The Alaotra Grebe (Tachybaptus rufolavatus), also known as Delacour’s Little Grebe or Rusty Grebe, is or was a grebe found only on Lake Alaotra and surrounding lakes in Madagascar. The last sighting (which may have been a hybrid with the Little Grebe) was in 1988 and it may well be extinct, but all areas of remaining habitat have yet to be thoroughly searched.
This species declined in the course of the 20th century, mainly due to habitat destruction and predation by introduced snakehead murrel (Channa striata) (Andrianandrasana et al., 2005). Also, the few remaining birds increasingly hybridized with Little Grebes which use the wetlands as a migration stopover site; as the species differed in several key aspects, the hybrid birds may have suffered from decreased fitness, to the detriment of the rufolavatus gene pool.
The rediscovery of the Madagascar Pochard in 2006 (which also went extinct on Lake Alaotra) may be taken as an indication that searches should not be postponed. Unlike this species however, the grebe had poor powers of dispersal and was never found elsewhere.
Filed under: CRITICALLY ENDANGERED |