A study expected to be released next week reveals a dramatic decline of two endangered seabird populations over a 20-year-period on Kauai.

Andre Raine, project manager of the Kauai Endangered Seabird Recovery Project, is the lead author of the study that reveals a 94 percent decline of the a’o (Newell’s shearwater) and a 78 percent decline of the ua’u (Hawaiian petrel) between 1993 and 2013, according to news release by the Department of Land and Natural Resources.

The study is expected to be published Monday in Condor, a scientific peer-reviewed journal.

In the release, Raine said feral cats, rats, fatal crashes into power lines and attraction to lights are factors in the decline of the endangered seabirds. “With the majority of our radar sites showing massive decreases in numbers of these birds over the years, populations of the birds are in a rapid downward trajectory — particularly in the south and east of the island. The study highlights just how critical recent conservation initiatives for the species on Kauai are if we are to have to have a hope of reversing the situation.”

About 90 percent of the world’s a’o population and a sizable ua’u population inhabit Kauai.

Since 1993, biologists have used radars mounted atop vehicles at 15 sites around the island to track the endangered seabirds.

The Kauai Endangered Seabird Recovery Project — a joint project of DLNR and the University of Hawaii — will continue to monitor the endangered seabirds this summer through mid-July.