Ornithology- Exam II

advantage of high metabolism

activity not constrained by low ambient temperatures

disadvantage of high metabolism

water and energy demands are often spatially/temporally scarce

__ in an environment determine what species can occur where

abiotic conditions

Q10

coefficient of temp, the change in the chemical reaction rate as a function of temp (C); holds under ‘normal’ metabolic rates

avian respiratory system

no diaphragm, sternum moves, anterior and posterior air sacs, old air and new air never mix, unidirectional air flow

how many air sacs can birds have?

from 6-12

how many air sacs do most birds have?

9

what happens to the sternum when birds breathe?

sternum lowers during inhalation, sternum and ribs contract during exhalation

how does the furcular increase respiratory efficiency?

expands and contracts air sacs as wings flap to further force air; creates greater pressure differentials

advantages of inhaling through nostrils

folds of the conchae cleanse/heat inhaled air and remove water from exhaled air; reduces water/energy loss and aids in thermoregulation

what is the correlation between metabolic rate and oxygen demand

positive correlation

the avian heart is ~ _ of their mass relative to <1% for small mammals

2-4x

mitochondrial-packed muscle fibers

metabolism

energy expenditure (KJ/Kcal) or O2 consumed per unit body mass per unit time

surface area to volume ratio

the larger the organism, the lower the metabolism; as body size increases, volume decreases

Passerine’s generally have _ metabolism rates than non-passerines

higher

Bergmann’s rule

as we increase in latitude, body size tends to increase within a species; increased surface area = lower heat loss

example of Bergmann’s rule

a decline in body mass of Red-billed Gulls from climate change, body mass decline was related to environmental changes, not genetics; environmental degradation/heat stress during development may have been the main factor (Teplitsky)

importance of temperature regulation

maintain metabolic processes, stabilize internal body temp, enzymatic functions

what happens to a bird’s metabolism in the winter?

metabolism increases, feathers alone do not completely maintain internal body temp

thermoneutral zones

range where metabolism is at its lowest due to ambient temps

what is the purpose of feather fluffing?

retain heat

Why do shore birds/other birds ruffle their feathers, bend their wings, pant or expose their legs?

increase blood flow to dissipate heat

which of the 5 senses do birds rely on that differentiate them from other vertebrates?

vision

what birds are believed to have the best vision

songbirds and raptors

why do birds heavily rely on vision?

mate choice, hunting/foraging, predator/threat detection

what type of vision is responsible for peripheral vision?

monocular vision

what type of vision is responsible for depth perception?

binocular vision

eyes of the European starling account for ~ _ of its head mass

15%

what percentage of a humans head mass are taken up by the eyes?

~1%

how are monocular and binocular vision related?

inversely

why might a bird bob its head?

to increase depth perception

tapetum lucidum

present in nocturnal birds, reflects light back through the retina for increased light capture

nictating membrane

third eyelid, functions to clean the cornea and protect the eyes

how do Robins use combined senses?

locate subtle sounds of moving worms in the soil, use hearing and vision during the actual strike

how does cone density in avian eyes differ from human eyes?

cone density is 2-5x that of humans

how might a bird utilize UV vision?

rodent urine reflects UV light, Common kestrels can use this to locate it when hunting

potential functions of UV transmitters in feathers

species/sex recognition, indicate offspring health, sexual cues

> _ of ~140 species of ‘monomorphic’ species are dimorphic in the UV

90%

how do birds use the magnetic field?

migration

how do birds (potentially) detect the magnetic field?

magnetite particles in ophthalmic nerves become polarized, carotenoid-porphyrin-fullerene molecule detects a magnetic field when excited by light

magnetic field detection in pigeons

magnetite and maghemite particles located in their beaks, potentially creates a magnetometer

what happens beyond the upper/lower critical temps of the thermoneutral zone?

shivering or evaporative cooling; ex) snow buntings begin to shiver at ~ 10 degrees C

how do non-migratory birds retain heat in the winter

increase feather mass up to 65% for extra insulation

torpor

energy-saving state, characterized by low internal body temp and low activity, decrease in respiration increases predation risk; 6 families, include hummingbirds, swifts, nightjars

salt gland

most developed in oceanic birds, folded nasal tubes extract salt from the blood via capillaries, salt is excreted near the nostrils; ducks can enlarge theirs when drinking saltwater, passerines don’t have them

eye location for monocular vision

sides of the head

why do raptors attack at an angle?

photoreceptors located at 22 to > 45 degree line of sight, creates drag-visual acuity dilemma for fast-moving raptors, diving at an angle maintains increased visual acuity and diving speed

how can water birds reduce heat loss in the winter?

regulate blood flow to their feet

why are bills so diverse in shorebirds?

character displacement due to interspecific competition

woodpecker tongue morphology

probing, spearing tongue with barbs, hyoid apparatus used to greatly extend tongue

fish-eating tongue morphology

tongue with rear directed hooks

hummingbird tongue morphology

split and fringed tongue, hyoid apparatus used to greatly extend tongue

duck tongue morphology

tongue with fringes to extract plants and organisms in the water

digestive tract

2-chambered stomach, crop, intestines, cloaca

2-chambered stomach

proventriculus secretes acid and gastric juices, gizzard further digests enzyme-laden foods; sand/stones may help grind food here

crop

stores and softens food; hoatzins ferment plant tissue

what happens to nutrients in the intestines?

nutrients is absorbed

function of cloaca

excretion

why might some plants rely on bird gut passages?

to scarify seeds

what tree species relied on the Dodo?

Calvaria trees

Meta tool use

using one tool to modify or enhance anither

tool use in Caledonia Crows

they construct