Behavior

Orinoco Geese are mainly terrestrial, but will perch in trees during the breeding season. They appear to maintain a strong pair-bond year-round, and are usually seen in pairs, but large noisy groups can also be seen congregating on beaches, in trees, or on oxbow lakes. When with flightless young, birds typically escape threats by entering the water. Young goslings dive below the water from a very young age, possibly indicating the importance of land and aerial predators rather than aquatic predators such as caiman.

Most foraging is done in daytime in open areas near water, although they may also forage some at night. They prefer to undertake major moves between feeding and resting areas in crepuscular hours and migrate almost exclusively during twilight or nighttime hours (Davenport et al. 2012).

Both males and females spend considerable time alert to predators, although the male spends significantly greater time than the female alert, especially prior to the breeding season (Kriese 2004).

Orinoco Geese are strongly territorial during the breeding season, and males perform a territorial display in which they expand their chest, pull back their heads, flap their wings, and then rush towards a rival animal. At the nest, males will stay near the nest while the female sits on eggs, staying in contact with her through very high soft whistling.

Orinoco Geese form strong pair-bonds and nest in tree cavities. Only the female incubates eggs. Pairs fight over preferred cavities and foraging grounds, engaging in territorial displays and vocalizations on the ground and in trees.

A pair studied with satellite telemetry in Manu National Park, Peru migrated together to the Llanos de Moxos, Bolivia, with the pair traveling together to their final destination (Davenport et al. 2012), supporting Kriese's suggestion that Orinoco Geese stay with their mates year-round (Kriese 2004).

Orinoco Geese spend most of their time in pairs and family groups. On beaches and wetlands, Orinoco Geese co-occur with several species that forage on similar habitats, including Muscovy Ducks (Cairina moschata), whistling-ducks (Dendrocygna sp.), Horned Screamers (Anhima cornuta), and capybara (Hydrochoerus hydrochaeris), but they are not known to forage in conjunction with any of these species, nor to displace or avoid these species.

Only a few reports of predation on Orinoco Geese are known. Kriese (2004) reported that both mammals and birds predated nests of Orinoco Geese, with Black-Eared Opossum (Didelphis marsupialis) considered to be the main predator in Venezuela. In the Río Juruá, Brazil, Davenport observed a Great Black Hawk (Buteogallus urubitinga) predate a juvenile on a beach with 2 different families of Orinoco Geese (unpublished report). Edwin Meneses (personal communication) reported on a black caiman (Melanosuchus niger) predating an adult Orinoco Goose at Barba Azul Nature Reserve, Bolivia, during a territorial fight in which one goose was knocked from a tree to the water's edge. Sick (1997) reported on individuals with feet mutilated by piranha in the Brazilian Xingu region. However, humans may be the main predator of adult Orinoco Geese in the wild (Endo, Haugaasen, and Peres, in press).