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169 Cards in this Set
- Front
- Back
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variation in wing shapes
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wing area
wing loading (weight of bird/area of wing) wing aspect ratio |
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wing area increase
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lift and drag increase
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wing loading increase
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need more lift
low loading efficient at low speed (lowers Vmp) |
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wing aspect ratio
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wspan^2 / area = higher = pointier
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thermal soaring
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areas where air is warmed faster have rising air currents, ride those up, glide down, repeat
low-to-moderate wing loading separated wing tips to counter drag |
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dynamic soaring
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albatross, frigate, petrel
use wing shape + wind (current of air on surface of water) to fly at low expense |
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hummingbird hovering
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necessary for floral foraging
"expensive" so eat rich diet (flower nectar) back stroke is nearly symmetrical much of mass is wing muscle and feathers |
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formation flying
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continuous vortex
slip-stream on other bird's wing tip vortices |
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wing propelled diving
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Auks, diving petrels, penguins
fluid is more difficult high loading (drag is much higher, so smaller wing) |
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flightless birds
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ostrich, extinct moas, elephant birds (eat a lot of vegetation, fast running, large)
kiwi (nocturnal, largest egg for body size) stephen's island wren (extinct due to cat before confirmed flightless) |
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arboreal theory of origin of flight
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jump out of trees!
associated with "thecodont" hypothesis and aerodynamic hypothesis for the origin of feathers support: lift is cheaper at speed (falling) (eg S.E. Asian rainforests) |
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cursorial theory of origin of flight
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running along the ground
associated with theropod hypothesis and thermoregulatory theory of origin of feathers support: already terrestrial, bipedal, with increasing length of hands prey capture movement like flight |
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theories of origin of the flight stroke
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arboreal: gliding=> flight stroke, continuous vortex, then derive rings
cursorial: ring is primitive |
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shoulder girdle evidence for arboreal
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(adv. shoulder girdle needed for ring vortex)
Archaeopteryx: no modern shoulder girdle, but asymmetrical feathers Confuciusornis: keeled sternum, pygostyle (fused tailbone), alula allows for laminar flow over leading edge, land on branches Enantiornithes: strut-like coracoid, raises shoulder, creates trioseal canal |
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*microraptor*
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4 wings (legs and arms), all with asymmetrical feathers (aerodynamic hindlimbs)
(it seems that first stage in development of wing is elongate wing feathers) |
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anchiornis huxleyi
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elongate limb feathers, not aerodynamic
elongate feathers for display |
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evidence for cursorial
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K. Dial: wing-assisted incline running
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avian breathing apparatus
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trachea (air pipe) branches into two lungs
air sac system around the lungs (abdominal, posterior thoracic, anterior thoracic, cervical, interclavicular) |
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avg body temp
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102-107 degrees F
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alveoli
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human breathing apparatus, branched, inefficient
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parabronchi
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birds avoid static equilibrium
series of tubes packed in a hexagonal array air flows in opposite direction as blood flow, constant exchange of O2 through hemoglobin |
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avian breath
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inhale into posterior air sacs
exhale into lungs inhale into anterior air sacs exhale out of the body |
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hinged ribs
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allow sternum to move relative to backbone
increase volume of body |
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avian four-chambered heart
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mammals and birds (used to think theropods didn't, but they do)
depleted blood in right auricle right ventricle lungs left auricle left ventricle => rest of the body |
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counter-current heat exchange
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in legs: also mostly tendons, so don't freeze easily
create a constant gradient, isolating the cold in the feet |
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thermoneutral zone
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maintain body temperature (~107) with least energy
below which, shiver above which, evaporative cooling (through breathing, no sweat glands) zone can evolve |
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birds keep warm by:
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fluffing plumage (feather erector/depressor muscles which also streamline flight) – lubricated by a layer of fat
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behavioral responses to heat stress
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panting, fluffing feathers on the back, defecate on legs
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torpor
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physiological state: energy conserved, basal temp goes down – (like hibernation) – (eg Poorwill in AZ, hummingbirds, and birds in Northern edges of zone)
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excretion
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paired kidneys – uric acid (not urea, kidney stone material), possibly saves weight
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tubenoses
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sodium load above the eyes – secrete salty solution through the nasal tubes
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bill
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toothless, shaped for diet: – forcep-typed seizing beaks (herons, bee-eating birds), cracking beak (short and squat): seeds, shoveler (spoon-shaped, sieving), chopping beak (raptors), cross-bill (finch): steal seeds from pine cones
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abaural identity
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in the identity development of the face, inside of mouth decides to become outside
suppresses signal to grow teeth – (can force it to grow teeth in egg, although it dies afterwards) |
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raptors
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seize prey with feet, kill with beak, then use beak to slice meat, grab it off
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lamelle
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ridge-like structure that acts as a sieve
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cranial morphology of the upper beak
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light-weight (air bubbles), can move upper beak because of the nasofrontal hinge, rhynchokinesis (bend more distal positions at tip or center of beak)
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rhynchokinesis
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can bend more distal positions at the tip or center of the beak
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Jugal
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upper jaw bone
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coevolution of birds and plants
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hummingbird beak shapes: flowers bribe birds to pollinate (sugar!), need high-fidelity pollinators, so make itself distinctive and pollen difficult to reach – elaborate beak shapes to fit the flower, coevolution
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ramphotheca
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beta-keratin hard covering of the beak
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flamingo specialized tongue
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ridges on tongue + beak = seive
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esophagus
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first part of the digestive track
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crop
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storage place for food (variation in size and shape)
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proventriculus
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glandular: preliminary acid-release on food
(before gizzard) |
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ventriculus (gizzard)
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grinding structure (ingest rocks to aid crushing food, possibly facilitates loss of teeth)
can create a pellet, regurgitate phenotypic plasticity: gizzard mass goes up in response to fiber content, liver mass goes down (body responds to diet) |
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phenotypic plasticity
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when the body responds to diet, not due to evolutionary changes
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small and large intestines
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lots of different shapes
small: nutrient absorption large: water absorption, balance => feces |
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glandular organs
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salivary glands (swifts construct edible nests)
pancreas (hormones, digestive enzymes, insulin) gall bladder bursa of fabricious (outpocket of intestines, part of immune system) cecum (digest plant material) |
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cecum
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digest plant material, extension of intestine
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bursa of fabricious
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outpocket of intestines, part of immune system
also related to aging (like mammalian thymus) |
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hyoid apparatus
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long y-shaped bone, curls around the head
in the tongue of birds so tongue is used to eat, not really to vocalise like mammals |
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birds with unusual diets
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Hoatzin (stinky turkey) : stupid, leaf-eating, digestion in the crop
Honey guide: guides honey badger to the hive, eats wax after badger tears open for honey parrots: chelation (clay to neutralize toxins) |
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sugar metabolism
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sucrose (double sugar) only digested by some
starlings died in 24 hours |
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tool use
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Woodpecker finch: darwin's finch that uses cactus spines to get beetles out of holes in wood
bait fishing herons: tiny thing thrown on water, fish investigate |
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prey impaling in Shrikes
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nasty beak, weak feet
impales prey to keep them secure more than necessary during mating season |
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plumage function in foraging
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painted redstarts: twitch, white flash scares bugs out of the wood, catches them
darkened tail feathers causes failure in foraging |
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dorsal nerve tube
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tube that runs down the body, carrying cns
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brain parts
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medulla (near spinal cord)
cerebellum: coordination of movement (cauliflower) forebrain: optic lobes, olfactory lobes, cerebrum (advanced processing) |
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peripheral nervous system
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somatic: willful
autonomic: involuntary nerves (cranial nerves) sympathetic: excitatory parasympathetic: inhibitory |
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differences between mammalian and bird brains
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bird: smaller olfactory bulb, larger cerebrum, larger optic lobe (most)
mammals: cerebral cortex folds, |
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reasons birds aren't actually as stupid as we thought
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bird song
cortex is not the only place of complex thought for birds regional specialization |
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three regions in brain associated with song learning
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auditory pathway: brings sound in from ears to cerebrum
vocal pathways: anterior (forecerebrum) vocal processing/analysis center, receives info from the posterior, compares info from sound to the result of motor output posterior : motor impulses that create the shape and form of the song |
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krushinsky problem
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can you infer where the food went if it goes behind a swinging door?
crows can |
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memory of food storage
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Clark's Nutcracker: finds 33,000 pine seeds buried each autumn, will go back and move seeds if they suspect they were watched
also Chickadees and titmice: hippocampus larger in species that store food (could be plasticity though) |
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nest/brood parasites
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cowbird lays eggs in other birds' nests
monitor sets of nests, lay eggs at the right times females have larger hippocampus except in the one species that pair bonds and hunts together |
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evidence of planning for the future
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scrub jays
3 compartments, on alternate mornings placed in the one with/without food after 3 days can store food in all compartments, store more food in no food compartment |
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tool use
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New Caledonian Crow: use rachus of leaf to extract bugs
naive birds given a pipe cleaner will bend it to hook a food basket also woodpecker finch, galapagos finch |
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Alex the African gray parrot
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taught to talk, describe colors, shapes, food (novel objects with 80% accuracy), what's the same/different
probably not how parrots communicate in wild, but plasticity of brain with human input |
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Avian ear components
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ear drum (tympanum)
one middle ear bone (columella) cochlea/inner ear: fluid-filled sack |
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cochlea/inner ear
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hair cells that extend into the fluid
tuned to specific frequencies in the waves cochlea shaped so that some places resonate more for some frequencies than others loops of semicircular canals are orthogonal for spatial, positional, balance perception |
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birds sensitivity to loudness
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less threshold sensitivity than humans (maybe) except in owls
(eg. hummingbirds are so tiny, not much space) |
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binaural comparison
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compare when the sound hits each ear to locate it
increased distance helps pinpoint owls have asymmetrical ears, holes underneath feathers with feathers of face as parabola to direct sound into ears |
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sonar
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oil-bird: nocturnal frugivore, functional echo-location
cave swifts (collacalia) : cave-dwelling insectivores with adv. echo-location barn owl forages in complete darkness |
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Herbst corpuscle
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pressure sensitive, in avian skin (and pits on the beak)
(unique to birds) |
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avian touch
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Herbst corpuscles (pressure sensitives)
filoplumes: probably sensory information about plumage movement (no pain receptors, desensitized by feathers) |
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olfaction
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most have reduced olfactory bulb
except : procellariiformes, falconiformes, kiwi-apteryx (need for diet) |
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procellariiformes
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pellagic (sea) birds
detect "breath" of plankton |
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evidence of olfactory navigation
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tubenoses taken to scotland, half with anaesthetic in nose, normal ones make it back much quicker
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turkey vultures (Cathartes)
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new world forest vulture
need good olfaction to be a forest vulture other birds use them as evidence of prey descend on gas leaks |
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bird pheromones
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Crested Auklet: pelagic bird, produces tangerine odor in mouth, rubs on others in the "ruff-ruff" display
metabolic derivative of xanthophyll carotenoid pigments |
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components of the avian eye
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cornea
lens (crystalline proteins, packed together so as to be transparent) vitreous humor image-forming retina (nerve processing cells) |
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rods (vision)
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B+W
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Cones (vision)
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different opsin molecule in each cone type, receptive to different portions of visible light
colors: ultraviolet (ultra-short wavelength sensitive cone), red (long wavelength sensitive cone), green (medium wave-length sensitive), blue (short wavelength sensitive) oil droplet in pathway of light, has carotenoids that filter out wavelengths (pre-vertebrate feature, marsupials also have it) double cones: substantial part of retina, but not sure how they function (maybe magnetic orientation?) |
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raptor and night owl vision adaptations
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larger eye, globos shape (almost tubular instead of flat)
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focusing
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change shape of lens with Brucke's muscle and the sclerotic ring (inter-ocular set of bones)
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*pecten*
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avian novelty in the eye
looks like a radiator/comb (thin laminate tissue) capillaries inside feed retina, vitrous nutrients instead of blood supply in front of retina (mammals) creates a blind-spot and shadow though |
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saccades
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rapid movements, in this case of the eye, so as to mix the vitreous humor
creates currents |
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fovea
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wrinkle in the retina with great density of rods and cones
some birds (swallows) have 2 (central, temporal) |
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binocular vision
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multiple sensors (eyes) overlapping = greater breadth of sensitivity
woodcock: has more than 180degrees of visual acuity in each eyes (less than 5degrees seen with both eyes, binocular vision) |
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stereo vision
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stereo processing of binocular input (Can have binocular vision without stereo processing)
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opsin protein
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small molecule of red retinol within 7-transmembrane molecule
receptive to different portions of visible light b/c molecular changes |
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ways to determine what birds are seeing:
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1. train pigeon to hit lever when it sees a triangle, then change color of triangle
2. study opsin molecules reactivity 3. excise eye from living bird, see what gets a reaction |
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double cones
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substantial part of retina, not certain of function (magnetic function?)
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why do birds see those 4 colors?
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active selection through evolution
eg UV cone and LWS for most mammals (nocturnal, no overlap) => UV tuned down to blue, LWS differentiates into green and red with close overlap |
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oil droplet
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carotenoid pigment in droplet absorbs low wavelength, only correct wavelength hits the cone
sws: "clear" mws: yellow lws: red (uv no droplet) less good at low light |
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avian color space
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(angle is hue, length/r is saturation or chroma)
fills only 26% of color space (see more colors than they can make) constrained by materials: carotenoids and melanins are a small pallet, structural colors allow much more |
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uv colors
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matter to mates (sunscreen decreases mateability)
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purity of color
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pure spectrum colors are furthest from white (at vertices in color triangle)
color triangle vertices are dif. for birds, so see dif pure colors |
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migration
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predictable displacement of a population between seasons
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dispersal
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movement of individuals among population
or eratic/eruptive movements (unpredictable: eg when owls move south for more food) |
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most extreme ex of migration
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Arctic Tern: 22-25,000miles/year (far north to antarctic, Arctic terns probably Antarctic terns who decided to stay)
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altitudinal migrants
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move up/down mountains
eg blue grouse go up in the winter, juncos, frugivores (esp. hummingbirds) in the Andes |
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austral migration
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migration in the southern hemisphere (north to warmer climes in winter)
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flyways
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pattern of migration
sometimes restricted by geography (eg try not to cross Mediterranean) unusual: blackpoll warbler gains weight, flies into the atlantic and catches trade winds to south america (in fall only) |
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advantages to diurnal migration
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often can feed while migrating (swallows)
thermal soaring |
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technology and migration
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gps on birds (track albatross to decrease attrition by fishing boats)
radar : wwii invasion, mass migration of snow geese delays cross-country flights (Kansas), can even determine bird from size geolocators: indiv dataloggers, solar-pwrd, detect solar position, must recapture -purple martin : south 500 km/day, north more slowly -wood thrush: north 200-250 km/day |
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preparation for migration
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fat storage sub-cutaneous
eg: Red Knot consumes 10x metabolic energy/day (gain 15% of weight/day) -Bar-headed goose: Flies over Himalayas, hemoglobin molecule evolved for greater O2 affinity |
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evidence of the genetic component of wintering grounds
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-Blackcap warbler: historically wintered in Spain/portugal, then some began to winter in England in 1940s
-shorter trip to England -return earlier, breed earlier (stable isotopes in feathers and toenails shows where they wintered) => speciation -also rufous humingbird (Alabama) -naive bird in funnel shaped cage, ink on bottom, open sky, jumps most towards correct direction in migration season -interbreeding begets intermediates -juvenals in the wrong place (non-group migration) = genetic mutation, species gets to search for better places |
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pathway summation
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know your previous paths, figure out where you are/want to go
(ants, not inter-continental migration) |
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zugunruhe
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migratory restlessness
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Emlen funnel
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cone shaped cage, open to sky (with netting), bottom has ink, sides have white paper
(test Zugenruhe) |
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hypotheses of evolution of migration
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Southern Home Hypothesis: start in south, but evolve to migrate to avoid competition for breeding (dispersal derives later)
Dispersal Migration hypothesis: migration evolves from post-mating dispersal (breeding range is primitive), dispersal to warmer climes encouraged by seasons (evidence) |
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compass + map system
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compass : reliable way of generating direction
map : relative position of things |
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compasses
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(reliable way of generating direction)
sun stars magnetic |
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experiments on sun compasses
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must know what time of day it is...so
-raise birds in aviary with a clock-shifted sun, sunrise at 5, not 6 -consistently 15 degrees off counter-clockwise -earlier dawn = counterclockwise error; later dawn = clockwise error -not sure how clock works |
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experiments on star compasses
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detect movement of stars around North Star (N. Hemisphere)
-planetarium: birds change orientation if you change stars -naive birds respond to a different "North star" (pattern of movement, not star pattern) |
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experiments on magnetic compass
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-Charles Walcott: pigeons disoriented at magnetic anomolies when cloudy
-helmholtz coils: electromagnet in a coil of wire on head and neck, connected to backpack -homing pigeons trained to feed at different platforms based on the magnetic field |
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Theories of mechanisms of magnetic reception
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-magnetite: iron crystals in the body (nose, brain or neck)
-removing opthalmic nerve confused ability to eat at correct place (control: olfactory) -photochemical: "see" magnetic fields, through retinal cryptochromes -singlet (electrons excited but cancel out), absorb photon => triplet => paramagnetic (singlet-triplet radical pair) -happens in picoseconds -shown in petri dish -blue contact lenses confuse pigeons (blue doublecones) |
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maps
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(poorly understood)
need orthagonal info, opposing gradient -magnetic? (second direction??) -olfaction |
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olfactory maps
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Papi "stink" experiments: not replicated, anaesthetizing nose confuses, try to change direction of olfactory cues
how do albatross use smells? |
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calibrate compass
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magnetic with celestial: capture, change magnetic field as sun sets => fly in wrong direction => second night back on track
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Syrinx (pl. syringes)
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novel vocal organ (others vocalize with larynx which in birds is part of the bony tongue)
located where trachea branches into two bronchi (usually tracheal-broncheal, but sometimes entirely tracheal) |
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lack a syrinx
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new world vultures
(can only hiss) |
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syrinx is composed of
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bone, cartilage (supporting elements)
tube is membrane nerves (direct motion) hooked up to breathing system (air in and out) (sometimes pessulus between bronchi?) |
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sound creation
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pressure waves
periodic disruption of air flow creates song -frequency (pitch) -amplitude (volume) |
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three possibilities of syringeal phonation:
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oscillation: membranes flap (probably most birds, contingas
pulsatile: open and close lumen (inside of tube) (ossean song birds) aerodynamic whistle: restrict lumen so that air whistles through |
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ways to test syringeal phonation theories
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-fiberoptic cable down throat to view
-thermometer in throat (air moving will cool it) |
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how does oscillation work?
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Bernoulli effect: moving air changes pressure??
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sources of vocal modulation
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frequency modulation
amplitude modulation post-source modulation |
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frequency modulation (FM)
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frequency = pitch (Hertz = cycles/sec)
muscles pull, creating tension in the membranes which can create different frequencies (greater tension = higher pitch) |
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amplitude modulation (AM)
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loudness in decibels
AM-FM coupling (higher notes are louder) |
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post-source modulation
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filtering by the airway (after the syrinx)
can filter out harmonics Jeff Podos + Steve Nowiki -trombone-like trachea acts as a resonant chamber |
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components to vocal complexity
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within a song (notes, syllables and phrases) and among songs (repertoire)
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sonograms
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used to show that birds can indep modulate sounds on either side of the syrinx (two-voice model)
usually in 1000cycles/sec (kHz) |
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Two-Voice model
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C. Greenewalt
-filter above and below a certain tone to show that the notes are modulated independently -need two membranes, 2 resonators to do it -can alternate airways seamlessly (right = higher, left=lower) |
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breathing in songs
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yes. breath rapidly between notes
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asymmetry in vocal tract
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right is smaller = higher notes
left is larger = lower notes mimics converge on same solution of switching as the orig. bird (even with a computerized model) |
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lowest sounding bird
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cassuary : probably "hears" mostly through ground vibration
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harmonics
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multiples of the fundamental frequency of a note (easy to double frequency)
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repertoire size of Marsh Wrens
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eastern: ~40 songs, syncopated, rollicky notes
western: ~150 songs, quacky, highpitched, chappy notes with harmonics |
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examples of increasing repertoire
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Wood Thrush: introductions + flourishes (mix and match)
Hermit Thrush: intro note + terminal flourish, but set order of transitions between songs |
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experimental evidence of syringeal function
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Herissant: puncture interclavicular air sac = mute roosters (thought air pumped in + valve)
Ruppel: excised syrinx and produced sounds with it in a glass bubble 1962: Bernoulli effect: realize it's not valves, but movement of air |
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songs
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function in mate choice/display and territoriality
-richer in structure, more complex -diverse -a lot are learned, but some are innate |
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calls
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other social circumstances
-shorter, less diverse, stereotyped -eg: vocalization in the egg, begging for food, contact calls, alarms |
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alarms
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terrestrial threats: immediately disarmed when seen, so call is localizable
-stopping/starting has edges -broad frequency -like trad. Brit siren Aerial threats -unlocalizable (thin, high, wispy) -like trad. Amer siren |
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heliox
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mixture of helium and oxygen (some nitrogen)
given to crane, expected to transpose songs up did, but higher than sonogram (lower note w/ nitrogen) helium's density is lower than air |
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trachea
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airway: can coil outside body cavity, under skin and in the hollow cavity of the sternum
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mechanics of PSM
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open beak and pull back neck => shorten airway => smaller acoustic structure => higher frequencies
closed beak, extended neck = reverse |
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+Diet's effect on song ability+
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larger beaks for tougher foods (eg. nuts) = slower
force vs speed (warblers are insectivores with small beaks) feedback btwn choice of mate's song/diet compatibility |
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motor challenges of pure trills
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trade trill rate for bandwidth
(filtering out harmonics) |
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innate calls
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eg. Alder Flycatcher raised in captivity without any accoustic input will create the classic call
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vocal learning
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4 lineages of birds (bats, whales, some primates) learn vocal cues from their social environment
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4 vocal developmental stages
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(early and late) subsong
plastic song full song |
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early and late subsong
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disorganized vocal production, few or no typical species sounds
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plastic song
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notes, but not congealed like an adult's, lots of species typical notes
(Rebecca Irwin: perhaps mimics never move past here) |
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full song
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modulated notes, species typical, recognized by other individuals, not going to change
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Screaming Piha
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tilts head way back, neck in, beak open, tongue out
PSM: but innate! |
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acoustic privation
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explore role of external material in learning process by depriving of all sounds except those you control
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sensitive period
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: after 30-60 absolute silence can develop full-fledged song
:social tutor extends that |
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Song template
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innate learning preference for songs of your kind (true of most birds)
can evolve |
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social tutor
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interact with living organism (expands sensitive period and can stretch template more)
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neurobiology of learning
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Pallial (complex) thought in forebrain, not just cortex
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4 phylogenetically distinct origins of vocal learning in birds
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parrots, hummingbirds (maybe not all), oscine passerines, Procnias bellbirds (Cotingidae)
independently evolved, but similar proportions and layout |
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evidence of new brain cell growth
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canaries learn new songs each spring
F. Nottebohm |
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bird dreams
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songs in REM
solidification or variants? (REM convergently evolved, crocodiles don't have it) |
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directed singing vs undirected singing
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directed (male/female): motor function but no analysis
undirected (male/male): motor function AND analysis =motivation/intention |
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Song Culture
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in one population: elements of culture live longer than creator, success/failure of creator not related to song (indigo bunting)
in regions: dialects = cultural drift (little environmental feedback) (white crown sparrows) overall: >65 million years ago = lots of culture |
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individual improv (songs)
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sedge wren: all sing unique song within a framework
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vocal mimicry
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Mockingbird, not territorial (other birds ignore it)
Rebecca Irwin: always juvenal, never acquire terminal song |
