BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Phase Transition and Ergodicity Breaking During Avian Foraging - M ichael Assaf (Hebrew University of Jerusalem) DTSTART:20240905T151500Z DTEND:20240905T160000Z UID:TALK218020@talks.cam.ac.uk DESCRIPTION:In this talk we review two recent works dealing with the model ing of anomalous animal movement during foraging.\nIn the first work we st udy ergodicity breaking in foraging of avian predators. Indeed\, quantifyi ng and comparing patterns of dynamical ecological systems requires averagi ng over measurable quantities. Yet\, in nonergodic systems\, such averagin g is inconsistent\; thus\, identifying ergodicity breaking is essential in ecology. Using rich\, high-resolution\, movement data sets and continuous -time random walk modeling\, we find subdiffusive behavior and ergodicity breaking in the localized movement of three species of avian predators. Sm all-scale\, within-patch movement was found to be qualitatively different\ , not inferrable and separated from large-scale inter-patch movement. Loca l search is characterized by long\, power-law-distributed waiting times wi th a diverging mean\, giving rise to ergodicity breaking in the form of co nsiderable variability uniquely observed at this scale. This implies that wild animal movement is scale specific\, with no typical waiting time at t he local scale.\nIn the second work we study foraging of \;Egyptian fr uit bats using a non-Markovian and nonstationary model of animal mobility\ , which incorporates \;both exploration and memory in the form of pref erential returns. Notably\, a \;mean-field version of this model\, fir st suggested by Song et al. [Nat. Phys. 6\, 818 (2010)] was shown to well describe human movement data. Exact results for the probability of visitin g a given number of sites are derived and a practical WKB approximation to treat the nonstationary problem is developed. Our results are shown to ag ree well with empirical movement data of the fruit bats when accounting fo r interindividual variation in the population. We also study the probabili ty of visiting any site a given number of times and derive a mean-field eq uation. Our analysis yields a remarkable phase transition occurring at pre ferential returns which scale linearly with past visits. Following empiric al evidence\, we suggest that this phase transition reflects a trade-off b etween extensive and intensive foraging modes. LOCATION:Seminar Room 1\, Newton Institute END:VEVENT END:VCALENDAR