Birds rely on their ability to maneuver adeptly through the air for many essential behaviors like catching prey, escaping predators, and migrating long distances. A bird’s tail plays an important role in flight control and steering, along with its wings and body posture. But do birds actually use their tails to steer themselves in flight? Let’s take a closer look at the evidence.
What does a bird’s tail do?
A bird’s tail serves multiple functions related to flight:
- Stabilizer – The tail helps stabilize and balance the bird while flapping its wings. It acts as a counterweight and rudder to stabilize yaw, pitch and roll.
- Drag – By fanning or spreading its tail, a bird can increase aerodynamic drag and slow itself down for landing.
- Lift – The tail can also generate some additional lift by changing its angle of attack.
- Maneuvering – Fine adjustments and fanning of the tail feathers allow a bird to maneuver and turn in flight.
So in summary, a bird’s tail plays a crucial role in controlling body posture, drag, lift, and steering while flying. But it’s not the only factor.
How do birds steer and maneuver?
Birds have four primary means of steering themselves during flight:
- Asymmetrically adjusting wing angles – By changing the angle of attack of one wing slightly differently than the other, a bird can roll its body and bank into a turn.
- Warping wings – Some birds can warp or flex their wrist joints to angle just the outer wing feathers independently of the rest of the wing. This allows finer adjustments and tighter turns.
- Leaning their bodies – Birds can shift their center of mass and weight to lean into turns. Some birds can even rotate their legs beneath the body to aid in steering.
- Moving their tails – Fanning, twisting, and adjusting tail feathers allows a bird to expand drag and lift on just one side of their bodies.
So while the tail does play an important role, changing wing angles and posture are usually a bird’s primary means of steering and maneuvering through the air. The tail acts more as a stabilizer and compliment to steering initiated by wing and posture adjustments.
Is the tail more important for some species?
The relative importance of the tail for steering does differ between various bird species and families:
Swallows
Swallows such as barn swallows have extremely long, forked tails. They rely heavily on their tails when making the types of highly aerobatic, swooping maneuvers they use to catch insects in midair. Fanning their long tails likely provides considerable lift and drag to aid rapid turns.
Woodpeckers
Woodpeckers like the downy woodpecker have stiff, pointed tail feathers they use as a prop while climbing vertically up a tree trunk. So the tail plays a critical role in maintaining position, but not for steering.
Hummingbirds
Hummingbirds have relatively short tails compared to the size of their bodies and wings. While the tail contributes, they steer primarily by asymmetric wing adjustments and leaning their bodies when making quick directional changes.
Gulls
Gulls are able to make precise steering adjustments using their long, pointed wings rather than relying heavily on their tails. This allows them to utilize tails more for stabilization.
So for certain families like swallows, an expanded tail surface likely takes on a larger role in rapid steering and maneuvering compared to other groups. But the tail generally works in concert with wings, posture, and center of mass adjustments when birds negotiate through the air.
Research studies on the role of a bird’s tail
Scientists have conducted studies specifically analyzing the aerodynamics of a bird’s tail and its contributions to flight control:
Wind tunnel experiments
In 2006, researchers tested real bird tails in a wind tunnel to measure the aerodynamic forces generated.[1] They found that a bird’s tail does produce noticeable amounts of lift and drag when spread. The researchers also noted that small adjustments to tail fanning and angle of attack modified these forces in ways that could aid maneuvering.
Tails compared to wings
A 2007 study examined how wing size versus tail size related to flight agility across numerous bird species.[2] Species with the highest agility tended to have proportionally larger, longer tails in comparison to their wings. This suggests the tail does play a greater role in maneuvering for these agile fliers.
Tail clipping studies
Some studies have clipped bird tails and then observed flight ability. In one experiment on doves, birds with clipped tails showed impaired take-off ability and overall performance, indicating the tail does contribute.[3] But the doves could still fly, suggesting wings and posture make greater steering contributions overall.
Turning radius experiments
Researchers have analyzed how reducing tail area affects the turning radius of birds. One 2013 study on pigeons found only modest impacts of tail clipping on minimum turning radius, further supporting the idea that tails play a secondary role in most steering maneuvers.[4]
Conclusion
In summary, a bird’s tail does function as part of its flight control and steering system, along with its wings, posture, and center of mass. But for most species, the tail’s primary roles are in stabilization, drag, and lift, while wings and body movements seem to play a larger role in initiating turns and maneuvering.
The tail takes on a more significant steering function for certain specialized groups like swallows that are built for agile, swooping flight patterns. It also aids some species in skilled maneuvers like hummingbirds. Overall though, a bird skillfully coordinates movements of its entire body when steering through the air – not just the tail alone.
