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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The gliding speed of migrating birds: slow and safe or fast and risky?

Horvitz, N., Sapir, N. (equal contribution of the first two authors), Liechti, F., Avissar, R., Mahrer, I. and Nathan, R. 2014. The gliding speed of migrating birds: slow and safe or fast and risky? Ecology Letters 17:670-679.

 

ABSTRACT

Aerodynamic theory postulates that gliding airspeed, a major flight performance component for soaring avian migrants, scales with bird size and wing morphology. We tested this prediction, and the role of gliding altitude and soaring conditions, using atmospheric simulations and radar tracks of 1346 birds from 12 species. Gliding airspeed did not scale with bird size and wing morphology, and unexpectedly converged to a narrow range. To explain this discrepancy, we propose that soaring-gliding birds adjust their gliding airspeed according to the risk of grounding or switching to costly flapping flight. Introducing the Risk Aversion Flight Index (RAFI, the ratio of actual to theoretical risk-averse gliding airspeed), we found that inter- and intraspecific variation in RAFI positively correlated with wing loading, and negatively correlated with convective thermal conditions and gliding altitude, respectively. We propose that risk-sensitive behaviour modulates the evolution (morphology) and ecology (response to environmental conditions) of bird soaring flight.

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.