Birds

DiversityDiversity

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.

DiversityDiversity

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,

DiversityMost 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.

Diversity

General CharacteristicsRespiratory 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 CharacteristicsRespiratory 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

Circulatory systemFour chambered hearts, just like humansAllows 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 systemVery 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

FlightCharacterized primarily by feathers, forelimbs are

modified as wingsSome birds are flightless

Include: penguins, ostrich, kiwi, and the extinct DodoFlightless species are vulnerable to extinctionAdaptations 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

ReproductionOviparous (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

General Characteristics

ClassificationClassification

Birds form a class, whose scientific name is Aves.

The earliest known species of class Aves is Archaeopteryx lithographica, from the Late Jurassic period.

ClassificationClassification, cont.

Modern birds are divided into two superorders:1. Paleognathae—mostly flightless birds

Ex: ostriches, emus, kiwi

ClassificationClassification, 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)