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Chapter 13

Chapter 13. Birds of Prey. Birds of Prey. Also called raptors Carnivores (secondary consumers) in all N. American ecosystems: Help maintain natural balance between living organisms and food supplies by controlling populations of birds, reptiles, rodents, other small animals

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Chapter 13

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  1. Chapter 13 Birds of Prey

  2. Birds of Prey • Also called raptors • Carnivores (secondary consumers) in all N. American ecosystems: • Help maintain natural balance between living organisms and food supplies by controlling populations of birds, reptiles, rodents, other small animals • Toes equipped with claw-like talons for grasping and killing prey • Three toes pointed forward and 4th toe pointing backward

  3. Birds of Prey (Cont.) • Beaks are sharp, shaped to tear raw flesh • Strong jaws and feet • Exceptional eyesight • Nest called “aerie”

  4. Birds of Prey Comparedto Seed Eating Birds

  5. Four Families of Hawk-Like Birds 1. Eagles, hawks, kites 2. New World vultures 3. Ospreys 4. Falcons (Falconiformes)

  6. Eagles, Hawks, and Kites • Diurnal: active only during daylight • All similar in shape • Major differences include size, diet, and preferred habitats

  7. Eagles, Hawks, and Kites (Cont.) • Debate regarding whether they mate for life; may simply mate with same partner for one or more seasons • Some are polygynous: male mates with more than one female • A few polyandrous: female mates with more than one male • Both parents typically care for young; will aggressively protect, even attack humans • Males help incubate eggs

  8. Eagles, Hawks, and Kites (Cont.) • Establish territories around nesting area that they defend against others of their kind • Except for marsh hawks: live/nest in colonies • Females often larger than males, particularly when prey is fast

  9. Examples of Eagles • Bald Eagle (Haliaeetus leucocephalus) • Classified as a fish eagle: prefers coastal habitats or rivers and lakes • Scavengers (eat carrion) • National bird of U.S. • Range: throughout much of U.S. and Canada, most abundant in AK, but avoids far northern tundra biome • Young called eaglets • No feathers on legs

  10. Examples of Eagles (Cont.) • Golden Eagle (Aquila chrysaetos) • Range: across much of AK and Canada, throughout western U.S. and south to Mexico • Rarely eats carrion • Will also kill domestic animals (lambs, small goats, young pigs, chickens)

  11. Hawks • Harriers • Genus of hawks • Excellent hunters in tall vegetation; nest in close proximity to each other • Accipiters • Genus of small-medium size hawks • Swift, agile, with long tails and short, rounded wings • Called chicken hawks because they prey on domestic birds

  12. Hawks (Cont.) • Kites • Have long square or forked tail, long wings with pointed tips • Small population; found only in warmer areas of N. America, mostly in southeastern and Gulf Coast states, few in CA • Include: swallow-tailed kite, black-shouldered kite, Mississippi kite, snail kite, white-tailed kite • Everglade Snail Kite (Rostrhamus sociabilis) • Found in FL Everglades; endangered

  13. Examples of Hawks • Red-Tailed Hawk (Buteo jamaicensis) • Range: breeds northward from U.S. and Canadian border; normal range throughout most of U.S. and parts of Mexico • Adapted to range of habitats (desert to tundra) • Diet: small rodents, insects; helps manage rodent populations

  14. Examples of Hawks (Cont.) • Swainson’s Hawk (Buteo swainsoni) • Has many color phases • Range: much of the western half of N. America; flocks migrate to Argentina (covers 11,000–17,000 miles annually) • Diet: rodents, small animals, large insects • Monogamous; mated pairs return to same nesting sites every year

  15. Harrier Example • Northern Harrier (Circus cyaneus) • Widely distributed in N. America • Uses acute hearing to find/catch mice hidden in tall vegetation • Family groups gather roost together on the ground each night

  16. Examples of Accipiters • Goshawk (Accipiter gentilis) • Range: much of N. America • Fly by flapping wings to gain speed, followed by long glide and can maneuver swiftly through trees and branches • Prey on medium-sized birds, game and domestic • Cooper’s Hawk (Accipiter cooperii) • Diet: mainly songbirds and woodland game birds, but will also eat small mammals and reptiles; hunt “on the wing” • Recently removed from IL state endangered species list • Similar, but smaller than goshawk

  17. Examples of Accipiters (Cont.) • Sharp-shinned Hawk (Accipiter striatus) • Small (wingspan of 21–22”) • Female is larger, often confused with male Cooper’s hawk, but is quicker in flight • Range: throughout deciduous and coniferous forests of N. America, into Canada and Gulf states • Appears on some state lists of endangered and threatened species

  18. Falcons • Similar to accipiters with feeding preference for birds, often including large game birds (pheasants or ruffed grouse) • Others prefer small birds, like sparrows and finches • Will also eat small mammals

  19. Examples of Falcons • American Kestrel or Sparrow Hawk (Falco sparverius) • Kestrel: means it can maintain fixed position above ground by hovering on rapidly beating wings, keeping eye on prey • Range: AK and southern Canada to Mexico

  20. Examples of Falcons (Cont.) • Peregrine Falcon (Falco peregrinus) • Range: AK and northern Canada along Rocky Mountains to Mexico • Removed from federal listing of endangered species in 1999, but still listed as endangered in some states • Captures prey in flight using fast dive (stoop) • Sometimes builds nests on tall buildings in cities where it can prey on pigeons

  21. Effects of Chemicals on Raptor Populations • Falcon populations dropped dramatically in 1900s with use of organic pesticides (DDT) • DDT caused weakness in eggshells which often broke during incubation • Chemicals used in agriculture or yards can accumulate in bodies of birds and reach harmful or even toxic levels

  22. Effects of Chemicals on Raptor Populations (Cont.) • Chemicals pass from plants to primary consumers to secondary consumers—and can persist in the food web for a long time • Chemicals with demonstrated long-term negative effects on wildlife or humans must not be used

  23. New World Vultures • Scavenging birds that eat carrion • Awkward on the ground, but graceful in flight • Clean up rotting flesh of dead animals • Excellent eyesight

  24. Examples of Vultures • Turkey Vulture (Cathartes aura) • One of largest birds in N. America • Range: most of U.S., Canada • Naked head helps keep bird clean

  25. Examples of Vultures (Cont.) • California Condor (Gymnogyps californianus) • Largest bird of prey in N. America • Endangered: • Only one breeding flock known to remain in southern CA; captive flocks being raised to prevent extinction • Result of loss of habitat, improper use of pesticides, disturbance by humans, slow rate of reproduction

  26. Osprey (Pandion Haliaetus) • Only one species known • Sometimes called fish hawk or fish eagle because of diet • Mate for life • Range: northern and coastal regions of U.S. and Canada, except for far northern regions along rivers, lakes, seacoasts

  27. Owls • Two families in N. America: typical owls and barn owls • Unique characteristics as compared with other birds: • Have down on margins and tips of wing feathers to deaden sounds of flight • Excellent vision allows them to see quite well at night • Highly developed sense of hearing: can hunt by sound alone

  28. Owls (Cont.) • Found in any habitat with suitable food supply • Nocturnal; hunt mostly at night • Prey on rodents, rabbits, birds, reptiles, fish, insects; diet generally not specialized

  29. Typical Owls • Also known as “true” owls • Large round heads, large eyes, hooked bills, fluffy plumage to muffle sound • 17 species identified in N. America

  30. Examples of Typical Owls • Great Gray Owl (Strix nebulosa) • Largest owl in N. America • Facial disk: feather pattern on face helps direct sounds toward ear openings • Range: bogs and marshes of AK, Canada • Great Horned Owl (Bubo virginianus) • Has large, yellow eyes, and ear tufts or “horns” on round head • Range: most of N. America

  31. Examples of Typical Owls (Cont.) • Elf Owl (Micrathene whitneyi) • Smallest owl in N. America (size of sparrow) • Range: Saguaro desert region in southwest • Snowy Owl (Nyctea scandiaca) • Range: migratory; ranges throughout Canada and into northern arctic region • Diet: mainly lemmings

  32. Examples of Typical Owls (Cont.) • Other examples include: • Eastern Screech Owl (Otus asio) • Western Screech Owl (Otus kennicottii) • Burrowing Owl (Speotyto cunicularia) • Spotted owl of the Pacific Northwest and British Columbia (endangered)

  33. Barn Owls (Tyto Alba) • Only one type found in N. America • Distinctive, heart-shaped faces • Range: much of U.S. in woodlands, prairies, farms, and suburban areas • Attracted to highways in winter where mice travel; highway mortality causes significant losses to population

  34. Barn Owls (Cont.) • Nest in protected areas, including barns • Considered “friend of man” because it preys on rodents and lives in close proximity with humans

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