Introduction to Ornithology

Ornithology is a branch of zoology that concerns the “methodological study and consequent knowledge of birds with all that relates to them.”

u  The word “ORNITHOLOGY” comes from the late 16 century Latin 'ornithologia' meaning “bird science”.

u  The history of ornithology largely reflects the trends in the history of biology, as well as many other scientific disciplines, including ecology, anatomy, physiology, paleontology, and more recently, molecular biology.

Classification

Kingdom: Animalia

    Phylum: Chordata

        Class:     Aves

            Orders:     27

                Families:     166

                    Genera:     2045

                        Species:     8700

Birds are the most successful terrestrial vertebrates on Earth. There are about 8700 living species of birds compared with 3000 amphibians, 6000 reptiles, and 4100 mammals. Fishes, which live in a much less demanding aqueous environment, number around 20,000 living species. Among the invertebrates, insects are overwhelmingly the most successful and dominant class, numbering over 800,000 species. They too owe much of their dominance to their ability to fly.

Why do we study birds?

1. The pleasure of Hunting (without the mess)
2. Collecting
3. Beauty
4. Camaraderie
5. Curiosity
6. Easily Studied
7. Variety
8. Birds are environmental indicators
9. Lifetime learning

Bird Characteristics:

• Two-legged (bipedal) vertebrates
• Backbones that also include mammals, amphibians, reptiles, and fishes

Feathers

• Distinguished from other (modern) vertebrates by feathers (unique modifications of the outer skin)
• Filamentous, soft in texture, flexible, lightweight structures
• Dead structures of feathers replace regularly
• Essential for both temperature regulation (maintaining high body temperature) and flight (wing generates lift and thrust).

Bill

• Distinctive attribute that facilitates instant recognition.
• Varies greatly in form and function.
• Toothless and covered with a horny sheath.
• No exact parallel among other extant vertebrates; it is approximated only by the snout of the duck-billed platypus.
• Lack of teeth appears to be a weight-reducing adaptation for flight.

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Digestive system

• Birds   lack   teeth (the digestive  system is specialized to process unmasticated food)
• Instead of teeth, birds have gizzards (a functional analogue of mammalian molars).
• The large, strong, muscular structure is used primarily for grinding and digesting tough food.
• Gizzards of grain eaters and seed eaters, such as turkeys, pigeons, and finches, are especially large and have powerful layers of striated muscles.
• Turkey gizzards can pulverize English walnuts, steel needles, and surgical lancets.
• Internal grinding surfaces of gizzard are covered with rough pleated or folded surfaces with many grooves and ridges.
• It contains large quantities of grit, which grinds food.
• Gizzards of moas, extinct ostrich-like birds of New Zealand, have been found to contain as much as 2.3 kilograms of grit.
• The gizzard is not so muscular in birds that eat softer foods such as meat, insects, or fruit.

Body Structure

• The entire avian body is structured for flight
• Bird bones are typically lightweight, spongy, strutted, and hollow.
• Skeleton strengthened and reinforced through fusions of the bones of the hands, head, pelvis, and feet.
• Horizontal, backward-curved projections called uncinate processes on the ribs to overlap other ribs and strengthen the walls of the body.
• Furcula, or wishbone, compresses and rebounds like a powerful spring in rhythm to the beat of the wings.
• The wing is a highly modified forelimb (incapable of functions other than flight)
• Fused hand bones support and maneuver the large and powerful flight feathers.

Temperature regulation and flight energy

• Birds are endothermic; they are warm-blooded and maintain high body temperatures (40°-44°C) over a wide range of ambient temperatures
• Avian physiology accommodates the extreme metabolic demands of flight and temperature regulation.
• Red fibers of flight muscles have an extraordinary capacity for sustained work and can produce heat by shivering
• The circulatory and respiratory systems of birds include a powerful four-chambered heart and efficient lungs.
• Deliver fuel and remove both waste and heat produced by metabolic activities.

Reproduction

• Unusual reproductive system.
• Produce large, richly provisioned external eggs.
• No bird species bears live young like those produced by other classes of vertebrates.
• Provide paternal help require for eggs and nurturing of young ones.
• Most birds form monogamous pair bonds. 
• Some for life; but many, it turns out, engage in additional sexual liaisons (eggs in one nest may be of mixed paternities and even maternities).