Birds have different shapes of Wings and Tails. These shapes determine how they fly and hunt .
There are four general wing shapes that are common in birds: Passive soaring, active soaring, elliptical wings, and high-speed wings.
- Passive soaring wings have long primary feathers that spread out, creating “slots” that allow the bird to catch vertical columns of hot air called “thermals” and rise higher in the air. Examples of birds with this wing type include eagles, most hawks, and storks.
- Active soaring wings are long and narrow, allowing birds to soar for a long time. However, these birds are much more dependent on wind currents than passive soaring birds. Examples of birds with this wing type are Albatrosses, Gulls, and Gannets.
- Elliptical wings are good for short bursts of high speed. While they allow high speed, the speed cannot be maintained. Examples of birds that have this wing type are crows, ravens, blackbirds, sparrows, and thrushes
- High-speed wings are long and thin, but not nearly as long as birds with active soaring wings. As the name suggests, birds with this wing type are incredibly fast, but unlike those with elliptical wings, these birds can maintain their speed for a while. Examples of birds that have this wing type are swifts, ducks, falcons, terns, and sandpipers.
Like the wings shape, the tail shape is also a result of adaptation to kind of habitat, hunting methods and flying patterns. While wings provide the Lift & Thrust and reduce Drag to assist in flying , the tail provides the ability to steer and gives direction.
The various tail shapes are Graduated, Forked, Forked with Streamers, Central Streamer, Long and Narrow, Spines, Broad and Fanned
The Long and narrow tail provide lot of stability to flight. But they also limit the ability to take sharp turns and change flight patterns. So birds like Eagles , Vultures etc who need a stable flight and their prey is relatively slow moving have this type of tail.
These birds also use the thermal effect to soar in the sky , they spread their tails to increase the surface area to gain advantage of hot air.
The flycatchers , swallows and other birds that hunt in Mid air have forked tail. This makes their flight unstable but provides great ability to twist and turn. This helps them catch fast moving prey like dragon flies etc.
The fork tail can also be fanned out to slow down like brakes when the tail is spread and when it takes a sharp turn the tail is closed.
Some birds have very strong tails that can support their body weight .. Like the woodpecker and Tree creeper . this helps them stay upright against the tree trunk
The tail is also used to indicate Adulthood ( like in Asian Paradise flycatcher) or breeding season ( Pheasant tail Jacana). Some birds also have streamers extending from the forked tails. This happens in breeding time and helps them attract their opposite sex. ( Wire tailed swallow)
Source : Wikipedia, Beat About the bush -Birds by Trevor Carnaby
Photo Credit : Saravanan Janakarajan