OBU Dr Pruett Ornithology mini exam 2

cyclopean area

combined frontal and lateral visual fields

rods

black and white vision

cones

color vision

visual acuity

· Ability to discriminate 2 points

· Some birds 2.5-3 times better than humans

cochlea

· Sound converted into nerve impulses

· Sound waves cause the tympanic membrane to vibrate

semicircular canals

three fluid-filled canals in the inner ear responsible for our sense of balance

echolocation

· In 2 families

o Steatornithidae (oil birds)

o Apodidae (cave swiftlets)

· Orientation in caves

· Produce clicking sounds and interpret echo

oscine

song bird. More complex syrinx and more developed brain pathways for song learning

suboscine

Passeriforme subfamily Tyranni

-simple muscles & songs

-invariant

conspecific

same species

song dialect

locally distinct version of a song, possibly due to genetics, social adaptation, or historical separation

Fixed repertoire

after reaching adulthood the song reperoire no longer makes any big changes

song repertoire

· Typically 5-14 song types, but some unlimited

· Some only 1 type

· Each type has a different meaning

interspecific

between different species

intraspecific

within a species

territory

any defended area

roost

a place where birds rest or sleep

colonial waterbird

birds that breed in high-density, often massive groups to increase survival and foraging efficiency

stable flock

smaller flocks with established pecking orders

mobbing

flocks of small birds harassing a predatory bird for defense

fitness

reproductive output

lekking

The gathering of males in an area for the purpose of displaying to attract females.

inclusive fitness

an explanation for altruism that focuses on the adaptive benefit of transmitting genes, such as through kin selection, rather than focusing on individual survival

predator swamping

an anti-predator strategy whereby the probability of an individual being eaten decreases with numbers.

nictitating membrane

· On top of cornea

· Has lubricating duct

· Unique to vertebrates

· Ocular cleansing

· Protection

sclerotic ring

· Ring of bony plates surround iris

· Also in reptiles

· Adjust shape of cornea for visual acuity/support

tapetum lucidum

· Layer at back of eye

· Acts as a mirror/reflects light back through the retina

· Nocturnal birds

· Produces eyeshine

monocular vision

o Wide field of view; no head turn

o Pigeons 300 degrees

o American woodcock 360 degrees

o Poor depth and distance perception

binocular vision

· Eyes at front

· Owls and diurnal raptors

· Similar to humans, 180 degrees

· Good distance and depth perception

pecten

o Vascular structure projects from retina

o Glucose diffuses from it and absorbs lactic acid

o Pecten interferes less with vision than blood vessels

they have pecten and no blood vessels

how does the vascular system in the avian retina differ from mammals?

outer ear lacks pinnae, only one middle ear bone, can regenerate hair cells of inner ear

what are the differences between the avian and mammal ear

asymmetrical ear openings allow them to triangulate sound on a horizontal and verticcal plane, tell the difference in intensity and timing of founds

How do owls use sound localization

simple call notes, complex songs, substrates, feathers, and syrinx

What do birds use to produce sounds and songs

they have two seperate passageways in their syrinx that can be controlled individually

Why can birds produce two different sounds at the same time

they have more syringeal muscles, non oscines have 2, but oscines can have up to 6 pairs

Why can oscines make more complex songs

songs are loud, often long, important in reproduction

calls are simple, mainly for behavior coordination, not primarily sexual

what is the difference between songs and calls

mate identification, territory establishment and defense, predator distraction, activity coordination, stimulate females, attract females for EPCs, mate guarding

What are the major functions of songs and calls

territorial defense, mate defense, mate attraction, coordinate breeding activities

What is the purpose of female song

prevent 'exhaustion' of nerves and muscles and stop others from getting habituated to their cal

what are the functions of having a repertoire of songs

Critical learning period, silent period, subsong period, song crystallization

What are the four periods of song learning

Critical learning period

a. Information stored for later use

b. < year

c. Can extend to the first breeding season

d. If they do not hear a male sing it during this time period, they will not learn it

silent period

a. Memorized components stored in brain

b. Up to 8 months

Subsong period

a. Practice without communication

b. Low volume, unstructured notes

possibly where dialects are differentiated

Song crystallization

a. Song becomes less plastic

b. Adult version sung

duration, frequency and pitch

What is innate in most birds

syllables, rhythm

what is learned in oscines

syllables in some, duration, rhythm, frequency and pitch

what is innate in non oscines

vocal mimicry

ability to copy and imitate sounds in 15-20% of passerines

o Increase song complexity

o Attract mates

o Defend territories

o Stimulate mates

what are the intraspecific functions of vocal mimicry

establish territory by associating mimicked song with aggression

what are the interspecific functions of vocal mimicry

duetting

overlapping vocal or non vocal sounds by mates

establish territory, pair bonding, mate guarding

Why do birds duet

Type A territoriality

mating, nesting, and feeding in territory, ex. songbirds

Type B territoriality

mating and nesting territory, forage elsewhere

Type C territoriality

nesting territoriality ex. colonial waterbirds

time, energy, risk of injury

What are the costs of territoriality

access to resources

what are the benefits of territoriality

o Scarce/unreliable resources

o Abundant resources (too many competitors and unnecessary)

When is it not worth defending a territory

predator swamping, mutual nest defense

what are 2 advantages of nesting in colonies

Competition, attract predators, diseases

what are some disadvantages of nesting in colonies

reduce risk of predation, cooperative foraging

Why do birds flock

they have a pecking order which reduces aggression, recognize each other

what are the benefits of making a stable flock

monogamy

· Pair bond with one member of the opposite sex

· 92% of species

· Pair bonds for single or many breeding seasons

· Can get divorced even if they breed "for life"

polygyny

· 1 male mates with >1 females

· Females mate with same male

· Parental care mainly by female; male my guard territory

· ~2% birds

polyandry

· Female mates with >1 males

· Parental care typically by males

· <1% of birds

promiscuity

· Indiscriminate sexual relationships, usually of brief duration

· ~6% of all birds

male dominance polygyny

lekking, males sucess depends on age, experience, status, and display

extra pair copulation

breeding outside social pair

o Fertility insurance

o Genetically diverse young

o Access to resources

What are the benefits of EPCs for females

o Increased fitness

o Possible future mate acquisition

o Insurance against mate's infertility

What are the benefits of EPCs for males

o Male retaliation

o Risk of injury

o Harassment from extra-pair males

What are the costs of EPCs for females

o Sperm depletion

o Cuckoldry

o Reduction in parental care

o Divorce

What are the costs of EPCs for males

intraspecific brood parasitism

sometimes lay eggs in the nests of other birds in their species

obligate parasitism

lay eggs in the nests of other species

egg mimicry, hard shelled eggs, destruction or removal of host eggs, nestlings kill competitors, lining of mouth mimic hosts

What are some adaptations of brood parasites

attack adult parasites, desert parasitized nests, bury egges under new nest floor, eject eggs from nest

what are some adaptations of birds to combat against brood parasites

cooperative breeding

helpers provide parental care, food, defense, nest construction, incubation, (rare)

inclusive fitness, lack of skill, dispersal is risky, home has essential resources

why would a bird choose to be a helper in cooperative breeding