Puna Grebe

Description and biology

Grebes are swimming birds that inhabit quiet waters around the world. They resemble both the loon (to which they are related) and the duck (to which they are not related). The Puna or Junín grebe has a grayish–brown plumage (covering of feathers) on the top portion of its body.

Its underparts and neck are white. An average Puna grebe measures 13 to 15 inches (33 to 38 centimeters) in length. It has a long neck and a fairly long, pointed bill. Its diet consists primarily of fish.

Puna grebes spend most of the year in close flocks numbering less than 12 birds. A male–female pair breeds in patches of tall vegetation in deep water. After breeding, they build a nest in a colony with other mating pairs on semi–floating vegetation beds. A colony consists of 8 to 20 nests, which are generally situated 3 to 13 feet apart.

A female Puna grebe lays one to three eggs between November and March. Biologists (people who study living organisms) are unsure how long it takes the eggs to hatch. After hatching, the young are carried by the male. This leaves the female free to dive to obtain food for herself and her young.

Habitat and current distribution

This species of grebe is found only on Lake Junín (Lago de Junín) in the highlands of west–central Peru. Located at an altitude of 13,000 feet (3,962 meters), Lake Junín is a large, shallow lake bordered by extensive reed beds.

During breeding season, the grebes forage along the coast of the lake in open water. During the dry season, the birds move into the deeper central parts of the lake.

In the 1980s, scientists estimated the Puna grebe population to be between 200 and 300. In the early 1990s, that population had slumped to about 50, but after a good breeding season in 1998, the population was estimated to be back up to around 200, and rose to 300 the following year.

History and conservation measures

At one time, several thousand of the birds inhabited Lake Junín. By the 1970s, the Puna grebe population was less than 400. It continued to drop steadily to a low of less than 50 birds in the early 1990s, but has since rebounded to about 300 individuals. It remains in very risky circumstances.

The number of Puna grebes declined primarily because Lake Junín has become polluted by the runoff of poisons from nearby copper mines. In addition, these mines receive their water supply from the lake.

As the demand for water to the mines has increased, the lake’s water level, which is regulated by a hydro–electric power plant, has decreased. In 1992, open water was left only in the center of the lake. Little suitable nesting habitat remained for the Puna grebes. In 1998, when the population grew, it was due to better water levels in the lake.

Wildlife researchers tried to relocate four adult grebes to nearby Lake Chacacancha in 1985, but the birds disappeared in just two years. Local fishermen believe the birds had been caught in fishing nets intended to snare trout. A suitable relocation site for the surviving grebes has yet to be found.

There has been no long–term study of the Puna grebe. In recent years, the plight of the species has been taken up by a conservation group in Peru called PeruVerdes.