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Food & Habitat Selection

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Presentation on theme: "Food & Habitat Selection"— Presentation transcript:

1 Food & Habitat Selection

2 Foraging Behavior Optimal Foraging Theory What should you eat?
Constraints?

3 Optimal Foraging – Reto Zach and Northwestern Crows
Large Whelks break more easily than small ones Drops of 5 meters best Large Whelks 2.0 Kcal, 0.5 to open. Medium Whelks, 0.3 Kcal loss.

4 European Starlings Eat Yellow Jacket Larva
How many should they get each trip? Harder to get more as mouth fills (Constraint).

5 Oystercatchers Lots of small and large mussels available
Can not open the large ones (Constraint) Next size down 50 mm have too many barnacles Select mm range

6 Garden Skink – Predator Issues
Many Factors can influence optimality: Presences of Predators Control-scented lizards spent more time in open habitat grew faster in the first 6 months

7 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.

8 Habitat Selection?

9 Why? Food! Ideal Free Distribution (Manfred Milinski)
Competitive Unit Model (Parker & Sutherland)

10 Genetics? Experience? Males and Females raised on Cellulose or Cedar bedding Males generally prefer what they are raised on. Females generally prefer cedar by at least the third day. Older females switch to cedar faster than younger females. Males influenced by early experience whereas females are more influenced by genetics.

11 Genetics vs. Experience

12 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. Some Terms…

13 Habitat - Changes due to temperature
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. Avoid Risk Yellow-eyed Junco Accept Risk

14 Territories – Mating Some animals might defend territories for mating purpose Antlered flies – defend territories on rotten logs

15 Territory – Changes due to Rocks
Side-Blotched Lizard Defend Rocky Territories Less Rocks, larger territories More Rocks, smaller territories more competition. Average 1 female in both

16 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

17 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.

18 Body Condition affects migratory route
Birds with low fat reserves (A) Birds with high fat reserves (B)

19 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

20 How do you know where to go?
Various Sensory Abilities: Visual Cues Stars Magnetism

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23 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 P445. (A) clock shifted birds fly west. B) Laboratory raised butterflies who were raised on a normal light-dark cycle for autumn fly south (C) Butterflies from natural populations fly south. A is the experiment and B is the control that shows you can raise them under artificial conditions that mimic natural sunlight conditions. Normal condition = fly south in the fall (as winter approaches). Clock shifted (A)….they think that summer is approaching and they are moving towards a north migration.

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25 Migration – Using Earth’s Magnetic Field
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26 Green Sea Turtles 26

27 Green Sea Turtles 27

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29 Migration – Using Stars
Emlen funnel Ink on feet mark footprints. Left (spring), Middle (fall) Right (when night sky is obscured.

30 Habitat Selection in Pill Bugs
Types of Movements: Taxis: Directed movement towards/away from a stimulus Kinesis: Random movements

31 Choice Chambers


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