HONOLULU — The initial phase of a federal and state effort to rid Mokapu Island of rats has been completed.

Officials say the eradication project using a rodenticide will be declared a success in two years if no rats are found on the island north of Moloka'i.

A helicopter was used Feb. 6 and 12 to drop fish-flavored, compressed cereal grain pellets containing the poison diphacinone.

Officials say aerial application was the only safe and practical method of spreading the rodenticide to areas as steep as those on Mokapu.

The island is home to Polynesian rats, which are known to kill and eat native seabirds and to eat rare plants and their seeds.

Officials say eliminating the rats will greatly benefit the island's native species.