Food & Habitat Selection

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

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.

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

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

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

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? 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.

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. Some Terms…

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

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 Defend Rocky Territories Less Rocks, larger territories More Rocks, smaller territories more competition. 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 Birds with low fat reserves (A) 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 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.

Migration – Using Earth’s Magnetic Field 25

Green Sea Turtles 26

Green Sea Turtles 27

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