Habitat Preference - Choosing a Place to Live - Migration

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Habitat Preference - Choosing a Place to Live -
Migration
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Dispersal Migration Territory
HABITAT PREFERENCES
1. DISPERSAL
2. MIGRATION
3. TERRITORY
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Passive dispersal
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Dispersal Migration Territory
Dispersal
Definition - generally one-way and permanent
movement of animals from one place to another
Natal Philopatry vs Natal Dispersal
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Dispersal Migration Territory
Dispersal
Natal Dispersal
Natal Philopatry
Costs - energy used in dispersal
Costs - inbreeding depression
- increased predation
- increased competition
- lack of local familiarity
Benefits - inbreeding
Benefits - reduced inbreeding
- local familiarity
- avoid competition
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Dispersal Migration Territory
Dispersal
Lions - sex dependent dispersal patterns
Remain in pride
Females
Males
Form new pride
Transfer to another pride
Nomads
Left area
Died
Disappeared
0
100
of lions
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Dispersal Migration Territory
Dispersal
Inbreeding Depression
- field mice
Outbreeding mothers
not breeding
Inbreeding mothers
Days since mating
Margulis Altman. 1997. Anim. Beh.54 397
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Dispersal Migration Territory
Dispersal
Inbreeding Depression
Seychelles warbler - Acrocephalus sechellensis
.7 .6 .5 .4 .3 .2 .1 0.0
Closely related r gt.35)
Moderately related - .1 lt r lt.35)
related breeders in adjacent territories
Dispersal distance
Eikenaar et al. 2008 J. Evol. Biol. 21 1106
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Dispersal Migration Territory
Dispersal
Outbreeding Depression
- song sparrow
Females





Discrimination
Males


Distance apart
signficantly different from random
Searcy et al, 2002
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Dispersal Migration Territory
Dispersal
Schistocerca gregaria - migratory locust
signficantly different from random
Searcy et al, 2002
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Dispersal Migration Territory
Dispersal
Schistocerca gregaria - migratory locust
signficantly different from random
Searcy et al, 2002
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Dispersal Migration Territory
Dispersal
Solitary Dispersing
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Dispersal Migration Territory
Migration
Recognized for long time
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Dispersal Migration Territory
Migration
Functional Classification
1. Exploratory
Dispersal
2. Removal
3. Return migration
4. One-way migration
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Dispersal Migration Territory
Migration
3. Return migration
Long range
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Dispersal Migration Territory
Migration
3. Return migration
Short range
Three wattled bellbird Procnias tricarunculata
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Migration
Dispersal Migration Territory
Components

• Periodic timing
• -daily
• -tidal
• -lunar
• -annual - 1 - many years

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Migration
Dispersal Migration Territory
Components
2. Track pattern
Loop
One direction
Multispecies
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Migration
Dispersal Migration Territory
Components
3. Plane of movement
1. Horizontal
2. Vertical
Plankton
Elk
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Migration
Dispersal Migration Territory
Components
4. Geographical direction
-most are north - south
Albatross - east -west
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Migration
Dispersal Migration Territory
Components
5. Direction ratio
Variation about mean direction
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Migration
Dispersal Migration Territory
Processes governing migration
W. Rowan (1925)
Treatment Response
Control Natural winter daylength No gonad growth No migration
Experimental Increased Photoperiod (simulate spring) Gonad growth Northward migration (even in winter)
Junco
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Migration
Dispersal Migration Territory
Processes governing migration
Increased hormone secretion
Change in photoperiod
Gonad maturation
Migration
Preparation
Initiation
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Migration
Dispersal Migration Territory
Preparation
1) Increase fat deposition
-rapid eating
-increase in stomach volume
-increase in fat load
100 80 60 40 20 0
Fat load ( of lean body wt)
Non-migrants
Short distance
Mid-distance
Long distance
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Migration
Dispersal Migration Territory
Preparation
1) Increase fat deposition
Level of reserve can affect direction
e.g. red eyed vireo
Lean birds
Fat birds
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Migration
Dispersal Migration Territory
Preparation
2) Zugenruhe - migratory restlessness
Before onset
After onset
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Migration
Dispersal Migration Territory
Initiation
Must determine a direction
1) Piloting - recognition of familiar landmarks
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Migration
Dispersal Migration Territory
Initiation
Must determine a direction
2) Orienting - recognize and maintain compass
direction
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Migration
Dispersal Migration Territory
Initiation
Must determine a direction
3) True Navigation - identification of home
from any direction
Need a) map sense - determine location relative
to goal
b) compass sense - maintain direction relative
to position
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Migration
Dispersal Migration Territory
Initiation
Must determine a direction
How do you tell an orienting from a navigating
animal??
Move animal
Move animal
Orienting
Navigating
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True Navigation in Lobsters
Pagurus
Boles Lohmann, 2003. Nature 421 60
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Migration
Dispersal Migration Territory
Initiation
Without external cues
Food item
Cataglyphis
591 m
140 m
Nest
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Migratory Cues - Sun Compass
Kramer
Starling
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Sun Compass
Kramer
Overcast
Clear Skies
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Is there an internal clock?
45º
45º
45º
Direction at 0900 under natural sky
Direction at 1500 under natural sky
Direction at 1500 under natural sky after
biological clock is delayed by 6h
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Changing position of the sun in the sky - azimuth
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Star Compass
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Polarized light
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Polarized light
0900
Dawn
area of darkness
plane of polarized light
1200
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Magnetic field
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Magnetic field
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Magnetic field
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Magnetic field
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Migrating in groups
Naïve birds singly
Group experiment
Experienced birds singly
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Migrating in groups
Energetic costs
Pelicans
100 50 10


Wingbeats /min

Heart beats /min
Gliding Alone (50 m) Alone (1m) In
formation
Weimerskirch et al, 2001
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Migrating in groups
Energetic costs
Pelicans
1
2
3
4
5
6
100 50 10


1

Wingbeats /min





2
3
6
4
5

Heart beats /min
Gliding Alone (50 m) Alone (1m) In
formation
Weimerskirch et al, 2001
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Evolution of Migration
1. Higher incidence in ephermeral or unstable
habitats
2. Reproduction - allows exploitation of
seasonally rich food supply
3. Predation and reproductive synchrony
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Migration as a conditional strategy
Turdus merula
European blackbird
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Migration as a conditional strategy
Turdus merula
Resident in preceding winter
Migrant in preceding winter
resident
resident
migrant
migrant
Male
Female
Male
Female