Birds

Question 1

Very diverse

Answer 1

size

plumage

Habitat

Mating systems - monogamy - polygyny - polyandry (male raises young) - Polygynandry - 2 male + female

Bills

Question 2

Feathers

Answer 2

defining characteristic of birds

evolved from scales

light, soft, filamentous

Made from keratin - light - strong - waterproof

No. of feathers roughly constant for species

5 types - contour - down - semipume - filoplume - bristle

first 4 found in all

Question 3

Contour feathers

Answer 3

Give smooth round shape - outer most feathers

Flight feathers - remiges - modified contour

Tail feathers - retrices - modified

First level of defence - sun/vegetation

Colours - pigments - melanins - made by bird (black/grey/tan) - carotenoids - diet (red/organge/yellow)

Bright male = good hunter/forager

Structures for colour - reflectance - blue/green - interference using hollow structures - iridescence

Structure:

Rachis - hollow, central shaft providing backbone

Barbs - extend either side

Barbules + hooks - stiffness + flexibility - fastens feathers together

Question 4

Down feathers

Answer 4

Smaller than contour

Lack barbules + hooks

Soft + fluffy

Insulation - closest to skin

Question 5

Semiplume

Answer 5

Intermediate between contour

Help keep form

Help with insulation

Question 6

FIloplume

Answer 6

Hairlike - few barbs at tip

Covered by other feathers

Pressure + vibration receptors - many have endings

Help contour stay in correct shape + form

Question 7

Bristle

Answer 7

Stiff - few barbs

Occur round eyes + mouth of some birds

Protective/filters

Funnels for insectivores

Question 8

Feather function

Answer 8

Crypsis - blending in background - predation - anti predation

Attraction - mates - males usually brighter - stand out - females not bright to protect young

Insulation - primary evolution driving force of feathers - vital for endothermy - denser plumage in winter

Flight

Question 9

Feather care

Answer 9

Preening - most basic care - bill on feathers- clean - rearrange plumage - apply oils from uropygial gland - water proofing

Allopreening - preening each other - social function

Bathing - water - worse flying - hide after - sunning - spread out in sun - softens waxes so can be removed - anting - lie in ants that produce formic acid and deal with ectoparasites

Moulting - replaced old feathers with new ones - 1+ times a year - lot of energy - not in breeding/migrating seasons - replaced in orderly predictable sequence

Question 10

Adaptions for flight

Answer 10

feathers - lightweight - strong - streamlined - flexible

Lightening - skeleton - reduced no of bones- hollow - lack marrow - skull lost heavy jaw - beak is toothless - gizzard for grinding

Reproduction - organs enlarge seasonally - oviparous - external fertilisation

Strengthening:

• skeleton - fusion of bones - wish bone - keel extension of breast bone - anchor of flight muscles - deeper keel = more powerful flight
• muscles - pectoralis - up to 35% total weight - supracoracoideus pulls wings up

Brain + sensory organs - main sense is sight - large eyes - large brain for processing visual info

Wings - Elaborate joints - fused hand bones - powerful tendons + compact muscles - airfoil shape

Question 11

Flight mechanics

Answer 11

Acting forces - weight vs lift - drag vs propulsion

Lift generated by flow of air over wings - speed of air flow relates to pressure

Airfoil shape - air travels further over top - speeds up - decreases pressure - wing sucked upward/ shorter distance underwing- air slower - pressure increases - wing pushed upward

More curved the airfoil - greater the lift

friction drag - air flow over body

Induced drag - consequence of lift - swirling vortices created at wing tips - produces downwash

Thrust created by wing flapping - most from downstroke - simple recovery upstroke

Gliding - weight used to overcome air resistance to forward motion - heavier birds can glide further with same loss of height

Soaring - Maintain of altitude without flapping:

slope soaring - wind deflected upward by side of object

Dynamic soaring - local updrafts where wind meets waves

Thermal soaring - uneven heating of air near ground- convection currents - fly in circles within

Hovering - maintaining stationary positon:

Wind hovering - fly into headwind - use thrust to stay in same position

True hovering - wing airfoil shape in up + down stroke- humming bird

Question 12

Wing loading

Answer 12

body weight/wing area

low = large wing area for body - more efficient flight

high = small wing area for weight - energetically costly - difficulty taking off

Question 13

Aspect ratio

Answer 13

Wing area 2/ wing breadth

high = fast - low manoeuvrability

Question 14

Elliptical wing

Answer 14

Low AR - good manoeuvrability

Woodpeckers - forest raptors

Short rounded - large wing slots

Fast take off - pheasants + grouse

Large amounts of induced drag - slotting helps reduce

Question 15

High lift wings

Answer 15

Moderate AR

Broad wing

Heavily cambered

Carry heavy load - minimise energy

Terrestrial species - eagles - vultures - storks

Question 16

High speed wing

Answer 16

High AR - slender tips - no slots

Swept back

Flat profile

Ariel feeding - swallows + swifts (mate + sleep on wing)

Long migrations

Question 17

Soaring

Answer 17

Long narrow - high AR - no wing slots

reduced drag while gliding

Sea birds in wind swept environments - albatross

Question 18

Non vocal sound

Answer 18

Frigate - clacking mandibles

Snipe - special feathers

Woodpeckers - Drum on tree bark

Palm cockatoo - bangs stick on branch

Question 19

Vocal production

Answer 19

Respiratory system

Syrinx

Storks + vultures dont have - grunt + hiss

Found where trachea branches into primary bronchi

Surrounded by clavicular air sac

Internal tympanic membrane - vibrates when air passes over

sound modified by constriction of throat

100% of air converted to sound

Can use two sides independently

Thrushes - rising on one side - falling on other

Canaries - breathe through one - sing through other

Question 20

Types of vocalisation

Answer 20

Songs - limited to passeriformes - complex - important in reproduction

Dawn chorus - air is still - good transmission - fewer predators - insects less easy to find - not losing time on foraging

Calls - most species - acoustically simple - not primarily sexual - generally important in maintenance activities - both sexes call equally

Question 21

Vocal functions

Answer 21

Chicks use calls from inside egg to provide temp info - synchronise hatching - begging calls to indicate hunger

Mate attarction - sedge warblers - establish territory in reed beds - singing complex songs - variability + complexity - more likely to get mate

Danger - white browed scrubwrens - live in pairs/small groups - predator - pied currawong - eats eggs, nestlings, fledglings + adults - trill call given + additional info

Recruitment - Pied babblers - Kalahari desert - open habitat - ground digging for prey - adults give periodic purr call - attracts others to caller - share foraging patch

Defence of territory - great tits - males establish woodland territory - sing once settled - variability + complexity - less males go to territory

Duetting - Australian magpie larks