Marines at Käne'ohe Bay are due to help endangered native birds this week by driving amphibious assault vehicles through the mud as part of three days of exercises that begin today.

The annual exercises at the Nu'upia Ponds Wildlife Management Area at Marine Corps Base Hawai'i are called "Mud Ops."

The vehicles break up weeds on mudflats, improving foraging and ground-nesting opportunities for endangered Hawaiian stilts that live there.

Without these efforts, the invasive pickleweed would crowd the birds out of their natural habitat.

The number of Hawaiian stilts using the ponds has grown to 160 from 60 since the Marines began Mud Ops 28 years ago.

Other native and migratory waterbirds have also started using the Windward O'ahu ponds more.