Food & Habitat Food & Habitat Selection Selection
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