The decline of the Atitlán grebe began in 1958 and again in 1960 after smallmouth bass ( '' Micropterus dolomieu '' ) and largemouth bass ( '' Micropterus salmoides '' ) were introduced into Lake Atitlán . These invasive species reduced the crabs and fish which the grebes depended on for food and the fish even killed the grebe chicks . The population of the Atitlán grebe declined from 200 individuals in 1960 to 80 in 1965 . Thanks to the conservation efforts of Anne LaBastille , in 1966 a refuge was established where this species was able to rebound . The population recovered to 210 in 1973 . Unfortunately after the 1976 Guatemala earthquake , the lake bed fractured . An underwater drain led to a fall of the water level and to a further severe decrease of the number of grebes . In 1983 only 32 individuals were left , of which the largest part were hybrids with the pied-billed grebe . The last two birds were seen in 1989 , and after they disappeared the Atitlán grebe was declared officially extinct
1976 Guatemala earthquake
1976 Guatemala earthquake
Atitlán grebe