Birds

1. Birds Sarah Hayden Boring Rucker Meghan Daughdrill

2. General Characteristics • Appendages modified as wings  • Feathers • Endothermy  • High Metabolic rate   • Vertebral column modified for flight • modern birds possess a horny bill and lack teeth. 

3. Bird Evolution and Phylogenic Relationships • In south France and Spin birds were drawn on the walls of caves. • Birds were images of ancient Egyptian and American cultures. • Humans have marveled at birds and bird flight for thousands of years. • T. H Huxley described birds as “gorified reptiles” in the 1860. • He included them in a single class Sauropsida. • Birds descended from ancient archosaurs ( a lineage shared by the dinosaurs and crocodilians) • Fossils of a dozen theropod dinosaurs bearing feathers have been discovered showing the possible connection.

4. Order Sphenisciformes  • Heavy bodied  • Flightless • Flipperlike wings for swimming  • Well Insulated with Fat • Penguins

5. Order Anseriformes  • South American screamers  • webbed feet • Posses a wide, flat bill and an undercoat of dense down.  • ducks • geese • swans

6. Order Falconiformes  • Strong • hooked Beak • Their wings are long and fairly broad, suitable for soaring flight, with the outer 4–6 primaries emarginated. • Falconiformes have strong legs and feet with raptorial claws and an opposable hind claw. • Almost all Falconiformes are carnivorous, hunting by sight during the day or at twilight. • They are exceptionally long-lived, and most have low reproductive rates. • Females are bigger than males • Vultures, secretarybirds, hawks, eagles, ospreys, falcons.

8. Order Columbiformes • Dense feathers loosely set into skin • pigeons, doves, sandgrouse.

9. Order Strigiformes  • Large Head with fixed eyes directed forwards • Raptorial foot • owls

10. Order Passeriformes • Largest avian order • 69 families of perching birds • perching foot • variable external features • swallows, larks, crows, titmice, nuthatches, and many others, 

11. Bird External Structure and Locomotion • The covering of birds of feathers on Birds  • Feathers have two primary functions essential for flight (They form the flight surfaces that provide lift and aid steering and they prevent excessive heat loss.) • There are many different types of feathers. Pennaceous feathers that cover the bodies of birds. Flight feathers which line the tip and trailing edge of the wing. Contour Feathers are usually symmetrical and line the body and cover the base of the flight feathers. Plumulacerous feathers have rudimentary shaft to which wispy tuft of barbs and barbules is attached and includes down feathers, which lie below contour feathers.  • Feathers have been considered reptilian scales that elongated and gew fringed edges, barbules, and hamuli, but is not

12. Bird External Structure and Locomotion cont. • Preening is when birds rub their beaks over their feathers keeping themselves clean.  • Mature Feathers receive constant wear: this all birds periodically shed and replace their feathers in a process called molting.  • Bones of birds are lightweight yet strong.  • Birds have a reduced number of skull bones. • A lighter, keratinized sheath called a bill replaces the teeth.  • The wings of birds are adapted to different types of flight.  • Air passing over the wing travels farther and faster than air passing under the wing

13. Bird Nutrition And the Digestive System • Most birds have ravenous appetites which supports a high metabolic rate that makes endothermy and fight possible. • Birds bills and tongues are modified for a variety of feeding habits and food sources. • In many birds, a diverticulum of the esophagus, called the crop, is a storage structure that allows birds to quickly ingest large quantities of locally abundant food. • They seek safety while digesting their food. • Crops are less well developed in insect-eating birds because insectivorous birds feed throughout the day on sparsely distributed food.

14. Bird Nutrition And the Digestive System cont. • Birds stomachs are modified into two regions, the Proventriculus which secrets gastric juices that initiate digestion and then the ventriculus has muscular walls to abrade and crush seeds or other hard materials. • Birds may swallow sand and other abrasives to aid digestion. • Birds usually eliminate undigested food through the cloaca. • Owls form pellets of bone, fur, and feathers that are ejected from the ventriculus through the mouth.

15. Bird Circulation, Gas Exchange, and Temperature Regulation • The heart has completely different separated atria and ventricles, resulting in separate pulmonary and systemic circuits. • This prevents any mixing of highly oxygenated blood with less oxygenated blood. • Repository system is complex and efficient. • Consists of external nares that lead to nasal passageways and pharynx. • Voice box called syrinx located where the trachea dive into bronchi. • Have air sacs that occupy much of the body. • Lungs are made of smaller air tubes called Parabronchi. • It takes two ventilatory cycles to move a particular volume of air through the repertory system of a bird. • Birds have a greater rate of oxygen consumption than any other vertebrate due to flying.

16. Bird Nervous and Sensory Functions • Forebrain is very large. • The midbrain receives sensory input from the eyes. • Birds eyes are much larger relative to body size. • Double-focusing mechanism. This allows a bird of prey to keep focus on a fish throughout a brief, but breathtakingly fast, descent. • Some birds have two foveae per eye. • The position of the eyes on a head of the bird influences the degree of binocular vision. • Olfaction plays a minor role in most birds. External nares open near the base of the beak but the olfactory epithelium is poorly developed. • Well-developed hearing • Feathers called auriculars cover the external ear openings.

17. Bird Excretion and Osmoregulation • Birds and reptiles face identical excretory and osmoregulatory demands. • Like reptiles, birds excrete uric acid, which is temporarily stored in the cloaca. Water is also reabsorbed in the cloaca • As with reptiles the excretion of uric acid conserves water and promotes embryo development in terrestrial environments. • Some birds have supraorbital salt glands that grain excess sodium chloride through the nasal opening to the outside of the body. (very important in marine birds) • Salt glands can secrete salt in a solution that is two or three times more concentrated than any other body fluids. • Salt glands compensate for the kidneys inability to concentrate salts in the urine.

18. Bird Reproduction and Development • All birds are oviparous • No intromittent organ and sperm are transferred by cloacal contact when the male briefly mounts the female. • Monogamous (single male and female pair for breeding season) • Some pair for life • Some are polygynous ( Males mate with more than one female) • Few are polyandrous (The female mates with more than one male) • Nests form after pair formation • Clutch is the group of eggs laid and chicks produced by a female. • Birds turn the eggs to ovoid embryo deformation • Those that are fully dependant on their parents are said to be altricial and are often naked at hatching. • Precocial young are alert and lively hatching.

19. Bird Migration and Navigation • Aristotle discovered bird migrating to escape the winter cold and summer heat. • Some migrate long distance. • Migration refers to periodic round trips between breeding and nonbreeding areas. • Most migrations are nesting areas in northern regions and wintering grounds in the south. • Birds use route-based navigation where they keep track of landmarks on the journeys. • Also use location-based navigation based on establishing the direction of the destination from information available at the journeys site of origin.

20. Contour Feathers – Cover the body, wings, and tail of the bird. Responsible for plumage colors. • Down Feathers – Feathers that provide insulation for adult and immature birds. • Flight Feathers – They line the tip and trailing edge of wings of a bird and are asymmetrical with longer barbs on one side of the shaft. • Clutch – The number of eggs laid and chicks produced by a female bird. • Altricial- An animal that is helpless at hatching or birth. • Precocial – Having developed to a high degree of independence at the time of hatching or birth. • Migration – periodic roundtrips of animals between breeding and nonbreeding areas or to and from feeding areas.