KIHEI >> Researchers are concerned about the number of cats near a Maui wildlife sanctuary that’s home to endangered birds.

A survey in an area that includes Kanaha Pond State Wildlife Sanctuary found more than 1,000 free-roaming and feral cats. While the survey showed the cats don’t congregate in large numbers at the sanctuary, experts say there should be increased efforts to ensure native species are protected, the Maui News reported Monday.

"Kanaha Beach Park has a very high density of outdoor cats and should be an area of serious management attention," said wildlife biologist John Boone. The local chapter of the Humane Society of the United States contracted with Boone to coordinate surveys at Kanaha and Iao Valley.

The local chapter of the Humane Society of the United States said a survey was necessary to get a handle on Maui’s cat population and monitor management efforts. Estimates have ranged from a few thousand to a half a million.

"Obviously these cats ended up here through no fault of their own, and it’s our responsibility to do what we can for them," said the society’s Hawaii state director, Inga Gibson. "There’s no easy answer. This issue has been going on for many years but I’m optimistic we’re taking steps in the right direction."

There were pockets of areas such as in lower Kanaha Beach Park were many cats weren’t sterilized, Boone said.

"If you’re trying to manage cats, if most of the city has a high sterilization but there are four or five pockets that have low sterilization rates, those four or five pockets can do a lot of damage to the overall enterprise," he said. "Incomplete sterilization coverage can have a lot more of a negative effect than people appreciate."