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

Contrasting aspects of tailswinds and asymmetrical response to crosswinds in soaring migrants

21 February 2018

Becciu, P., Panuccio, M., Catoni, C., Dell'Omo, G., and Sapir, N. 2018. Behavioral Ecology and Sociobiology 72(28). https://doi.org/10.1007/s00265-018-2447-0  

Hovering hummingbird wing aerodynamics during the annual cycle. II. Implications of wing feather moult

21 February 2018

Achache Y, Sapir N, Elimelech Y. 2018. Hovering hummingbird wing aerodynamics during the annual cycle. II. Implications of wing feather moult. Royal Society Open Science 5: 171766. http://dx.doi.org/10.1098/rsos.171766  

Moving in the Anthropocene: Global reductions in terrestrial mammalian movements

24 January 2018

Science 359 (6374): 466-469 http://science.sciencemag.org/content/359/6374/466  

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Flight modes in migrating European bee-eaters: heart rate may indicate low metabolic rate during soaring and gliding

Sapir, N., Wikelski, M., McCue, M.D., Pinshow, B. and Nathan, R. 2010. Flight modes in migrating European bee-eaters: heart rate may indicate low metabolic rate during soaring and gliding. PLoS ONE 5(11): e13956.

 

ABSTRACT

Many avian species soar and glide over land. Evidence from large birds (mb>0.9 kg) suggests that soaring-gliding is considerably cheaper in terms of energy than flapping flight, and costs about two to three times the basal metabolic rate (BMR). Yet, soaring-gliding is considered unfavorable for small birds because migration speed in small birds during soaring-gliding is believed to be lower than that of flapping flight. Nevertheless, several small bird species routinely soar and glide.

Methodology/Principal Findings

To estimate the energetic cost of soaring-gliding flight in small birds, we measured heart beat frequencies of free-ranging migrating European bee-eaters (Merops apiaster, mb~55 g) using radio telemetry, and established the relationship between heart beat frequency and metabolic rate (by indirect calorimetry) in the laboratory. Heart beat frequency during sustained soaring-gliding was 2.2 to 2.5 times lower than during flapping flight, but similar to, and not significantly different from, that measured in resting birds. We estimated that soaring-gliding metabolic rate of European bee-eaters is about twice their basal metabolic rate (BMR), which is similar to the value estimated in the black-browed albatross Thalassarche (previously Diomedea)melanophrys, mb~4 kg). We found that soaring-gliding migration speed is not significantly different from flapping migration speed.

Conclusions/Significance

We found no evidence that soaring-gliding speed is slower than flapping flight in bee-eaters, contradicting earlier estimates that implied a migration speed penalty for using soaring-gliding rather than flapping flight. Moreover, we suggest that small birds soar and glide during migration, breeding, dispersal, and other stages in their annual cycle because it may entail a low energy cost of transport. We propose that the energy cost of soaring-gliding may be proportional to BMR regardless of bird size, as theoretically deduced by earlier 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.