Atitlán Grebe

The Atitlántaucher ( Podilymbus gigas), known by its distinctive call as Poc, was a bird from the family of grebes. He was the closest relative of the binding diver ( Podilymbus podiceps ), however, was almost twice as large as this. He was endemic in the Lago de Atitlán in Guatemala at an altitude of 1700 m. Thanks to the research of the American biologist Anne LaBastille the course of decline has been fairly well documented. LaBastille studied this way over a period of about 25 years. She also wrote a book about her experiences at Lake Atitlan, entitled " Mama Poc ".

Characteristics and lifestyle

The Atitlántaucher reached a length of 46 to 50 cm. The reputation and appearance were quite similar to the binding diver. The top of the plumage had a dark brown color with dashed edges. The underside was dark gray with white speckles. The head was almost black. The neck was mottled white in spring and dark brown in winter. The legs were slate gray. The eyes were brown. The Atitlántaucher had very small wings with a length of 12 to 14 cm and was unable to fly.

The big, strong beak, its color varied from white to brown in spring in other seasons, had a black vertical band in the middle. He was endowed with a strong musculature and adapted to the snapping of crustaceans. These dietary specialization is unique among grebes. Crustaceans were extremely common before the introduction of alien fish species in Lake Atitlán. In addition to crustaceans of Atitlántaucher ate small fish and a small proportion of aquatic insects

The nest consisted of 4-5 white eggs, which was built in the dense reeds. Both parents have been involved in the breeding season.

Endangerment and extinction

The decline in Atitlántauchers began in 1958, when anglers the smallmouth bass ( Micropterus dolomieu ) and largemouth bass ( Micropterus salmoides ) exposing the lake. Introduced predatory fish multiplied so much that the food of Atitlántauchers declined dramatically. The perch were eating the young birds. This, and the annihilation of the reed belt led to a drastic decline of the diving population of 200 in 1960 to only 80 in 1965.

1966 launched Anne LaBastille a large-scale campaign to save the Atitlántauchers. A small reserve was created through their efforts. 1969, efforts were made by the lake to build a power plant, resulting in a lowering of the lake at 13 m would have resulted and the reed beds would have completely destroyed. This plan has not translated into action, so that the population could recover to 210 individuals in 1973. At that time there were but two new threats. Along the lake originated apartments, and the population on the lake increased so much that the reed belt diminished further. Another danger was the spread of the binding diver at Lake Atitlan. It came not only to increased competition for food between the two species, but also to a hybridization and thus a depletion of the gene pool.

In February 1976, there was a severe earthquake in Guatemala. In this quake broke the seabed, and a submarine outflow made ​​sure that the water level dropped by more than 6 m. The divers Reserve now lay on dry land, and thousands of Schilfkolben had to be replanted to save the Atitlántaucher. 1982 this action was interrupted when Edgar Bauer, a long-time companion and supporter was murdered by Anne LaBastille of unknowns.

By 1980, 60 % of the reed belt had been destroyed by the lake. 1983, the existence of the divers had fallen to 32 animals. To the great terror, it was found that most of the surviving birds were hybrids and were no longer able to reproduce. 1989 were counted only two copies. When these two remaining birds also disappeared, the Atitlántaucher was officially declared extinct.

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