Behavioral Ecology: Movement & Orientation I.Why move? A.Types of movement B.Metapopulations II.Local Distribution A.Home Range B.Territoriality III.Migration - Mass movements A.Breeding B.Over-wintering IV.Movements of juveniles - Dispersal V.Homing/Orientation

I. Why move? Reasons to move: Mortality can be high when individuals move from one habitat to another

A. General types of movement Herps are not distributed randomly! Some places are better than others… 1)Station keeping: movements directly related to the acquisition of resources within a home range 2)Ranging behavior: exploring new habitats or resource patches 3)Dispersal: juveniles leaving their parent’s home range to find their own

B. Metapopulations – populations of populations Spatially subdivided populations

II. Local distribution of individuals A.Home ranges = area which individuals move within & do not defend from conspecifics  Association between body size & home range –Resources Food, shelter, thermoregulation sites, escape routes –Social activities Finding mates  Calculating home range – minimum polygon method

Minimum polygon method of calculating home ranges –  Measure the area that encompasses all of the outer points within which an individual occurs.  Most widely used method  Good for species living in 2D habitats  Does not take into consideration amount of time or relative frequency with which an individual might use different parts of the home range

Anolis transversalis -

Home range can vary through time/space Terrestrial amphibians, during non-breeding season have small home ranges away from water –Pond breeding species, home range breaks down during breeding events Microhabitat specificity a factor Vary w/sex & reproductive state

Resource dispersion & home range Habitat = resource patches Depleted / not depleted How rapidly will resources be replenished? –Abundant resources = limited home range –Resources renewed slowly = wider home range

Masticophis (whiptail) – has to go where the food is… Herbivores – wider food sources, but abundant…

Dermochelys coriacea Hoplocephalus bungaroides Iguana iguana

B. Territoriality Territory = area within the home range which is defended against conspecifics & other species Usually has some sort of defendable resource –Defense results in exclusivity Most often males defend territory –Direct combat –Threats –Avoidance Selection favors those that control & use resources in a way that positively influences their reproductive success

Plethodon cinereus Dendrobates pumilio Amphibians exhibiting territoriality:

III. Migration - Mass movements A. Breeding migrations Amphibians - Triggered by rainfall & temp, usually starting at night – but continuing through day Mass movements – explosive breeders, i.e. Ambystoma & Bufo move en masse to and from breeding ponds Reptiles – Vipera, Kinosternon, Chelydra, Crocodylus, Iguana, Sea turtles

Loggerhead turtle –movement monitored via satellite

B. Over-wintering movement Seeking more hospitable climate Flowing water of streams vs. frozen water of lakes/ponds

IV. Dispersal usually refers to juveniles leaving home ranges of parents to find a home of their own, reasons to disperse: Costs =

V. Homing Behavior Ability of displaced individuals to return to their original location – animals must be able to sense the direction they are moving

ORIENTATION Pilotage - orientation with respect to fixed landmarks home

Mechanisms of orientation Local environmental cues (landmarks) –Smells, visual cues Compass orientation –X-Y axis orientation Depends on sunny conditions Must have built in sense of daily changes in the sun’s position (internal clock) Celestial orientation Magnetic orientation

Navigation - orientation without fixed landmarks