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ornithology > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

The goal of an annual cycle is to….

A

Spread out energetically costly life stages (reproduction, molting, migrating, and overwintering)

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2
Q

What happens when an American Redstart fledges lots of young?

A

Its molt it delayed, so it must molt while migrating. This causes birds to have duller feathers, causing them to be less successful in the next breeding season.

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3
Q

What are the consequences of an early laying date?

A
  • young are not born at the same time as food is available
  • vulnerability of offspring to unpredictable spring weather (cold snaps wipe out the nest)*

*best answer

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4
Q

How does climate change interact with migration distance?

A
  • birds do not reach the right point at the right time
  • breeding cues do not match between nest site and overwintering site
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5
Q

How does light pollution influence annual rhythms?

A
  • night time window strikes
  • sleep deprivation

ex) exposure to constant dim light causes decreased testicular width in european blackbirds

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6
Q

Migration

A

A seasonal cycle of departure and return - may be local (across elevations) or long distance (latitude)

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7
Q

How is a migration route determined? (4)

A
  1. type and frequency of barriers (bodies of water etc)
  2. historical distribution of species
  3. migratory stopover points
  4. predictability of resources
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8
Q

What types of birds migrate at night? (5)

A
  • passerines
  • rails
  • owls
  • cuckoos
  • shorebirds
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9
Q

What are the benefits of migration occurring at night?

A

-avoid predation
- refuel at stopovers during the day
- night air is cooler, moister, and thermoregulatory costs are minimized

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10
Q

What types of birds migrate during the day?

A

hawks, soarers, swifts, swallows

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11
Q

What are the benefits of migration occurring during the day?

A

it is most advantageous for birds that utilize thermals or feed on the wing

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12
Q

What types of birds migrate flexibly? (during day or night)

A

Birds like waterfowl, gulls, and some passerines migrate to maximize favorable conditions

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13
Q

How do birds prepare for migration?

A

building up fat reserves

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14
Q

What are the costs and benefits of stopping at a refueling site?

A

Benefits
- arrive at breeding site in good condition
- predictability of resources influence priority of stopover sites
- continue migration

Costs
- in some places, for example with unpredictable resources, the costs of cold weather and foraging is greater than the cost of continued flight

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15
Q

What are the costs and benefits of not migrating for a tropical resident?

A

Benefits
- year round stability
- favorable conditions

Costs
- cannot take advantage of seasonal resources
- competition due to high density
high concentration of nest raiding predators

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16
Q

What are the costs and benefits of not migrating for a temparate resident?

A

Benefits
- does not incur costs of migrating
- take advantage of seasonal food availability
- decreased competition when migrants leave
- bread earlier than migrants

Costs
- endure periods of scarcity
- overwinter survival costs

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17
Q

What are the costs and benefits of migrating?

A

Benefits
- move to where food is available

Costs
- must breed later than residents
- susceptible to climate
- energetic costs

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18
Q

Resident

A

a bird that stays in one area year round

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19
Q

Obligate migrant

A

birds that always migrate

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20
Q

Obligate annual migrant

A

all individuals migrate

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21
Q

Obligate partial migrant

A

only some individuals migrate - but the individuals that migrate stay consistent

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22
Q

Facultative partial migrants

A

a variable number of individuals within a population will migrate and the degree to which any migrate will vary

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23
Q

Irruptive migrant

A

High seasonal variability and low predictability
ex) crossbill

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24
Q

What is the difference between a facultative partial migrate and an obligate partial migrant?

A

obligate partial
- due to genetic polymorphism
- a variation in physiology, morphology, behavior
- the individuals that migrate will always migrate

Facultative partial
- individuals migrate or not due to complex reasons, one individual may migrate one year and be a resident the next

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25
Q

Differential migration in dark eyed juncos

A

males migrate a shorter distance than females, and young birds will always migrate a shorter distance than older birds (young males < adult males < young females < adult females)

due to differing selection pressures
- young birds have higher mortality over larger distances (young birds migrate shorter distances than adults)
- male birds benefit more from increased proximity to breeding grounds than females (males migrate shorter distances than females)

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26
Q

How do birds navigate?

A
  • experience (having migrated the same route before)
  • the sun
  • the stars
  • earth’s magnetic field
  • visual landmarks
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27
Q

there are magnetoreceptor cells in the bird’s ______ and _______

A

retina, hippocampus

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28
Q

Spacing of birds varies among… (3)

A
  • among species
  • among individuals
  • between seasons
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29
Q

Territory

A

a fixed area or resource that is continually defended

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30
Q

How is a territory defended?

A

displays and chases, by males or pairs

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31
Q

What types of displays are used to defend a territory?

A

-vocal and nonvocal sounds
- plumage
- behavior

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32
Q

What are the costs and benefits of territoriality?

A

Benefits
- easy access to resources
- exclusive access to resources

Costs
- investing in territory defense
- risk of injury in confrontation

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33
Q

What types of resources create territorial birds?

A

When resources are predictable and defendable

ex) a swift is not going to defend a territory because insects are not a defendable resource

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34
Q

When are territories favored?

A

When resources are at intermediate levels

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35
Q

When is dispersal favored?

A

When resources are low

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36
Q

When is flocking favored?

A

When resources are high

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37
Q

_____ and ______ displays indicate status

A

threat, appeasement

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38
Q

Can a badge of status, like in the harris’ sparrow be cheated?

A

No, dominant birds will beat the shit out of you

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39
Q

Signals can be static or _______ like the crest of a stellar’s jay

A

dynamic

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40
Q

What are the costs and benefits of flocking?

A

Benefits
- safety in numbers
- mating availability
- sharing of information
- thermoregulation

Costs
- competition for food and for mates
- increased chances of disease and parasites

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41
Q

Flocking behaviors are encouraged when resources are… (3)

A

ephemeral, limited or abundant (the OPPOSITE of a territory)
- birds do not need to be as vigilant and can devote more time to foraging because many eyes watch for predators

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42
Q

Dilution effect

A

‘if there are 10 birds in a flock, then there is a 1 in 10 chance I will be targeted by a predator’

individual risk of predation is lower

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43
Q

flocking increases _______ fitness

A

individual

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44
Q

Hamilton’s rule

A

if benefits x relatedness - costs > 0 then a behavior will be favored

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45
Q

Communal roosting

A

a nighttime congregation during the nonbreeding season, same costs and benefits as flocking

important thermoregulatory functions

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46
Q

Colonial nesting

A
  • common in seabirds
  • favored when food is unpredictable and distant
  • increased exposure to parasites and predators
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47
Q

Sexual selection

A

caused by differential access to mates based on individual characteristics

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48
Q

Bateman’s principle

A

describes behavior of males vs females and sexual selection
- sperm are ‘cheaper’ than eggs
- females are limited by the number of offspring that are produced
- males are limited by the number of eggs that they can fertilize (# of mates)
- sexual selection operates more strongly on males, the unlimited sex
- females, who are the limited sex, desire high quality offspring, so they are more choosy with their mates

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49
Q

What is the most common bird mating system and how can we describe it?

A

Social monogamy is characterized by pairs of birds that raise offspring together, but extra pair copulations occur for both males and females

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50
Q

When is the force of sexual selection the strongest?

A

When there is a greater variance in reproductive success (ex - some males produce as many as 40 offspring, but many produce zero)

this is represented on a graph by a steeper slope

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51
Q

in general ______ fitness increases more with number of mates than ________ fitness

A

male, female

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52
Q

intrasexual selection

A

sexual selection that occurs among members of the same sex
- size, aggression, alternate mating strategies, or sperm competition

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53
Q

intersexual selection

A

sexual selection that occurs between members of different sexes (females choose males)
- showy males with displays, dances, and fancy feathers

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54
Q

Why do male turkeys often display in dominant/subordinate pairs where the subordinate male does not mate?

A

pairs of males are often brothers, so the subordinate male gains fitness indirectly by being a wingman

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55
Q

Hamilton’s rule

A

benefits*relatedness - costs > 0

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56
Q

Describe the alternate mating strategies of ruffs

A

3 genetic polymorphisms caused by autosomal differences
- territorial males - darkly colored, defend and maintain territories/display in leks
- satellite males - lightly colored, do not defend and maintain territories/display in leks
- faeder - female mimics, who mate sneakily

  • females prefer for there to be multiple males present
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57
Q

Name some adaptations that make sperm more competitive

A
  • larger testes
  • larger sperm stores
  • larger copulatory organs (duck corkscrew penis)
  • more frequent copulations
  • mate guarding
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58
Q

How do females choose mates (3 reasons)

A
  1. direct benefits
  2. good genes
  3. arbitrary choice or runaway selection
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59
Q

Widowbirds

A

long tail is an honest signal of mate quality, because the tail encumbers the male and only high quality males can support the male

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60
Q

What are direct benefits that females use to choose mates?

A
  • food
  • high quality territory
  • parental care indicated by feeding and territory
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61
Q

By selecting for large comb size, red junglefowl females ensure that their offspring get….

A

good genes
- red junglefowl comb size is directly correlated with offspring condition/quality
- males were vasectomized and females were artificially inseminated to prove that there is no female bias

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62
Q

This type of protein is responsible for presenting antigens to white blood cells. Individuals with the greatest diversity of this protein have better immune function. What type of bird mates to produce offspring with the most diversity of the protein?

A

MHC proteins, house sparrows

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63
Q

Blue tits want to choose mates with the greatest amount of….

A

heterozygosity

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64
Q

When females choose mates arbitrarily, their choice is often due to….

A

sensory bias

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65
Q

What type of sensory bias to zebra finches and grass finches have towards males?

A

females zebra and grass finches love males with white crests

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66
Q

What is the result of arbitrary choice on selection?

A

runaway selection may occur

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67
Q

Runaway selection

A

preference and expression of trait become linked due to assortative mating

this leads to runaway selection (like the ever increasing length of widowbird tails)

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68
Q

What is the traditional explanation for ornamented females?

A

ornamentation does not serve a purpose, it is simply a side effect of selection for ornamented males

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69
Q

What is the contemporary view of ornamented females?

A

males prefer ornamented females

highly ornamented female bluethroats are larger than their dull counterparts, which is a trait preferred by males

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70
Q

When does mutual mate choice occur?

A

monomorphic, monogamous species where both adults care for offspring

ex) inca terns choose mates based on length of moustache

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71
Q

How does ‘bird monogamy’ differ from ‘human monogamy’

A

-sexual exclusivity does not occur in bird monogamy ONLY social exclusivity
- extra pair copulations are common for birds

  • human monogamy is sexually AND socially exclusive
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72
Q

Monogamy

A

a social pair bond with a single member of the opposite sex

the pair bond may last 1 breeding attempt or 30 years

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73
Q

What is the most common mating system for birds?

A

monogamy - up to 90% are socially monogamous

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74
Q

What percentage of birds are actually genetically monogamous?

A

VERY FEW - only 14%

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75
Q

Extra pair paternity rates vary by species and are an important source of ________

A

sexual selection

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76
Q

Barn swallows that have rustier plumage sire _______ offspring via extra pair copulation

A

more

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77
Q

polygamy

A

any system where an individual has multiple pair bonds with members of the opposite sex

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78
Q

is polygamy common among birds?

A

NO - only 3% of species

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79
Q

polygyny

A

multiple females mate with a single male

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80
Q

polyandry

A

multiple males mate with one female

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81
Q

polygynandry

A

multiple males and females form a breeding group

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82
Q

when is polygyny favored?

A

occurs when resources are clumped and defendable
- common in fruit eaters or reed breeders
- females join a harem becasue they do as well or better than solitary females on shitty territory

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83
Q

What are the costs and benefits of polygyny for females?

A

costs: must share male and resources the male defends, loss of parental care from male

benefits: dilution effect, information sharing, good genes (males that can maintain a large territory have better genes)

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84
Q

Why is polyandry rare?

A
  • biparental care is a better system for birds
  • based on the current system, it is more advantageous for males to mate multiply than females (the circumstances that cause the opposite are rare)
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85
Q

This hormone drops more rapidly in biparental and polyandrous systems due to the antagonistic relationship between levels of this hormone and parental care.

A

testosterone

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86
Q

What is one example of polygynandry?

A

male and female smith’s longspurs mate with multiple partners
- clutches have mixed paternity
- nests are cared for and defended by multiple males

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87
Q

What are the costs and benefits of extra pair paternity for males?

A

costs: predation risk on nest (males must leave nest undefended to seek out other females), female is left unguarded (and may seek her own extra pair copulations), energetic costs associated with sleeping around

benefits: increase reproductive success

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88
Q

What are the costs and benefits of extra pair copulations for females?

A

costs: increased risk of diseases, injury risk from other females, males reduce their parental investment

benefits: more diversity of genes in the nest, care from extra pair males, fertility insurance, extra pair males may be higher value, extra pair males may have higher heterozygosity

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89
Q

in polyandry, what sex does sexual selection act most strongly on?

A

females

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90
Q

What is brood parasitism?

A

laying your eggs in another female’s nest

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91
Q

What is the difference between interspecific and intraspecific brood parasitism?

A

interspecific: parasites lay eggs in the nests of birds of another species (brown headed cowbird)

intraspecific: parasites lay eggs in the nests of birds of the same species (american coots)

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92
Q

What is the difference between obligate and facultative brood parasites?

A

obligate brood parasites ONLY reproduce via parasitism and are always interspecific parasites. facultative parasites opportunistically lay eggs in the nests of others, but have a nest and raise some of their own chicks.

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93
Q

European starling brood parasitism

A

european starlings lay eggs in the nests of other european starlings
- female EUSTs do not count their eggs
- before starting to lay, females remove all eggs in the nest, if present

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94
Q

American coot brood parasitism

A

coots opportunistically lay eggs in the nests of other coots
- brood parasitism is so common that female coots learned to count their eggs
- variable egg coloration helps females keep track of which eggs belong to them
- females reject eggs by ejecting them, burying them in nest material, or pushing them to suboptimal incubation spots (causing a smaller chick size at hatching)

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95
Q

Obligate specialist brood parasite

A

only lay eggs in the nests of specific species
- old world cuckoos target warblers and crows
- african whydas target waxbills and pytillias
- honeyguides target bee eaters and woodpeckers

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96
Q

cuckoo adaptations to brood parasitism

A

-cuckoos mimic host egg coloration (females will only parasitize a single species whose eggs are matched most closely - forming a ‘race’ of birds that only parasitize one species)
- eggs are thicker shelled and larger
- eggs may be incubated before laying
- young push out eggs of competitors (NOT true for BHCBs)

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97
Q

Why do BHCB chicks not evict other nestmates?

A

presence of host offspring actually increases food availability for the parasite

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98
Q

indigobird example

A

indigobirds learn the host species song, and the closest imitation is the most attractive

imitation ability is correlated with gape similarity, essential for parasite acceptance

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99
Q

Obligate generalist brood parasite

A
  • parasitize a large number of species
  • one female can parasitize many different species in a single season
  • some species will accept the eggs and some will reject them

ex) brown headed cowbird (BHCB)

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100
Q

Why do some bird species not reject eggs from a parasite?

A
  • cognitive differences
  • similarity of eggs: rejection depends how closely cowbird eggs naturally resemble the eggs of the host
  • ability to reject: small birds may not be able to reject large eggs, or risk destroying their own eggs to reject a parasite egg
  • mafia behavior from BHCBs: cowbirds destroy nests that reject eggs
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101
Q

Why do BHCBs not match their eggs to their hosts?

A

cowbirds put all their energy into egg production, and can produce 40 offspring in a season

being able to parasitize many nests of many different species is more advantageous than specializing

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102
Q

Great spotted cuckoo example

A
  • great spotted cuckoos are a nonevicting parasite of carrion crows
  • they produce noxious secretions when grabbed by predators
  • carrion crowns will not reject cuckoo chicks or eggs because these noxious defenses help them fledge more offspring than they may have been able to before
  • this is mutualism, both species benefit
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103
Q

Obligate specialist brood parasites can be described as being in an _______ _______ ______ with their host species

A

evolutionary arms race

104
Q

Name at least 3 adaptations for brood parasitism

A
  1. noxious cuckoo secretions (great spotted cuckoo)
  2. chicks mimic gape of host chicks (indigobird)
  3. eviction behaviors of parasitic chicks
  4. eggs mimic host eggs
  5. incubation is headstarted before laying
105
Q

Cooperative breeding

A

a breeding pair is assisted by helpers, occurs in ~250 spp

106
Q

why would individuals give up an opportunity to reproduce to assist others

A
  • relatedness to breeding pair
  • limitation of habitat
  • learning opportunity (be better parents)
  • helpers inherit territory of adults
107
Q

Scrub jays

A
  • previous year offspring help parents and defend/feed offspring
  • half of all pairs have up to six helpers
  • increases number of offspring fledged by pair
  • helpers gain indirect fitness benefits by helping
108
Q

superb fairy wrens

A
  • with helpers, females produce smaller eggs
  • chick size remains consistent between groups though
  • offspring can catch up due to helpers, female gets to lessen the burden of reproduction on herself
109
Q

Why do helpers stick around?

A

ecological constraints
- harsh environment
- limited breeding opportunity
- limited habitat

110
Q

Is helping behavior flexible? (number of helpers can vary depending on environmental conditions)

A

yes
ex) bee eaters have more helpers in years with decreased rainfall
ex) acorn woodpeckers have more helpers when territories are all full
ex) seychelles warblers had less helpers when lots of territories were vacant, and had more helpers as they filled up

111
Q

Why do females prefer to help when the primary territory belongs to the mother?

A

extra pair copulations mean that paternity is dubious but maternity is always absolute - the female can guarantee her relatedness to her mother but not her father

112
Q

white fronted bee eaters

A

form colonies of family members, mating occurs between groups
- birds know who is related and how closely, preferring to help kin

113
Q

long tailed bushtits

A

if a nest is depredated, the individuals will seek out the nests of kin to become a helper
- recognition of kin occurs via vocalizations learned in the nest

114
Q

Why do helpers assist breeders? (4)

A
  1. indirect fitness benefits are greater than possible direct fitness benefits
  2. limited territories or resources
  3. inheritance of high quality territory
  4. higher lifetime reproductive success is gained by being a helper
115
Q

Which avian sex chromosomes designate a female? a male?

A

Female: ZW
Male: ZZ

116
Q

How can we describe a bird that has the sex chromosomes ZW?

A

heterogametic female

117
Q

what is a gynandromorph? How does it occur?

A

a gynandromorph is a bird that is 1/2 male and 1/2 female. These birds demonstrate sex determination differences between birds and mammals. The sex determination of birds is “locally” controlled or gene mediated while mammal sex determination is “globally” controlled or hormone mediated

118
Q

Bilateral gynandromorph zebra finch

A

the gynandromorphic zebra finch we discussed in class developed a song control system on the male side (underdeveloped on the female side)

it sang and tried to mate with female zebra finches

119
Q

How is sex typical morphology/behavior regulated?

A

by hormones (HPG axis)
- Gonadotropin releasing hormone (GnRH) is released by the hypothalamus to communicate to the anterior pituitary
- The anterior pituitary releases luteinizing hormone (LH) and follicle stimulating hormone (FSH)
- LH and FSH act on the target tissue, stimulating production of primary hormones

120
Q

What does luteinizing hormone do in the male?

A

stimulates production of testosterone from Leydig cells

121
Q

What does luteinizing hormone do in the female?

A

stimulates ovulation of mature follicles, production of testosterone and progesterone

122
Q

What does follicle stimulating hormone do in the male?

A

triggers sperm production from sertoli cells

123
Q

What does follicle stimulating hormone do in the female?

A

triggers follicular development

124
Q

What unique adaptation do birds use to reduce weight during the nonbreeding season?

A

they reduce the size of their reproductive systems cyclically

125
Q

While males develop both testes, females only develop one ovary. Which one is it?

A

the left ovary

126
Q

List the anatomy a developing egg moves through in order, what occurs in each place and how long the egg stays there (7)

A
  1. ovary - yolking and ovulation (4-16 days)
  2. infundibulum - fertilization (20-30 minutes)
  3. magnum - albumin (1-3 hours)
  4. isthmus - membrane (1-2 hours)
  5. shell gland - shell (19-20 hours)
  6. vagina - laying
  7. cloaca - laying
127
Q

What are the three membranes that surround the egg?

A
  1. amnion
  2. chorion
  3. allantoic sac
128
Q

What does the amnion do?

A

surrounds the embryo in water and salts

129
Q

What does the chorion do?

A

protects the embryo

130
Q

what does the allantoic sac do?

A

has blood supply, functions in respiration and excretion of uric acid

131
Q

What are some characteristics of the shell of the egg?

A
  • has pores
  • provides support
  • protective function from microbes, inverts, etc
  • gas exchange occurs
  • prevents water loss
132
Q

What selection pressures act on egg shape?

A
  • egg length is correlated with body size (increased size = longer egg)
  • egg shape is correlated with flight strength (elliptical = better flier)

It is theorized that strong fliers want to provision eggs better while minimizing girth of the egg

133
Q

what factors influence clutch size?

A
  • energy and resource availability: for every 1 kJ of yolk, 5kJ must be eaten (20% of energy makes it to the egg)
134
Q

what is the most demanding part of egg production?

A

yolking

135
Q

Where does the energy for egg production come from in capital based breeders? What type of birds use this system?

A
  • the fat stores
  • larger birds
136
Q

Where does the energy for egg production come from in income based breeders? What type of birds use this system?

A
  • daily intake of energy
  • smaller birds
137
Q

what are some costs associated with egg production?

A
  • energy investment
  • increased flight costs (heavier)
  • decreased immune function
  • decreased aerobic capacity
138
Q

What are some functions of nests?

A
  • protection from predators
  • protection from parasites
  • insulation
139
Q

What are some nest materials that birds use?

A
  • vegetation
  • feathers
  • hair
  • gravel
  • bark
  • mud
  • spiderwebs
  • saliva
140
Q

What are some costs and benefits of cavity nesting?

A

benefits:
- stable thermal environment (better insulated)
- more protection from predators

costs:
- o2 may be restricted
- higher levels of ectoparasites
- hard to find a suitable location to build nest

141
Q

What are some costs and benefits of open cup nesting?

A

benefits:
- less ectoparasites
- more o2
- more available locations to build nests

costs:
- thermal environment may fluctuate
- more exposed to predators

142
Q

How do rosy faced and yellow collared lovebirds demonstrate that nest building may have a genetic component?

A

rosy faced lovebirds transport nesting material by tucking it into the tail

yellow collared lovebirds carry it in the bill

hybrid lovebirds try to tuck it into the tail and fail

143
Q

How do village weaver birds show that nest building has a genetic component?

A

hand raised male village weaver birds can build nests, but nest quality will improve with age

144
Q

what is the difference between a primary and a secondary cavity nester?

A

primary cavity nesters must excavate a cavity (woodpecker), secondary cavity nesters find and use old cavities (bluebirds)

145
Q

what is the ideal temperature for incubation?

A

37-38C or 99-100F

146
Q

True or false? Eggs must be incubated as soon as they are laid or the embryo will die

A

False. eggs do not need to be incubated immediately, but once they start incubation, it cannot stop

147
Q

What are some costs of incubation?

A
  • energetic costs of generating heat
  • predation risk
  • lost time investment (foraging, mating defending etc.)
148
Q

Eider duck example

A

eiders with larger clutch sizes incur greater costs such that in the following year costs persisted
(more eggs = reduced immune function, smaller clutches laid, laid later)

149
Q

What is the most common method of incubation (who incubates?)

A

biparental incubation is the MOST common, then female only, then males only, then no incubation (least common)

150
Q

In which species is there female only incubation?

A

North american passerines
hummingbirds
galliformes
ducks

in female only incubation, the male often feeds the female on the nest

151
Q

in which species is there male only incubation?

A

ratites

152
Q

in which species is there biparental incubation?

A

seabirds, hawks, etc.

153
Q

What is a brood patch?

A

an area with no feathers, that has increased blood flow to heat eggs. the skin on the brood patch is softer and firmer. Either sex can develop a brood patch.

154
Q

Name 3 methods of incubation

A
  1. belly flap (penguins)
  2. feet (boobies)
  3. mounds
  4. brood patch
155
Q

What species can never develop a brood patch?

A

brown headed cowbirds

156
Q

When temperatures are too hot, how do birds cool eggs?

A
  1. shading them
  2. wetting them
157
Q

how is heat generated for mound builders?

A

rotting vegetation, tended by the male, provides the heat to incubate the eggs

158
Q

What hormone regulates incubation/brood patch formation

A

prolactin

159
Q

this hormone opposes prolactin

A

testosterone

160
Q

synchronous brood

A

all eggs are laid before incubation begins, all babies hatch at once
all babies are the same size

161
Q

asynchronous brood

A

eggs hatch at different times, incubation begins immediately

sets up a sibling hierarchy based on size and encourages competition

162
Q

blue tits

A

prefer synchronous broods to recruit male help

163
Q

what causes nest attentiveness to increase?

A

increased mate feeding (by extension, lower predation), decreased ambient temperature, increasing body condition

164
Q

what causes nest attentiveness to decrease?

A

increased ambient temp, decreasing body condition, decreased mate feeding (and by extension, increased predation)

165
Q

Does incubation have a genetic component?

A

Yes, crested mynahs cannot increase their incubation time when introduced to cold climates, common starlings can

166
Q

Chicks communicate to parents via _______ while still in the egg

A

vocalizations (occurs late in development)

167
Q

Why do birds rotate their eggs?

A

prevent the chorioallantois from adhering prematurely to the shell

168
Q

How long is incubation?

A

10-14 days (songbird)
80-90 days (long lived seabirds)

169
Q

What factors cause incubation length to increase?

A

increased lifespan

170
Q

Describe how a chick hatches

A

the embryo punctures the membrane that encloses the air chamber, then punctures the shell around the fat side of the egg and pushes the top off

171
Q

How do parents care for their young? (7)

A
  1. brood young
    - thermoregulatory help
    - NOT incubating (incubating is for eggs, brooding is for chicks)
  2. feed chicks
  3. teach young
    - tool building
    - where to find food
    - how to fly
  4. remove wastes
  5. transfer of antibodies
  6. allopreening
  7. protection
172
Q

How can we describe precocial young?

A

nearly self sufficient upon hatching
(this is the ancestral condition)

precocial young still have parental care though - they follow parents that provide protection and lead them to food sources

173
Q

What is the difference between precocial young and superprecocial young

A

superprecocial young do not recieve any parental care and are completely independent from the moment they hatch
- this is common for mound builders

174
Q

How can we describe altricial young?

A

blind, naked, and helpless young that require lots of parental care/feeding/protection before becoming independent

175
Q

Who grows faster? Altricial or precocial young?

A

altricial young

176
Q

Ricklefs theory on offspring growth

A

Ricklef’s suggests that altricial young grow faster due to a tradeoff between growth of tissue mass vs maturation of tissue function
- precocial chicks must follow parents, so all tissues must be fully functional, inhibiting growth ability
- all altricial chicks do is grow, they do not need to mature their tissues for a significant amount of time

177
Q

What type of curve can we use to describe the growth of chicks? (sigmoidal, hyperbolic, or linear?)

A

sigmoidal curve (growth is the slowest early and late in development)

178
Q

Why do aerial insectivores like swifts and aquatic predators like penguins overshoot their adult weight as fledglings?

A

they require an energy reserve or buffer while they learn to fly and hunt on the wing all at the same time

179
Q

What can we say about the relationship between adult size and growth of a chick?

A

large birds grow slower

180
Q

What can we say about the relationship between predation pressure and offspring growth?

A

As predation pressure increases, growth rate increases
- therefore, a cavity nester like a flicker would have offspring that grow slower than an open cup nester of similar size

181
Q

Who develops thermoregulation faster- precocial or altricial chicks? Why?

A

Precocial chicks - they are already well insulated by down/have more muscle mass for shivering compared to altricial chicks

thermoregulatory ability also improves as surface area:volume ratio decreases

large broods retain heat better

182
Q

What types of investment by parents do we expect in a precocial chick?

investment in the egg, investment in feeding, and/or investment in brooding

A

investment in the egg

peak energy investment occurs when young are in the egg

183
Q

What types of investment by parents do we exprect in an altricial chick?

investment in the egg, investment in feeding, and/or investment in brooding

A
  • investment in feeding
  • investment in brooding

peak energy investment occurs when young are nestlings

184
Q

Would we expect for precocial or altricial birds to have more monogamy?

A

altricial birds
- growth patterns encourage biparental care, encouraging monogamy

185
Q

When does parent-offspring conflict occur?

A
  • parents want to balance costs and benefits of parental care ie) to fledge the largest amount of offspring for the least cost
  • parents need to consider their personal fitness and their future reproductive efforts
  • offspring are the most successful when parents invest the maximum amount
  • offspring want parents to invest the maximum amount regardless of personal cost

“conflict that occurs over the amount of parental care that is optimal for parental fitness vs offspring fitness”

186
Q

Name some costs of parental care (3)

A
  1. energetic costs (expenditure increases by 50%)
  2. time costs (less foraging, less mate attraction)
  3. predation risk (must take care of several screaming, immobile mouths for several weaks)
187
Q

How do offspring beg for food? (4)

A
  1. change posture
  2. open beak (brightly colored gape)
  3. peck at parent’s beak (gulls)
  4. vocalize
188
Q

is begging an honest signal of offspring hunger?

A

when offspring beg more, parents bring more food. however, begging more often increases the costs incurred by begging, keeping the signal ‘honest’

189
Q

What are some costs of begging? (3)

A
  1. increase predation risk
  2. energetic cost of increased activity
  3. increased cortisone levels
190
Q

How might parents reduce the number of their brood in lean times?

A
  • create a size hierarchy, encouraging competition
191
Q

How is a size hierarchy created in birds?

A
  1. asynchronous incubation
  2. differences in egg size
  3. differences in egg composition
  4. differences in incubation quality
192
Q

Why is a sibling size hierarchy advantageous?

A
  • get more young when resources are abundant
  • bet-hedging strategy
  • reduce brood size when resources are scarce
193
Q

American coot sibling conflict example

A
  • adults vary egg investment by changing composition
  • incubate asynchronously
  • initially, the youngest offspring is fed first, then parents switch and feed the oldest first
  • coot chicks have ornamental plumage, so parents will favor the most ornamented chicks
  • the disparity between more highly ornamented chicks and less ornamented chicks (experimentally altered) increases over time, so it is advantageous to hatch first, especially if you are not very ornamented
194
Q

In which species is siblicide common?

A

boobies
eagles
egrets

195
Q

Why is siblicide common in egrets, but not in herons, a closely related group?

A

egret prey is more easily monopolized than heron prey, so it is easy for heron chicks to get all the food and kill their siblings
- herons in egret nests become siblicidal
- the behavior does not disappear when egrets are placed in heron nests

196
Q

Why would a female want to bias the sex ratio of her offspring?

A
  • since females are heterogametic, they determine offspring sex
  • male reproductive success is largely determined by condition
  • in lean times, female offspring have higher reproductive success than males
  • female parents desire more ‘grandchildren’ to increase her fitness
  • when resources are scarce, like when the female is in poor condition or she has to take care of offspring by herself, the offspring are likely to be in poor condition (unlikely for males to have reproductive success)
197
Q

Who provides parental care for fledgelings?

A

the male

198
Q

Fledging

A

nest leaving behavior by altricial birds

199
Q

Why is the sex ratio 1:1?

A

there is a strong advantage to being the limited sex (EVERYBODY wants you)

so like frequency dependent selection, where the ideal frequency is 50% males 50% females

200
Q

What is a life history trait?

A

a trait that describes a ‘life event’ such as
- growth rate
- age at maturity
- clutch size
- lifespan
- offspring size at hatching

201
Q

What is a tradeoff?

A

organisms only have a finite amount of resources across growth, reproduction, and self maintenance (survival)

tradeoffs occur when some traits are invested in while others are not
- long life span, less offspring per breeding attempt
- short life span, more offspring per breeding attempt

202
Q

kestrel example of an evolutionary tradeoff

A

kestrels raising artificially larger broods are less likely to survive
- investing more in current reproductive attempts takes away investment in survival

203
Q

senescence

A

a late life decline in survival and/or reproduction

204
Q

Rate of living theory

A

aging is inevitable caused by accumulated damage to cells and tissues (via replication errors, accumulation of toxic byproducts, etc)

205
Q

What predictions can we make with the rate of living theory?

A
  1. aging and metabolism are correlated (live fast, die young)
  2. species should not be able to evolve a longer life span
206
Q

Is rate of living theory supported or unsupported? Why?

A

rate of living theory is unsupported because despite having very high metabolisms, birds live much longer than other animals of similar size

207
Q

Evolutionary reasons for senescence

A

-wild animals often do not die of old age
- natural selection may favor traits that are deleterious in old age, but increase breeding success at younger and younger ages, especially when there is high offspring mortality

208
Q

Collared flycatcher example

A
  • females that breed at age 1 have smaller clutches compared to birds that breed at age 2
  • females given artificially larger broods have smaller clutches than control females
209
Q

Explain the relationship between mortality, age at maturity, and fecundity

A

as annual mortality increases, age of maturity decreases, and fecundity increases
OR
as annual mortality decreases, age of maturity increases, and fecundity decreases

210
Q

Lack’s hypothesis

A

selection will favor the clutch size that produces the most surviving offspring
- the factor that limits clutch size the most is food availability

211
Q

Why do great tits have less offspring than predicted by lack’s hypothesis?

A
  • there is a greater benefit from saving energy for future reproductive attempt
  • higher quality offspring have greater reproductive success than low quality offspring
212
Q

What is the main shortcoming of lack’s hypothesis?

A

it assumes that there is no tradeoff between current reproduction and survival and future attempts

offspring number comes at a cost to long term offspring quality

213
Q

Skutch’s hypothesis

A

tropical birds lay smaller clutches due to higher predation rates
- they feed less often to prevent predators from locating the nest

214
Q

What predictions can we make using skutch’s hypothesis and what are the results of testing? (3)

A
  1. parents visit larger clutches more
  2. nests visited more often are more likely to be depredated
  3. parents feed offspring less than in temparate climates
  • predation rates are not higher in the tropics
  • tropical species do not visit nests less often
215
Q

What factors influence clutch size and how? (3)

A
  1. Food availability (lack’s hypothesis) explains clutch sizes within a species
  2. predation rates (skutch’s hypothesis) explains clutch sizes within latitudes
  3. annual mortality explains clutch sizes between latitudes
216
Q

Explain investment differences between tropical and temperate birds

A

tropical birds have higher nestling mortality, so investment is greatest later in life

temperate birds have higher annual adult mortality, so there is high investment early in life

217
Q

How does natural selection generate negative correlations between reproduction and longevity?

A

there is a depletion of genetic diversity - selective events limit ‘intermediate’ combinations of longevity and reproductions

218
Q

Name some roles that birds serve in ecosystems and human culture

A
  1. religious significance
  2. relationship between humans and honeyguides
  3. pollinator
  4. seed disperser
  5. scavenger
  6. pest control by insectivores
  7. ecotourism
219
Q

Name some threats that birds face

A
  1. habitat destruction (deforestation, agriculture, human development)
  2. climate disturbances
  3. light pollution
  4. pollution (pesticides, etc.)
  5. disease
  6. invasives (feral cats, rats/mice, mustelids etc.)
220
Q

Name some invasive species that have adverse effects on bird populations

A
  1. cats
  2. rats
  3. mice
  4. cattle
  5. goats
  6. mustelids (weasels, stoats, skunks etc.)
  7. malaria
  8. influenza
221
Q

what is the number one anthropogenic threat that birds face?

A

agriculture

222
Q

open cup nesters tend to have relatively _______ incubation periods than cavity nesters

A

shorter - due to predation pressure differences (higher for open cup nesters)

223
Q

species with precocial young tend to have relatively ______ incubation periods than species with altricial young

A

longer (more invested in development while still in the egg)

224
Q

longer lived species tend to have ____ clutches than shorter lived species

A

smaller - invest in lower reproductive output over a longer period of time

225
Q

species in areas of low predation tend to have _____ clutches than species in areas of high predation

A

larger - skutch’s hypothesis - less young means feeding them less and drawing less predators to the nest with activity

226
Q

species in areas of abundant food tend to have _____ clutches than species in areas with scarce food

A

larger - lack’s hypothesis

227
Q

altricial hatchlings grow _____ than precocial hatchlings

A

faster - tissue maturation hypothesis

228
Q

larger birds grow _____ than smaller birds

A

slower

229
Q

cavity nesters grow ____ than open cup nesters

A

slower - due to predation pressures

230
Q

species with low annual mortality grow _____ than species with high annual mortality

A

slower

231
Q

what is the primary environmental cue that birds use to time transitions between stages of the annual cycle?

A

day length or photoperiod

232
Q

what hormone is responsible for triggering the production of testosterone

A

LH or luteinizing hormone

remember that follicle stimulating hormone triggers the development of follicles in the female, and sperm in the male - generally responsible for production of gametes in some way. LH is responsible for triggering primary hormone production (estrogen in females and testosterone in males) for both sexes.

233
Q

what hormone shifts activity away from reproduction towards survival?

A

corticosterone or CORT

234
Q

noise pollution and zebra finches

A

groups are exposed to either bird song or traffic noise prenatally/postnatally in varying combinations (song/noise, noise/noise, etc)

all groups have the same average clutch size

however, birds exposed to noise are less successful at hatching offspring (noise/noise = most severe, combinations with intermediate effects)

the relationship between hatching success and egg size goes away when birds are exposed to noise

birds that were exposed to noise also had lower hematocrit, tarsus length and telomere length, persisting even after exposure

235
Q

Considering temperate residents, tropical residents and migrants, who has the highest species density, with more competition?

A

tropical residents

236
Q

Considering temperate residents, tropical residents and migrants, who has the shortest breeding season?

A

migrants

237
Q

Considering temperate residents, tropical residents and migrants, who has the fewest broods annually

A

migrants

238
Q

Considering temperate residents, tropical residents and migrants, who has the highest annual mortality rates?

A

temperate residents - low food availability in winter and harsh conditions

239
Q

which hypothesis predicts that female fitness is limited by the number of eggs produced, while female fitness is limited by the number of eggs that are fertilized?

A

bateman’s principle

240
Q

according to this mechanism of sexual selection, evolution of elaborate male traits is favored because trait preference and trait expression become genetically linked through assortative mating

A

runaway selection

241
Q

these birds have a testis on one side of the body and an ovary on the other

A

bilateral gynandromorphs

242
Q

this egg membrane aids in embryonic respiration and excretion

A

chorion

243
Q

levels of this hormone increase rapidly in response to stressors such as escaping a predator, lighting for a territory and enduring bad weather

A

corticosterone or CORT

244
Q

in this mating system, several males and females form a communal breeding unit

A

polygynandry

245
Q

proposed that clutch size is limited primarily by food availability

A

lack’s hypothesis

246
Q

list two functions of nests

A

thermoregulation, protection from parasites, protection from predators

247
Q

Who has higher variation in reproduction in monogamous birds, males or females?

A

neither, variance is equal

248
Q

who has higher variation in reproduction in polyandrous birds, males or females?

A

females

249
Q

who has higher variation in reproduction in polygamous birds, males or females?

A

males

250
Q

females often choose males for showy displays or ornaments. what are two possible benefits of female mate choice?

A

good genes: superiorly ornamented males produce better offspring

heterozygosity

direct benefits: a male’s ability to provide parental care or territory, gift giving male behaviors

251
Q

describe precocial vs altricial hatchlings

A

precocial
- grows slowly
- feathered, much better at thermoregulating early
- only need to be led to food
- larger at hatching
- mobile

altricial
- grow quickly
- featherless, not good at thermoregulating early
- helpless
- smaller at hatch
- blind
- require much parental care
- not mobile

252
Q

Given that facultative brood parasites do not always engage in brood parasitism, under what conditions are they likely to parasitize another nest?

A
  • low body condition
  • have already laid many eggs
  • the opportunity arises
  • harsh environmental conditions
253
Q

Give one reason (hypothesis) why a host of an obligate brood parasite would NOT evolve defenses against parasitism

A
  • retaliation by the parasite (cowbird mafia)
  • parasites provide benefits to the host via predator deterrence
254
Q

Why would a female brood parasite remove one of the host’s eggs before laying her own in the nest?

A
  • reduction of competition for her offspring
  • egg counting behaviors by the host
255
Q

List two specific adaptations of host species that decrease the impact of brood parasitism

A
  • unique begging calls and gape patterns, egg recognition, egg counting, and moving suspicious eggs to subpar spots for incubation
256
Q

How do helpers benefit female superb fairy wrens?

A

helpers allow the female to lessen costs to her without sacrificing reproduction
- there is less yolk, but feeding is increased after hatching by helpers

257
Q

With respect to the pattern of differential migration that is seen in Dark Eyed Juncos, what are the three selective pressures acting on the sex/age classes and as a result of these selective pressures, how are the sex/age classes arranged on their wintering grounds?

A
  1. mortality caused by migration is higher for young birds than old birds, therefore young birds migrate a shorter distance than older birds
  2. reproductive success is influenced by time of arrival on the breeding grounds, specifically for males: it pays to be earlier, so males stay closer
  3. overwinter survival increases the further south a bird migrates (less competition) so there is selection on all individuals to go as far south as possible

young males - closest to breeding grounds (more north)
old males - 2nd closest
young females - 3rd closest
old females - farthest (furthest south)

ornithology (7 decks)

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