Population and Conservation in Birds
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Questions and Answers

What is one major consequence of habitat fragmentation on bird populations?

  • Greater gene flow
  • Higher mortality rates (correct)
  • Increased dispersal capabilities
  • Improved nesting success

Which of the following species is known to have been successfully reintroduced after facing near extinction?

  • Passenger Pigeon
  • Hawaiian Honeycreeper
  • Carolina Parakeet
  • California Condor (correct)

How have human actions contributed to bird extinction in North America?

  • Through the establishment of nature reserves
  • By promoting bird watching activities
  • Through the introduction of non-native species
  • By causing habitat destruction and hunting (correct)

What role do corridors play in fragmented landscapes?

<p>They provide connectivity for dispersal. (A)</p> Signup and view all the answers

What significantly impacts migratory bird species from a conservation perspective?

<p>Working to conserve both breeding and wintering grounds (D)</p> Signup and view all the answers

What factor has contributed to the decline in grassland bird species?

<p>Change in climate leading to habitat loss (C)</p> Signup and view all the answers

What is a common consequence of edge effects for birds nesting close to a forest edge?

<p>Increased risk of nest predation (D)</p> Signup and view all the answers

Which factor was responsible for the near extinction of Peregrine Falcons in eastern North America during the 1950s and 1960s?

<p>DDT pesticide use (B)</p> Signup and view all the answers

Which of the following species is known for its unique migratory pattern within Central America?

<p>Resplendent Quetzal (C)</p> Signup and view all the answers

What is the estimated percentage decrease in the total population of North American birds over the past 50 years?

<p>One third (D)</p> Signup and view all the answers

What is the term used for a rapid loss of population size leading to reduced genetic diversity?

<p>Population bottleneck (C)</p> Signup and view all the answers

What factor is primarily responsible for population regulation through negative density dependence?

<p>Predation pressure (A)</p> Signup and view all the answers

Which bird species example illustrates the phenomenon of density-dependent effects on reproductive success?

<p>Great Tits (A)</p> Signup and view all the answers

Which of the following species has shown significant decline due to human activities, specifically habitat loss?

<p>Northern Pintail (A)</p> Signup and view all the answers

What percentage of bird species are classified as endangered, according to the IUCN Red List?

<p>28% (D)</p> Signup and view all the answers

Which introduced species is known for its dramatic population increase after being released in 1896?

<p>European Starling (D)</p> Signup and view all the answers

What role does citizen science play in bird population monitoring?

<p>Provides crucial data on population trends (C)</p> Signup and view all the answers

What environmental threat directly impacts bird populations through habitat degradation and loss?

<p>Urbanization (C)</p> Signup and view all the answers

Which bird species faced dramatic population declines primarily due to the effects of DDT?

<p>Brown Pelican (D)</p> Signup and view all the answers

Which of the following is a key factor in causing short-term population fluctuations among birds?

<p>Food availability (D)</p> Signup and view all the answers

What is the expected result of increased population density in certain bird species, as evidenced by the Black-throated Blue Warblers?

<p>Decrease in fledging rates (D)</p> Signup and view all the answers

What significant consequence of habitat loss is frequently noted in bird populations?

<p>Reduction in nesting sites (D)</p> Signup and view all the answers

What is a direct consequence of the invasive European Starlings competing with native species?

<p>Reduction in native nesting sites (A)</p> Signup and view all the answers

What factor primarily buffers short-term fluctuations in bird population sizes?

<p>Population regulation (D)</p> Signup and view all the answers

What is the primary reason for the significant fluctuation in the population size of Scaled Quail over time?

<p>Rainfall variation (C)</p> Signup and view all the answers

Which example illustrates the effects of a population bottleneck on genetic diversity?

<p>New Zealand bird populations (A)</p> Signup and view all the answers

What trend has been observed regarding bird species associated with human habitats?

<p>They consistently show explosive population growth. (D)</p> Signup and view all the answers

What was a significant cause of Bald Eagle population decline in North America?

<p>Pesticide application, particularly DDT (B)</p> Signup and view all the answers

What major conservation action has been undertaken to address the decline of Northern Pintails in the 1960s?

<p>International management plan (D)</p> Signup and view all the answers

What percentage of the IUCN Red List species are classified as vulnerable?

<p>787 species (A)</p> Signup and view all the answers

What human-induced factor is a primary threat to birds due to its widespread nature?

<p>Habitat loss (D)</p> Signup and view all the answers

Which bird species shows a density-dependent decrease in fledgling numbers as population density increases?

<p>Black-throated Blue Warblers (D)</p> Signup and view all the answers

What role has citizen science played in understanding bird populations?

<p>Documenting population trends of non-game species (B)</p> Signup and view all the answers

Which factor is most closely linked to the decline of endemic bird species in tropical regions?

<p>Loss of habitat due to deforestation (D)</p> Signup and view all the answers

What is a critical impact of habitat fragmentation on bird populations?

<p>Reduced dispersal and increased mortality (B)</p> Signup and view all the answers

Which aspect of connectivity is most vital for conserving migratory bird species?

<p>Protection of breeding and wintering grounds (C)</p> Signup and view all the answers

What was a significant cause behind the extinction of the Hawaiian Honeycreepers?

<p>Avian malaria (A)</p> Signup and view all the answers

Which characteristic makes island species particularly vulnerable to extinction?

<p>Small population sizes and isolation (B)</p> Signup and view all the answers

What is a notable outcome of the California Condor's reintroduction program?

<p>Gradual population recovery over decades (B)</p> Signup and view all the answers

What is the primary reason for the significant decrease in the North American bird population over the past 50 years?

<p>Climate change and habitat loss (C)</p> Signup and view all the answers

Which feature of corridors is essential for bird conservation in fragmented landscapes?

<p>Facilitating gene flow and dispersal (A)</p> Signup and view all the answers

What was the primary driver for the near extinction of the Passenger Pigeon?

<p>Overhunting and commercial exploitation (A)</p> Signup and view all the answers

What ecological importance does the loss of bird species imply beyond their existence?

<p>Loss of ecosystem services essential for humans (C)</p> Signup and view all the answers

Flashcards

Habitat Loss from Climate Change

Destruction of natural environments due to changing climate patterns, especially deforestation in tropical regions.

Habitat Fragmentation

Breaking up large habitats into smaller, isolated pieces, negatively impacting bird populations.

Edge Effects

Negative impacts on birds nesting near fragmented forest edges, due to increased predation.

Bird Dispersal

The movement of birds from one area to another, crucial for their survival, which is hampered by fragmented habitats.

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Conservation Corridors

Connecting habitats to allow bird movement, gene flow, and migration.

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Connectivity in Conservation

The importance of linking breeding and wintering grounds to support migratory birds.

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Extinction of Bird Species

The complete disappearance of bird species, often caused by human activities.

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Island Birds Vulnerability

Island species often face higher extinction risks because of smaller ranges and unique threats.

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Successful Reintroductions

Bringing endangered species back from the brink of extinction successfully, like Whooping Cranes and California Condors.

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Impact of DDT on Peregrines

The pesticide DDT nearly drove Peregrine Falcon populations to extinction due to bioaccumulation.

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Bird Population Fluctuations

Bird populations change in size over time, sometimes dramatically, driven by short-term events like storms or long-term trends like habitat loss.

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Population Growth Potential

Some bird species have high potential for rapid population increases, especially smaller birds with faster reproduction.

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Population Limitation

Factors that restrict population growth, including habitat availability, food supply, disease, and predation.

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Population Regulation

Density-dependent effects on population size. Increased density negatively impacts survival and reproduction.

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Population Trends

Changes in bird populations over time, documented by citizen science efforts and government recordings.

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Population Bottleneck

A significant and rapid decline in a population's size which reduces genetic diversity and increases inbreeding.

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Bird Population Crashes

A quick and sudden drop in the size of a bird population.

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Inbreeding Depression

Reduced fitness and survival in populations due to mating among closely related individuals.

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Threats to Birds

Many factors, including habitat loss, climate change, disease, pollution, and human-wildlife conflict, pose risks to bird populations.

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Habitat Loss

The destruction or alteration of a bird's natural environment, making it less suitable for survival and reproduction.

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Negative Density Dependence

Reduced survival and reproduction rates as a population increases in density, directly impacting the population size.

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IUCN Red List

International classification system that categorizes species by extinction risk (e.g., endangered, vulnerable).

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Citizen Science

Collection and analysis of data by non-scientists who contribute to scientific research.

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DDT

A pesticide that, when used excessively in the past, impacted birds by interfering with eggshell formation and directly killing individuals.

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Introduced Species

A species that has been moved to a new habitat by humans, often causing ecological disruption.

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Population Density

The number of individuals within a population per unit of area or volume.

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Population Fluctuation (Short Term)

Bird populations can change drastically over short periods due to factors like storms or droughts, but they often recover quickly.

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Population Fluctuation (Long-Term)

Changes in bird numbers over long periods, potentially impacting the species' overall survival, often driven by factors like habitat loss or climate change.

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What is population limitation?

Factors that set a limit on how many birds can exist in an area, like habitat size, food availability, disease, or predators.

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What is population regulation?

How population density impacts a bird's survival and reproduction, often with higher density leading to lower rates.

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What role does citizen science play in studying bird populations?

Volunteers collect data about birds, helping scientists understand population trends and conservation needs.

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Challenges faced by birds today

Birds are threatened by habitat loss, climate change, disease, pollution, and human activities like hunting and collisions.

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Importance of the IUCN Red List

A global system that classifies species by their risk of extinction, helping to prioritize conservation efforts.

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Where did DDT harm birds?

The pesticide DDT impacted bird populations by interfering with eggshell formation, causing eggs to break before hatching.

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Deforestation's Impact

Cutting down forests, especially in tropical areas, is a major threat to bird populations due to habitat loss and the loss of endemic species.

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Endemic Species

Species found only in a specific geographic area, often with limited ranges, making them more vulnerable to habitat loss.

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Wetland Loss & Birds

The destruction of wetlands through drainage and land use changes negatively affects waterfowl and shorebirds, impacting their breeding and feeding grounds.

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Fragmentation Effects

Breaking up large habitats into smaller, isolated patches increases the risk of mortality and restricts dispersal for birds.

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Edge Effects & Predation

Birds nesting close to the edge of fragmented habitats are at higher risk of predation from predators that can access both the forest and open areas.

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Migratory Bird Complexities

Protecting migratory birds requires conserving both their breeding and wintering grounds, often in different locations and facing different threats.

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Extinction in Birds

Humans have driven many bird species extinct, particularly on islands, due to habitat loss, hunting, and introduced diseases.

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Reintroduction Success

By reintroducing critically endangered bird species back into their natural habitats, we have successfully restored some populations.

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DDT's Impact on Peregrines

The pesticide DDT caused a dramatic decline in Peregrine Falcon populations due to its bioaccumulation, interfering with eggshell formation.

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Study Notes

Population and Conservation

  • Population: group of interbreeding individuals and their offspring
  • May refer to individuals or entire species
  • Fluctuations in bird populations can be dramatic (short-term) or gradual (long-term)
  • Factors like storms, drought, and rainfall can cause short-term changes
  • Some populations exhibit large changes over longer periods
  • Introduction of House Finch to eastern North America: rapid population growth followed by decline

Growth of Population

  • Birds: potential for explosive population growth
    • Large-bodied: slow reproductive rates (10-30%)
    • Small-bodied: fast reproductive rates (50-100%)
  • Introduced species: dramatic population growth example (European Starlings)
  • Introduced in NYC in 1896
  • Population increased dramatically over the next century
  • Major invasive pest, competing with native species

Limitation and Regulation

  • Population limitation: any ceiling on population growth
  • Population regulation: effects of population density on population size (negative density dependence)
  • Factors influencing population size:
    • Habitat
    • Food
    • Disease
    • Predation
  • Examples:
    • Great Tits: mean clutch size and number of fledglings affected by density; Lay fewer eggs in high-density populations
    • 60% of variation in clutch size due to population density
    • Survival and reproductive rates regulated by population density
  • Data on population fluctuations:
  • Fish and Game departments (game birds)
  • Extensive records of citizen science (Christmas bird counts, eBird)
  • Population regulation & limitation interplay to determine population size changes
  • Food limitation reduces population size & density
  • Reduced density reduces negative density dependence, leading to population growth
  • Ducks (Waterfowl): decline in the 1960s
  • Northern Pintails: drop from 10M breeding pairs to 1M in breeding pairs

Example: Black-throated Blue Warbler

  • Density-dependent stabilization on breeding grounds: young fledged decreased as population density increased.
  • Rate of population grows (r) is negatively related to population density

State of Birds Today

  • Many bird species are threatened, endangered, or declining.
  • Greatest threat in high-diversity tropical areas due to developing countries/high human pop. pressure
  • 1/3 of US species require urgent conservation action
  • Migratory species, grassland species, those with small ranges are at risk
  • Species associated with humans are increasing in number (Rock Pigeons, European Starlings, House Sparrows, etc.)

Endangered Species

  • Classifies species by risk of extinction (IUCN Red List)
  • Examples: Parrots
  • 673 endangered species globally
  • 787 vulnerable globally
  • 66 species data deficient
  • 28% of species threatened, 56% decline; only 9% increasing

Threats

  • Bird species are threatened by habitat loss, climate change, disease, chemicals, collisions, hunting, and fishing (bycatch).
  • Human induced factors: habitat loss, climate change, disease, (human-introduced avian malaria), chemicals, collisions, hunting & fishing

Birds and DDT

  • Pesticide applications (especially DDT) led to population declines for birds.
  • DDT interferes with eggshell production, causing population declines (Bald Eagles)
  • Populations increased after DDT bans in 1973
  • Brown Pelicans also suffered eggshell problems due to DDT, placed on endangered species list in 1973

Habitat Loss

  • Habitat loss is the greatest current threat to birds.
  • Direct losses through habitat destruction
  • Reduction in habitat quality due to fragmentation, invasive species, etc.
  • Loss of habitat due to changing climate

Fragmentation

  • Fragmentation of habitats increases mortality and decreases dispersal.
  • Edge effects – negative impacts of nesting close to forest edges, increased nest predation.
  • Corridors are crucial for fragmented landscapes, providing connectivity for dispersal, gene flow, and local migrations.

Connectivity

  • Birds are unique for their ability to connect distant locations, complicating conservation efforts for migratory species.
  • Important to conserve both breeding and wintering grounds (often different pressures).
  • Often within continents (e.g., Resplendent Quetzals in Central America) or between continents (many species).

Extinction

  • Humans have caused many bird extinctions (Passenger Pigeon, Carolina Parakeet, many Hawaiian Honeycreepers, New Zealand Moas, Dodo, Elephant Bird of Madagascar).
  • Island species are particularly vulnerable

Reintroductions

  • Successful programs for species near extinction (Whooping Cranes, Peregrine Falcons, and California Condors)
  • DDT drove Peregrine Falcon populations to near extinction in eastern North America, but reintroduction efforts reversed the decline
  • Nesting boxes in cities for reintroduction efforts

Frightening Reality

  • Total North American bird population has decreased by one-third over the past 50 years.
  • Habitat loss (breeding and wintering grounds), climate change, and loss of species will have increasingly critical impacts extending beyond the birds themselves.
  • Example of loss: Largest vulture in North America, once widespread (last individual captured from wild in 1987). Raised in captivity, first reintroduction in 1992, and slow recovery (488 living wild in 2018).

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Related Documents

Orni 11 PDF: Population and Conservation (Lecture 11)

Description

This quiz explores the dynamics of bird populations, factors affecting their growth and decline, and the impact of introduced species. It also covers concepts like population limitation and regulation, highlighting examples such as the House Finch and European Starlings. Test your knowledge on how these factors interplay in conservation efforts.

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