratio of a bird’s body weight compared to its wing area. Birds with higher wing loading need greater lift forces to fly. This requires faster flapping and airflow over the wings, creating more sound.
Small birds like hummingbirds have very low wing loading, so they can beat their wings slowly and quietly. Larger heavy birds like swans have higher wing loading and make more noise in flight. Wing loading also varies based on a bird’s flight style. Birds in a controlled glide have lower effective wing loading and generate less sound.
How do different flight styles affect sound?
Birds make different sounds depending on their flight style at the moment. Gliding, flapping flight, takeoff, and landing all produce distinct sounds:
- Gliding – With wings spread steady, air flows smoothly over wings, creating a hushed whooshing sound.
- Flapping – Regular flapping generates swooshing sounds punctuated by small bursts on each downstroke.
- Takeoff – Wings beating at high speed make a loud whirring or thrashing sound.
- Landing – Wings spread wide and tilted upward, producing a low-pitch whooshing sound.
Birds like owls and eagles are specialized for silent flight, producing minimal sound even while flapping. They rely on stealth when hunting. Other birds like pigeons and gulls flap noisily between brief glides.
What sounds do different bird groups make in flight?
While every species has a unique sound, some general patterns emerge in the sounds made by broad groups of birds:
Songbirds
Small passerines like sparrows and finches have a fluttering sound made by rounded wings flapping rapidly. Larger thrushes and jays have a louder whooshing sound.
Waterfowl
Ducks and geese produce loud whooshing or whistling sounds with their broad wings. They also generate noise with their stiff tail feathers.
Birds of Prey
Owls, eagles, hawks and falcons have adapted for silent, stealthy flight. At close range their flight sounds like soft swooshing.
Wading Birds
Herons, egrets and other long-legged waders have broad rounded wings that create a deep swooshing sound in flight.
Woodpeckers
Despite their short broad wings, woodpeckers flap quietly with a gentle fluttering sound.
Swifts and Hummingbirds
These small birds beat their wings incredibly fast, producing distinctive buzzing or humming sounds.
Pigeons and Doves
With their small tapered wings, pigeons and doves create a throbbing percussive sound with each flap.
How does speed affect the sound of a bird’s flight?
Faster flight speed always increases the volume of sound produced by a bird’s wings. As birds accelerate, they flap faster and airflow over the wings becomes more turbulent. Gliding is the quietest flight style, while diving and rapid ascent create loud whirring or thrashing sounds.
During takeoff birds use maximum flapping speed, generating a loud whirring noise. In level cruising flight there is a steady rhythmic swooshing sound. Before landing, birds spread their wings broadly, producing a hushed whoosh.
Do birds make noise when perching or taking off?
Both takeoff and landing generate distinct sounds as a bird transitions between perching to flight:
Takeoff:
- Wings thrash rapidly against the air, making a quick loud whirring sound.
- First 1-3 wingbeats produce the loudest sounds.
- Sound diminishes quickly as the bird gains altitude.
Landing:
- Wings spread wide and flap slowly, creating a deep whoosh sound.
- Light fluttering or skimming sound right before touchdown.
- Wings or tail may slap noisily against a perch when landing.
The sounds birds produce while taking off and landing can provide information to birders about the species, its size, wing shape and flight habits.
What sound do hovering birds make?
Hovering birds like hummingbirds and kestrels are specialized to produce sustained lift by beating their wings very rapidly. This allows them to remain stationary in midair as they feed on flowers or hunt prey. The aerodynamics of hovering requires fast, horizontal flapping, which generates a distinct buzzing or humming sound.
The wings of hummingbirds beat up to 80 times per second, producing a high-pitched hum. Larger birds like kestrels flap more slowly so hover with a deeper buzzing sound. The rapid fluttering and rotation of the wings churns the air, creating the unique sounds.
How does habitat affect the sounds birds make in flight?
The sounds birds produce in flight are amplified and filtered by the environment around them. Habitats such as forests, open plains, or urban areas transmit or absorb sounds differently. Dense foliage in forests often absorbs and muffles wing sounds. Open habitats like grasslands allow sounds to carry further through unobstructed air. Hard surfaces in cityscapes can create echoed and amplified wing sounds.
Birds may alter their flapping and wing positioning to take advantage of soundscapes. For example, owls rely on stealth when hunting in open environments, so they evolved specialized wings to dampen noise.
How do birds vocalize using their wings?
Though not as common as calls and songs produced vocally, some birds also make deliberate sounds with their wings as a form of communication:
- Wing clapping – Some grouse slap their wings together loudly to signal alarm or attract mates.
- Wing drums – Snipes vibrate their outer tail feathers in dives to create a drumming sound.
- Wing whirring – Hummingbirds and dove sometimes produce loud wing whirs in courtship displays.
- Wing trills – Manakins and birds-of-paradise make mechanical trills with specialized wing feathers during mating dances.
Specialized wing and feather structures allow some birds to intentionally create non-vocal sounds for communication purposes.
What techniques do ornithologists use to study flight sounds?
Ornithologists use a variety of techniques to study the sounds birds produce in flight:
- Field recordings – Microphones and recorders capture high fidelity sound in the field.
- Lab simulations – Wind tunnels and particle imaging visualize airflow patterns.
- Video analysis – High speed video lets researchers correlate wing motions with sounds.
- Tailoring feathers – Altering feathers reveals how structure affects acoustics.
- Telemetry devices – Miniaturized microphones can be worn by birds to record in-flight noises.
Analysis of acoustic recordings, airflow studies, and correlating wing kinematics are key to deciphering precisely how birds generate such amazing diversity and complexity of flight sounds using just their wings and feathers.
How can identifying bird flight sounds help birders in the field?
Paying attention to the unique sounds birds make while flying can help birders identify species in the field. Here are some ways flight sounds can assist bird identification:
- Distinctive fluttering, buzzing or swooshing can indicate bird size and wing shape.
- High or low pitch of sound provides clues about a bird’s wingspan and flapping habits.
- Sudden bursts reveal flapping motions specific to certain families.
- Swift changes between gliding and flapping narrow ID possibilities.
- Sounds of takeoff and landing identify stealthy versus noisy fliers.
Cataloging species’ flight sounds prepares birders to recognize birds just by listening. Interpreting the acoustics in field conditions takes practice, but boosts identification skills.
Conclusion
Birds generate a remarkable range of sounds using just their wings and feathers as they pass through the air. Variations in wing shape, size, feather structure, and flapping speed combine to give each species a unique voice in flight. Listening carefully to flying birds provides clues for identification and reveals their aerial tricks and talents. The sounds of birds’ wings as they take to the skies are as much a part of their natural history as their songs and plumage.