Lecture 8

Front 1

What do birds eat?

Back 1

OmnivoresGranivores (few obligate)CarnivoresFrugivoresNectarivoresInsectivoresHerbivoresPiscivores

Front 2

Bird's Bill Morphology

Back 2

Rhamphotheca

- karatin layer

- worn down and replaced

Tomia

-Cutting edge underneath

Bony layer underneath

Front 3

Flamingo Beaks

Back 3

Lamellae

Filter tiny food from water

Front 4

Swift Beaks

Back 4

Aerial Insectivores

Wide gape

Front 5

Eagle and Hawk Beaks

Back 5

Diurnal raptors (hunt in the day)

hook like for tearing

Front 6

Shoveler Beaks

Back 6

Spatula shaped

Filter mud and water

Front 7

Crossbill Bills

Back 7

"crossed bill"

extract seeds from pine cones

Front 8

Heron Bills

Back 8

Spear fish and amphibians

Front 9

Avocet Bills

Back 9

Up curved

Sweep side to side in the water to get small invertebrates

Or use it like forceps

Front 10

Woodpecker Bills

Back 10

Chop wood to expose insects, insect larvae or sap

Front 11

Wren bill

Back 11

Capture small insects

Front 12

Curlew Bills

Back 12

Probe mudflats for small invertebrates

Front 13

Hawfinch Bills

Back 13

Seed eaters

Crack them open

Front 14

Macaw Bills

Back 14

Strong, hook like

Feed on Nuts

Front 15

Variation of bill morphology in shorebirds:

Plovers

Back 15

Variation allow probing in sand and mud at different lengths

Short bills

small invertebrates on surface

Front 16

Variation of bill morphology in shorebirds:

Common Redshanks and waders

Back 16

Moderate bill lengths

Top 4 m

Worms, bivalves, crustacea

Front 17

Variation of bill morphology in shorebirds:

Curlews and Godwits

Back 17

Deep burrowing prey

Lug-worms

Front 18

What does different style and size of raptors mean for the increase of prey hunting efficiency for each species

Back 18

No geographical overlap

Diff size prey

diff habitats

hunt at diff times of day

Front 19

Shrikes feeding mechanism

Back 19

Eat small vertebrates

Use large plant spines to help tear prey

Front 20

Kea's feeding mechanism

Back 20

video

Front 21

Kingfisher's feeding mechanism

Back 21

video

Front 22

Skimmer's feeding mechanism

Back 22

Movie

Front 23

Aerial Insectivores: Pure courser

Back 23

Swifts

Fly efficiently

Maintain high speed

Front 24

Aerial Insectivores: Pure Hawker

Back 24

Flycatcher

Need perches near prey

Accelerate rapidly

Very manuverable

Front 25

Aerial Insectivores: Hawking courser

Back 25

Swallows

Combining both methods (Courser and Hawker)

Front 26

Flush-pursuit foragers

Back 26

Flash the white pattern of their tail

Startles insects

Catch them

Front 27

Cattle Tyrant Feeding Mechanism

Back 27

Sits on the back of Capybara

Catches the insects it turns over

Front 28

Oxpeckers Feeding Mechanism

Back 28

Pick ticks off animals

Front 29

Dippers Feeding Mechanism

Back 29

Eat aquatic insects

Haven't aquired aquatic morphology adaptations

Oily feathers create an air bubble around them while diving (acts as insulation)

Front 30

Woodpeckers Tongue Feeding Mechanism

Back 30

Modified tongue: long, extensible, & 'barbed' at the tip to facilitate the capture and extraction of prey (like insect larvae) from bark crevices

Harpoon like

Modified hyoid apparatus attached

Front 31

Acorn Woodpeckers Feeding Mechanism

Back 31

Collect acorns at place in little holes in the tree trunk - Called "granaries"

Front 32

Sapsuckers Feeding Mechanism

Back 32

Peck small, precise divits in the bark - leads to leakage of sap and trapping on insects

(Some other animals steal it often)

Front 33

Nectar feeders

What birds are they

Their tongue morphology (nectar transport mechanisms)

Back 33

hummingbirds, sunbirds, spiderhunters, & honeycreepers

tongues

(brushy tips that "lap" the nectar up???)

- Old idea: Capillary action (tiny tubes that draw up the nectar but don't really move)

- New idea: Tongue tip is biforcated and traps nectar by rapidly changing their shape during feeding (opens and closes)

Front 34

Rainbow Lorikeets

Back 34

Movies

Front 35

Hummers and Flowerpiercers

Back 35

Movies

Front 36

Honeydew

Back 36

Movie

Front 37

Green backed Firecrow

Back 37

Need to have a balance of nitrogen and nectar

Have to supplement diet with fruitflies (protein)

(though challenging since a lot of energy hummingbird to catch flies)

Front 38

Canada geese

Back 38

Herbivores

Movie

Front 39

Behavioural Adaptations:

Seasonal Variation in Diet

Back 39

With change the ratio of different foods throughout the year in different seasons

Front 40

Behavioural Adaptations:

Food Caching

Back 40

Like the shrike's and acorn woodpeckers - aquire and store food for later

Front 41

Avian Geophagy

Back 41

Geese, parrots, cockatoos, pigeons, cracids, passeriforms, hornbills, & cassuaries

Consume dirt, gravel, clay

For digestion aid (absorb toxins or break down food)

Diet supplement (Minerals)

Front 42

How Birds try and have a "Balanced Energy Budget"

(Foraging and choosing foods to intake)

Back 42

Make energy intake = energy expenditure

- Maximize energy intake

- Choose wisely among alternative foods

- Minimize foraging time, be efficient

(dangerous and energy expensive)

Front 43

Obesity

Back 43

Rare

Only in premigratory time

Front 44

How to forage for food optimally

What question do they "ask" themselves

and what trend can you expect at food patch sites

Back 44

1. Are selective, pick the most optimal of foods if there are many choices available (size, easiness to catch)

2. At a food resource station (eg a Berry patch)

- Time (0)

Rate of finding food high

- Time (increasing)

Rate of finding food is diminishing
(but some still present)

Cost of leaving station = travel cost

Optimal time to move from station?

Time when there is a balance is reached between cost of travel and lowered feeding rate at station

Front 45

Foraging optimally means?

Back 45

Foraging optimally means decreased time foraging (so less danger and energy expenditure) with highest yield of food collected

Front 46

How are Whitewag tails optimal feeders

Back 46

Selective of the flies they catch

Medium sized fly, not the biggest) because

easiest for them to catch

(overall bigger reward)

Front 47

Costs and Rewards of Being Fat in the Winter

Back 47

Being Fat Cons

Slower = caught by predator

Takes more energy to fly (less aerodynamic)

Being Fat Pros

Fuel for flight

Thermoregulation

Won't starve

Front 48

Interrupted Foraging Hypothesis

Back 48

should be fat with higher predation rates because it allows you to survive less predictable feeding times

Experiment with Great Tits

Contradicted this hypothesis

Increased risk decreased the amount of fat

Front 49

Bully Hypothesis

Back 49

dominant birds should carry less fat because they have more predictable access to food and subordinate birds should carry more fat

Experiment with Great Tits

Supported this hypothesis (Dominant birds can regulate their fat)