Parrots overcame the Andes only once

Various populations of the parakeets in South America originated from today's Chile

South American Rock Parakeets at the feeding place. © Fabian Llanos
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Birds can even overcome hostile high mountains to reach new habitats - but this is extremely rare. Researchers have found this out with the help of gene analyzes of South American Rock Parakeets. According to this, the approximately 45 centimeters large parrot species crossed the Andes from west to east about 120, 000 years ago. The animals probably flew over a more than 3, 000-meter-high pass near the Aconcagua, the highest mountain in the Andes, reports the German-Austrian research group in the journal "Frontiers in Zoology".

"Contrary to our expectations, the species was originally created on the Pacific side of the Andes, where today is Chile and where today only small colonies occur. From there, the species crossed the Andes only once, "says Juan F. Masello of the Max Planck Institute for Ornithology. This confirms that the Andes are indeed an effective barrier to the exchange of genes.

Colorful cross-border commuters

Rock parakeets breed in colonies in sandstone and limestone cliffs. Suitable nesting sites are rare and exist mainly in the valleys on both sides of the Andes, but also on the cliffs of the Atlantic. According to the researchers, the colorful birds are especially good at investigating how animals spread out in suitable habitats - thereby overcoming natural barriers.

For the study, the international research team collected feathers of the parakeets in 66 colonies on both sides of the Andes. With the help of the genetic material from these feathers, they deciphered the relationships between the individual colonies. Thus, the species originally lived only on the western side of the Andes. From there she made the jump over the high mountains.

"From this starting population, two new subspecies have developed in Argentina. Of these, one has successfully spread along the rivers to the Atlantic, where now the largest colonies can be found. In El Condor, the species forms the world's largest colony of all parrot birds, with more than 35, 000 pairs, "say the researchers. display

The crossing of the Andes took place 120, 000 years ago

Using genetic data and fossil dating, they also succeeded in determining the timing of their eastward spread. "So we could estimate that the crossing of the Andes took place over 120, 000 years ago, " says Petra Quillfeldt, also from the Max Planck Institute for Ornithology.

The new findings are not only important for the reconstruction of the propagation history of parrots. As the researchers emphasize, they could also help to improve the protection of birds. For example, the subspecies threatening in Chile today is considered to be seriously threatened with extinction. There are only about 5, 000 to 6, 000 of these animals left. (Frontiers in Zoology, 2011; DOI: 10.1186 / 1742-9994-8-16)

(Max Planck Institute for Ornithology, 15.07.2011 - DLO)