Seasonal variation in the foraging ecology of the Wood Stork in the southern llanos of Venezuela

The southern llanos of Venezuela are tropical wet savannas distinguished by a severe flood-drought alternation throughout the year. I analyzed the seasonal Variation in use of habitat, foraging behavior and diet exhibited by the Wood Stork (Mycteria americana) in response to the changing conditions of this environment. With the beginning of the rainy season, streams and lagoons overflowed and inundated extensive marshes, which became the preferred foraging sites for storks. Amphibians and aquatic invertebrates proliferated in these flooded areas and accounted for half of the food consumed; the remaining half was composed of fish. The Wood Stork population was dispersed over the widely inundated area, and individuals foraged solitarily or in small groups. Groping and foot-stirring were the most common foraging behaviors. These patterns changed gradually with the cessation of rains. Shallow marshes dried up rapidly and became inadequate as feeding sites. Wood Storks then formed large foraging aggregations in the few ponds and lagoons that still kept water, where they foraged by groping together in close proximity. Fish accounted for more than 99% of the diet of Wood Storks during the dry season.