Habitat Selection
Habitat Selection?
Some Terms…
► Habitat
– Place where
an organism lives
► 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.
Why choose a certain habitat?
►
Why do you live where you do?
Why do animals choose a certain
habitat?
► Genetics
vs. Early Experience
Why do animals choose a certain
habitat?
► Food
► Ideal
Free
Distribution
(Manfred Milinski)
Genetics and Early 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.
How do animals pick a habitat:
Genetics and Early Experience
Factors: Early
Experience
Foraging Behavior
► Barn
Owl
► What to
eat?
More on Patch Ecology
► Risk-Sensitive
–
Animals that can tell
one patch from
another patch
 Risk-Prone:
Animals willing to
take risk
 Risk-Averse:
Animals not willing
to take the risk
Changes in the strategy: Are
animals risky or safe?
► “Risk
Prone” willing
to take risks
► “Risk-averse” avoid
risk and will take
the safer option.
Changes in the strategy:
Caraco et. al. and YellowEyed Juncos
► Birds
choose 1)
variable (0 to 6
seeds) or 2)
constant (3 seeds)
► Done at 1°C and
19°C.
► Birds are risk-averse
at 19°C, risk-prone
at 1°C.
Risk-Averse animals will go
here
1st
hour
Risk-Prone animals will go
here
1st hour
2nd hour
Patch #1
2nd hour
Patch #2
Why do animals choose a certain
habitat?
► Food
► Food
and
the Ideal
Free
Distribution
(Manfred
Milinski)
Why do animals choose a certain
habitat?
► Your
tax dollars (or
mine) at work!
► Competitive
Unit Model
Territories
► An
area actively
defended by an animal
► Why Defend?
► Anolis
► Not
Food!
► Temperature and
Predator Avoidance
Territories
► Anolis
lizard arrive quicker on experimental plots and
use the site more.
► Lizards LEARN where good habitats are by watching
others.
Territories - Conditional
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
►
Territories - Changing
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 – Defend for Mating
► Some
animals might
defend territories
for mating purpose
► Antlered flies –
defend territories on
rotten logs
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.
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
(add to
words)
► Ink on feet
mark
footprints.
► Left (spring),
Middle (fall)
Right (when
night sky is
obscured.
Factors Effecting Migration
Some populations
migrate, others do not.
► Leapfrog effect
► A does not leave.
► Further north, the
further south they
travel.
► Why?
► Might miss food, might
not return quick
enough for breeding
territory.
►
Factors effecting migration
► Sometimes
migrates
► Older, more dominate
males migrate less.
► Juveniles make the best
of what they can,
migrate until larger?
► Researchers not quite
sure.
Factors effecting migration
1) Birds with low fat
reserves (A)
2) Birds with high
fat reserves (B)
Habitat Selection in Pill Bugs
Types of Movements:
Taxis: Directed movement towards/away from a stimulus
Kinesis: Random movements
Choice Chambers
Thing to think about?
► What
do they eat?
► What eats them?