Birds

Birds are warm-blooded (endothermic) animals with wings, two legs and feet (bipedal) that lay eggs. They are the most numerous of the tetrapod (4 limbed) vertebrates with about 10,000 species living today.

Birds inhabit all regions and countries across the earth from the Antartic to the Arctic. They range in size from the 2 inch Bee Hummingbird to the Ostrich of about 10 feet.

Characteristics of birds today is their four- chambered heart, strong but light weight skeleton, feathers, a beak and no teeth, laying of hard-shelled eggs.

The wings of birds are forelimbs with which most of them can fly, with the exception of a few such as the Penguin.

They are among the most intelligent of species with some having been observed making and using tools and the transferring of knowledge to their offspring in many of the social species.

Their digestive and respiratory systems are designed to be highly efficient in flight or when migrating.

Birds communicate in many different ways and are very social. Some examples of communication are visual signals, calls, and songs.

They also practice other behaviors such as cooperative breeding and hunting, mobbing and flocking of their enemies.

Most birds are socially monogamous (having one sex partner) for one breeding season and sometimes for several years but rarely for life. There are a few that are polygynous (many females) and rarer still polyandrous (many males).

The parents incubate the eggs that are laid in a nest and most have a period of parental care after the eggs are hatched.

Some species are used as a source of food through the use of farming and hunting, while others are others are popular for pets, such as parrots and songbirds.

The harvesting of guano or bird droppings is used for fertilizer.

Birds have been a part of the human existence as far back as recorded history.

Approximately 120-130 species of birds have become extinct in the last 300-400 years because of human activity. Efforts are under way to save about 1200 species that are being threatened today.