Download Migration and Navigation Sci Show Assignment

Migration and Navigation
Migration is …
Sci Show Assignment
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Due by 11am, April 28th!
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Password for the youtube site is: animalbehavior
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Updated instructions on how to access the youtube
channel are posted on the course website
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Any questions?
Animals migrate in response to changes in the environment • Migration
– Relatively long-distance two-way movements
the seasonal (temporary) movement b/w distant sites
Steve McSweeney
Many bird examples
19,000 km!
Migration and changing resources
some bats migrate to
hibernacula
seals often migrate twice to
feeding grounds each year
gnu head north during dry season
baleen
whales
migrate to
tropics
• In the
Serengeti,
mammals
appear to
track available
biomass of
grass and its
quality
Homing by Pacific salmon
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*
*
*
Olfactory
imprinting
*
• Salmon migrate to the
ocean for 3-5yrs to feed
before returning to natal
stream to spawn
Evidence of migration costs
Costs of Migration
1. Must accumulate
large energy stores
2. Excess mass limits
evasive ability
3. Journey may expose
animal to predators &
risk of drowning
Benefits of Migration
1. Adaptive response to
temporal variability in
climate & resource
availability
Body condition affects
migratory route in redeyed vireos
– e.g. birds come north to
capitalize on longer
day-length
– e.g. some whales
migrate to tropics to
allow their calves to
conserve energy
Resource variation and migration in neotropical birds
• Research question: What factors are important in
determining whether a species migrates or not? (Boyle
& Conway 2007)
• Hypothesis: Migration evolved to allow individuals to:
(1) take advantage of spatial variation in conditions and
(2) avoid seasonal resource depression at different
locations
• Prediction: Species exposed to high degree of fluctuation
in environmental conditions and resources will be more
likely to migrate than species that live in more stable
resource environments
Resource variation and migration in neotropical birds
• Results:
– Insectivorous species in forest habitats
were less likely to be migratory than
non-forest species
– No relationship between habitat type
and migration in frugivorous species
• Conclusion:
– Fluctuations in resource levels and
environmental conditions can affect
migratory behavior
Resource variation and migration in neotropical birds
• Methods:
– Collected previously published
data on 300 species in Tyranni
– For each species, determined:
• Migrant or sedentary
• Insectivore or frugivore
• Habitat use (tropical forest
habitats more stable than
nonforest habitats)
The evolution of migration
• If some individuals in a
population have higher
fitness when migrating,
then population may
exhibit partial migration
• If all individuals who
migrate have higher
fitness, then population
becomes migratory
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Maintenance of polymorphism in migratory
behavior
• Migratory behavior could be a fixed, genetic trait,
and frequency-dependent selection maintains the
polymorphism
• Migratory behavior is dependent on individual
condition
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Navigation: How do
animals find their way?
Animals use multiple compass systems to determine direction • Orientation
– Determination and maintenance of a proper direction
• Navigation
– Determining a particular location and moving toward it
Animals use multiple compass systems to determine direction • Orientation
– Determination and maintenance of a proper direction
• Navigation
– Determining a particular location and moving toward it
• Sun compass
– Use of sun for orientation
• Star compass
– Use of stars or constellations to orient
• Geomagnetic compass
Figure 9.14. Whale migration. (a) Gray whale. (b) Whale migration route
along the North American coast. Blue indicates southbound migration and
orange indicates northbound migration.
– Ability to orient using the earth’s magnetic field
From%Nordell%and%Valone,%Animal'Behavior:'Concepts,'Methods,'and'Applica7ons,%©%2014%by%Oxford%University%Press%%
Monarch butterfly migration
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Bicoordinate navigation in birds
• Research question: Do birds display
bicoordinate navigation? (Chenetsov, Kishkinev, &
Mouritse 2008)?
– Bicoordinate navigation: Ability to identify a geographic
location
– Mental map
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Bicoordinate navigation in birds
• Methods:
– Eurasian reed warblers
(Acrocephalus scirpaceus)
– Migrate between sub-Saharan
Africa and Eurasia
– Captured birds during spring
migration
– Displaced half 1000 km east
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Bicoordinate navigation in birds
• Methods:
– Placed in Emlen funnels to
measure orientation
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Geomagnetic compass
Bicoordinate navigation in birds
• Results:
– Displaced birds oriented to
northwest to compensate for
being displaced
• Conclusion:
– Eurasian reed warblers display
bicoordinate navigation
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Navigation and magnetic maps in sea turtles
• Research question: Do sea turtles use the earth’s
magnetic fields for navigation? (Lohmann et al.
2001)
Navigation and magnetic maps in sea turtles
• Methods:
– Juvenile loggerhead sea turtles (Caretta caretta)
– Exposed to three magnetic fields
– Measured orientation and movement
Navigation and magnetic maps in sea turtles
• Results:
– All turtles oriented to
appropriate direction
• Conclusion:
– Sea turtles can use the
earth’s magnetic field to
orient in different
directions, and this ability
is inherited, not learned
Figure 9.22. Turtle orientation apparatus. Diagram of the apparatus used to characterize
orientation direction of sea turtles. The magnetic field inside the apparatus can be changed
(Source: Lohmann 1991).
From%Nordell%and%Valone,%Animal'Behavior:'Concepts,'Methods,'and'Applica7ons,%©%2014%by%Oxford%University%Press%%
Figure 9.23. Turtle orientation. (a) Control turtles attempted to move north-northeast. (b)
When the magnetic field was reversed, turtles attempted to move toward the new position
of magnetic north-northeast. Each dot represents data for one turtle, and the mean
direction is indicated by the arrow (Source: Lohmann 1991).
Figure 9.24. Pigeon magnetoreception. When small magnets are placed on their
body, pigeons have trouble orienting properly.
From%Nordell%and%Valone,%Animal'Behavior:'Concepts,'Methods,'and'Applica7ons,%©%2014%by%Oxford%University%Press%%
From%Nordell%and%Valone,%Animal'Behavior:'Concepts,'Methods,'and'Applica7ons,%©%2014%by%Oxford%University%Press%%
Quick Review
Quick Review
In an ultimate sense, why do animals disperse?
a. To avoid competing with kin and/or conspecific
competitors of higher-quality than themselves.
b. To obtain mates with whom they are not closely
related.
c. To capitalize on seasonal food abundance and
favorable climatic conditions.
d. all of the above
e. both a and b
A young male lemming emigrates from the area
where he was born and permanently occupies a
new meadow far away. The male has exhibited …
a. natal migration
b. breeding migration
c. natal dispersal
d. breeding dispersal
e. philopatry
Quick Review
The tendency for offspring of closely related parents
to have lower fitness than offspring of genetically
unrelated parents is called __________________.
a. intraspecific competition
b. sex-biased dispersal
c. philopatry
d. inbreeding depression
e. selfish herd
Territoriality and Habitat Selection
• Territory
A territory is …
– An area defended to obtain exclusive access to the
resources it contains
a defended space
•
• Home range
Costs
•
1. ???
– Areas of repeated use that are not defended from
conspecifics
Benefits
1. ???
Territoriality
A territory is …
a defended space
•
Costs
1. reduced feeding rates
2. injury risk
3. predation risk
associated w/ displays
4. less time & energy for
parental care
•
Benefits
1. exclusive access to
food, shelter or mates
•
When is it beneficial?
1. When limited resources are clumped and
ephemeral?
2. When limited resources are uniformly distributed in
time and space?
Territoriality
• Far from universal
• Beneficial when a limited resource is uniformly
distributed in time & space
Red-winged blackbird