Breeding ecology of the Orinoco Goose (Neochen jubata) in the Venezuelan llanos: The paradox of a tropical grazer

Research efforts focused on specific threatened waterfowl taxa are essential to examine factors limiting population size. Habitat loss is believed to be one of the primary threats to Orinoco Geese. I undertook a study of the breeding ecology of Orinoco Geese in Venezuela and examined: (1) nest site selection and limitation; (2) quality and availability of grazing habitats; and (3) behavioral patterns exhibited during the breeding season. Data from this study assessed potential habitat limitations during the breeding season and provided recommendations for additional research needed to develop sound conservation plans to protect this near-threatened species.;Orinoco Geese preferred large cavities located <300 m from open water in habitats with few surrounding trees. Cavities were not a limiting resource despite the large population of geese (>800 individuals) and low cavity density (0.35 cavities/ha) at my study site. Nest boxes had higher hatching success than cavities, but predation rates were high for both box and cavity nests.;Orinoco Geese fed primarily in habitat characterized by short, grazed vegetation and associated with flooded savannas or riverbanks. Plant protein concentrations were higher in habitats where geese were grazing than where geese were absent, but were lower than plants consumed by arctic-nesting geese. Grazing pressure by Orinoco Geese and capybara did not affect plant protein concentrations but resulted in plants with lower fiber content.;Pre-breeding males were more alert than pre-breeding females, but both sexes were highly alert during brood rearing. Increased vigilance by females ensured at least one parent was alert 62% of the time. Grazing was the dominant behavior of Orinoco Goose goslings but plant protein concentrations may have been a factor affecting slow gosling growth.;The population status for Orinoco Geese is unclear. Habitat loss and hunting may be factors limiting Orinoco Goose populations, but there is no data on habitat use during the non-breeding season, migration and dispersal, or survival estimates. Conservation efforts for Orinoco Geese should focus on population surveys, habitat protection, and enforcement of laws banning hunting as priority actions. Continued research should focus on data needed to effectively guide conservation efforts and recovery management actions.