1. Birds

2. 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.

3. 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,

4. 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.

5. 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)

6. 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

7. 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

8. 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

9. 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

10. 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.

11. 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.

13. 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.

14. 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.

15. 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

16. 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

17. 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.

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

19. 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)