The jabiru stork, Jabiru mycteria (Lichtenstein, 1819), a large, long-legged wading bird occurring in lowland wetlands from southern Mexico to northern Argentina, is considered endangered in a large portion of its distribution range. We conducted aerial surveys to estimate the number of jabiru active nests in the Brazilian Pantanal (140,000 km²) in September of 1991-1993, 1998, 2000-2002, and 2004. Corrected densities of active nests were regressed against the annual hydrologic index (AHI), an index of flood extension in the Pantanal based on the water level of the Paraguay River. Annual nest density was a non-linear function of the AHI, modeled by the equation 6.5 · 10-8 · AHI1.99 (corrected r² = 0.72, n = 7). We applied this model to the AHI between 1900... |