Food & Habitat Selection

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 30-45 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.

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

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

25. Migration – Using Earth’s Magnetic Field

26. Green Sea Turtles

27. Green Sea Turtles

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