Updates from the Field

Attention Teachers: Download this week's location data for the banded Siberian Cranes that we are tracking this fall Week 11 Poyang Lake Basin Our final field update for fall 2007 focuses on the Poyang Lake Basin (right), the wintering area for the eastern Siberian Crane population in northern Jiangxi Province. One of the banded cranes that we are tracking this fall arrives in the basin this week - the end of its nearly two month migration that began over 3,000 miles to the north in Siberia. Poyang Lake is the largest freshwater lake in China (the total area of the lake is over 3,000 km2). Five rivers flow into the lake, which then empties into the Yangtze River to the north. During most of the year, water enters the lake via the five rivers and flows in a south to north direction. However, during the Yangtze's late summer flood season, the flow of water can reverse and flow north to south from the Yangtze into the lake. The maximum difference in water level between dry and rainy seasons is 10 meters, but can reach 14 meters during extreme floods. These dramatic changes between seasons characterize the wetlands and directly influence the extensive wintering habitats and abundant food available for Siberian Cranes and a variety of other waterbirds. Poyang Lake is one of the most important wintering areas for waterbirds in Asia, with 98% of the world population of Siberian Cranes, 60% of White-naped Cranes, 50% of Swan Geese, 90% of Oriental White Storks, and hundred of thousands of other waterbirds, such as herons, egrets, grebes, ducks and a wide range of shorebirds. Wintering waterbirds feed on a number of different foods at Poyang: tubers (the starchy swellings on the roots of plants - a potato is a tuber), fish, microscopic invertebrates, and grasses or sedges (eaten by grazing geese). In 1998, the International Crane Foundation and Poyang Lake Nature Reserve (PLNR) began a project to study the ecological relationships among birds, plants, and water within PLNR. This research has focused on Siberian Cranes and other tuber-feeding species (e.g. White-naped Cranes, Tundra Swans and Swan Geese). Tuber growth is primarily influenced by water levels, water quality, and the timing of changes in water levels during the growing season when Poyang Lake typically floods. Though water levels in winter do not influence plant production (the plant is not growing at this time), they still determine where birds can feed (e.g. if the water is too deep, cranes cannot wade and if it is too dry, cranes cannot probe in the mud). Understanding the relationships between birds, plants and water levels is critical to understanding the Poyang Lake ecosystem, for designing effective conservation programs, and for predicting impacts to the system from development projects, such as the Three Gorges Dam. ICF researchers are currently working with PLNR staff to capture and band five Siberian Cranes on their wintering grounds this fall. The researchers hope to follow the birds during the winter months to learn more about their habitat use within the reserve and the larger lake basin. In spring 2008 we will track the birds as they migrate north to their summering grounds. Researchers are curious to see if the banded cranes follow the same migration route as the birds that were banded in the mid 1990s (the migration that we have followed this fall). They also are interested in following young, unpaired birds, which may not summer in the same area as breeding adults. We will post updates on this project on the Tracking Cranes website in late winter in preparation for the beginning of the spring migration and will follow the migration through the spring.

Field Updates Student Activities Yakutian Birds Geography: Taiga and Tundra Ecoregions Field Work in the Tundra Science: Studying Animal Behavior Environmental Camps Team Building: Crane Egg Game Fall Migration Geography: Tracking Cranes Waterbird Lead Poisoning in Yakutia Social Studies: Raising Awareness Northeast China Discussion: Changing Landscapes Songnen Plain Science: Wetlands as Filters Student Exchanges Writing: School News Birding in China Science: Classroom Bird Feeders Bohai Bay Math: Waterbird Populations Poyang Lake Basin

		Siberian Cranes and Tundra Swans (upper left) winter in the Poyang Lake Basin, feeding on abundant plant tubers and other foods found in the lakes. The Siberian Cranes and other migratory waterbirds benefit from the unique ecology of Poyang Lake, which provides diverse habitats for birds and people (the basin is an important region for rice cultivation in southeastern China). ICF staff are working with researchers from the Poyang Lake Nature Reserve to study the changing water levels and tuber distribution (left) within the reserve to better understand the ecology of the region. Photos by Jeb Barzen.