Birds People Good Things Birds Do For Us
Birds & People
Good Things Birds Do For Us • Food • Eggs • 2 billion chickens per year (18 kg/person) • 100 million turkeys • 11 million ducks
Good Things Birds Do For Us • Feathers ornamentation
Good Things Birds Do For Us • Guano - fertilizer • Peruvian islands
Good Things Birds Do For Us • Insect control • Northern Flicker removed >60% of over-wintering cornborer larvae from Mississippi cornfield • Bird houses - Purple Martin - mosquitoes
Good Things Birds Do For Us • Rodent control • Hawks, owls - small rodents
Good Things Birds Do For Us • Scavengers • Vultures, gulls, crows
Good Things Birds Do For Us • Recreation • Hunting economics • Falconry
Bad Things Birds Do To Us • Crop damage • U. S. - 6 million bushels of corn/year • Waterfowl, doves, crows/jays, robins, starlings, blackbirds, turkeys
Bad Things Birds Do To Us • Competition • Wild game, fish
Bad Things Birds Do To Us • Fouling of roosts • Droppings - pigeon 2. 5 kg/year • Odor, corrode masonry • Histoplasmosis, chlamydiosis
Bad Things Birds Do To Us • Airport problems • Plane strikes • ~15, 000 collisions/year in U. S. • $300 million/year • 300 people deaths • Gulls - 31%, blackbirds - 13%
Bird Trauma Through Time • 3 million years ago 25% of birds went extinct at beginning of Pleistocene • Major climatic changes – Habitat changes – Distribution changes – Viability impacts
Human Impacts • Humans have become a major factor affecting birds • ~1000 species now threatened
Human Impacts • Destruction of habitat • Excessive human predation • Introduced species • Toxins
Human Impacts • Many bird groups especially problematic • Neotropical migrants • Grassland species • Migrant shorebirds • Seabirds of Southern Hemisphere • Rain forest species with restricted ranges
Human Impacts • 10 countries now harbor 400 threatened species with restricted ranges
Human Impacts • Past 300 years • ~90 bird extinctions • 91% due partly to species introductions (especially on islands) • 32% due partly to habitat changes • 25% involved excessive human predation
In the U. S. • Endangered species - one that is in danger of extinction throughout all or a significant portion of its range • Threatened species - one that is likely to become endangered in the foreseeable future throughout all or a significant portion of its range
Small Island Effect • Island-bound flightless & nesting seabirds • Susceptible to rats, hogs, goats, cats brought to islands by ships/sailors • Dodo in western Indian Ocean • Great Auk of northern Atlantic Ocean – Food to resupply ships that had crossed Atlantic
Hawaiian Island Problems • Bird pox & malaria brought by introduced mosquitoes • Worse problem caused by first Polynesian colonists 1500 years ago • Lowland forest destruction - extinction of 39 spp. of land birds
Modern Threats • Human activities directly responsible for deaths of ~270 million birds/year • Does not include losses due to destruction of breeding habitat, interference with reproduction
Modern Threats • Hunters - 120 million • Vehicle collisions 57 million • Windows - 80 million – 2/3 of hunter kill – IL house - 61/year – NY house - 47/year
Modern Threats • CATS! 1 billion!
Environmental Poisons • Pesticides - DDT • Bald eagle, other raptors • Reproductive failure 15 -20% thinning of eggshells • Reproductive output cut by nearly 2/3 until DDT ban • Recent recoveries to near normal
Environmental Poisons • Xenobiotics • Chemicals that interfere with endocrine system • Disrupt normal course of development • Fungicides, herbicides, insecticides, assorted chemicals, food products, metals
Environmental Poisons - PCBs • May lead to: • Thyroid dysfunction • Compromised immune systems • Decreased fertility • Decreased hatching success • Gross birth deformities, behavioral abnormalities, sex reversal Cormorants
Environmental Poisons - PCBs • • • Extra eggs Female-female pairings Feminization High male mortality Embryonic/chick mortality • Reduced growth • Deformities • Altered nest defense, incubation behavior Herring Gulls Lake Michigan, Ontario
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