Grouping behavior and the evolution of animal migration

Participants

Andrew Hein
Ana Hocevar
Daniel Jones
Oana Carja
Kyla Dahlin

Project Summary

In the first week of the CSSS Ian Couzin presented models suggesting that migrating animal populations may evolve into sub-populations of individuals that are more informed and individuals that are more social (see an example [[1]]). However, his approach is far removed from the actual constraints that migrating animals experience. Starting from Couzin's model, we developed a framework that includes the amount of fuel animals can store and how that fuel is lost when the animals communicate or are force to travel at sub-optimal velocities to maintain a flock. As an initial model we have used data for migratory birds, assuming a small (N=300) population travelling 2000 km without stopping to refuel. We find that the added pressure to maintain fuel stores will drives the population to be more informed than was found in the Couzin papers.

Questions/ Objectives (current and future):

(1) How does limitation in fuel storage affect population viability?
(2) Is there a trade-off between time/distance taken to reach target and number of informed individuals?
(3) Is maximum group size related to the radius of socialization?
(4) Does varying the amount of mutation / selection algorithm change the results significantly?

Background Info

This figure shows flight time for a 1kg bird as a function of flight velocity. The blue curve is a bird that is storing 50% of its body weight as fuel. The black curve is 25% and the red is 10%. Note the difference in optimal speed. This is an approximation but I think it gives the basic idea.

What is migration? (Dingle & Drake 2007)