Lecture 3: Bird senses

Question 1

proximate mechanisms of behaviour, role of the senses (short pathway through body) with being late

Answer 1

• Sensory input (I SEE you are late)
• processing in brain (compare time expected, time observed)
• motor response [behaviour] (threat display)

Question 2

avian vision: human eye vs falcon eye

Answer 2

human eye: one fovea

falcon eye: two foveas (some cases fovea is strip not spot)

Question 3

sensitivity is :

Answer 3

The ability to see in poor light (owls see better than us in poor light = better sensitivity).

Question 4

Resolution is

Answer 4

The ability to resolve things, how much detail can you see? (falcons have higher resolution than we do – see better, more clearly at a distance). Resolution decreases with decreasing light levels (seeing at dusk vs on a bright clear day)

Question 5

in vertebrates eyes theres a trade of between

Answer 5

sensitivity & resolution and a limit to eye size

Question 6

cock of the Rock (female and male differences )

Answer 6

male in light: glows
male in dark: almost cryptic
-female: orangey colour
–>Sexual selection

Question 7

cone cells in the avian retina

Answer 7

contain a colour oil droplet, allowing them to see a greater array of colour

Question 8

cone cells types in birds and other taxa

Answer 8

humans: have 3 type of cone cells (3 types of photoreceptors that translate light into nervous impulses)
birds: have 4, can see in UV as well.

Question 9

Why is ultraviolet vision important?

Answer 9

• Urine trails

- Male quality

Question 10

avian and human hearing compared:

Answer 10

pretty similar in hearing

Question 11

where is hearing processed?

Answer 11

cochlea

Question 12

avian cochlea:

Answer 12

• straighter than humans

- hair cells range in height from tall to short

Question 13

can birds go deaf ?

Answer 13

no, they have the ability unlike humans to repair the hair cells in the cochlea

Question 14

touch receptor (ultra structure) in a ducks beak:

Answer 14

• sensitive as fingertips
• contains blood vessels, grandry corpusles, herbst corpuscles.
• pitted bits all round the outside

Question 15

avian smell: do they smell?

Answer 15

• generally assumed birds have no sense of smell
• But, anatomical evidence suggests some birds do
• anatomical evidence: olfactory bulb size & complex nasal conchae

Question 16

nasal conchae in birds:

Answer 16

more curled, greater SA, better smell

Question 17

olfactory bulb in lesser honeyguide:

Answer 17

for its body size has large olfactory bulb

Question 18

comparative study of olfactory bulb sixe in birds:

Answer 18

In 1960s Bang & Cobb measured linear dimensions of olfactory bulbs in 107 bird species (Note: no control for phylogeny or allometry)
Largest olfactory bulb occurred in the Snow Petrel

Question 19

An olfactory seascape:

Answer 19

Certain albatrosses and petrels can smell DMS ~ dimethyl sulphide, released from predated plankton, to locate feeding areas

Question 20

turkey vulture sense of smell:

Answer 20

can smell ethyl mercaptan (aka methanethiol) from carcasses

Question 21

who studied taste in sensory apparatus of the mallard’s bill including taste buds

Answer 21

Herman Berkhoudt in 1981

Question 22

location of taste buds inside a duck’s mouth:

Answer 22

• none on the tongue
• upper mandible
• -one at tip
• • 3 set further back
• lower mandible
• -one at tip

taste buds are surround an opening to a salivary gland (req moisture) mallards have about 450 taste buds on inside of upper and lower bill

Question 23

mechanical events for which ducks eat:

Answer 23

• grasp at tip
• stationing (to taste)
• throw back (catch)
• taste
• transfer back
• collection