Behavioural Ecology Habitat Preference - Choosing a Place to Live

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

HABITAT PREFERENCES 1. DISPERSAL 2. MIGRATION 3. TERRITORY Dispersal

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

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

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

Dispersal Migration Territory Dispersal Migratory locust

Dispersal Migration Territory Migration Recognized for long time

Functional Classification Dispersal Migration Territory Migration Functional Classification 1. Exploratory Dispersal 2. Removal 3. Return migration 4. One-way migration

Dispersal Migration Territory Migration 3. Return migration Long range

Migration 3. Return migration Short range Three wattled bellbird Dispersal Migration Territory Migration 3. Return migration Short range Three wattled bellbird Procnias tricarunculata

Migration Components Periodic timing -daily -tidal -lunar Dispersal Migration Territory Components Periodic timing -daily -tidal -lunar -annual - 1 - many years

Migration Components 2. Track pattern Loop One direction Multispecies Dispersal Migration Territory Components 2. Track pattern Loop One direction Multispecies

Migration Components 3. Plane of movement 1. Horizontal 2. Vertical Dispersal Migration Territory Components 3. Plane of movement 1. Horizontal 2. Vertical Plankton Elk

4. Geographical direction Migration Dispersal Migration Territory Components 4. Geographical direction -most are north - south Albatross - east -west

Migration Components 5. Direction ratio Variation about mean direction Dispersal Migration Territory Components 5. Direction ratio Variation about mean direction

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

Increased hormone secretion Migration Dispersal Migration Territory Processes governing migration Increased hormone secretion Change in photoperiod Gonad maturation Migration Preparation Initiation

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

2) Zugenruhe - “migratory restlessness Migration Dispersal Migration Territory Preparation 2) Zugenruhe - “migratory restlessness Before onset

2) Zugenruhe - “migratory restlessness Migration Dispersal Migration Territory Preparation 2) Zugenruhe - “migratory restlessness Before onset After onset

Must determine a direction Migration Dispersal Migration Territory Initiation Must determine a direction 1) Piloting - recognition of familiar landmarks

Must determine a direction Migration Dispersal Migration Territory Initiation Must determine a direction 2) Orienting - recognize and maintain compass direction

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

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

Migration Initiation Without external cues Food item Nest Dispersal Territory Initiation Without external cues Food item Cataglyphis Nest

Sun Compass Kramer Starling

Sun Compass Kramer Clear Skies Overcast

Changing position of the sun in the sky - azimuth

Star Compass

Polarized light

Polarized light 0900 Dawn = area of darkness =plane of polarized light 1200

Magnetic field

Magnetic field

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

Migration as a conditional strategy Turdus merula Resident in preceding winter Migrant in preceding winter resident resident migrant migrant

Passive dispersal