News

Welcome aboard to our new student Eran Altschuler

25 October 2018

We welcome our new M.Sc. student Eran Altschuler!

Congratulations and warm wishes to our students Inbal and Yosef

27 January 2018

To Inbal for the birth of her daughter, and to Yosef for the birth of his son. We wish them and their families joy and happiness

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New publications

Feather moult and bird appearance are correlated with global warming over the last 200 years

05 July 2019

Kiat, Y., Vortman, Y., and N. Sapir. (2019) Feather moult and bird appearance are correlated with global warming over the last 200 years. Nature Communications 10 (2540). doi: https://doi.org/10.1038/s41467-019-10452-1 ABSTRACT...

Fruit consumption in migratory passerines is limited by water ingestion rather than by body water balance

05 July 2019

Domer, A., Shochat, A., Ovadia, O., and N. Sapir (2019) Fruit consumption in migratory passerines is limited by water ingestion rather than by body water balance. Journal of Avian Biology...

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Deriving movement properties and the effect of the environment from the Brownian bridge movement model in monkeys and birds

Buchin, K., Sijben, S., van Loon, E. E., Sapir, N., Mercier, S., Arseneau, T. J-M. and Willems, E. P. (2015). Deriving movement properties and the effect of the environment from the Brownian bridge movement model in monkeys and birds. Movement Ecology 3:18.

ABSTRACT

Background: The Brownian bridge movement model (BBMM) provides a biologically sound approximation of the
movement path of an animal based on discrete location data, and is a powerful method to quantify utilization
distributions. Computing the utilization distribution based on the BBMM while calculating movement parameters
directly from the location data, may result in inconsistent and misleading results. We show how the BBMM can be
extended to also calculate derived movement parameters. Furthermore we demonstrate how to integrate
environmental context into a BBMM-based analysis.
Results: We develop a computational framework to analyze animal movement based on the BBMM. In particular, we
demonstrate how a derived movement parameter (relative speed) and its spatial distribution can be calculated in the
BBMM. We show how to integrate our framework with the conceptual framework of the movement ecology
paradigm in two related but acutely different ways, focusing on the influence that the environment has on animal
movement. First, we demonstrate an a posteriori approach, in which the spatial distribution of average relative
movement speed as obtained from a “contextually naïve” model is related to the local vegetation structure within the
monthly ranging area of a group of wild vervet monkeys. Without a model like the BBMM it would not be possible to
estimate such a spatial distribution of a parameter in a sound way. Second, we introduce an a priori approach in which
atmospheric information is used to calculate a crucial parameter of the BBMM to investigate flight properties of
migrating bee-eaters. This analysis shows significant differences in the characteristics of flight modes, which would
have not been detected without using the BBMM.
Conclusions: Our algorithm is the first of its kind to allow BBMM-based computation of movement parameters
beyond the utilization distribution, and we present two case studies that demonstrate two fundamentally different
ways in which our algorithm can be applied to estimate the spatial distribution of average relative movement speed,
while interpreting it in a biologically meaningful manner, across a wide range of environmental scenarios and
ecological contexts. Therefore movement parameters derived from the BBMM can provide a powerful method for
movement ecology research.

About us

We are a group of scientists devoted to the study of animal flight, including animal movement ecology, behavior, physiology and biomechanics. We study wild animals in the field and in the lab using a diversity of research approaches. We welcome applications for M.Sc. and Ph.D. studies and post-doctoral work in our group at the Department of Evolutionary and Environmental Biology at the University of Haifa.