Greater rhea  (Rhea americana)

The greater rhea has undergone a marked decline as a result of hunting for meat, eggs and skins, and for its feathers, which are used to make feather dusters. In recent years, these threats have been compounded by habitat loss as vast areas of grassland are converted for agriculture and cattle ranching (2) (12) (17). Farmers and ranchers often accuse rheas of eating crops and competing with cattle for food, and chase the birds off their land (2), although there is evidence that the greater rhea actually feeds on important weed and pest species (18). Physical barriers like roads can also prevent the birds dispersing, so increasing the risk of inbreeding. In addition, the greater rhea can suffer serious injuries if it becomes caught up in barbed wire fences (2) (5).

The greater rhea is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in the species should be carefully controlled (4). However, levels of both international and domestic trade in the greater rhea may need further monitoring, and restrictions on hunting and trade need effective enforcement (12). As increasing grain production within the species’ range appears inevitable, education and outreach programmes may be needed to help ensure the long-term survival of the greater rhea in agricultural areas (17). In recent decades, commercial farming of rheas for feathers, meat and skin has become increasingly popular, and studies into captive breeding of the species have led not only to improved production (for example, by using ‘adoptive’ males rather than artificial systems to rear chicks (19) (20)), but also the possibility of reintroduction of captive-bred rheas into the wild. Captive breeding has therefore been suggested as a possible conservation tool as wild populations continue to decline (5) (21).