A Comparative Study On Food Habits Of Red-crowned Crane And White-naped Crane During Breeding Period In Zhalong Nature Reserve

From March to September of2011, we comparatively analyzed the sympatry distribution of Red-crowned Crane(Grus japonensis)and White-naped Crane(Grus vipio)in Zhalong Nature Reserve throughout the period of breeding. By using fecal microscopical analysis technique, we identified species of feeding plant and the nutrient contents analysis of main plant species gazed were measured by feed proximate analysis. We calculated the trophic niche breadth and overlap between these two species, which compared the breeding of the food composition and niche index difference, the results show that:During the breeding period, Red-crowned Crane consumed51plant species belonging to21families and White-naped Crane consumed50plant species belonging to21families. The experiment shows that the feeding plant species between Red-crowned Crane and White-naped Crane is similar, but the proportions of their diet compositions were different, both Red-crowned Crane and White-naped Crane mainly took Gramineac and Cyperaceae as the main diet in breeding season. From the feeding plant groups speaking, during the courtship period, Gramineae, Cyperaceae and Polygonaceae were the main food of Red-crowned Crane, but White-naped Crane took Gramineae, Cyperaceae and Potamogetonaceae as the main food. During the incubation period, Gramineae, Cyperaceae and Leguminosae were the main food of Red-crowned Crane, but White-naped Crane took Gramineae, Cyperaceae and Alismataceae as the main food. During the brood period, Typhaceae, Gramineae and Cyperaceae were the main food of Red-crowned Crane, but White-naped Crane took Cyperaceae, Gramineae and Alismataceae as the main food. From the feeding plant species speaking,the different stages in the breeding season, Red-crowned Crane took Zea may,Phragmites australis,Scirpus fluviatilis,Carex meyerina and Typha orientalis as the main food,but White-naped Crane choosed Zea mays,Phragmites anstrali,Suaeda glanca,Potamogeton malaianus,Carex tristachya and Carex meyerina as the main food source. The experiment shows that, although Red-crowned Crane and White-naped Crane breeding prefer taking Zea may, Phragmites australis and moss grasses as their main food, but there is a significant correlation between their choice food source and the nutrition of the food ingredients in the different stages of the breeding season,the higher feeding rate of food composition generally have higher crude protein,higher crude fat and lower crude fiber characteristics.The breeding in Red-crowned Crane and White-naped Crane nutrition niche overlap degrees in courtship period for91.67%, the incubation period for88.28%, the brood period for52.05%, explain that the competition because of food scarce between the White-naped Crane and Red-crowned Crane of is fierce during the courtship period, and with the change of the season in different breeding stages, overlapping degree has decreased.During the period of incubation and brood that has enough food resource and limitation of activities scope, the food resources impact on the competition between Red-crowned Crane and White-naped Crane was not obvious.Based on the research results, with the distribution of the domain of White-naped Crane and Red-crowned Crane’s competition and coexistence mechanism are preliminary discussed in Zhalong Nature Reserve.The results show that:Red-crowned crane and White-naped Crane and through nutritional niche differentiation to reduce competition, to achieve benign symbiotic relationship in the same area.The richness food resources,diversity of diet and nutrients composition has the vital significance between Red-crowned crane and White-naped Crane during the breeding period.