This large atoll consists of 39 islets, most of which are flat and densely vegetated.
The island supports a substantial, mixed species, seabird colony with a high numbers of breeding sooty terns. in addition the island holds important numbers of bristle-thighed curlew during the northern winter.
Non-bird biodiversity: There is a substantial population of coconut crabs, numbers estimates at 2,200 individuals. Small numbers of green turtles may use the island as a nesting area.
Pressure/threats to key biodiversity
There are large numbers of Pacific rat (Rattus exulans) on the island. The island is currently inhabited resulting in some damage around the habitations. Associated with this is the danger of increased numbers of alien species colonising the island together with an upsurge in the extent that poaching of birds and other fauna may occur.
Habitat and land use
Most of the islets are densely vegetated with forests of Pisonia grandis, Cordia subcordata and Tournefortia argentea (Heliotrope). Other areas of the atoll have scrub-type vegetation.
BirdLife International (2022) Important Bird Areas factsheet: Millenium (Caroline) Island. Downloaded from
http://www.birdlife.org on 17/01/2022.