The Chacabuco Valley, the heart of Patagonia Park, serves as one of the last safe places for some of Chilean Patagonia’s most threatened species. Best known are the park’s huemul deer, which represent 10% of the world’s entire population. The park’s Darwin’s rhea population (also known as Lesser rhea or ñandú), are yet another reason to protect the valley in perpetuity. With a regional designation of “Endangered” by the Chilean Wildlife authority, the park’s estimated 25 rheas could play an instrumental role in the revival of the species. For over a century this population has congregated on the eastern side of the park by the border with Argentina. Isolated by livestock activity and fencing, the rhea population has been subject to poaching and stolen eggs for many years.
To reverse the negative population trend, in 2015 Conservacion Patagonica launched a Darwin’s Rhea Conservation Program to protect, monitor, and hopefully increase the population of this endangered bird. Highly susceptible to predation and losses of nests and young by culpeo foxes, pumas, grisons, armadillos, pampas cats, domestic dogs, and poaching by humans, it is unlikely this population will be able to rebound on its own. A relative of the ostrich, the Darwin’s rhea of Patagonia are smaller in stature, brown, grey, and white in color, and though flightless, can run at speeds of up to 35 mph. Once poached for their feathers, rhea eggs are also often sought after by humans or eaten by predators. In 2014, CP hired park warden Manuel Cabrera to guard and monitor the park’s rheas. With help from a grid of camera traps, Manuel patrols the area on foot, recording rhea sightings and identifying predators.
In December 2014 the Chilean border police (Carabineros de Chile) found two orphaned rhea chicks and, in accordance with the Chilean Wildlife Authority (SAG), brought them to CP’s ñandú park warden station at Puesto Ñandu to be part of a breeding program for the species. In winter the chicks were monitored and rehabilitated indoors, though soon they had grown too large to be inside. By summer the Wildlife Team had constructed an outdoor corral for the two chicks. The adoption of the two rhea chicks instigated the creation of the first Darwin’s Rhea Conservation Breeding Center in the region, and set in motion the integration of ten new rhea chicks from a separate captive Patagonia population located further north. After decades of isolation, this is a unique opportunity to expand the current population’s numbers and gene pool.
In March 2015, volunteers assisted the Wildlife Team in building a second corral, just in time for the arrival of the ten new rhea chicks. The chicks were transported by airplane in special cages and landed in the eastern park’s airstrip. The chicks adjusted well to their new surroundings during austral winter, though sadly two chicks were lost due to natural and unavoidable occurrences. As the chicks come of age (rheas reach sexual maturity around age two), the birds will start to pair off to produce chicks in order to develop repopulation and augmentation efforts. Depending on the survival and breeding success of the program, a release plan considering a proper combination of numbers and gender will be submitted to the wildlife authority.
In November 2015 the team discovered the first egg produced in the corrals. Though it is unlikely that any eggs laid right now will hatch, the birds are showing promising breeding behavior. Rheas are unique in that the males are responsible for incubating the eggs as well as rearing the chicks. Rheas are also polygamous—males will mate with several females, who will then deposit their eggs into the male’s nest. After a 40-day incubation period, the chicks will all hatch within a 1 to 2 day period.
If all goes well, the breeding program will welcome new Darwin’s rhea chicks by September 2016, which will hopefully be released into the wild around January 2017. The first program of its kind in Chile, the team will need to closely observe the behavior and health of the rheas as we move forward with this new program. This initiative has the support of the Chilean Ornithologists Union (Aves Chile), as well as international and recognized experts on the species and researchers from the University of Chile. The rheas are already working as conservation ambassadors by bringing attention to our park creation and recovery efforts. CP has received incredible assistance from the border police (Carabineros de Chile), who instigated the program when they rescued the two original chicks. Children from the local school in Cochrane enjoyed an exciting field trip to visit the rheas, which have been incorporated into the science curriculum.