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 challenges of the first migration: movement and behavior of juvenile versus adult white storks with insights regarding juvenile mortality

Rotics, S., Kaatz, M., Resheff, Y. S., Feldman Turjeman, S., Zurell, D., Sapir, N., Eggers, U., Flack, A., Fiedler, W., Jeltsch, F., Wikelski, M. and Nathan, R. (2016), The challenges of the first migration: movement and behavior of juvenile versus adult white storks with insights regarding juvenile mortality. J Anim Ecol. doi:10.1111/1365-2656.12525

 

ABSTRACT

Migration conveys an immense challenge especially for juvenile birds coping with enduring and risky journeys shortly after fledging. Accordingly, juveniles exhibit considerably lower survival rates compared to adults, particularly during migration. Also, juvenile white storks (Ciconia ciconia), which are known to rely on adults during their first fall migration, presumably for navigational purposes, display much lower annual survival than adults. 2.Using detailed GPS and body acceleration data, we examined the patterns and potential causes of age-related differences in fall migration properties of white storks by comparing first-year juveniles and adults. We compared juvenile and adult parameters of movement, behavior and energy expenditure (estimated from overall dynamic body acceleration, ODBA) and placed this in the context of the juveniles’ lower survival rate. 3.Juveniles used flapping flight versus soaring flight 23% more than adults and were estimated to expend 14% more energy during flight. Juveniles did not compensate for increased flight costs by increased refueling or resting during migration. When juveniles and adults migrated together in the same flock, the juvenile flew mostly behind the adult and was left behind when they separated. Juveniles showed greater improvement in flight efficiency throughout migration compared to adults which appears crucial because juveniles exhibiting higher flight costs suffered increased mortality. 4.Our findings demonstrate the conflict between the juveniles’ inferior flight skills and their urge to keep up with mixed adult-juvenile flocks. We suggest that increased flight costs are an important proximate cause of juvenile mortality in white storks and likely in other soaring migrants, and that natural selection is operating on juvenile variation in flight efficiency.

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.