Migration: Biodiversity on the Move

1
Migration Biodiversity on the Move

• Overview
• Case Histories

16 November 2009
2
Definition

• The movement of animals from one place to another
  
• occurs regularly
• usual seasonal
• round-trip
• example Pacific Brandt migratory route

3
Migration known from all classes of vertebrates
and some insects

• Fish salmon, eels
• Reptiles sea turtles
• Mammals gray whale, African hoofed animals
• Birds widespread
• Amphibians California newt
• Insects butterflies, bees, beetles

4
Non-migratory geographical movements

• Emigration, immigration
• Irregular movements irruptions
• Wandering nomadism

5
Techniques for Studying Migration

• Direct Observation
• Visual
• Sound
• Preserved Specimens
• Marking
• Bands
• Radio Tracking
• Satellite Tracking
• Radar Observation
• Laboratory
• Orientation and Navigation
• Physiology of Migration

6
Migratory Patterns Birds

• Flyways and Corridors
• Patterns of Migration

7
Why migrate?

• A way to use habitats or resources that are only
  available seasonally
• Food
• Breeding areas
• Retreats from high predation

8
How did migration evolve?

• Benefits must outweigh costs.
• Possible fitness costs
• Cost of navigation mechanism
• Energetically demanding journey
• Run gauntlet of predators, conditions, diseases
• Competition with same or other species

9
Resources

• Weidensaul, Scott. 2000. Living on the Wind
  Across the hemisphere with migratory birds.
  North Point Press
• U.S. Fish and Wildlife Service