Food & Habitat Selection
Foraging Behavior
► Optimal
Foraging Theory
 What should you eat?
 Constraints?
Optimal Foraging – Reto Zach and Northwestern Crows
1) 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 Starlings
1) Eat Yellow Jacket Larva
2) How many should they get each trip?
3) Harder to get more as mouth fills
(Constraint).
Oystercatchers
1) 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 Issues
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 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?
Why?
► Food!
► Ideal
Free
Distribution
(Manfred Milinski)
► Competitive Unit
Model (Parker &
Sutherland)
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. Experience
Some Terms…
► Habitat
– Place where
an organism lives
► Patch – An area of
food
► Home Range – Area
that an organism
occupies during its life
► Territory – An area
occupied and defended
by an organism
► Migration – The long
distance movement,
and subsequent
return, from one
location to another.
Habitat - Changes due to
temperature
► Birds
Yellow-eyed Junco
choose 1)
variable (0 to 6
seeds) or 2)
constant (3 seeds)
► Done at 1°C and
Avoid Risk
19°C.
► Birds are riskaverse at 19°C,
risk-prone at 1°C.
Accept Risk
Territories – Mating
► Some
animals might
defend territories
for mating purpose
► Antlered flies –
defend territories on
rotten logs
Territory – Changes due to Rocks
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 Food
Pied Wagtail
► Eats insects
washing on
shore.
► Lots of food,
allows Satellites
(help defend
territory….have
less knowledge
of food pattern)
► Byproduct
Mutualism in
under certain
circumstances
►
Large Changes – Migration…
► When
territories or habitats change drastically
over time, what do you do?
► Migration – Long distance movement and
subsequent return from one location to another.
Body Condition affects migratory route
1) Birds with low fat
reserves (A)
2) Birds with high fat
reserves (B)
How do you know where to go?
Different animals have different abilities to
tell where they are:
► Piloting – Recognizing landmarks
► Compass Orientation – Able to tell specific
directions
►
How do you know where to go?
►
Various Sensory Abilities:
 Visual Cues
 Stars
 Magnetism
Migration – Using the Sun
► Raised
in captivity and then released:
► b) first 5 minutes of autumn migration
► a) Clock shifted butterflies fly west
► c) Natural population fly south
Migration – Using Earth’s Magnetic
Field
Green Sea Turtles
Green Sea Turtles
Migration – Using Stars
► Emlen
funnel
► Ink on feet
mark
footprints.
► Left (spring),
Middle (fall)
Right (when
night sky is
obscured.
Habitat Selection in Pill Bugs
Types of Movements:
Taxis: Directed movement towards/away from a stimulus
Kinesis: Random movements
Choice Chambers