Birds

Diversity Diversity Birds are found in every niche/habitat on Earth. This makes them the most diverse class of terrestrial vertebrates. Birds feed on nectar, plants, seeds, insects, rodents, fish, rotting animal flesh/decaying matter, or other birds.

Diversity Diversity Range in size from the tiny hummingbirds to the huge Ostrich and Emu. There are about 8,800–10,200 living bird species About 120–130 more species have become extinct in the span of human history in the world,

Diversity Diversity Most birds are diurnal (active during the day). Some birds are nocturnal (night hours) or crepuscular (twilight hours). Many birds migrate long distances to utilize optimum habitats (e.g., Arctic Tern) While others spend almost all their time at sea (e.g. the Wandering Albatross). Some, such as frigate birds, stay aloft for days at a time, even sleeping on the wing.

General Characteristics Respiratory system Birds have a high oxygen demand (because of high metabolic rate) They meet this by having as respiratory system more efficient than that of a mammal or a reptile. Birds ventilate their lungs by means of posterior and anterior air sacs (typically nine)

General Characteristics Respiratory system Three sets of organs involved in respiration: the anterior air sacs the lungs the posterior air sacs The posterior and anterior air sacs expand during inhalation. Air enters the bird via the trachea. A diaphragm is absent in birds

General Characteristics Circulatory system Four chambered hearts, just like humans Allows for efficient nutrient dispersion throughout the body which provides birds with the energy they need to fly and lead highly active lives. FYI: A hummingbird's heart beats at a rate of 1000 beats per minute, that is about 16.5 beats per second

General Characteristics Digestive system Very high metabolic rate Why? To keep up with their constant need for energy (constantly mobile) Bony beak with no teeth Possess gizzard (for grinding food) Complete digestive tract Includes stomach, gizzard, intestine, anus, mouth

General Characteristics Flight Characterized primarily by feathers, forelimbs are modified as wings Some birds are flightless Include: penguins, ostrich, kiwi, and the extinct Dodo Flightless species are vulnerable to extinction Adaptations for Flight Hollow bones Large wing span Great sight and/or hearing

General Characteristics Process whereby a chick acquires feathers until it can fly is called "fledging". Types of feather Contour feathers are the predominant feathers covering the bird's body. Can be divided into flight feathers and body feathers Covert feathers are small contour feathers Cover the bases of the wing and tail feathers. Semiplume feathers are important in thermal insulation.

General Characteristics Types of feather Filoplumes have a long fine shaft and short barbs or barbules. Provide sensory information about the position of adjacent contour feathers. Down feathers are fluffy feathers that may be found over the entire body Used for insulation Powder-down feathers shed a white waxy powder composed of keratin. Form a waterproof barrier for contour feathers.

General Characteristics Reproduction Oviparous (lay hard-shelled eggs) Some birds, such as pigeons, geese, and Red-Crowned cranes, remain with their mates for life (or for a long period) and may produce offspring on a regular basis.

General Characteristics Social systems and parental care Birds are polyandry, polygyny, or monogamy Monogamy is seen in approximately 91% of all bird species. Monogamous species of males and females pair for the breeding season. In some cases, the individuals may pair for life. Ex: geese, most pigeon species Male birds are just as adept at parental care as females.

General Characteristics Birds and Humans Important food source for humans Birds grown for human consumption are referred to as poultry. Birds long been used by humans to perform tasks. Homing pigeons were used to carry messages Falcons are still used for hunting Canaries were used in coal mines to indicate the presence of poisonous gases

General Characteristics Birds and Humans, cont. Pets Parrots, parrotlets, canaries Bird can carry diseases that can be contracted by humans Include salmonella, Newcastle's disease, avian tuberculosis, and the avian influenza

Classification Classification Birds form a class, whose scientific name is Aves. The earliest known species of class Aves is Archaeopteryx lithographica, from the Late Jurassic period.

Classification Classification, cont. Modern birds are divided into two superorders: Paleognathae—mostly flightless birds Ex: ostriches, emus, kiwi

Classification Classification, cont. Modern birds are divided into two superorders: 2. Neognathae—containing all other birds Ex: ducks, albatross, loon, penguins, pelican, stork, falcon, quail, crane, dove, pigeon, parrot, owl, hummingbird, woodpecker)