The removal of predators from several islands and the protection of the birds on migration and wintering areas have enabled the population to increase from approximately 800 birds in 1974 to 33,496 birds in the winter of 2000.
(The removal of predators from several islands and the protection of the birds on migration and wintering areas; have enabled; the population; to increase from approximately 800 birds in 1974 to 33,496 birds in the winter of 2000) (the population; to increase; from approximately 800 birds)
The removal of predators from several islands and the protection of the birds on migration and wintering areas the population
have enabled to increase
the population to increase from approximately 800 birds in 1974 to 33,496 birds in the winter of 2000
from approximately 800 birds