"In Conversation" Series
Lecturer:
Prof. Michael Assaf (Hebrew University)
Title:
Order versus disorder in bird and bat foraging strategies
Abstract:
In this talk we review two recent works dealing with the modeling of anomalous animal movement during foraging. In the first work, by combining high-resolution movement data with continuous-time random walk modeling, we discover ergodicity breaking in the localized movement of three species of avian predators. Small-scale, within-patch movement was found to be qualitatively different from large-scale inter-patch movement. Local search is characterized by long, power-law-distributed waiting times with a diverging mean, giving rise to subdiffusive motionand ergodicity breaking in the form of considerable variability across trajectories. This implies that while there areonly a few ways to commute, there are many ways to hunt, which may provide key evolutionary advantage to these predators compared to standard searchers.
In the second work we study foraging of Egyptian fruit bats using anon-Markovian model of animal mobility, which incorporate memory in the form of preferential returns. Exact results for the probability of visiting a given number of sites, and for the mean number of revisits to a particular site are derived, and are shown to agree well with empirical data. Our analysis yields a remarkable phase transition occurring at preferential returns which scale linearly with past visits. Following empirical evidence, we suggest that this phase transition reflects a trade-off between extensive and intensive foraging modes, which optimizes balance between energy expenditure and risk management.
Short Bio:
I did my B.Sc. in physics and computer science at the Hebrew U. Then I went anddid my M.Sc and PhD in physics at Hebrew university, under the guidance of Prof. Baruch Meerson. Roughly during the same time I also completed my master’s degree from the Music Academy in Cello performance. Then I went on a postdoc in 2010 at the University of Illinois under the guidance of Prof. Nigel Goldenfeld, and since 2013, I am a faculty member at the Hebrew U.
Location:
Eilat Hall, Feldman Building, Second Floor, Edmond Safra Campus.