Food & Habitat Selection. Foraging Behavior ► Optimal Foraging Theory What should you eat? ...

Food & Habitat Food & Habitat SelectionSelection

Foraging BehaviorForaging Behavior

►Optimal Foraging TheoryOptimal Foraging Theory What should you eat?What should you eat? Constraints?Constraints?

Optimal Foraging – Reto Zach and Northwestern Crows1) Large Whelks break more easily than small ones

2) Drops of 5 meters best

3) Large Whelks 2.0 Kcal, 0.5 to open.

Medium Whelks, 0.3 Kcal loss.

European StarlingsEuropean Starlings1) Eat Yellow Jacket Larva

2) How many should they get each trip?

3) Harder to get more as mouth fills (Constraint).

OystercatchersOystercatchers1) Lots of small and

large mussels available

2) Can not open the large ones (Constraint)

3) Next size down 50 mm have too many barnacles

4) Select 30-45 mm range

Garden Skink – Predator Garden Skink – Predator IssuesIssues

Many Factors can influence optimality:

1) Presences of Predators

2) Control-scented lizards spent more time in open habitat grew faster in the first 6 months

Communicating about Communicating about Food…Food…

Round Dance – When Food is within 50 meters

Waggle Dance – Food is further away. Waggle indicated distance, direction is degrees to from sun.

In hive, dance is done vertically, uses gravity.

Habitat Selection?Habitat Selection?

Why?Why?

► Food! Food! ► Ideal Free Ideal Free

DistributionDistribution (Manfred Milinski)(Manfred Milinski)

► Competitive Unit Competitive Unit Model (Parker & Model (Parker & Sutherland)Sutherland)

Genetics? Experience?Genetics? Experience?1) Males and Females

raised on Cellulose or Cedar bedding

2) Males generally prefer what they are raised on.

3) Females generally prefer cedar by at least the third day.

4) Older females switch to cedar faster than younger females.

5) Males influenced by early experience whereas females are more influenced by genetics.

►Genetics vs. ExperienceGenetics vs. Experience

Some Terms…Some Terms…►HabitatHabitat – Place where – Place where

an organism livesan organism lives► PatchPatch – An area of – An area of

foodfood►Home RangeHome Range – Area – Area

that an organism that an organism occupies during its lifeoccupies during its life

► TerritoryTerritory – An area – An area occupied and defended occupied and defended by an organismby an organism

►MigrationMigration – The long – The long distance movement, distance movement, and subsequent return, and subsequent return, from one location to from one location to another.another.

Habitat - Changes due to Habitat - Changes due to temperaturetemperature

► Birds choose 1) Birds choose 1) variable (0 to 6 variable (0 to 6 seeds) or 2) seeds) or 2) constant (3 seeds)constant (3 seeds)

►Done at 1Done at 1°C and °C and 19°C.19°C.

► Birds are Birds are risk-risk-averse averse at 19°C, at 19°C, risk-prone risk-prone at at 11°C. °C.

Accept Risk

Avoid Risk

Yellow-eyed Junco

Territories – MatingTerritories – Mating

►Some animals Some animals might defend might defend territories for territories for mating purposemating purpose

►Antlered flies – Antlered flies – defend territories defend territories on rotten logson rotten logs

Territory – Changes due to Territory – Changes due to RocksRocks

Side-Blotched Lizard

1) Defend Rocky Territories

2) Less Rocks, larger territories

3) More Rocks, smaller territories more competition.

4) Average 1 female in both

Territories – Changes due to Territories – Changes due to FoodFood

► Pied WagtailPied Wagtail► Eats insects Eats insects

washing on washing on shore.shore.

► Lots of food, Lots of food, allows allows Satellites (help Satellites (help defend defend territory….have territory….have less knowledge less knowledge of food pattern)of food pattern)

► Byproduct Byproduct Mutualism in Mutualism in under certain under certain circumstancescircumstances

Large Changes – Migration…Large Changes – Migration…►When territories or habitats change When territories or habitats change

drastically over time, what do you do?drastically over time, what do you do?►Migration – Long distance movement and Migration – Long distance movement and

subsequent return from one location to subsequent return from one location to another.another.

Body Condition affects migratory Body Condition affects migratory routeroute

1) Birds with low fat reserves (A)

2) Birds with high fat reserves (B)

How do you know where to How do you know where to go?go?

► Different animals have different Different animals have different abilities to tell where they are:abilities to tell where they are:

►Piloting – Recognizing landmarksPiloting – Recognizing landmarks►Compass Orientation – Able to tell Compass Orientation – Able to tell

specific directionsspecific directions

How do you know where to How do you know where to go?go?

► Various Sensory Abilities:Various Sensory Abilities: Visual CuesVisual Cues StarsStars MagnetismMagnetism

Migration – Using the SunMigration – Using the Sun► Raised in captivity and then released:Raised in captivity and then released:► b) first 5 minutes of autumn migrationb) first 5 minutes of autumn migration► a) Clock shifted butterflies fly westa) Clock shifted butterflies fly west► c) Natural population fly southc) Natural population fly south

Migration – Using Earth’s Migration – Using Earth’s Magnetic FieldMagnetic Field

Green Sea TurtlesGreen Sea Turtles

Green Sea TurtlesGreen Sea Turtles

Migration – Using StarsMigration – Using Stars

► Emlen Emlen funnel funnel

► Ink on feet Ink on feet mark mark footprints.footprints.

► Left (spring), Left (spring), Middle (fall)Middle (fall)

Right (when Right (when night sky is night sky is obscured.obscured.

Habitat Selection in Pill Bugs

Types of Movements:

Taxis: Directed movement towards/away from a stimulusKinesis: Random movements

Choice Chambers