Zino's Petrel (Pterodroma Madeira), an endemic seabird of Madeira, is regarded as one of the most endangered seabird of Europe. It only breads on the island of Madeira, and nests in extremely steep ridges of the central mountain massif.

The reason this species was named Freira (which means nun in English) lies in the fact that these birds, during the breeding season and in their nocturnal visits to the nests, emit calls that sound like wailms. For many years these sounds were interpreted by the inhabitants of Curral das Freiras (Nun's Valley) as being the calls of the suffering souls of the nuns that had taken refuge in that valley from pirate attacks.

This specie was first described in 1903 by a German naturalist priest, Ernst Schmitz. In 1951 Jerry Maul from the Funchal Municipal Museum, collected a specimen, which was later considered the last trail of existence of this species for the following 18 years. In the sixties, the ornithologist Paul Alexander Zino made several attempts to find some evidence of the species, but only at the end of that decade did he manage re-track the Zino's Petrel.

In 1987, after observing that several eggs and young birds showed signs of predation, a conservation program was designed aiming to reduce and control the main predators of the species (rats and cats). This program was coordinated by the Freira Conservation Project and assisted by Madeira Natural Park and Funchal Municipal Museum.

Nowadays the Madeira Natural Park is at the head of the project and the activities which aim to conserve this species through the recuperation of its breading habitat are co-financed by the Life-Nature Program.

A short while ago the population of Zino's petrels was estimated to be about 30 reproducing couples, however, during 2003, new breading areas were found, thus increasing the existing population to about 65 couples.