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Published byDana Jenkins Modified over 6 years ago
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Behavioural Ecology Habitat Preference - Choosing a Place to Live
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Costs and Benefits Cost - any factor that reduces reproductive success (directly or indirectly) Benefit - any factor that increases reproductive success (directly or indirectly) Strategy - a set of behavioural courses of action with a given survival value under a particular set of conditions For a successful strategy C < B Or C/B<1
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HABITAT PREFERENCES 1. DISPERSAL 2. MIGRATION 3. TERRITORY Dispersal
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Definition - generally one-way and permanent movement of animals from
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 Natal Philopatry Natal Dispersal Costs
Migration Territory Dispersal Natal Philopatry Natal Dispersal Costs - inbreeding depression Costs - energy used in dispersal - increased competition - increased predation - lack of local familiarity Benefits - inbreeding - local familiarity Benefits - reduced inbreeding - avoid competition
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Dispersal Lions - sex dependent dispersal patterns Females Males 100
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 % of lions 100
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Dispersal Migration Territory Dispersal Migratory locust
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Dispersal Migration Territory Migration Recognized for long time
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Functional Classification
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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Migration 3. Return migration Short range Three wattled bellbird
Dispersal Migration Territory Migration 3. Return migration Short range Three wattled bellbird Procnias tricarunculata
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Migration Components Periodic timing -daily -tidal -lunar
Dispersal Migration Territory Components Periodic timing -daily -tidal -lunar -annual many years
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Migration Components 2. Track pattern Loop One direction Multispecies
Dispersal Migration Territory Components 2. Track pattern Loop One direction Multispecies
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Migration Components 3. Plane of movement 1. Horizontal 2. Vertical
Dispersal Migration Territory Components 3. Plane of movement 1. Horizontal 2. Vertical Plankton Elk
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4. Geographical direction
Migration Dispersal Migration Territory Components 4. Geographical direction -most are north - south Albatross - east -west
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Migration Components 5. Direction ratio Variation about mean direction
Dispersal Migration Territory Components 5. Direction ratio Variation about mean direction
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Processes governing 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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Increased hormone secretion
Migration Dispersal Migration Territory Processes governing migration Increased hormone secretion Change in photoperiod Gonad maturation Migration Preparation Initiation
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1) Increase fat deposition
Migration Dispersal Migration Territory Preparation 1) Increase fat deposition -rapid eating -increase in stomach volume -increase in fat load 100 80 60 40 20 Fat load (% of lean body wt) Non-migrants Short distance Mid-distance Long distance
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2) Zugenruhe - “migratory restlessness
Migration Dispersal Migration Territory Preparation 2) Zugenruhe - “migratory restlessness Before onset
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2) Zugenruhe - “migratory restlessness
Migration Dispersal Migration Territory Preparation 2) Zugenruhe - “migratory restlessness Before onset After onset
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Must determine a direction
Migration Dispersal Migration Territory Initiation Must determine a direction 1) Piloting - recognition of familiar landmarks
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Must determine a direction
Migration Dispersal Migration Territory Initiation Must determine a direction 2) Orienting - recognize and maintain compass direction
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Must determine a direction
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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Must determine a direction
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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Migration Initiation Without external cues Food item Nest Dispersal
Territory Initiation Without external cues Food item Cataglyphis Nest
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Sun Compass Kramer Starling
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Sun Compass Kramer Clear Skies Overcast
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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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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 Resident in preceding winter Migrant in preceding winter resident resident migrant migrant
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Passive dispersal
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