The fate of the critically endangered Siberian crane looks hopeful thanks to international conservation efforts, according to a report released on Wednesday.

China, Iran, Kazakhstan and Russia -- four countries along the bird's dramatic migratory routes -- have rehabilitated some 7 million hectares of wetlands helping to sustain the remaining 3, 000 to 3,5000 Siberian cranes, the United Nations Environment Program report said.

"The Siberian Cranes need the wetlands to rest and to feed," Achim Steiner, the head of the UNEP, said.

The majestic bird breeds in northern Siberia and flies south to China and Iran in the winter. During these immense journeys, the cranes cross some of the highest mountains on the Earth, as well as some of the harshest deserts.

However, in recent years, the draining of critical wetlands, where the birds normally take respite on route, as well as hunting, have threatened the survival of the cranes and other migratory waterbirds.

Some 60 percent of wetlands worldwide -- and up to 90 percent in Europe -- have been destroyed in the past 100 years, principally due to drainage for agriculture, according to the Global Environment Facility (GEF).

The 10-year conservation project, financed by GEF with 10.3 million U.S. dollars, has helped protect key wetlands across Eurasia -- a landmass equivalent to Ireland or 3.5 times the area of Israel.

On the Songnen Plain in northeastern China, livestock wetland grazing impacts were mitigated through community development programs to help local herdsmen better manage the grazing of their animals on the wetlands, said the report.

While the project has been largely successful on the Eastern Flyway, which is used by most of the Siberian Cranes and spans Russia and China, more attention will be given to the Western Flyway that covers Russia, Kazakhstan and Iran where hunting and wetland drainage continues to endanger birds.