Lecture Exam 4 Flashcards
What are the characteristics of birds?
- Endothermic reptiles w/scales on legs
- All lay eggs, no live birth
- Two legs
- Feathers
- Keratinized beak
- One-way respiration w/air-sacs
What features are unique to birds?
idk
How do birds breathe?
One-way respiration w/air-sacs. Take two breaths for air to move all the way through the respiratory system
What are the different parts to feathers?
- Rachis – the central shaft of the feather
- Quill – the anchor point of the feather
- Vane – major portion of the feather
- Barbs – part of the vane that comes off the rachis
- Barbules – split perpendicularly from the barb
- Hooks and catches – on nearby barbules hold the barbs together
What are feathers made of?
- Keratin (90%)
- Water (8%)
- Lipids (1%)
- Other proteins and pigments (1%)
What are the purposes of feathers?
- First evolved for insulation
- Flying
- Camouflage
- Communication
- Waterproofing
What are pterylae and apteria?
Pterylae - Regions of body w/feathers
Apteria - Regions of body w/o feathers
What are the different types of contour feathers?
- Flight feathers
2. Covert Feathers
What is the function of down feathers?
Insulation
What is the function of Semiplumes?
Insulation for adult birds
What is the function of Filoplumes?
Detect air displacement while flying
What is the function of Bristles?
Protective/sensory hairs on face
What is a biochrome pigment?
Natural compounds that absorbed certain wavelengths of light
What are the different types of pigments seen among birds?
- Carotenoids - Yellow, red, and orange
- Porphyrins - Bright brown and magenta
- Melanins - Eumelanins - Greys and blacks
- Pheomelanins - Brown and tans
How do birds get their red/orange/yellow pigments?
Carotenoids
What are structural colors?
Air pockets w/in the feather vanes creates iridescence. Air pockets amplify certain wavelengths of light and mute others (create a prism!)
How do birds make iridescent green feathers?
“green” feathers are made from structural blue over yellow carotenoid pigments
Why do bird feathers reflect UV light?
Sexes that look similar to us, look different to each other under UV light. It helps birds differentiate.
What is the function of the keeled sternum?
increased muscle attachment
What is the function of the pygostyle?
Fused tailbone for tail feather attachment
What are the four forces involved in flight?
- Lift
- Weight
- Thrust
- Drag
What muscle is responsible for the powerful downstroke of bird flight?
Pectoralis Major
What muscle brings the wings back up? Where is it located?
Supracoracoideus, the chest
What is the angle of attack, and how does it help with flying?
The orientation of the wing in a current of air.
Increased angle=greater lift
How do birds land?
- Adjust their AoA
- Spread their tailfeathers
- Rotate their legs outward - Must be done close to the ground or the bird will stall-out too soon and fall
How do the feet of birds vary depending on their environment and/or mode of locomotion?
- Walking - Standard 4-toed foot
- Running - Fewer toes
- Swimming - Webbed feet or toes
- Wading - Very long and skinny toes to displace body weight in water
- Climbing - 2 toes in front, 2 toes in back
- Grasping - Large talons w/claws to grab and shred prey
- Perching - Small toes stay clenched shut, 3 in front, 1 in back
How do the beaks (and tongues) vary between the different diets of birds?
- Generalists - Have beaks that can seize both animal and plant foods (American Robin)
- Fish-eating - Have long beaks w/hook at tip (Cormorant)
- Large-seed eaters - Large, stout beaks (Cardinals)
- Probers - Gather aquatic inverts w/long pointed beaks (Sandpipers)
- Filter-feeders - Eat small aquatic organisms w/sieve-like structures around beak (Flamingo)
- Dip-netting - Lower jaw used to scoop water and prey (Pelican)
- Raptorial - Large, hooked beak to tear flesh (Hawks)
- Scavenging - Large, hooked beak w/large nostrils (turkey vulture)
- Chiseling - Sturdy pointed beak used to pierce wood (woodpeckers)
- Fruit-eating - Large bills used to gather and handle fruit (toucans)
What is the purpose of the crop, proventriculus, gizzard, and cecum of birds?
- Crop - Enlarged region of the esophagus for food storage and transportation to babies
- Proventriculus - Secretes digestive enzymes
- Gizzard - Hard and muscular, squeezes and grinds food w/small rocks
What traits do birds have to help with vision?
- Large eyes
- Optic lobes
- Cerebellum
How many cone cells do birds have? How many do mammals have?
Birds - 4
Mammals - 3
How does visual acuity and flicker-fusion frequency differ between birds and humans?
- Visual acuity (sharpness) varies
o Wedge-tailed eagles see 2.5x better than humans
o Falcons are on par w/humans
o Pigeons may be inferior - Flicker-fusion frequency of humans is 60Hz, but it is up to 145Hz in birds, allowing them to “see faster”
How does the cochlea of bird differ from that of mammals?
Cochlea (inner ear organ) are about 10% the size of mammals
How does the asymmetrical skull of owls help them to catch prey in complete darkness?
Many have asymmetrical skulls for directionality
How do birds use olfaction in nature?
- Homing pigeons depend on olfaction when returning to their roosts
- Many seabirds are consuming floating plastics in the ocean. Plastic is covered in bacteria that release dimethyl sulfide, which smells like krill
- Vultures smell carcasses at great distances. Olfactory bulbs are 25% of brain
- Kiwis use nostrils at the tip of their beak. Stick beak in dirt to sniff-out earthworms
Why do birds make vocalizations?
- Sounds connect individuals over long distances and thru vegetation
- Some species can identify individuals by their sounds
- Demonstrate territoriality
- Mate attraction and courtship
What are non-vocal sounds?
- Stomping
- Flapping
- Tail slapping
- Woodpecker drumming
What is the syrinx?
Where bottom of trachea meets the two bronchi, used to vocalize instead of vocal chords.
How do the trachea and larynx help with vocalization?
- Mammals have vocal cords in larynx
2. Trachea length also affects the sounds produced
How do birds control their syrinx and the tones of their songs?
Muscles contract the sides of syrinx as air passes through it. Birds control sound by flaring and closing their throat and beak
What is the difference between calls and songs?
- Calls are simple and brief
2. Songs are long and complex
Which birds inherit their songs?
o Chickens, doves, flycatchers
How do birds learn songs?
- Sensory learning phase
- Listen to songs of dad and nearby males
- Auditory feedback
- Sensorimotor phase
- Produce own song practicing until it’s right
- Like a baby babbling
- Song eventually becomes crystallized
What are dialects?
Regional differences in songs
What are open-ended learners?
Continue to learn songs throughout life
Describe reproduction in birds.
idk
Which sex is heterogametic in birds?
Females
What is the significance of calcium in the shells of bird eggs?
- Forms the skeleton and powers muscles
2. Shell thins throughout gestation - Easier for baby to break-through
Describe the coevolutionary arms race seen between brood parasites and their hosts.
idk
What are sexual selection and runaway selection?
Sexual Selection: Freq of fancy plumage, intricate songs, displays, etc. change w/reproductive success
Runaway Selection: Traits get more extreme over time - tails of the peacock
Describe some of the courtship displays seen among birds.
- Fancy plumage
- Intricate songs
- Displays/dances