BIRDS 1 I Characteristics A Phylum Chordata Class

BIRDS 1

I. Characteristics A. Phylum: Chordata Class: Aves 1. Birds are endothermic reptile-like animals with an outer covering of feathers, two legs used for walking or perching and front limbs modified into wings that usually do not have useful claws, and they have feathers. 2

2. Birds have: Feathers Hollow bones Forearm modified wings Toothless beak **Egg tooth Streamlined Hard shell **Usually 4 toes 3

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**Toe pattern (one in back 3 forward) Wishbone Keel Right aorta **Nucleated RBC **Air sacs **No diaphragm **Sclerotic bone in eye Bone fusion 18 -35 cervical bones ***Similar characteristics with reptiles 5

II. Feathers and Flight A. Birds have three different types of feathers contour feathers, powder and down feathers. 1. Contour feathers are large feathers that cover a bird’s body and wings. 2. Certain contour feathers, known as flight feathers are long and stiff. 6

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3. Down feathers grow underneath and between the contour feathers. 4. Down feathers are short, soft, and fluffy. These feathers trap warm air close to a bird’s body, insulating the bird. 5. Baby birds of many species area covered with down feathers for a period of time after they hatch. 8

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6. Powder feathers are important to birds that live on or in water. 7. As they grow, these feathers release a fine white powder that repels water and keeps it from penetrating the layer of down feathers. 8. Birds also produce waterproof oil in special glands near their tail. 10

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C. Characteristics of feathers 1. Feathers on the bird are twice as heavy as the bones. 2. The height or lift from the air occurs on the top of the wing. 3. Each feather has a set of muscles to allow spreading the feathers apart or keeping them together. 12

D. Origin of Flight 1. There is the hypothesis called Areberial hypothesis of flight. 2. There were animals that leaped fro limb to get food. 13

3. Eventually there were animals such as the flying squirrel, flying lizards, flying frogs, flying snakes and flying fish. 4. The theory is that a birds forearm evolved into a wing and the pectoral muscles evolved for flight. 14

5. Flying is a good way to avoid predators. 6. The theory states that the feathers evolved from scales for thermal regulation. (Birds are endothermic) 7. They became bipedal (walk on 2 limbs) to increase ground speed. 15

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E. Power of lift 1. The power for flight comes from the primaries. 2. The power of lift comes from secondary and then primaries. 17

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3. Clipping birds feathers to control distance of flight- clip primaries. 4. To reduce drag (pulls bird backward) the bird is stream lined. 5. To land the bird “crashes” by grabbing on a twig or water with their feet. 19

6. Flight speed: Song birds: 20 mph Duck: 40 mph Eagle/attack: 120 mph 20

F. Types of Wings 1. Elliptical wing- not good for long distance. Great for maneuvering, non-migrating, glides very well. 2. Migrating birds feathers- more pointing, longer, not good for maneuvering. Good for high speed and long distance. Example- High speed is much longer and wider. 21

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3. High-speed wing- wing are tapered, may have swept back wing look. 4. High lift slotted wing- vultures, buzzard’s wide wings lots of slotted wings. Good for thermal soaring. 5. Thermal soaring: Uses the heat and wind pattern in the afternoon to soar. 24

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G. Migration 1. Irregular migration is not usual. This is when birds will migrate to find food. 2. Displacement- When young of the year gets pushed out from parents. 26

H. Types of migration 1. Piloting- Migration by land marks, geese. Parents take their young and the young will follow. If parents take the wrong way the young will continue year after year to go the wrong way. 2. Orientation- Use the sun to know which way to go- north or south. 27

3. Navigation- this migration is the most difficult to understand. Lots of research has been done and many birds are missing because of it. 28

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I. When to migrate 1. Ultimately it is how much food is left or not left will determine when birds start to migrate. 2. It is thought that birds are genetically predetermined to know when to migrate. 3. The male birds are the first to migrate. 30

4. Female birds are second to migrate. 5. Males need to establish territory. If the males migrate to early they will die from cold and lack of food. 6. The more dominant males will come first and the less dominant males will come second. 31

7. The less dominant males have a higher survival rate than the more dominant males. 8. Survival also depends on the amount of fat that is on the bird, if they are able to survive low amounts of food. 32

II. Anatomy of a bird A. Feeding 1. Birds have high metabolic rates and burn many calories just to keep warm. Birds need to eat large amounts of food. 2. Carnivorous birds such as hawks and eagles catch prey in razor-sharp talons and slice them to pieces with a pointed beak. 33

3. Insect-eating birds do everything from picking insects off leaves and branches to catching them on the fly. 4. Their tongues are often equipped with a brush like structure at the tip for lapping up nectar and fruit juices. 5. Fruit-eating and seed-eating birds may have short, stout beaks or long, sharp ones, depending on the fruit or seed eaten. 34

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6. The digestive system of birds, much like that of reptile shows specializations for carnivores and herbivores diets. 7. Many birds have organs called crop and gizzard. 8. Crop is an organ that food can be stored and moistened before it enters the stomach. 36

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9. The gizzard is a specialized muscular part of the stomach that often contains small bits of gravel swallowed by a bird. 10. The muscular wall grind the gravel and food together, thus crushing food particles and making them easier to digest. 38

B. Respiration 1. The respiratory system of birds is extremely efficient at taking in oxygen and eliminating carbon dioxide. 2. Bird’s lungs are connected at both the anterior and posterior to large air sacs in the body cavity and bones. 39

3. When a bird inhales, air travels through passageways that lead into the lungs. 4. Some of this air remains in the lungs, where gas exchange occurs. 5. Most of the air goes through the lungs into posterior air sacs. 40

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6. When a bird exhales, air from the posterior air sacs passes into the lungs for gas exchange. 7. Birds are able to remove oxygen from air when they inhale as well as when they exhale. 42

C. Internal transport 1. Birds have four-chambered heart and two separate circulatory loops. 2. One half of the heart receives oxygen –poor blood from the body and pumps this blood to the lungs. 43

3. Oxygen –rich blood returns to the other side of the heart to be pumped throughout the rest of the body. 4. Bird’s heart beats fast-from 1501000 beats per minute. 44

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D. Excretion 1. Birds eliminate nitrogenous waste filtering them from the blood in the kidneys. 2. Urine, which contains wastes in the form of uric acid, flows to the cloaca through the ureters. 46

3. Most water is reabsorbed in the cloaca, leaving uric acid crystals in a white paste like form. 4. These crystals are “bird droppings. ” 47

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E. Response 1. Birds are quite intelligent animals. 2. Bird’s cerebrum, which controls such behaviors as flying, nest building, care of young, courtship and mating. 3. The cerebellum’s also well developed. 49

4. Birds have extraordinarily well developed eyes. Their eyesight is reflected pair of sizable optic lobes in the brain. 5. Birds see color very well in many cases better than humans. 6. A hawk can see 400 times better than a human. 50

7. Bird’s eye is very similar to humans but hey have pectin. It is unknown what the purpose of this is. 8. A bird blinks different than humans. In birds the lower eyelid comes up to close the eye. 9. A bird has a third eyelid, it is clear and it can’t be seen. 51

10. Ocean birds have a temporary contact lens to go over their eyes so they can see under water. 11. Birds usually have a broader range of vision. A human can see at 85 -90 degree angles. A hawk can see at 110 -degree angels. 52

12. Humans have 9, 000 taste buds in their mouth. A bird- 37. A bird has the same basic tastes: sweet, sour, bitter and salty. 13. Birds lack external ears; they have ear openings in their head. Many bird species can hear quite well. Example- owls 53

F. Reproduction 1. The reproductive system of birds is similar to that of reptiles. Both males and female reproductive tracts open into the cloaca. 2. In many female, birds, only one side of the reproductive tract develops, this is to minimize weight. 54

3. Birds have a hard outside shell; their internal structure and membranes are similar to those of reptiles. 4. Most birds incubate their eggs until the hatch. 5. Incubation varies from specie to specie about 13 days to more than 50 days. 55

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6. Sex chromosomes in humans XX (female) Xy (males) In aves= Wu(female) WW(male) 7. In birds the female determines the sex of the offspring. 57

8. Expected ration 50/50 of sex. Some species are different some ducks- 40% female, 60% male. House sparrow, 45% female 55% male. Red winged black birds 16% female 84% male. 58

9. Many birds are monogamies – only have one mate for a lifetime. Monogamies – 93% Polygamous- 3% Polyandry - 1% Promiscuous - ½% 59

10. Most species of birds have very unique courtship rituals. 11. Male birds do 99% of chirping or calls. This is to call for his female or to stake our territory rights. 12. Many birds will undergo courtship behaviors, dancing, fighting, fluffing and many other characteristics. 60

G. How birds fit in the world 1. Birds are very important to identify pollution, disease or other health issues. 2. Birds are very important in the ecosystem. Help to control the insect population and small rodent population. 61

3. Birds also help to pollinate flowers. 4. Some species of birds help to clean up waste-vultures. 5. Some species of birds are hunted. 62

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