Lecture 20

Question 1

what do cattle egerets do to give the early laid chicks an advantage?

Answer 1

spike the earlier laid eggs with high doses of androgens, make earliest hatched chicks more aggressive and gives them an extra advantage over later hatched chicks

Question 2

——— is the best strategy wen food is poor because it facilitates brood reduction

Answer 2

asynchrony

Question 3

can parents adjust the degree of hatching asynchrony if food supply is partly predictable?

Answer 3

female american kestrels hatched clutches synchronously in good vole years and more asynchronously in poor years

Question 4

alternate hypothesis for hatching asyncrhony

Answer 4

1. peak load reduction hypothesis. spread out energy during feeding
2. sibling rivalry reduction maintaing a stable violent hierarchy
3. keep eggs fresh. incubates early to keep eggs fresh
4. hurry up, parents are trying to accelerate the hatching of some
5. nest survival, parents ar ejust trying to incubate asap to hatch asap

Question 5

female flight time —– with brood size

Answer 5

increased

Question 6

optimal working capacity:

Answer 6

the level beyond which parents suffer increasing risk of fatigue and starvatuon or predation. above this point their lifetime reproduction will be reduced

Question 7

what do parents do with liar kids?

Answer 7

parents are selected to ignore the exaggerated signal and parents that can detect and rely on honest signals will be favored over evolutionary time

Question 8

a reliable begging system uses

Answer 8

the begging signal corresponds to the actual conidtion of the nestlings

Question 9

how would red gape colour signal hunger?

Answer 9

if blood is shunted away from the mouth to the stomach in order to digest food, the nestling is not hungry

Question 10

what other tool has gape colour been suggested for for communicating to the parent?

Answer 10

may signal the quality of their immune system and thus offspring quality. Carotenoid pigments in the blood and these are believed to enhance immune function

Question 11

what is one theory for how coots choose which cootie to kill?

Answer 11

cooties that have more orange plumes may cue parents use in deciding which chicks they wish to feed. Orange plumes may signal offspring quality

Question 12

what was the conclusion for the barn swallow red food colouring experiment?

Answer 12

nestlingd with gapes that were reddened by food colouring received more food while chicks whose gapes were yellowed did not.

Question 13

sex allocation:

Answer 13

the manner in which parents distribute resources between sons and daughters

Question 14

parents can bias their allocation in 2 ways:

Answer 14

1. They can produce mor eoffspring of one sex

2. they can provide more resources to offspring of one sex

Question 15

what bird distributrs resources unequally?

Answer 15

songlarks

Question 16

songlark mothers are biased toward what gender?

Answer 16

their sons! Males become larger than females during this bias.

Question 17

what is the benefit of raising large male offspring?

Answer 17

larger sons, although a huge cost on mon, have the best chance of passing on her genes since the community is polygynous

Question 18

mortality is very high after fledgling, often approaching 50% but survivorability is correlated with what?

Answer 18

greater mass

Question 19

brood division:

Answer 19

parents divide the brood after fledgling, each takes care of a subset of the offspring. Nestlings may be divided by size or sex or randomly

Question 20

possible 4 functions of brood division:

Answer 20

1. reduce sibling rivalry
2. spread the risk that the whole brood is departed
3. one sex of parent may prefer to feed 1 type of nestling
4. increase feeding efficieny