ornithology exam 3

what kind of sex determination do birds have

Z and W chromosomes

which sex is homogametic

males, ZZ

which sex is heterogametic

females, ZW

what is the cascade of hormones that trigger reproductive behavior in males

hypothalamus releases GnRH into anterior pituitary, which releases FSH and LH into the testes, releasing testosterone

how many testes do males have

two

how does male teste size differ in breeding season compared to the rest of the year

teste size increase dramatically as breeding season approaches

what is the function of the seminiferous tubules

miosis occurs within the wall, then travels inward and becomes sperm cells

how does male teste size differ

larger in birds that breed colonially, higher breeding density means greater sperm competition

what is the cascade of hormones that trigger reproductive behavior in females

hypothalamus releases GnRH into anterior pituitary, which releases FSH and LH into ovary, producing estrogen

how many ovaries do females typically have

one ovary and oviduct, 2 in most falconiformes

what is the cloacal protuberance

in males the cloaca protrudes when mating

how does copulation typically occur

from touching the cloacas together

how do male Anseriformes differ from other avian males

presence of external genatalia

what are sperm storage tubules

sperm is stored within oviduct to save for later use, 10 days-2 weeks

what are the layers/functions of the shell

shell, shell membranes (inner and outer) protect from bacterial invasion and prevent water loss

what are the layers/functions of the albumen

outer liquid layer, dense albuminous sac, inner liquid

what are the layers/functions of the vitelline membrane(yolk sac)

yellow yolk-more fat, day. white yolk-more proteins, night

what is the chalaza

protein fibers that anchor the yolk

what are the layers of the extraembryonic membrane

chorion(outermost layer), amnion(contains embryo), allantois, yolk sac

how does gas exchange happen through the shell

through pores in shell, carbon dioxide flows out, oxygen flows in

how does the amount of yolk vary based on developmental strategy

precocial(least developed at hatching) 20% yolk, altricial(most developed at hatching) 70%

steps of egg formation: infundibulum

top of oviduct, where fertilization occurs, directly below ovary

steps of egg formation: magnum

first layer of albumen(egg white) added

steps of egg formation: isthmus

inner membrane, outer shell membrane, and more albumen added

steps of egg formation: uterus

more albumen, shell is formed, pigments added

what happens to the cloaca during egg laying

part of cloaca/last segment of oviduct turned inside out, vent is everted, prevents feces from contaminating egg

how do embryos grow

starts as small cell, grows larger, yolk transformed into body mass as embryo develops

what are capital breeders

store energy/nutrient reserves to produce eggs, large energy reserves and expensive eggs

what are income breeders

ingest on daily basis resources needed for egg production

what is sexual selection

two special kinds of natural selection

what is female preference sexual selection

members of one sex create a reproductive differential in the other sex by preferring some individuals as mates

what is male competition sexual selection

members of one sex create a reproductive differential among themselves by competing for opportunities to mate, lekking

how does reproductive investment differ among males and females

females have expensive gametes, more investment- find the best mate

males have cheap gametes, less investment- find the most mates

long tailed widowbird sexual selection

males show off long tails by flying slowly over their territory, females prefer males with the longest tails for mating

what is a lek

aggregation of males which display and vocalize together

evolution of leks: hot spot model

males gather at sites where they’re most likely to encounter roaming females, least supported theory

evolution of leks: hot shot model

males gather around experienced, attractive, or dominant males to increase chances of being noticed

evoloution of leks: female prefrence model

females prefer to visit large clusters of males over small clusters or solitary males

sexual selection in birds of paradise

most are polygynous,males have elaborate courtship displays evolved to show off specialized plumages

sexual selection in bowerbirds

build structures(bowers) to attract females, collect colored items similar to their coloration, provide courtship/copulation platforms

male choice

some male birds appear to adjust their investment in parental care in relation to quality of their mate

mate choice: good genes hypothesis

exxateraged male plumages/courtship displays truthfully signal genetic/physiological superiority

mate choice: direct benefit hypothesis

sexual ornaments communicate mates ability to provide resources/protections

mate choice: arbitrary choice/runway hypothesis

sexy males will have sexy sons that will be more popular, driving evolution of genes for the ornament and genes for the preference

what is social monogamy

one female forms a lasting pair bond with one male, she may also copulate with other males

what is polygamy

any mating system that includes multiple mates of the opposite sex

what is polygyny

one male, multiple females 2 types- resource defense/ female defense

what is polyandry

one female, multiple males, 2 types- serial/territorial

what is polygynandry

female mates with multiple males, who also mate with several females

what is promiscuity

no prolonged pair bonds formed, grouse

what is serial monogamy

monogamous within the breeding season

what is cuckoldry

older males sneak copulation with another female

what is egg dumping

female drops her egg into another females nest, female does not have to raise chick

how do extra pair copulations attempts relate to a females fertile period

when male believes female is past her fertile period, they leave her unguarded allowing other males to gain more EPCs

what is resource defense polygyny

male defends resource-based territory with resources females need, red winged black birds

what is female defense polygyny

when females aggregate, males compete with each other for right to mate with them

what is serial polyandry

females lay a clutch of eggs for a series of different males

what is territorial polyandry

female defends a territory containing sufficient resources to attract multiple males each cares for his own clutch

what are brood parasites

lay eggs in nests of other birds, no biological parental care, obligate and non obligate

how do obligate parasites mimic host species

some produce eggs that mimic specific host species

strategies for obligate parasites

cryptic movements, eat/discard host egg, high egg laying abilities, short incubation, and rapid growth

strategies for host species against parasites

shift breeding period to not correspond with parasite, attacking, warning calls, conceal nest, egg/young discrimination

why is cooperative breeding adaptive

unpredictable or difficult breeding conditions and long term territoriality, frequent in areas with low rainfall, high temps, and high climactic variance

cooperative breeding: florida scrub jay

one pair bonded couple, 1-6 helpers

cooperative breeding: mexican jay

multiple breeding pairs, multiple generations of helpers, permanent breeding territories, monogmous breeding adults

cooperative breeding: groove billed ani

1-4 breeding pairs, occasionally helpers, communal nests

cooperative breeding: acorn woodpeckers

territories based on maintenance and defense of graneris(food stores), 1-2 breeding females, 1-4 breeding males, communal nest

cooperative breeding: siberian jay

offspring remain with parents up to 5 years, dominant brood members evict sub members, delayed dispersal increases number of breeding years

cooperative breeding: white fronted bee eater

stable colonies, clans with 2-3 pairs of helpers and offspring defend territory

nest types: no nest

nightjars(camouflage), emperor penguins(egg at feet)

nest types: scrape nest

produce camouflaged eggs- killdeers and shorebirds

nest types: platform nests

platform up in a tree- herons

nest types: floating nest

build on top of vegetation/small platform- waterfowl

nest types: simple cup nests, statant

on top of physical hard support

nest types: simple cup nests, pensile

supported by rim- hummingbird

nest types: simple cup nests, adherent

attached to surfaces

nest types:pendulous nests

hang down from branch, involve complex weaving job

nest types: domed nest

roof built over top of cup, ground nesters, globular

nest types: retort

globular nests, entrance is tunnel, too small for predators to fit through

nest types: mound nests

mainly produced by megapodes

nest types: cavity nests

half of all orders, primary-creates cavity(woodpeckers), secondary- use existing cavity

nest types: burrows

dig holes in ground- king fishers

nest types: communal nests

sociable weavers build largest, most complex communal nests

plant materials used in nest construction

sticks/twigs, reeds/grasses, green vegetation, aromantic plant materials

other materials used in nest construction

spiderwebs, mud, sand/rocks

nest construction: polygynous species

female only

nest construction:

nest construction: monogamous species

males may build many nests for females to choose from, male gathers/female builds, male builds/female adds lining

how is the nest a part of the birds extended phenotype

they are a complex product of birds genes, morphology, behavior, and previous social experience interacting with its environment

what are the three types of passerine nests

cavity/hole nests, open cup nests, domed nests

what is the ancestral type of passerine nest

the most recent common ancestor likely had an enclosed, domed vegetation nest

what are the different types of swallow nests

mud nests, cavities, burrows

methods for nest construction

bills and feet are nest building tools; scraping, digging, drilling, piling, weaving, accumulating mud

nest building predation risk, crypsis

camouflage for ground nesters, dense clumps of grass, vine tangles, or hidden crevices

nest building predation risks, inaccessibility

seabirds nest on sheer cliffs, swifts nest deep in caves or behind waterfalls

nest building predation risks, defense

australian magpies defend nests aggressively, nest distraction displays-killdeer

nest building predation risks, deterrents

black chinned hummingbirds build nests near hawk nests, hawks force away hummingbird predators

nest microclimates are determined by

thickness of insulation, heat produced by parent, nest location(sun/shade), air humidity

what are fecal sacs

produced by nestlings of most passerines and woodpeckers, often eaten by parents for nutrition and sanitation

what are the physiological changes associated with incubation

rise of prolactin, testosterone drops after mating since it inhibits expression