Comparative breeding ecology of Lesser Sandhill Cranes (Grus canadensis canadensis) and Siberian cranes (G. leucogeranus) in Eastern Siberia

摘要

Populations of Lesser Sandhill Crane (Grus canadensis canadensis) have beenincreasing during the last decades in Eastern Siberia, an area historically known asbreeding grounds of endangered Siberian Cranes (G. leucogeranus). Significant overlapin niche dimensions between the two species may occur and could lead to competitionbetween them. Therefore, this study of comparative breeding ecology of commonLesser Sandhill Cranes and endangered Siberian Cranes was performed.From late May to early August 2000, I studied Lesser Sandhill and Siberian craneswithin a 30,000-ha part of Kytalyk Resource Reserve in the Republic of Sakha (Yakutia),Russia. My main objective was to compare dispersion patterns and resource use ofbreeding Lesser Sandhill and Siberian cranes in areas of distribution overlap.Lesser Sandhill Cranes used moderate-wet (polygon) areas as their nest sites andmain foraging areas, where terrestrial foods were scattered. In contrast, Siberian Craneswere nesting and foraging on low-basin wet areas, where aquatic foods were concentrated and dominant. Inter-nest distances were less for heterospecific cranes thanfor conspecific cranes, and more territorial behavior was projected toward conspecificsthan toward heterospecifics. Lesser Sandhill Cranes were more mobile and usedmoderate-wet (polygon) areas more than Siberian Cranes; however, both species spentsimilar time foraging and being alert.The two crane species used different vegetation types for nesting and foraging,had different time-activity budgets, and used different resources in the Siberian tundra.While the population of Lesser Sandhill Cranes in the study area has the potential toincrease, both species may simultaneously share the same geographic area due todifferences in ecological requirements.