Lecture 9

Question 1

Visual navigation cues

Answer 1

Landmarks
Navigating by stars
Using the sun as a compass
Polarised light

Question 2

Non visual navigation cues

Answer 2

Magnetoreception
Olfaction 
Wind and ocean currents
Genetic cues
Infrasound
Auditory cues

Question 3

Migration

Answer 3

Oriented, long-distance, seasonal movement of individuals (Able, 1980)
Persistent form of locomotion that is direct, straight and unwavering
Movement of much longer duration than seen in day-to-day activities
Seasonal movement, where different environmental endpoints serve different functions
Movement that results in the spatial redistribution of a population (Taylor, 1986)

Question 4

Benefits of migration

Answer 4

Reduced predation
Avoid adverse climatic conditions
Access to higher quality food
Access to mates

Question 5

Costs of migration

Answer 5

Increased energy expenditure
Exposure to severe weather
Increased predation
Competition of territories

Question 6

Endogenous control (of migration)

Answer 6

Arising from factors that originate within the animal, and rather little on learning (Gwinner, 1972)
Birds build up fat deposits before migration
Become restless if prevented from migrating
Berthold (1998) called these endogenous circannual rhythms

Question 7

What bird species was used to show that migratory behaviour has a strong genetic component?

Answer 7

Black cap (Sylvia atricapilla)
Berthold et al. 1990

Question 8

Chemical cues: salmon

Answer 8

Use chemical signals to migrate back to their natal streams
Anadromous
Streams have unique chemical odour
Juvenile salmon IMPRINTED chemically on home stream

Question 9

Using sun as compass

Answer 9

Known as ephemeris function: must have a stored representation of how sun moves across sky at the current location and season

Question 10

How do birds orientate?

Answer 10

With a magnetic compass calibrated daily from twilight cues