Lecture 19

Question 1

what 4 things might affect whether a bird has altricial or precocial young?

Answer 1

1. Food typies: self-feeding precocial chicks need easily accessible food such as seed or small invertebrates 2. Predation risk: if it is high, the young must leave the nest ASAP in order to survive 3. Length of foraging trips: long trips to sea by gulls and seabirds means nestling must be able to thermogregulate by themselves 4. Rapid growth: an advantage of altricial is that nestlings seem to grow quickly, although they require lots of energy input

Question 2

in terms of mass are juvenilles and adults the same?

Answer 2

yes!

Question 3

big birds grow more slowly or quicker than small?

Answer 3

more slowly. Albatross takes 303 days

Question 4

speed of growth varies with what 6 things?

Answer 4

1. Body size 2. Precocial VS altricial (altricial grow more rapidly) 3. Geography (tropical slower than temperate) 4. Ecology (pelagic slow compared to inshore) 5. Nest mortaility (higher predation risk leads to faster growth) 6. Feeding rates (parental feeding linked to faster growth)

Question 5

Predation selects for —– growth but limited food supply selects for —— growth

Answer 5

fast/ slower

Question 6

In part growth rates may be constrained by diet, give an example?

Answer 6

fruits do not contain much protein, frugivore nestlings may only grow half as quickly as nestlings on other diets. Many species supplement nestling diet with extra insects or bone fragments for protein and calcium

Question 7

energy to growth usually accounts for what percent of the energy budget?

Answer 7

21-40%

Question 8

what grows faster? birds, fish or reptiles or mammals?

Answer 8

birds grow an order of magnitude faster than fish and reptiles. Altricial grow about 2x faster than mamals and precocial birds similar to mammals

Question 9

what might explain the altricial/precocial growth rate spectrum?

Answer 9

precocial species need well-developed leg muscles so they hatch with more developed tissues but subsequently grow more slowly comapred to altricial species

Question 10

the duration of the brooding period depends on what 3 things?

Answer 10

1. the time needed for the young to dveelop the ability to thermoregulate 2. weather- young are brooded longer during cool, wet weather 3. Nest type- birds that nest in cavities with more stable microclimates, typically brood for shorter periods than open nesting species

Question 11

how do precocial and semi precocial nestling acheive 90% of adult thermoregulation capability within 1 week of hatching

Answer 11

acheived by mature leg and pectoral muscles to generate heat

Question 12

for altricial what helps with warmth?

Answer 12

large brood sizes helps with communal huddling

Question 13

what is the difference between brain size in altricial and precocial?

Answer 13

altricial has smaller when first hatched but once adult they have larger than precocial

Question 14

there is intraspecific variation in food delivered per nestling between diff pairs because of what 5 things?

Answer 14

1. weather 2. Quality of territory or the environment 3. parental foraging skills 4. quality of food type 5. brood size

Question 15

why would insectivores have flexible growth rates?

Answer 15

unpredictable food. chicks can become hypothermic and stop growing and survive up to 21 days without food.

Question 16

what is most common parental care?

Answer 16

75-81% had monogamous biparental care 9 % cooperative breeding 8% female only 1% with no care 1% male only

Question 17

what are the stages of evolution by care:

Answer 17

stage 1: female care started. stage 2: consortship may have evolved where the sexes spend increasing time together on males territory. he guards territory and nest while she lays eggs and get food stage 3: evolution of increasing male effort driven by females mate choice. stage 4: increasing care by male (substantial and predictable) allows evolution of alriciality because both parents contribute substantially after hatching

Question 18

what is contributed to raising young?

Answer 18

1. nest consruction or maintenance 2. incubation and brooding 3. feeding 4. nest defense 5. nest sanitation

Question 19

what are 5 questions that may determine balance of risk to self and benefit of defending against a predator.

Answer 19

1. what is renesting potential 2. what is lifespan (are you likely to liv for another year to try again) 3. sex of parent/assurance of paternity 4. offspring age and number 5. characteristics of the predator, mammal VS avian

Question 20

In mapies parents are more defensive when?

Answer 20

when a predator approaches and a nest of a brood is older

Question 21

what is an example of defense by nestlings?

Answer 21

petrel chick projectile vomit and young kestrels flip on their backs to grab predators.

Question 22

what are different feeding mechanisms?

Answer 22

1. small item in bill-to-bill transfer 2. regurgitation 3. crop milk excretions 4. injection of nectar directly into stomach of nestlings 5. seabirds with long foraging trips regurgitate oil from their proventriculus along with undigested fish bits.

Question 23

what are some consequences that could arise from feeding style?

Answer 23

1. prey size. how many trips must be made? could limit # of chicks reared 2. may influence nest placement 3. are one or both parents needed 4. implications for sibling rivalry

Question 24

gape size constraint hypothesis:

Answer 24

parents bring larger prey as nestlings grow older and if there is a range of nestling sizes in the nest because of hatching asynchrony parents may bring prey the small nestling can not swallow and could explain mortality of the runt nestlings in a brood,

Question 25

what is the parental care conflict?

Answer 25

should i take care of my kids or myself?

Question 26

the willingness of a parent to invest in or take risk for an offspring should be influenced by what 2 things?

Answer 26

1. the parents future prospects of reproducing
2. the relative value of the current offspring

Question 27

long lived animals should be ======== willing to risk their lives to protect their young compared to ============ aniamls

Answer 27

less, short-lived

Question 28

in general north american birds are shorter lived than comparable south american species, then should north americans take more risks to save their young?

Answer 28

No! reversed! North american birds reacted more strongly to predators and south american orth americans focused more on themselves then south american

Question 29

2 types of infanticide:

Answer 29

1. adults kill unrelated chicks
2. adults kill their own chicks

Question 30

siblicide:

Answer 30

chicks kill siblings to maximize their gain in resources, ensure their own survival. usually in asynchronous species

Question 31

why do parents facilitate siblicide?

Answer 31

1. insurance against hatching failure
2. environmental uncertainty

Question 32

obligate brood reduction:

Answer 32

in which younger offspring essentialy always die. the second off srping represents an easily cancelled insurance policy against the failure of the first offspring. Not possible to provide food for 2

Question 33

facultative brood reducers:

Answer 33

brood reduction does not always occur. the brood consists of 2 classes of offspring: core and marginal offspring. Marginal offspring are handicapped by the parents and are produced so that parents can take advantage of a good year.