Ornithology exam 3

Challenges to nesting

Predation, Starvation, Adverse weather

Most common cause of nest failure

Predation

What are nests constructed with?

Natural and inorganic materials.

Basic categories of passerine nests

Cavities, Open-Cup, Domed

How do young birds learn to construct a nest?

Genetics, practice leads to skill.

Do monogamous male passerines in NA assist in nest building? Why?

Yes, assist for sexual selection and protection.

Definition of secondary cavity nester

Tree cavity nesters that do not make their own holes.

How do bird parents reduce predation?

Many attack trespassers.

Where can birds nest for safety?

Cryptic and difficult locations.

Nests most vulnerable to predators

Ground nests/nesters like waterfowl and tooth-billed pigeons.

Why is nest microclimate so important and how does it influence the eggs, young, and adults?

Influences energy of adults, water loss rates and warmth, all crucial to survival of young

What hormone mediates incubation behavior?

Prolactin

Why is nest success higher in northern latitudes and in cavity-nesters?

Cavity nests are safer with better microclimates. Northern latitudes do not get too hot.

What happens to males that incubate in terms of hormonal changes?

Testosterone drops.

How do incubation shifts influence predation rates?

Predation decreases with reduced parental activity.

Incubation period definition

Interval between laying and hatching last egg.

Relationship between incubation periods and adult lifespan

Longer incubation period = longer adult lifespans.

How do parents ensure simultaneous hatching of eggs?

Wait to incubate until all eggs are laid.

Brood patch definition

Bare skin on breast appearing during incubation.

Do all birds have brood patches?

No, gannets and boobies incubate eggs with feet.

Describe the process of a chick hatching. What structures / muscles does the chick use to emerge?

hatching muscle, egg tooth

Why adult birds remove eggshells

To camouflage and protect nest.

Morphological differences between precocial and altricial young

Precocial: feathered, open eyes, mobile; Altricial: naked, blind, immobile.

Was precocial or altricial young the original mode of development among birds?

Precocial.

What is bird “milk”? Specifically ,what does it contain and where does it come from in birds?

Contains protein and fat from the lining of the crop.

What is the tissue allocation hypothesis and how / what does it influence regarding the growth of young birds?

Channeling resources efficiently into growth; delays wing and flight muscle development, postpones maturation etc.

Influences on young bird growth rates

Quality/quantity of food, feeding pattern, temperature.

Definition of siblicide

Chicks killing siblings for competition of resources.

How does parenting affect disease susceptibility in birds?

Energetically expensive and stress affects immune system.

Do parents always prefer largest nestling? Example?

No, e.g., American coot favors smaller colorful chicks.

Advantages of asynchronous hatching

Protects from losing entire brood, manages food demands, promotes siblicide.

Nestling period definition

Interval between hatching and departure from nest.

Fledgling period definition

Interval between hatching and flight.

Is the ability to identify danger innate, learned, or both in young birds? Provide an example.

Both. Domestic chickens and turquoise browed motmots.

Sexual imprinting definition

Choosing mates that resemble parents.

Annual fecundity definition

Number of young successfully fledged in a year.

Fecundity in short-lived species

High fecundity due to higher mortality.

Fecundity in long-lived species

Low fecundity due to lower mortality.

How does annual survival and reproduction (i.e., number of young produced) change with age in adult birds?

Starts low, increases, then decreases.

Definition of fecundity

Number of young raised successfully.

3 major influences on lifetime reproductive success

Age at first breeding, lifespan, annual reproductive performance.

4 major influences on annual fecundity

#of nesting attempts, rate of success, # of eggs laid, age/experience

Definition of double brooded female

A female that lays a second clutch after a successful first.

Clutch size limit in precocial birds

Limited by egg nutrition requirements.

Clutch size limit in altricial birds

Limited by parents' ability to feed young.

Advantages of delaying breeding

Maximizes reproductive success during high competition.

Effect of clutch investment on physical condition

Depletes condition influencing future reproductive potential.

Food limitation hypothesis definition

Clutch size is determined by food availability.

Benefits of raising smaller clutches

Higher rates of chick survival.

Actuarial senescence definition

Death rates that increase with age.

Senescence definition

Age-related declines in immune function.

Changes in population size are a result of changes in...?

Survivorship and fecundity changes.

Annual growth potential definition

Maximum rate a population can increase in size within a year.

How does recruitment drive local population growth?

Includes young from other places.

What are the four major attributes that specify performance of the average bird in a population?

Age at 1st reproduction, fecundity, survival of young, longevity.

Threats to bird populations from white-tailed deer

They eat understory needed by many birds.

Why are slow-maturing species easily endangered?

Slow to replace reproductive adults.

Understand population sources and sinks.

Sources produce excess young; sinks cannot sustain without immigration.

Population limitations definition

Ceilings on population growth e.g., habitat, food.

What are population regulations? Provide an example.

Effects of population density on population size, like changing birth and mortality rates

How does habitat and food supplies influence population size? Provide examples.

Special habitat needs yield smaller population sizes (RCWP). Seabird populations mirror overfishing trends.

What is NAWMP and what does it do?

North American Waterfowl Management Plan for habitat conservation.

Assortative mating effect on speciation

Isolates populations from similar populations.

Biological species concept definition

A species can interbreed and produce fertile offspring.

Phylogenetic species concept definition

Species defined by unique evolutionary history.

Allopatric speciation definition

Isolation of biological populations due to geography.

Importance of sexual selection in speciation

Shapes traits and adaptations within species.

Definition of secondary contact

Divergent sister taxa interactions that can lead to hybridization.

Ring species definition

Two reproductively isolated forms connected by interbreeding populations.

How did the Pleistocene climate (i.e., glaciers) define many modern birds of northern continents?

Populations fragmented around glaciers, and birds followed when glaciers retreated

How does natal dispersal influence gene flow?

Movement of young birds from hatching to breeding sites. Larger distances = more gene diversity, smaller distances = genetic isolation

Difference between natural selection and gene flow

Natural selection propagates genotypes; gene flow moves alleles.

Hybridization definition

Breeding with individuals outside a species.

Common group for hybridization

Waterfowl.

How / why are different genera able to hybridize?

Retained genomic compatibility.

Define Haldane’s Rule.

The sex with two different sex chromosomes tend to be sterile (females, in birds)

Are male or female hybrids more likely to be sterile? Why?

Female hybrids due to ZW chromosome difference.

F2 Breakdown definition

Incompatible gene combinations disrupting embryo development in 2^nd generation offspring.

When is biological species status warranted?

No hybrids, clear reproductive isolation.

Hybrid zone definition

Location where species interbreed.

Define the bounded superiority model

Hybrid zones occur in intermediate ecological or climatic conditions

Dynamic equilibrium model definition

Stable hybrid zone as a sink of inferior hybrids.

Cultural transmission effect on speciation

Influences sexual selection and reproductive isolation.

Closed Communities

stable combinations of species drawn from a larger pool of possible colonists

Environmental filtering definition

Adaptation to specific temperature regimes along gradients.

Habitat type with higher species diversity

Tropical habitats.

Species richness definition

Total number of different species in an area.

Community diversity definition

Variety of species interactions within a specific area.

Alpha diversity definition

Species diversity on a local scale.

Beta diversity definition

Ratio of regional to local species diversity.

Gamma diversity definition

Total species diversity in a landscape.

Why does alpha diversity increase with forest complexity?

More foraging opportunities in varied habitats.

Influence of food availability on species diversity

More food equals greater diversity, especially in tropics.

If tropical and temperate forests don’t differ in overall heterogeneity / complexity, why are there more species in the tropics?

More specialized behaviors and less foraging overlap.

What are some benefits and costs of being a resident and non-resident?

Residents adjust to changes in food and weather; Non-residents exploit abdundant food periods.

Influence of climate on adaptations

Extreme climates need physiological adaptations, affecting community structure.

Definition of interspecific competition

Coexisting species competing for the same resources.

Definition of intraspecific competition

Same species competing for resources.

Foraging guild definition

Group of species eating the same resources together.

Hutchinson’s ratio definition

Coexisting species have 2x the body mass of the next smallest.