Exam 3

The number of eggs a bird lays in a set is known as the

• clutch

What is the name of the length of time required by embryos to develop (between the laying of the egg and the emergence of the chick)?

• incubation period

Which of the following situations is most common in birds?

• Both parents incubate.

Which sex chromosomes does a female bird have?

• ZW

In House Finches, the red coloration of the males relates to the quality of the territory and therefore the access to nutritious food that would be available to potential nestlings. Females choose males with brighter red coloration. This is an example of:

• the "direct benefits" hypothesis

following factors is the most common cause of nest failure?

• Nest predation

Which mating system is most common in birds?

• monogamy

Which of the following are functions of the albumen?

• helps moderate the egg temperature

• provides water for the embryo

A aggregation of displaying males is known as

• A lek

What is fitness?

• Survival and reproductive output

What is one draw back to contest amount male birds?

• May result in characteristics that decrease survival but increase reproductive success

Good genes hypothesis says what?

• plumage and displays are a true genetic signal of fitness

• Can survive with these ornamental “handicaps”

• Plumage may reflect lower parasite load

Arbitrary Choice hypothesis say what?

• Not necessarily exclusive of good genes (Females may choose males not on appearance but territory)

• Female favor slightly more elaborative ornaments or displays “runaway selection” can occur

Different mating systems:

Polygyny

• Resource defense- males control access to females by monopolizing resources (hummingbirds, red-winged blackbirds)

• Female defense (harems)- males control access to females

• Male-dominance- males directly compete for females (hierarchy), may form leks, no resource control

Polyandry

• females mate with multiple males, each male tends a nest (< 1% birds)

Polygynandry

• several females and males form a cooperative breeding unit (tinamous, flightless ratites, a few songbirds)

• Male ratites and tinamous tend clutches of eggs from several females

Brood Parasitism

• Lay eggs in another birds nest so those parents can raise them.

What is Kin selection?

• helping relatives helps your own genes (he’s main male in display like dancing)

What happens if there’s a problem in the first mitotic division?

• A bird that is half male and female.

Two processes

• Formation and deposition of yolk layers (Yolk added before ovulation)

• Differentiation, growth, and maturation of the germ cell

• Rest of egg forms while passing through the oviduct

Copulation

• “Cloaca Kiss”

Albumen (50-71% of egg mass)

• Water storage

• Shock absorbing

• Temperature insulation

Yolk

• energy rich food supply

• Lipids (21-36% of yolk)

• Proteins (16-22%)

• Remainder is water

• Spherical eggs

• maximize shell strength

• heat conservation

• shell materials (surface area-volume)

Pointy eggs

• require less coverage by parents

• won’t roll off edges

What is a brood patch?

• Bald patch for incubation

Optimal development

• 37-38 C

What is the link between nests a hatchlings ability’s

• The more defenseless the hatchling the more elaborate the nests

Altricial characteristics

• naked

• blind

• immobile

• large bellies and viscera to support rapid growth

Precocial characteristics

• larger eggs

• fuzzy or natal down

superprecocial

• wholly independent

precocial

• hatchlings leave nest immediately and follow parents

• can pick up food immediately, parents assist in finding food

subprecocial

• leave nest immediately but are fed by parents

semiprecocial

• capable of thermoregulating, mobile but stay in the nest and are fed by parents

Behavior

• Learned

Innate responses

• Instinctual

Four important variables

• age at first reproduction (birds that have delayed age at first reproduction are often of conservation concern (e.g., California Condor, Whooping Crane))

• fecundity (# young produced each year)

• survival of young

• longevity (life span of adult)

What is Fecundity?

• # successfully raised offspring

• Factors: age of breeding, longevity, annual reproductive performance

David Lack first theorized that food limitation controlled clutch size

Number of offspring reared negatively effects survival of parents.