What Are Birds?

6th June 2010

Not all flying animals are birds; and not all birds can fly. The ability to fly has developed independently many times throughout the history of the Earth. Bats (flying mammals), pterosaurs (flying reptiles from the time of the dinosaurs), and flying insects are not birds.

 

Moving - flying, running, and swimming


Bird locomotion is quite varied; most can fly, some can run very well, some swim, and some do combinations of these. Some birds cannot fly.

Most birds can fly. Flying birds' wings are shaped to provide lift, allowing them to fly. These light-weight animals have adapted to their environment by flying, which makes them efficient hunters, lets them escape from hungry predators (like cats), and takes them away from harsh weather (migration).

 

The peregrine falcon is one of the fastest birds, and has been clocked at 90 miles per hour in a dive (and some people say that they can dive at 200mph).

Feathers are highly modified scales.

 

There are different types of feathers that have different uses.

 

Male birds are frequently more brightly colored than females. This is to attract females for mating purposes. The females are more dully colored, helping to camouflage her when she is caring for her young (although the male often cares for the young, with or without the female). The peacock (the male peafowl is pictured above) is very brightly colored. The peahen (the female peafowl) is dull brown in color.

Feathers are used for

Flying - flight feathers, grow in the wings and the tail.

Thermal insulation - soft down feathers that grow close to the skin keep birds from getting too cold or too hot

Courtship and mating displays - these vary tremendously from species to species.

Diet

Modern-day birds do not have any teeth (ancient birds did have teeth). Birds have a tongue, but unlike our tongue, a bird's tongue has a bone in it.


Birds spend most of their time looking for food. Some birds, like owls and eagles, are carnivores (meat-eaters). Some birds, like the hummingbird, grouse, and Canada goose, are mostly herbivores (plant-eaters). Other birds, like starlings, are omnivores (plant and meat-eaters).

 

Some amazing hunters, like eagles, have eyesight that is five to six times sharper than a person's. They can spot small prey from a mile away.

 

Birds mostly use their keen eyesight to find food. They use their beak and their claws to get bugs, worms, small mammals, fish, fruit, grain, or nectar.

 

Birds play a very important part in the natural control of insects and in the dispersal of seeds. Some birds, like the tiny, nectar-eating hummingbird are important pollinators of some flowering plants.

Nests and eggs

Birds bear their young in hard-shelled eggs which hatch after some time. Some birds, like chickens, lay eggs each day, others (like the maleo) may go for years between laying eggs.

The ostrich lays the largest birds' eggs which are up to 4.5 x 7 inches (11 x 18 cm) across and weigh 3 pounds (1400 g). Birds build nests for breeding in trees, on cliffs, or on the ground. Most birds are taken care of by at least one parent until they are able to fly and get their own food.

 

The incubation period of bird eggs varies from species to species. There's also some variability due to the temperature. Some birds, like cuckoos and some cowbirds, lay their eggs in other bird's nests. The non-related adult bird takes care of the cuckoo's egg unwittingly. Some cuckoos even kill the other eggs in the nest to insure that their egg gets enough food.

Migration

Many bird species migrate to a cooler climate for reproducing and summer feeding, and then return to a warmer climate for the winter. It is unknown exactly how birds are able to navigate accurately, but many people are studying this mystery of how birds know where to fly.

 

The classification of birds

Birds belong to the biological class Aves and live virtually everywhere on Earth. Birds are amniotes, animals whose eggs are protected from drying out (a group that includes the mammals, birds, dinosaurs, and reptiles). There are about 9,000 different species of birds, divided into 24 orders and 146 Families. Most birds alive today are Neognathae (a group distinguished by common palate structure). Another, much smaller group, is the Palaeognathae (again grouped by palate structure), which includes the ostrich, kiwi, emu, rhea, and others.

The evolution of birds

Birds probably evolved from meat-eating (theropod) dinosaurs during the Mesozoic Era, roughly 150 million years ago. Early birds, like Archaeopteryx, had teeth in their mouth and claws on their wings.

 

Bird songs

Birds sing beautiful and diversified songs. Many songbirds are becoming scarcer every year.

 

Songbirds have a vocal organ called the syrinx located in the throat. The muscular syrinx has two halves that each vibrate to produce songs, so the bird can sing two notes at a time. To sing, a bird blows air from the lungs through the syrinx.

Do bird have knees

Yes, birds have knees (they're often under the feathers and not easily visible), and they bend the same way our knees bend. The part of a bird's legs that bends backwards when it walks is the ankle.

Heart rate and breathing

In order to fly, birds need a lot of oxygen, which they get by breathing air using lungs. They also The incubation period of bird eggs varies from species to species. There's also some variability due to the temperature. Some birds, like cuckoos and some cowbirds, lay their eggs in other bird's nests. The non-related adult bird takes care of the cuckoo's egg unwittingly. Some cuckoos even kill the other eggs in the nest to insure that their egg gets enough food.

Why can birds perch on power lines

Birds can often safely perch on a power line without being electrocuted. For the bird (or other animal) to be electrocuted, a potential difference must exist across two points of the bird's body (its feet in the case of a bird on a power line). When perching on a single power line, there is no potential difference between the bird's feet, so it is safe. If the bird (or other animal) touched two power lines at a time, or one power line and a ground (like a ground wire or the earth itself), the animal would be electrocuted and die. Many large birds (like eagles and vultures) are electrocuted when their wide wings touch a power line and a ground wire at the same time (often while flying in to land on a power line).

 

This is why it is VERY unsafe to fly a kite near power lines. If the kite gets tangles in the power lines, the kite string acts as a ground, and you can be electrocuted.

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