Sea Turtles: General traits

• Cannot retract head into shell
• Legs modified into flippers
• Usually leave water only to lay eggs
• Lack teeth
• 8 species total

Sea Turtles: Species

• Green turtle, tropics, feed on seagrasses & seaweeds
• Hawksbill turtle, feed on encrusting organisms & seaweed
• Leatherback, largest (up to 2 m), eat jellyfish

Turtle Migration & Reproduction

• Migrate to specific beaches
• Some travel over 1,000 miles & up to 2 months
• Navigate by wave motion and magnetic fields?
• Return to nesting areas every 2-4 years
• Copulate in water, females go to shore
• Lay 100-160 eggs per nest
• Hatch in 60 days

Turtle Conservation

• All species are endangered
• Many natural enemies, especially young
• Adults & eggs traditionally eaten
• Hunted for shells, leather, and oil as well
• Leatherbacks ingest plastic bags
• Many drown in fishing nets
• Kemp's ridley turtles caught in shrimp trawls
• Loss of nesting grounds

Skeleton

• Many bones hollow (much reduced in loons, grebes, and anhingas).
• Air sacs from lungs enter the larger bones.
• Struts in bones.
• Breast bone lengthened into a keel, wing muscles attached here.
• Many of the vertebrae and bones of the pelvic region fused to increase strength.
• Head bones decreased to smallest functional size.

Lungs and Circulatory System

• Very large compared to body.
• Flow through system.
• Heart very large for body size, rapid heart rate.
• RBCs smaller and more numerous.
• Blood glucose levels much higher than for mammals.
• Rapid metabolic rate.

Weight Reducing Adaptations

• Sexual organs atrophied during off-season.
• No bladder.
• Feathers.

Miscellaneous

• Homeothermic.
• Egg-laying.

General Adaptations for Marine Living

• Webbed feet for swimming.
• Uropygial (preen) gland.
• Salt gland.
• Nearly solid bones in many diving birds.
• Long narrow wings in many pelagic birds.

Competition in Sea Birds

• Very little competition for food.
• Mostly competition for nesting space.

Scavengers

• Small to large birds, varied.
• Generalist bill, usually large.
• Eat flotsam and carrion.
• American Crow, Common Raven, TV, Gulls.

Seed and Insect Eaters

• Small birds.
• Strong seed cracking bill, or bristles around mouth.
• Swallows, Sparrows, Brewer's Blackbird, Starlings, Red-winged Blackbird, Marsh Wren.

Aerial Predators

• Medium to large.
• Eat other birds or small mammals, reptiles or amphibians sighted by air.
• Specialized talons and beak for grasping and tearing flesh.
• Golden Eagle, Hawks, Black-shouldered Kite, Falcons.

Shorebirds

• Small to medium sized.
• Probers and gleaners.
• Feet specialized for walking on sand and mud (or rocks); beaks long and narrow for probing mud and sand (or for opening shells).
• Sandpipers, Plovers, Willets, Turnstones, Oystercatchers, Rails.

Wading Birds

• Medium to large sized.
• Probe in mud or spear fish.
• Long legs, long spreading toes to keep from sinking in mud; long beaks for probing or spearing.
• Avocets, Stilts, Curlews, Godwits, Egrets, Herons, Bitterns.

Diving Birds

• Heavy-bodied birds with short pointed wings.
• Legs short with webbed feet, often placed far back on body.
• Medium-sized to long bill, pointed or hooked.
• Dive directly from surface, not from air.
• Scoters, Cormorants, Grebes, Murres, Pigeon Guillemots, Loons, Bay Ducks, Auklets.

Plunging Birds

• Small to large.
• Dive for fish or other prey that is near surface. Some scavenge for food right on surface.
• Usually with webbed feet; beaks often hooked, sharp, sometimes highly specialized.
• Gulls, Pelicans, Terns, Kingfishers, Petrels, Shearwaters, Albatrosses, Osprey.

Aerial Pirates

• Large birds.
• Harass other birds and make them drop food or prey on eggs or nestlings of other birds.
• Usually large, sharp beak.
• Jaegers, Skuas, Bald Eagle.