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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Hovering hummingbird wing aerodynamics during the annual cycle. I. Complete wing

Achache Y., Sapir N., and Y. Elimelech. 2017. Hovering hummingbird wing aerodynamics during the annual cycle. I. Complete wing. Royal Society Open Science 4: 170183. http://dx.doi.org/10.1098/rsos.170183

ABSTRACT

The diverse hummingbird family (Trochilidae) has unique adaptations for nectarivory, among which is the ability to sustain hover-feeding. As hummingbirds mainly feed while hovering, it is crucial to maintain this ability throughout the annual cycle—especially during flight-feather moult, in which wing area is reduced. To quantify the aerodynamic characteristics and flow mechanisms of a hummingbird wing throughout the annual cycle, time-accurate aerodynamic loads and flow field measurements were correlated over a dynamically scaled wing model of Anna’s hummingbird (Calypte anna). We present measurements recorded over a model of a complete wing to evaluate the baseline aerodynamic characteristics and flow mechanisms. We found that the vorticity concentration that had developed from the wing’s leading-edge differs from the attached vorticity structure that was typically found over insects’ wings; firstly, it is more elongated along the wing chord, and secondly, it encounters high levels of fluctuations rather than a steady vortex. Lift characteristics resemble those of insects; however, a 20% increase in the lift-to-torque ratio was obtained for the hummingbird wing model. Time-accurate aerodynamic loads were also used to evaluate the time-evolution of the specific power required from the flight muscles, and the overall wingbeat power requirements nicely matched previous studies.

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.