The movement ecology of Eurasian Cranes (Grus grus) overwintering and migrating through Israel

Currently In Progress
During the last two decades, we have witnessed a drastic change in the migration scheme of the
Eurasian Crane (Grus grus) in Israel. In the past, only few hundred individuals overwintered in
Israel, while nowadays tens of thousands of Eurasian Cranes overwinter in the country, the vast
majority (about 35,000) in the Hula Valley. Apparently, many of them, maybe entire
populations, which previously migrated to wintering grounds in Africa, changed their migration
program to a permanent stay in Israel during the winter months. The concentration of cranes in
the Hula Valley is a major tourist attraction, but in parallel a serious nuisance to agriculture,
requiring a feeding project which is both complex and expensive. In addition, such a large
concentration of so many individuals from one species in such a small area, elevates extinction
risks to entire populations, for example by infectious diseases, which can spread quickly, mainly
due to the poor physical condition of the cranes at the beginning of winter. Although the reasons
for these changes are quite evident (the creation of the Agamon wetland, the agricultural switch
to cultivation of grains as part of the peat soil lands reclamation, in addition to the growing
population of this species throughout its breeding range, as well as the global climate changes),
we still do not know which populations overwinter in Israel, why some cranes only pass
through (on their way to the south) while others choose to winter in Israel, what are the
movement patterns during winter in the Hula Valley and which factors explain them. The lack of
answers to these questions limits our ability to critically examine possible management solutions
for this huge crane-gathering phenomenon in the Hula Valley. Although many research efforts
were made during the last two decades, the information currently available on the
migration of cranes is very limited, and the differences in the migratory behavior (individuals
only passing by) and wintering (individuals staying for the entire winter) is unknown. As
specified in Sections 5 and 8, the reasons for the failure of previous efforts were cleared, new
information was gathered from various sources, and the existing tools, which were developed
only recently, allow us to deal with these issues and complete the missing critical information on
the movement ecology of Eurasian Cranes in Israel.