Birds! http://www.youtube.com/watch?v=2WNrx2jq184

Bird is the Word! To be considered a bird you must have feathers, winged, bipedal (2 legs), endothermic (warm-blooded), egg-laying and be a vertebrate. Around 10,000 living species.

Birds can range in size from the 5 cm (2 in) Bee Hummingbird to the 2 Birds can range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) Ostrich.

Birds and Dinosaurs The fossil record indicates that birds emerged within dinosaurs during the Jurassic period, around 160 million years ago.

Beaks of birds are absent of teeth. Eggs must have a hard shell. Birds also have a high metabolic rate. Have a 4 chambered heart (closer to humans).

Flight in Birds All living species of birds now have wings. The only exception used to be the Moa birds of New Zealand, which are now extinct. Flightless birds include ratites and penguins.

Rockhopper Penguins Kiwi Bird

Bird Morphology – Skeleton The skeleton consists of very lightweight bones with air-filled cavities. These cavities connect with the respiratory system. Spines are designed with extra neck vertebrae (bones) to allow for more flexibility at the neck but fused closer to the bottom of the bird to help with flight. They also have a large sternum to allow for the wings to attach

Bird Morphology – Excretory System Birds extract their urine through their digestive system, rather than through a bladder and urethra like humans. The opening is called a cloaca. Females will also lay eggs from this opening. Therefore their waste is a combination of both feces and urine together. The only exception to this is the ostrich, which excretes both separately. Birds also have a gizzard that helps to grind food because of their lack of teeth. This aids in rapid digestion.

Bird Morphology - Respiratory System Birds have one of the most complex respiratory systems of all animal groups. When they inhale, 75% of the air flows directly into a posterior air sac which extends from the lungs and connects with air spaces in the bones and fills them with air. The other 25% of the air goes directly into the lungs. When the bird exhales, the used air flows out of the lung and the stored fresh air from the posterior air sac is forced into the lungs. This ensures bird's lungs receive a constant supply of fresh air during both inhalation and exhalation. This also aids in birds creating songs!

Bird Morphology – Nervous System The most developed part of the brain is the one that controls the flight-related functions. Most birds have a poor sense of smell with notable exceptions including kiwis, New World vultures and tubenoses.

The eye system is usually highly developed. Water birds have special flexible lenses, allowing accommodation for vision in air and water.

Birds are tetrachromatic, possessing ultraviolet (UV) sensitive eyes as well as being able to see combinations of green, red and blue. This allows them to perceive ultraviolet light, which is involved in courtship. Many birds show plumage patterns in ultraviolet that are invisible to the human eye; some birds whose sexes appear similar to the naked eye are distinguished by the presence of ultraviolet reflective patches on their feathers.

Male Blue Tits have an ultraviolet reflective crown patch.

Most birds cannot move their eyes, although there are exceptions, such as the Great Cormorant Birds with eyes on the sides of their heads have a wide visual field, while birds with eyes on the front of their heads, such as owls, have binocular vision and can estimate the depth of field.

Intelligence in Birds Some birds, especially corvids and parrots, are among the most intelligent animal species. A number of bird species have been observed manufacturing and using tools. Many social species exhibit cultural transmission of knowledge across generations.

http://www.youtube.com/watch?v=TtmLVP0HvDg http://www.youtube.com/watch?v=K7ht0a2-OnA

Sociality in Birds Many species migrate long distances together. Communication can be through visual and vocal signals (calls and songs). They will co-operatively breed where siblings and other birds help raise the young. They will hunt, flock (fly in groups) and mob prey all together to increase their chances of survival.

Breeding Birds will pick one mate for one breeding season OR for many years at a time. Some species live in communities that are polygynous ("many females") or, more rarely, polyandrous ("many males"). Eggs are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching.

Birdnest