BIRDS class: Aves Chapter 42 Birds are the most diverse & widespread terrestrial vertebrates

What characteristic is unique to birds ? Wings? –Also found in bats (mammals), flying arthropods Beaks? –Also found in Turtles (reptiles), (squid) cephalopods Bills? – Also found in : platypuses (mammals) Feathers are unique to birds

There are seven characteristics all birds share: Feathers Wings Lightweight, rigid skeleton Endothermic metabolism Unique respiratory system Beak Oviparity

1. Feathers * Unique to birds (NO OTHER ANIMALS HAVE THEM!) *are modified scales that serve 2 functions: -providing lift for flight -conserving body heat. *Feather Parts: -shaft -two vanes -barbs -barbules

How do birds stay warm in the winter? Feathers!!! –Down feathers are very insulating vs cold. Down jacket anyone?

3 Types of Feathers: Down feathers - soft, fluffy feathers that cover young birds and provide an insulating undercoat in adults Contour feathers - smooth feathers that give adult birds’ bodies a streamlined shape and provide insulation Flight feathers - specialized contour feathers located on the wings and tail that are long and rigid

3 types feathers Downy Contour Flight

Feather Care: Preening occurs when birds use their beaks to rub their feathers with oil. Preen gland –located at the base of the tail –secretes oils that keep feathers healthy & waterproof. Molting - Birds periodically shed and regrow their feathers.

Birds who’s feathers get soaked through with oil usually freeze to death These guillemots are covered in oil. The feathers on their bellies should be pure white. Dozens of oil victims are cared for every year in the bird sanctuary at Ecomare. They are washed in a special bird washing machine. Afterwards, they need time to gain back their strength and get their plumage back to its water-repellent state. Eventually, they are returned to the open sea. Only 10% of the birds immersed in oil wash ashore alive. The rest die at sea.

2+3. Wings & Light-weight Skeleton Skeleton is light and strong. Bones are thin and hollow. Many bones are fused * more rigid than a reptile or mammal‘s. * Furcula - The fused pair of collar bones = “ WISHBONE” *A large keel-shaped sternum allows attachment of large flight muscles.

Avian Skeleton

More Flying Adaptations Birds have large, powerful flight muscles in the breast and wings. In some birds, flight muscles account for up to 50% of the body weight. The Pygostyle, fused terminal vertebrae, supports the tail feathers.

Pectoral muscles form the bulk of the fleshy mass & about 15 to 20 percent of the bird's total body weight.

4. High Metabolism Endothermic. Very high metabolic rate. –Rapid breathing –Rapid digestion of lots of food (A thrush can eat blackberries, digest them & excrete seeds 45 mins later.) Maintains a body temperature of degrees F.

The avian circulatory system is similar to that of both crocodiles and mammals. Birds have a four chambered heart. Deoxygenated blood is completely separated from oxygenated blood in the heart. Birds have a relatively rapid heartbeat. Unlike mammals, avian red blood cells have nuclei.

5. Unique Respiratory System Most efficient respiratory system of any terrestrial vertebrate.

6. Beak Jaws covered by tough horny sheath No modern birds have teeth. –(Achaeopteryx (bird ancestor) had teeth) Birds must swallow gravel or small rocks to help grind food in the gizzard.

The Avian Digestive System: Beak - breaks open or tears apart food Esophagus - passage from the mouth to the crop Crop - stores and moistens food Stomach - consists of two parts –proventriculus - digestive enzymes break down food –gizzard - kneads and crushes food aided by stones which the bird swallows Small intestine - absorbs nutrients Large intestine - absorbs water Cloaca - eliminates wastes from the body

7. Oviparity Lay Amniotic eggs in a hard calcium containing shell. Internal fertilization. Usually lay their eggs in a nest. One or both parents warm (incubate) the eggs and guard the nest. Birds sit on their eggs and cover them with a thickened featherless patch of skin called the brood patch. Birds usually provide extensive parental care.

Birds have two general patterns for rearing young. Precocial: –Young incubate for long periods. –Young can walk, swim, and feed as soon as they hatch. –This pattern is most often seen in ground- nesting birds. Altricial: –Eggs hatch quickly. –Young hatch blind, featherless, and helpless and require extensive parental care. –This pattern is most often seen in birds that nest above ground.

Parts of a Bird

Internal structures of a bird

Phylogenic diagram of relationships to birds

Similarities between birds & some dinosaurs: Flexible S-shaped neck Unique ankle joint Hollow bones Oldest known bird fossils: genus Archaeopteryx, which date from the late Jurassic period, have characteristics of both dinosaurs & birds.

Hypothesizes on Origin of Flight Ancestors of birds were tree dwellers that developed the ability to glide between trees. Ancestors of birds were ground- dwelling & first used feathers to stabilize them when they leapt after prey.

How many different kinds of birds can you name? Pennsylvania Game Commission photo gallery: w.asp?a=458&q=162298http:// w.asp?a=458&q= Good Field guide to birds

Birds are divided into 23 orders. Ten of the most familiar orders are listed: Anseriformes (swans, geese, ducks) Strigiformes (owls) Apodiformes (hummingbirds & swifts) Poittaciformes (parrots,parakeets, macaws,cockatoos) Piciformes (woodpeckers, toucans) Passeriformes (*the biggest group w/more than half total # bird species) (Robins,warblers,bluejays,wrens) Columbiformes (pigeons & doves) Ciconiiformes (penguins, storks, herons, egrets, raptors, vultures) Galliformes (Turkeys, pheasant, chickens, quail) Struthioniformes (**largest birds) (ostriches, emus, cassowaries)

Pennsylvania Audubon Society Another good site: URL: he_wing.htm he_wing.htm

Assignments: 1. Read page 850 in textbook Answer 3 questions page Read section 42-3 Answer questions Write the name of each of the ten most common orders listed in your book, then write down the type of birds in the order & at least 3 adaptations for each group Anseriformes Strigiformes Apodiformes Poittaciformes Piciformes Passeriformes Columbiformes Ciconiiformes Galliformes Struthioniformes

Avian Adaptations

Questions 1.Which of the following characteristics of Archaeopteryx is not shared by modern birds? A. tail B. teeth C. furcula D. feathers 2. Which of the following characteristics do birds share with dinosaurs? F. crop G. lack of teeth H. presence of feathers J. structure of the ankle joint

3. What is the function of the preen gland? A. to produce digestive enzymes B. to control salt balance in the body C. to release scents that help attract mates D. to produce an oily substance used to condition the feathers 4. Which bone supports the tail feathers? F. ulna G. furcula H. pygostyle J. pelvic girdle