Ornithology Lecture 20

Exam Information

  • The exam will be cumulative, covering the current unit and previous material.

  • The instructor will not be present for the final exam and it will be proctored by another professor.

Factors Impacting Populations

  • Discussion of factors impacting populations & corrections implemented.

Major Causes of Species Decline

  • Habitat loss.

  • Overexploitation.

  • Introduction of new species/invasive species.

  • Climate change.

Geological Epoch

  • Earth is in the Holocene epoch, with a proposed return to the Anthropocene epoch.

  • Large-scale changes to the planet are unprecedented compared to other processes.

Human Perceptions

  • Understanding the drivers that affect human perceptions is important for conservation biology.

  • Positive or negative experiences with wildlife influence outlook and future interactions, affecting environmental legislation.

Positive Experiences

  • Bird feeders benefit both people and birds.

  • Birds also benefit from garbage and human-built structures (nesting and perching sites).

Negative Impacts

  • Chemicals: direct and indirect (e.g., rodenticides bioaccumulating).

  • Land and habitat conversion.

  • Overhunting.

Historical Impacts

  • Hat Making: Fashion trends led to widespread bird losses.

  • Upwards of 1,400 birds per year killed for hat making.

Great Egrets

  • Great egrets were hunted almost to extinction in North America for their plumes during breeding season.

Conservation Efforts

  • Harriet Lawrence Hemingway and Mina Behar organized tea parties to drive sign-on by women to stop buying clothing using bird feathers. These parties led to the Massachusetts Audubon Society.

  • The Massachusetts Audubon Society was the precursor to the National Audubon Society.

  • These efforts led to the Lacey Act.

Lacey Act

  • The Lacey Act, influenced by the Audubon Society, bans trafficking and trade of wildlife and plant materials.

  • It covers animals (whole or parts) and plants, with exceptions for Native Americans using these materials for religious or ceremonial purposes.

  • It influences wildlife ownership on private land; landowners cannot own the wildlife on their land.

Migratory Bird Treaty Act

  • Focuses specifically on migratory birds.

Bald Eagle Protection Act of 1940

  • Aimed to protect the national bird from extinction due to hunting and pesticides.

Endangered Species Act (ESA) of 1973

  • The ESA's definition of "take" includes habitat degradation, but there are efforts to remove habitat loss as a violation.

  • Since its passing, 70% of listed birds have seen population recoveries.

  • Without the ESA, 16 species would have been predicted to go extinct.

Ecosystem Services

  • Wildlife values include intrinsic (liking something for what it is) and extrinsic (tangible benefits).

  • Ecosystem services such as pollination and seed dispersal.

  • Decomposers are vital for recycling atoms and elements on Earth.

  • Pest control is also a crucial service provided by birds.

Four Threats Policy in Maoist China

  • The policy targeted mosquitoes, flies, rodents, and sparrows.

  • Killing sparrows led to an increase in pests, contributing to the Great Famine.

Bird Watching

  • Supports over a million jobs and generates significant revenue.

  • Non-consumptive use (e.g., bird watching) is approaching and may exceed hunting and fishing in terms of economic impact.

Success Stories

  • Banning DDT led to the increase of raptor populations.

  • The pie chart illustrates species decline.

  • Increased raptor populations are attributed to DDT bans.

  • Bald eagle populations have recovered.

DDT

  • Intended to solve malaria problems, even advertised for in-home use.

  • Advertisements promoted DDT as safe.

Biomagnification

  • Chemicals accumulate in tissues faster than the body can remove them, increasing concentration at each stage.

  • Causes secondary death and shell thinning in birds due to impeded calcification.

DDE

  • A metabolite from DDT also has consequences in shell thinning.

  • Shell thinning led to high fatality on test.

DDT Ban

  • DDT was banned in the US in 1972.

  • Since then, raptor populations have increased.

  • Bald eagle populations were almost extinct but have recovered due to the DDT ban.

Peregrine Falcons

  • Peregrines have been almost completely lost in North America

  • Their recovery is attributed to hacking and banning DDT.

Hacking

  • The process of relocating at-risk nests to protected areas to increase offspring survivability; offspring imprint on the new location.

Seabird Restoration

  • Using mannequins to attract puffins to restored habitats; puffins use other individuals as a gauge of quality.

Eastern Turkeys

  • Translocation helped to save the species from habitat loss.

Egg Collecting

  • Egg collecting/poaching significantly reduces bird populations, particularly rare species.

Imprinting

  • Birds imprint on caretakers, which affects where birds migrate. So if birds imprint on humans they will follow them instead of migrating so they use costumes to prevent this.

  • Caretakers wear white suits and use ultralight aircraft to guide birds along migratory paths.

Actions Individuals Can Take

  • Participate in citizen science (bird counts, surveys, bio blitzes).

  • Reduce plastic use.

  • Use bird-strike-preventing windows.

  • Keep cats indoors.

  • Use native plants and avoid pesticides.

  • Drink shade-grown coffee.

  • Recognize everyone's stake in conservation.

  • Be careful with bird feeders to avoid bacterial contamination.

  • Don't buy wild-caught pets.

  • Get rid of lead ammo for hunting.

  • Support conservation organizations.

  • Make informed consumer choices (