Black River Gorges National Park is the last of the native forest of Mauritius, 68 square kilometres of ravines and plateau in the southwest of the island, folded into gorges too steep and wet to farm, and it held the rarest bird in the world when four Mauritius kestrels were left alive in 1974, the species that a captive-breeding trick brought back to hundreds, along with the pink pigeon and the echo parakeet. Barely two percent of the island's native forest survives, and it survived here, low wind-clipped trees that grow nowhere else on Earth, walked on the upland trails from the Pétrin entrance on the plateau, where a few minutes' walk reaches the first lookouts over the gorge dropping to the sea, best at dawn, since by early afternoon grey cloud rolls in and closes the view; trails leave the plateau and drop into humid forest until the trees open on a wall of stripped basalt with water coming over the lip, and a short steep path climbs to Piton de la Petite Rivière Noire, the highest point on the island at 828 metres. The kestrels were saved by taking their first clutch of eggs to hatch in captivity, so that the pairs laid again, doubling the birds each year.
The echo parakeets, the island's own parrots, reduced to fewer than twenty birds in the 1980s, lay in late September and are loudest through the austral spring, and the pink pigeons sit in the trees at the Pétrin gate. The forest's enemy is a fruit: Chinese guava grows into thickets so dense that no native seedling gets light beneath them, carried inland by the park's own animals, and the rangers cut it out of the forest while Mauritian families drive up with buckets from April to June to strip the red fruit across Plaine Champagne, the island's harvest. In the summer rains the falls that hang as threads through the dry winter drop in full white curtains. Black River Gorges is the forest Mauritius kept, and the birds it nearly lost are back in it.