Alien fish species and nylon nets have forced the extinction of a water bird in Madagascar, a conservation group said Wednesday.
The fragile bird, known as the alaotra grebe, was finally declared extinct 25 years after the last confirmed sighting, according to BirdLife International.
"Obviously the suspicion that it has disappeared has been there for some time," said Martin Fowlie, a spokesman for BirdLife, compiler of the "Red List" of threatened bird species.
Scientists hesitated to write the bird off too soon since it lived in a remote eastern part of the African island nation that was difficult to survey.
"We didn't want to declare something extinct and then two years later it pops up," said Fowlie.
There's little chance of that happening after an extensive search last year found no sign of the alaotra grebe.
BirdLife blamed chick-eating bass fish that were introduced to Lake Alaotra and the use of nylon fishing nets that drown the birds.
A similar fate appears to loom for the zapata rail bird, native to the swamps of western Cuba where it is threatened by mongooses and catfish once alien to the area.
BirdLife said wetland birds in particular are coming under pressure as their habitats become polluted and dry out.
Some bird species are recovering, however, including the azores bullfinch and the Colombian yellow-eared parrot, both of which have benefited from conservation measures.