ornithology final

Clutch size and parental care represent an evolutionary tradeoff between?

Current and future reproductive efforts

What are the extreme strategies of lifetime reproductive success

1. Semelparity- Invest all of your energy in one large reproductive effort

2. Iteroparity- invest your energy in many small reproductive effort

K selected species

Slow life history strategy:

Slow development

Low annual fecundity

Long life

Example of k selected species

Northern royal albatross

R selected species

Fast life history

Rapid development

High annual fecundity Long

Short life

Example of R selected species

White-throated sparrow

Lifetime reproductive success depends on?

Number of reproductive years x annual fecundity

Number of reproductive years depends on: (3)

1. Age at first breeding

2. Potential longevity

3. Age- specific mortality rate

Potential longevity is most strongly correlated with?

Body size

Typical life span for small bird:

Typical life span for large bird:

Small bird: 2-5 years old

Large bird: 20-50 years

Oldest known wild bird

Laysan albatross named wisdom

annual mortality rate is most strongly correlated with: (3)

1. Body size (higher in small birds)

2. Habitat (higher in land birds than seabirds)

3. Latitude (higher in temperate zone)

Main causes of mortality for adult birds: (4)

1. Starvation

2. Disease

3. Predation

4. Adverse weather

Define Annual fecundity (reproduction)

Number of young fledged per year

Annual fecundity depends on:

1. Number of nesting attempts

2. Clutch size

3. Number of young successfully raised to fledging

Environmental conditions determine exact number of eggs, within some determinate range

Indeterminate clutch size

What is the typical passerine clutch size?

2-12

Interspecfic variation among clutch size is most strongly correlated with:

1. Latitude: smaller clutch sizes

2. Predation risk: smaller clutch sizes in open cup nesters

What 4 factors influence the evolution of clutch size?

1. Food limitation

2. Seasonality of food resources

3. Nest predation

4. Lifetime resource allocation by parents

Due to ____ ________ clutch size is adjusted to:

Maximum number of nestlings that the parents can successfully raise

Why is food limitations relevant to latitudinal variation in clutch size

Longer day length (during breeding season) in temperate zone effectively increases

why is clutch size adjusted to seasonality of food resources?

reproduction utilizes any and all surplus of resources above that required to maintain the adult population

describe an aseasonal tropical environment

• constant resource availability

• little excess for reproduction

• small clutch size

describe a seasonal temperate zone environment

• superabundance of resources during temperate zone breeding season

• large excess for reproduction

• large clutch size

clutch size adjusted to risk of _______ rates

predation

why are large clutches more vulnerable to nest predation?

• more nestlings require more feeding trips to nest by adult

• longer exposure periods

• more nestlings = more noise at nest

_______ _____ clutches spread risk of nest predation across reproductive efforts (aka don’t put all your egg in one nest)

several small clutches

What is nest predations relevance to latitudinal variation in clutch size

nest predation long assumed to be higher in tropics than temperate zones

what is the criticism in relation nest predations relevance to latitudinal variation in clutch size

Criticism- nest predation may not be higher in tropics than in temperate zones after all

Clutch size is adjusted to optimal balance of _______ _______ ,between what 2 reproductive efforts?

resource allocation between current and future reproductive efforts

how might large clutches reduce adult survival?

physiological stress of feeding many nestlings impairs health and depletes fat reserves of adult

what criticisms are associated with lifetime resource allocation by parents?

Criticism- demonstrated for some species, but not for others

does not address latitudinal gradient in clutch size

ecology

the study of interactions between a living organisms and its environment (including other living organisms)

populations

all individuals of one species in one place

key attributes of population:

Population size

• abundance - number of individuals

• density- number of individuals per unit area

Key attributes of Communities

Species richness- number of species

Evenness- distribution of individuals across species

species composition- list of species

define population ecology

understanding the mechanisms that regulate population size

describe the components of the exponential growth model; what does it initially assume?

t= time

N= population size

r= intrinsic rate of population growth

describe the logistic growth of population model; what does it assume?

dN/dt= rN(1-(N/K))

It assumes that there are limits to population growth, an environmental carrying capacity = K

what factors limit population growth?

adverse weather, habitat availability, territoriality, prey availability, parasites, predators, pathogens, competitors

what abiotic factors limit population growth

imposed by physical environment ex: weather

what biotic factors limit population growth

imposed by ecological interactions with other biological species ex: competition, predation

Define density-independent factors

Effect does not vary with population size such as ex: weather

Define density-dependent factors

effect does vary with population size ex: competition

adverse _____ regulates population size; is it density-independent or dependent and/or abiotic or biotic

adverse weather

• density-independent

• abiotic

habitat _______ regulates population size; is it density-independent or dependent and/or abiotic or biotic

habitat availability

• density-independent

• abiotic and biotic

habitat is defined by? how is defined for terrestrial animals?

habitat defined by physical structure of the environment; for terrestrial animals mainly defined by structure of vegetation

habitat influences the density of:

prey, predators, competitors, nest sites

______ is a factor that regulates population size and can be defined are finitely “compressible”

territoriality

is territoriality density-independent or dependent and/or abiotic or biotic

density-dependent and biotic

what is the order of territorial occupancy?

• optimal habitat

• suboptimal habitat

• floaters

____ availability regulates population size; is it density-independent or dependent and/or abiotic or biotic

prey availability

• density-dependent

• biotic

____, _____, _____ (3 P’s) regulates population size; is it density-independent or dependent and/or abiotic or biotic

predators, parasites and pathogens

• density-dependent

• biotic

Give 3 examples of predators, parasites and pathogens regulating population size

• introduced rats led to extinction of many island birds

• introduced botflies led to population declines of finches in galapagos

• introduced west nile virus led to declines of crows, jays, and other birds (american crow)

is competition a factor that regulates population size?

yes

competition regulates population size; is it density-independent or dependent and/or abiotic or biotic

• density-dependent

• biotic

human-caused bird extinction during prehistoric period caused what?

causes include habitat loss, invasive species, direct exploitation

who were the vulnerable bird species and why?

large bird species

island bird species- have small population sizes, predator naive and ground-nesting

Recently extinct birds of north america (7)

• Labrador Duck

• Eskimo Curlew

• Great Auk

• Passenger Pigeon

• Carolina Parakeet

• Bachman’s Warbler

• Ivory - billed Woodpecker

What is the range, natural history and cause of extinction for the Labrador Duck

Range: atlantic coast of northern U.S. and canada

Natural History: may have fed on shellfish and crustaceans

Cause of Extinction: hunted by humans for food

last seen in 1875

What is the range, natural history and cause of extinction for the Eskimo Curlew

Range: map

Natural History: once very abundant

Cause of Extinction: market hunting by humans, destruction of migratory stopover habitat (tallgrass prairie)

Rarely seen after 1890s

What is the range, natural history and cause of extinction for the Great Auk

Range: North atlantic; Europe to North American

Natural History: only flightless alcid extant in historical period, ecological equivalent of penguin (convergent evolution)

Cause of Extinction: hunted by humans for food

Last seen in 1844

What is the range, natural history and cause of extinction for the Passenger Pigeon

Range: eastern United states

Natural history: Probably the most abundant bird in the world

Cause of extinction: market hunting by humans

last seen in 1914

What is the range, natural history and cause of extinction for the Carolina Parakeet

Range: eastern U.S. north to great lakes

Natural History: only parrot in north america

Cause of Extinction: hunted by humans as agricultural pest, destruction of habitat

last seen in 1918

What is the range, natural history and cause of extinction for the Bachmans Warbler

Range: southeastern united states

Natural History: a canebrake specialist

Cause of extinction: destruction of habitat

last seen in 1980s

what bird species is the largest woodpecker in the united states and was last observed in 1930s in Louisiana?

Ivory-billed Woodpecker

list the declining bird population in north america in descending order

• grassland birds (short-dist. migrants)

• some forest birds (long-dist. migrants)

• shorebirds

____ of all endangered birds in the U.S. are ____ birds

1/3 are native birds

what threats are native endangered birds facing?

• habitat destruction by invasive plants

• feral pigs, goats and sheep

• avian malaria

what are some of the causes of avian decline worldwide? (8)

• habitat destruction and modification

• invasive species

• toxic chemicals

• collisions with man-made objects

• predation by pets (cats)

• hunting

• pet trade

• climate change

define interspecific competition (when does it occur)

occurs when 2 or more species compete for a shared limiting resource; it is almost always asymmetrical

interference and exploitation competition are mechanisms of?

interspecific competition

define interference competition

is it direct or indirect?

one species aggressively excludes other from resource

direct interaction between individuals of competing species

define exploitation competition

is it direct or indirect?

one species depletes resource more efficiently than other

indirect interaction between individuals of competing species

what is competitive exclusion?

two species with identical niches cannot coexist because interspecific competition between the species will lead to one of two outcomes

what are the 2 possible outcomes of competitive exclusion?

1. extinction of one species

2. ecological displacement (niche partitioning) shifts in distribution, habitat use, diet

niche partitioning is a form of ________ and ______ displacement

ecological and character displacement

ecological displacement is? and what type of response is it?

shifts in distribution, habitat use, diet

ecological response

character displacement is? what type of response is it?

shifts in morphology (size, bill size)

evolutionary response

example of ecological displacement

five species of warblers of North American boreal forest specialize on feeding on different parts of the same trees

example of character displacement

five species of south american kingfishers have different sized bills and partition their niche based on prey size

describe the species/ area relationship

species richness increases with area

S= cA^z

S= species richness

A= area

c and z = constants that vary with region and taxon

describe the spatial components of species richness a(alpha) richness

number of species at a given point or site within habitat diversity

describe the spatial components of species richness y(gamma) richness

number of species in a given region

regional diversity (among manny habitats)

describe the spatial components of species richness B(beta) richness

rate of change in species composition across sites (habitats)

between-habitat diversity

describe the gamma diversity of breeding bird communities

Temperate zone (new york state) = 135 spp.

Tropics (colombia)= >1300 spp.

describe the alpha diversity of breeding bird communities

Temperate zone (new york state) = 30 spp.

Tropics (central south america) = 300 spp.

what is the stability-time hypothesis?

species richness (particularly y richness) is an equilibrium between rates of speciation (adds species to regional pool) and extinction (removes species from regional pool)

why do tropical regions have higher species richness?

Because they have existed for a long time (promotes speciation), are climatically stable (reduces extinction)

what evidence is there against stability-time hypothesis?

1. speciation can be rapid (long periods of time not necessary)

2. climate in tropics has not been stable

describe the unique resources hypothesis

tropical regions have higher species richness because of the presence of additional resources not found in the temperate zones or resources that aren’t abundant or constantly available in the temperate zones

what evidence supports the unique resource hypothesis?

there are species that exploit unique tropical resources

Describe the niche-partitioning hypothesis

in tropical regions:

• high species richness leads to intense interspecific competition

• intense interspecific competition is a selective pressure that favors specialization (narrow niches)

• specialization allows many species to “pack” into ecosystem (niche packing)

what evidence supports the niche partitioning hypothesis?

there are many highly specialized species in the tropics, compared to the temperate zones, where there are more generalist species

list some attributes of avian communities on islands compared to the mainland?

• low species richness

• high individual density

• species composition represents a subset of mainland community

Equilibrium theory of island biogeography:

Macarthur and Wilson

species richness on an island is a dynamic equilibrium determined by immigration and extinction rates

Equilibrium theory of island biogeography

at any given point in time what may happen to the rates of immigration and extinction?

immigration rate decreases with increasing distance of island to mainland

extinction rate decreases with increasing island size (area)

temporal changes in species richness can be due to

seasonal movements of migratory species

causes of habitat loss/ habitat modification?

conversion of agriculture or urbanization

forestry

effects of habitat loss/ habitat modification?

loss of area

modification of spatial structure