The Diego Ramírez Islands south of the South American southern tip are a rather uncomfortable habitat, where it rains a lot and over which severe storms regularly pass. Nevertheless, a small songbird managed to conquer these islands, which are only about 80 hectares in size, and in the process developed into a previously unrecognized bird species. According to Ricardo Rozzi from the Universidad de Magallanes and his team, the subantarctic knickers (Aphrastura subantarctica) is so different from a related species on the mainland that it is actually a separate species. This is reported by the working group in "Scientific Reports".
The first hint gave the completely different habitat that the two species inhabited. So far, the animals on Diego Ramírez have been part of the spiked tail slipper (Aphrastura Spinicauda), which is widespread in Chile and adjacent regions of Argentina, but is populated there by forests. On the other hand, neither trees nor bushes grow on the islands; The harsh conditions only allow grasses. Also a second species, the island panties (Aphrastura Masafuerae) from the Chilean island of Alejandro Selkirk, lives in its distribution area. Rozzi and Co were therefore amazed that the panties thrive well on Diego Ramírez.
During their stays there, the researchers caught a total of 13 individuals for several years and measured them: all animals were larger and heavier than their relatives from the mainland and Alejandro Selkirk. To do this, they had a stronger beak and a shorter tail. They also differ in behavior; Among other things, they breed in earth caves due to a lack of trees and rarely fly short distances. Finally, gene studies confirmed that the species differed significantly from each other and that in geologically recent past, no more exchange between the spiked tail and subantarctic slippers took place.
Diego Ramírez is located only 100 kilometers south of Tierra del Fuego, but the drake passage with its strong west winds and sea currents separates the two areas. It was probably an extreme coincidence that the ancestors of the subantarctic panties reached the tiny archipelago and survived there. And the way was lucky that they were also difficult to achieve or interesting for seafarers. As a result, no rats were introduced or murmur, cats and goats were exposed, as was the case in many other urins and which often led to the extinction of species. Since 2019, the islands in Diego Ramírez Islandsdrake Passage Marine Park have been protected.
