a web page by Don Roberson |
RHEAS Rheidae |
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The larger and more widespread species is Greater Rhea (left), shown here next to a huge termite mound in the Brazilian Pantanal, formed from the gray mud of that huge swampland. Their habitat is open pampas or broken grasslands in cerrado. The species ranges from eastern Brazil south to central Argentina. |
 Lesser
Rhea has two disjunct populations: one in the puna zone of northern
Chile, and the other in barren steppes of southernmost Argentina and
Chile. Murray Lord took this nice picture of Lesser Rhea
(right) of a bird from the latter population. The breeding behavior of
rheas is quite remarkable, as I first learned from wonderful footage in
David Attenborough's Life of Birds. During the nesting
season, males compete for territories on the plains. Once established,
each tries to attract groups of females by running quickly towards them
with outspread wings. Once sufficient females are assembled, he
displays with voice and wing-shaking. After copulation, the male leads
the female to a nest which he has previously prepared, and there she
will lay her egg. He tries to get as many females as possible to lay in
this group nest, and accumulates 13-30 eggs. The male alone incubates;
all eggs hatch synchronously within a 24-28 hour period. He alone cares
for the striped young, jealously guarding them against all comers for
the next six months (lost youngsters are sometimes "adopted" by other
males). When the young are half-grown they can wander on their own, but
generally they remain in their groups of siblings until 2-3 years old
(Folch 1992). |
Photos: The Greater Rhea Rhea americana in the Pantanal south of Poconé, Mato Grosso, Brazil, on 18 July 2010. Murray Lord photographed the Lesser Rhea Pterocnemia pennata near Torres del Paine Nat'l Park, Chile, in January 2001. Photos © Don Roberson & Murray Lord, respectively, used with permission; all rights reserved. Bibliographic note: There is no "family book" per se, but a fine introduction to this family, with some fine photos, is in Folch (1992). Literature cited:
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The
two species of flightless rheas are endemic to southern South America.
They are the New World equivalent of an Ostrich and, indeed, ostriches
and rheas evolved from a common ancestor after the African and South
America plates split from ancient Gondwanaland (Folch 1992).