Nearly a dozen islands off the far north Queensland coast will close to the public from today because of a rat problem.

The Queensland Parks and Wildlife Service will begin a three-week aerial baiting program targeting black rats on the Frankland Islands and Northern Barnard Islands, south of Cairns.

Ranger-in-charge Warrick Armstrong said the pest rats, or Rattus rattus species, posed a threat to thousands of nesting seabirds in the Great Barrier Reef world-heritage area.

“They cause major extinctions and a decline in island biodiversity around the world, and we certainly know on our Australian islands they have a huge impact on nesting seabirds,” Mr Armstrong said.

“Obviously these islands play a very important part in seabird and migratory shorebird habitat.

“They are damaging seabird eggs, eating hatchlings.

“We also have a lot of visitors to campgrounds, so there’s a risk of disease that’s carried by these pest rats.”

The rats are believed to have reached the islands by “rafting” over on logs during flooding events or by stowing away on boats.

“They are noticeable. There are signs of them, scats and droppings and tracks along the high-tide mark where they are foraging,” Mr Armstrong said.

“They are gnawing on the native cabbage to get moisture because some of these islands don’t have their own water source.”

Seabirds return after earlier baiting program

It is not the first time rangers have attempted to tackle a rat problem on the islands.

A control program was undertaken early in 2000 on the nearby South Barnard Islands.

“We’ve seen a huge return of seabirds to that area since that eradication program,” Mr Armstrong said.

A helicopter will drop baits over the islands for the next three weeks.

Tourism operator Elouise Collins runs a day-trip tour to Normanby Island, which is included in the public closure area.

However, she said the company would be allowed to continue to visit the island during set times.

Ms Collins said she was yet to see a rat on Normanby Island.

“Whatever we take in, we take out … it might be a bigger problem on the islands with campgrounds,” she said.

-ABC