My Science School

Birds are the only animals in the world with feathers, which provide a protective and warm covering and help them fly. Their wings make them the best fliers of all the flying animals. Like mammals, birds are warm-blooded. However, unlike most mammals, they lay eggs instead of giving birth to live young.

Feathers

Different feathers have very different shapes, depending on their job. The largest and strongest are the flight feathers on a bird’s wings and tail. Down feathers are small and fluffy, and sit next to the bird’s body to keep it warm. Contour feathers are longer and stiffer, and cover the outside of the body to give the bird a streamlined shape. Flight feathers are the longest and toughest feathers. They line the bird’s wings and tail, and push against the air to power the bird in flight.

Bill

Birds don’t have teeth. Instead, they have a light but strong bill for feeding. The bills have different shapes, depending on a bird’s diet. Rollers mainly eat insects.

Some of the most important aspects of a bird's bill are not specific features, but the general jizz of the bill. When first studying bird bills, look for the following features.

• Size: How large does the bill appear in proportion to the bird's head? Check for length as compared to the length of the head as well as the width of the bill and how that width may change along the bill's length.


• Shape: Bill shapes vary widely, from delicate triangles or thin, needle-like bills to thick, bulbous bills to sharply curved bills to radical shapes that include spoon-like tips or horny casques. When the shape is very unique, that can be a diagnostic clue for a bird's identity even if other field marks cannot be seen.


• Color: The color of a bill can be a clue for species, gender, or age. Note the overall color as well as any specific markings, such as a colored tip or base, sub terminal band or color differences between the top and bottom of the bill.

Tail

The tail is used like a rudder to steer when flying, or for balance when the bird is perched on a branch or walking on the ground. Birds use their tails to create lift and control drag during slower flights and to help steer during turns. They also furl their tails to reduce drag during faster flights. Bird tails have evolved to serve a number of specialized roles apart from flight and display. A woodpecker's tail, for instance, has a row of prongs that helps her hang against tree trunks while she jackhammers the bark. Her tail acts as a stabilizer that forms a tripod with her legs. Brown creepers' tails afford them similar vertical foraging. Bird tails can stand in for bird calls, too. The most dynamic example is probably Wilson's snipes. During courtship, their tail feathers whir and whistle as they engage in dizzying dances.

Feet

Birds are bipedal, which on two feet. They have between two and four toes, which end in a sharp claw. Hawks, eagles and owls have strong feet with long claws or talons to help them capture, grasp and kill their prey. Woodpeckers have four toes, two pointed forward and two pointed backward. This arrangement helps them grasp tree bark and climb. Song birds use their feet for perching and walking or hopping. Three toes pointing forward with one opposing toe helps them grasp their perch. Wading birds such as cranes and herons have long toes to help them walk through soft bottoms in wetlands in search of food. Swimming birds, such as ducks and geese, have webbing between their toes to help them paddle in water.

Wings

Instead of arms with hands, birds have wings. Birds fly either by flapping their wings or using them to glide in the air. A few birds can also hover. There are four general wing types:

1. Elliptical wings – found on bats and most small forest and scrub-dwelling birds, such as robins and sparrows. These wings allow a high degree of control and manoeuvrability in confined spaces, and minimize drag to allow rapid ascent and descent. Wing beat is usually rapid. Elliptical wings are highly slotted between the primary feathers which help to prevent stalling during sharp turns, low-speed flight, and frequent landing and takeoff.

2. High speed wings – found on swallows, falcons, shore birds, and ducks. Birds that feed on the wing or make long migrations. The bones are relatively long, and the wings taper to a point to allow for high flight speed with low drag, and low energy consumption during flight. Because the wings are also thin, they must be flapped for short glides and during descent, and flaps are fairly rapid but small. This type of wing is aerodynamically efficient for high-speed flight but cannot easily keep a bird airborne at low speeds.

3. Long soaring wings – found on terns, albatrosses, gannets, frigate birds, gulls and other sea birds. The wings have a high aspect ratio resembling those of sailplanes. The open spaces allow for long wings to create good lift with little energy expenditure. They are also adapted for high speed and dynamic soaring. However, they are less manoeuvrable than the wide, slotted wings of land soarers. Birds with this kind of wing can glide easily over large expanses of water and have exploited the sea winds.. However, the birds must usually run and take off into the wind to get off the ground, and usually land easily on water.

4. High-lift/Broad soaring wings – found on vultures, condors, hawks, ospreys, pelicans and eagles. These wings are broad and only relatively long, allowing for takeoff and landing in fairly confined areas, high lift, low speed soaring, and slow descents. Many of these birds are land soarers with good manoeuvrability required for tactic soaring in the air currents over land.

Eggs and nest

Most female birds make a nest, where they lay their eggs. The young grow inside, while the parents keep the eggs warm, taking it in turns to sit on them. When the time is right, the chicks peck their way out of the shell. Nests provide a safe place for eggs and young birds to develop. Bird nests are extremely diverse, although each species typically has a characteristic nest style. Some birds do not make nests at all and instead lay their eggs in a simple scrape in the ground. Other birds construct nests from natural materials, such as grass, leaves, mud, lichen, and fur, or from man-made materials like paper, plastic, and yarn. Nests can be found almost anywhere – on the ground, in trees, in burrows, on the sides of cliffs, in and on man-made structures, etc. Females typically build nests, but sometimes either parents or just the male will build it.

Picture Credit : Google