Research Interests:

I'm interested in ecology and conservation. In my research I combine an experimental approach with field observations and advanced modeling. I focus on movement ecology of birds and some of the associated interactions. For instance, the consequences of the bird movement pattern on seed dispersal and disease transmission.

Current projects:

The title of my PhD dissertation is: "Movement ecology of vultures: Foraging patterns, their underlying mechanisms and ecological consequences". Within this frame I'm engaged in few projects where different aspects of vultures' movements are studied, through observation and GPS tracking.

1.    The potential role of vultures in spreading anthrax at Etosha National Park, Namibia. This project is collaboration with Professor Wayne Getz's group from University of California, Berkeley (http://www.cnr.berkeley.edu/~getz/). Question regarding the foraging patterns of vultures are also included.

2.    The foraging patterns of vultures in a human dominated environment where most of available food comes from 'vultures restaurants'. This project is done in the arid parts of Israel, in collaboration with the Israel Nature and Parks Authority, and provides a unique opportunity to manipulate resource distribution on a large spatial scale. Effects like sociality, seasonal variation and internal motivation (e.g., hunger level) on the movement patterns, and the detection range are studied together with Roi Harel (M.Sc. student) and few undergraduate students.

My M.Sc. thesis was about seed dispersal by birds and focused on desert ecosystems which are usually over looked in frugivory and endozoochory research. I compared the disperser effectiveness of common bulbul (Pycnonotus xanthopygos) and of Tristram's grackle (Onychognathus tristramii) in dispersing the seeds of Ochradenus baccatus, a perennial shrub common throughout the Judean desert. Bird tracking, field observation and modeling where combine to address the questions in mind.

Publications

·         Spiegel, O. & Nathan, R. (2010) Incorporating density dependence into the directed-dispersal hypothesis. Ecology. 91(5), 1538-1548. PDF

·         Grodzinski†, U., Spiegel†, O., Korine, C. & Holderied, M.W. (2009). Context-dependent flight speed: bats minimize energy expenditure per time when foraging and per distance when commuting. J. Anim. Ecol. 78, 540–548. †Equal contribution. PDF

·         Schurr, F. M., Spiegel, O., Steinitz, O., Trakhtenbrot, A., Tsoar, A., & Nathan., R. (2009). Long-distance seed dispersal. In: Fruit Development and Seed Dispersal (ed. Østergaard, L.). Annual Plant Reviews, Wiley-Blackwell.

·         Holyoak, M., Casagrandi, R., Nathan, R., Revilla, E. & Spiegel., O. (2008). Trends and missing parts in the study of movement ecology. Proc Natl Acad Sci USA. 105, 19060- 19065.

·         Nathan, R., Schurr, F. M., Spiegel, O., Steinitz, O., Trakhtenbrot, A. & Tsoar, A. (2008). Mechanisms of long-distance seed dispersal. Trends Ecol. Evol. 23, 638-647. PDF

·         Spiegel, O. & Nathan, R. (2007). Incorporating dispersal distance into the disperser effectiveness framework: frugivorous birds provide complementary dispersal to plants in a patchy environment. Ecol. Lett.10, 718-728.

·         Bronstein, J.L., Izhaki, I., Nathan, R., Tewksbury, J., Spiegel, O., Lotan, A. & Altstein, O. (2007). Fleshy-fruited plants and frugivores in desert ecosystems. In: Seed dispersal: Theory and its application in a changing world (eds. Dennis, A.J., Schupp, E.W., Green, R.J. & Westcott, D.W.). CAB International, Wallingford, UK. 148-177.

·         Buckley, Y.M., Anderson, S., Catterall, C.P., Corlett, R.T., Engel, T., Gosper, C.R., Nathan, R., Richardson, D.M., Setter, M., Spiegel, O., Vivian-Smith, G., Voigt, F.A., Weir, J.E.S. & Westcott, D.A. (2006). Management of plant invasions mediated by frugivore interactions. J. Appl. Ecol., 43, 848-857.