Does the world’s rarest macaw hybridize?

An article by David Waugh, PhD, Scientific Director, Loro Parque, Tenerife. Published in a.f.a Watchbird (Volume XXIV, Number 5) September/October 1997  

Recent news from the Brazilian wildlife agency IBAMA suggests that the Spix’s macaw (Cyanopsitta spixii), the world’s most threatened parrot species, has hybridized in the wild state. Given that there is only one known individual left in the wild, a male, which under the circumstances has opted to form a pair with a female Illiger’s Macaw (Ara maracana), at least the potential for this to happen is not surprising. There are no written records of confirmed hybrids between the Spix’s Macaw and other species, either in captivity or the wild, but now there comes confirmation that an egg taken from the nest of this mixed pair contained an embryo.    

The egg was one of a clutch of three that were removed from the nest of the mixed pair in December 1996 by biologists of the Spix’s Macaw Recovery Project, financed by the Loro Parque Fundaciόn. The Committee for the Recovery of the Spix’s macaws (CPRAA) had authorized an experimental transfer of wild Illiger’s Macaw eggs to the nest of the mixed pair as a preliminary to the possible transfer of Spix’s macaw eggs from the 40-strong captive population.  Although intensively observed,  the mixed pair had never been known to hatch their own eggs, the principle supposition being that these were infertile, although it had not been possible to remove eggs from the nesting cavity until the experimental transfer last year.

Microscopical analysis of the eggs at the University of São Paulo showed no embryonic development in two of them, but the third had a well-formed embryo approximately 24mm long, with the head forming a third of the total length. In this embryo the beak was present, the wings well-developed and traces of the dorsal feather tracts visible. Its stage of development was equivalent to stages 32 to 34 of chicken embryo development which means seven or eight days of incubation and a total approximate age of 10 or 11 days. The embryo DNA was too degraded for direct study, but can still be studied through amplification techniques for comparison with Illiger’s Macaw DNA when samples are collected from the same region.

Until the DNA study is done we still do not know if the embryo is truly a hybrid or the result of a “sneaky mating” between the female Illiger’s Macaw and a male of her own species. However, the   field biologists confirm that the mixed pair is strongly bonded and the Spix’s Macaw guards his female well. Although of general interest, the potential occurrence of hybrids presents no immediate conservation advantage for the Spix’s macaw. The efforts to restore this species to the wild state will continue.

End of article

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( If you drive out nature with a pitchfork, she will soon find a way back)

Horace (65-8 BC)