TABLE OF CONTENTS
LECTURE OUTLINE I. INTRODUCTION TO NAVIGATION AND MIGRATION
A. Navigation is moving a particular course toward a specific
destination
B. Migration is the seasonal movement from location to another
1. Why migrate?
a. Examples of migration
2. Species use multiple tools for successful migration
a. Example of Sockeye salmon
II. FIVE STRATEGIES IN ANIMAL NAVIGATION
A. Trail following--a simple form of navigation
1. Sockeye salmon use olfaction to find their home stream
2. Tent caterpillars use complex pheromone signals
B. Piloting--learning how to use landmarks
1. Tinbergen's Digger wasp
a. Translocation studies demonstrate the importance of landmarks
C. Path integration--continuously updating a position relative to home
1. Example: Desert ants
a. Ants use the the sun to continuously update their position
b. Translocation studies
D. Compass navigation--a compass tells you direction, such as north
1. Sun compass
a. Use of the sun's position in the sky for animal orientation
1) Examples: Fish and bird migration
b. Importance of the sun and circadian clock in orientation
1) Experimental evidence
a) Altering the sun's position changes starling orientation
b) Sun Arc Hypothesis
Clock shift experiments
2. Polarized light
a. On cloudy days bees use polarized light to forage (Bee dance)
3. Star compass
a. Not all migrating species use the sun as a cue
b. Some nocturnal migrates, such as the Indigo Bunting, use the
patterns of the stars
c. Star movement around a common center is important
1) This stellar movement is learned as nestlings
4. Magnetic compass
a. Many different animals appear to use the magnetic field
b. Transequatorial migration presents problems
E. Map and Compass navigation
1. Use of maps to tell us where we are and where we want to go
2. Animals use sun position, landmarks, noises, etc. to provide maps
3. Displacement studies suggest that maps are used
a. Adult starlings adjust to a displacement, but juveniles do not **
III. HOW DO ANIMALS KNOW WHERE THEY ARE?
A. Role for the hippocampus in spatial memory
1. Spatial memories exist in many species
a. Example 1: Spatial memory of your bedroom in darkness
b. Example 2: Clark's nutcracker that stores seeds for winter
1) Role of visual cues in seed retrieval
2. The hippocampus is critical for learning spatial relationships
a. Hippocampal lesions prevent learning the direction of a food source (pigeons)
b. Cognitive maps for food storing is lost in birds following a hippocampal lesion
b. Place cells in the hippocampus mark an animal's position
1) Firing fields (an abrupt increase in firing of specific cells)
2) Rotating the arena does affect place cell function
IV. TWO EXAMPLES ON THE COMPLEXITIES OF MIGRATION
A. Example 1: Bobolink Migration
1. Bobolink migration to South America
a. Reversing magnetic field changes migratory direction in lab
b. Blue light is critical for proper orientation to a magnetic field
c. During migration, multiple cues are probably used for orientation
(e.g., sun, magnetic fields, and landmarks)
B. Example 2: Sea Turtle Migration
1. The life cycle of loggerhead turtles
2. Navigation route in the open ocean
a. Experimental evidence that the magnetic field is important
b. Navigating to stay within the gyre
C. What don't we know?
Using the magnetic field to navigate Using a magnetite-based map to navigate USGS thorough presentation on the migration of birds
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