Caracterización y selección del sitio de anidación de la grulla cubana (Grus canadensis nesiotes) en el herbazal del Refugio de Fauna El Venero, Cuba

Abstract

Characterization and selection of nest sites by the Cuban sandhill crane (Grus canadensis nesiotes) in the grasslands of the El Venero Wildlife Refuge, Cuba Grus canadensis nesiotes is an endemic threatened subspecies of crane that inhabits freshwater wetlands. We characterized its nesting site and analyzed nest-site selection at three spatial scales in grasslands of El Venero Wildlife Refuge (Cuba), during the breeding seasons of 2005-2007. We monitored 26 nests until hatching. We also measured vegetation height, coverage at 30 and 100 cm, and distance between grass stems at nests. These values were compared with values measured at points 100 m away from nests. We used a GIS to obtain distances to channels, roads and forest patches, as well as to determine percentages of grass, water, palm-grass and casuarina-grass in circles of 100, 400, 700 and 1,000 m of radius around both nests and random points. Vegetation variables around nests (height: 78.9 ± 2.1; coverage at 30 cm: 97.8± 0.6; coverage at 100 cm: 64.7 ± 1.6) were lower than those at 18 m away. There were no differences in vegetation variables or distances to forests and water between nests and random points located farther. Percentage covers of grassland and forest influenced nest site selection. Average distance between simultaneous active nests was 1,305.8 ± 106 m, the smaller area of potential use was 30,3 km2 and the mean influence area was 2,13 ± 0,36 km2. Nest site selection by cranes, as well as nest site characteristics, depended of the presence of extensive areas of grassland.