Scientific name: Rhea pennata, Rhea tarapacensis
Other common names: Lesser Rhea; Patagonian Rhea; Puna Rhea
The Darwin's Rheas are the slightly smaller, lesser-known cousins of the Greater Rhea. In 2014, this South American endemic was split into two species-- Lesser Rhea (R. pennata) and Puna Rhea (R. tarapacensis.). Unlike the popular Greater, Lesser and Puna Rheas are quite rare in captivity, and you are unlikely to encounter them. If you do, you have a special responsibility to focus on breeding birds to preserve the species for future generations. Take special care to identify your birds correctly, so that you don't hybridize Lesser and Puna, causing the natural forms to be lost to aviculture. You should almost certainly have experience with the more common ratites before you take on either of these species.
Like the Greater Rhea, the Puna Rhea has been rated as “near threatened” in the wild by the International Union for the Conservation of Nature and Natural Resources (IUCN), thanks to the conversion of its habitat to farmland, illegal egg collecting, and hunting. Both Lesser and Punas are birds of wide open spaces but, as the name suggests, the Puna is an upland plateau species.
The Lesser Rhea is a brownish ratite (tall, flightless bird) with white spots that's a bit smaller than the Greater Rhea. There's no black at the base of the neck as you would see with the Greater Rhea. The Puna Rhea is similar to the Lesser, but it's a grayer bird and the white spots are a bit less obvious.
As an added twist, these two rhea species are not easily sexed at a glance, unlike Greater Rhea, Ostrich, or Emu, the more popular ratites (flightless birds) of aviculture. You must rely on behavior or DNA testing to sex these birds. Despite this difference, Darwin's and Greater Rheas are close enough relatives that they have been hybridized in captivity, so you must never allow these birds to range together in your collection.
15 - 27 kilograms (33 - 60 lbs.)
15 - 20 years
Lesser Rheas are noted for having larger wings in proportion to their bodies than the other ratites. However, no matter how fast they run – several sources suggest that they can reach 60 kilometers/hour in bursts – they are never going to be able to get enough lift to fly.
Like other birds that spend a lot of time on the ground, Lesser and Puna Rheas may need a de-worming schedule. You will want an experienced veterinarian who is capable of handling a large bird capable of giving a hard kick. They also have a reputation for being exceptionally difficult to breed in captivity, so it's imperative that you network with other breeders, such as zoos, for the latest information.
Behavior / temperament:
As with most other ratites, adult male rheas become extremely territorial during the breeding season. Their aggression may be quite understandable, since one or more females will dump the eggs in the nest for him to incubate, hatch, raise, and defend, causing all of his paternal instincts to be fully engaged. Be aware that you will be able to have only one adult male on the territory and that he may be quite difficult for the keeper to handle.
It cannot be over-emphasized that if you are lucky enough to have a breeding pair or trio of Lesser or Puna Rheas, you must not place them with any other rheas. Early aviculturists made the mistake, which resulted in hybrid birds that did nothing to preserve the species in captivity. Otherwise, they have been kept successfully in accommodations similar to the territories suitable for Greater Rheas – at least 2,500 square feet of range, with a shelter against the wind, a sand pit for dust bathing, and possibly a shallow pond.
Lesser and Puna Rheas eat a tough high fiber diet, similar to the Ostrich. As grazing animals that have no crop, they swallow small stones to help grind up the grains they consume. As a result, it's possible they would also have an attraction to shiny objects and may try to swallow your jewelry or other metal items, so be as cautious with them as you would with the Greater Rhea. A good captive diet is a ratite or Ostrich pellet, supplemented with alfalfa or other browse, and treats like broccoli, carrot, or even grapes. Always have plenty of clean water available.
Written by Elaine Radford