HILO, HAWAII – Hawaii is the only state without rabies. It's also the lone one without native land snakes. Most of the flora and fauna arrived on the currents of wind and wave, and they've evolved with very few predators.

Protecting the endemic wildlife is a challenge, leading scientists to call the Aloha State the endangered species capital of the world. Whole flocks of sand-nesting birds have been ravaged by pet dogs let off the leash. Feral cats and mosquitoes pose constant threats to endemic songbirds, and fast-growing alien plants and trees crowd out the native rainforests.

Rep. Ed Case, who represents Honolulu in Congress, is concerned. He and fellow Democratic Rep. Tulsi Gabbard introduced a bill earlier this month to fight invasive species.

"Our bill, the Hawai'i Invasive Species Protection Act, will require the U.S Department of Agriculture (USDA) Animal and Plant Inspection Service (APHIS), in cooperation with other federal departments and the State of Hawai'i, to conduct visual, x-ray and canine inspections, as appropriate, on person, baggage, cargo and any other article destined for direct movement to the State of Hawai'i," Case said before the House of Representatives. "The inspections will search for high-risk invasive species and agricultural materials. The inspections will be conducted at airports, ports and postal sorting facilities prior to direct travel to the State of Hawai'i."

But for all the threats invasive species pose, policies in place by the U.S. government focus on keeping problem species in Hawaii and off the U.S. mainland, as federal officials note, rather than protecting Hawaii from incoming invasive hitchhikers

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service has screening equipment and staff scrutinizing luggage before it leaves Hawaii airports.

"Hawaii has many exotic plants, beautiful flowers and delicious fruits and vegetables that are unique to the state. Hawaii also has many insects and other pests that are common to the Islands but not found in the continental United States," says William Wepsala, a spokesman for the USDA Animal and Plant Health Inspection Service. "Some of these pests, such as Mediterranean fruit fly, could cause millions of dollars in damage, expensive eradication efforts, lost trade revenue and higher food prices if they were to establish in the mainland."

Passengers and luggage coming into the state, however, don't undergo the same scrutiny. Wepsala says the Hawaii Department of Agriculture has that responsibility, not the federal government.

That also causes problems for the state, the U.S. Fish and Wildlife Service says in a 2012 proposed rule published in the Federal Register. (A variation of the rule was finalized in 2013.)

"Pests of quarantine concern for Hawaii may be intercepted at Hawaiian ports by Federal agents but are not always acted upon by them because these pests are not regulated under Federal mandates. Hence, Federal protection against pest species of concern to Hawaii has historically been inadequate," the federal agency says. "Adequate staffing, facilities, and equipment for Federal and State pest inspectors and identifiers in Hawaii devoted to invasive species interdiction are critical biosecurity gaps."

Instead of screening luggage coming into Hawaii from the mainland, there's a declaration form and a voluntary amnesty bin where disembarking passengers leave forbidden fruit – and sometimes even snakes – before exiting the airport.

There's some dispute about the reliability of the forms: 71% of items found by detector dogs in the baggage claim area of Maui's Kahului Airport – primarily apples, bananas and oranges – were not declared on the forms in a 2000-2001 risk assessment survey conducted by the plant quarantine branch of the Hawaii Department of Agriculture.

But Jonathan Ho, acting manager of the Plant Quarantine Branch, defends the forms.

"The questionnaires are successful and all incoming domestic flights have the forms submitted to state plant quarantine inspectors for review. Inspectors routinely confiscate regulated fruits and vegetable and occasionally illegal animals," Ho says.

He says the alternative of screening incoming passengers and luggage would be "orders of magnitude more expensive," likely tens of millions of dollars.

Printing, tabulating and processing the forms costs about $657,000 annually, which is paid by the Hawaii Tourism Authority with funding it receives from the state Legislature. One side of the form contains the mandatory agriculture declaration; the flip side is a voluntary survey used by the tourism agency.

The educational value alone makes the forms worth the expense, Phyllis Shimabukuro-Geiser, chairwoman of the state Board of Agriculture, said in testimony earlier this year to the state House Committee on Agriculture and Tourism.

"Like all regulations, education is the primary mechanism to gain compliance as the vast majority of the public are able and willing to comply with the rules and regulations. The declaration form is an invaluable educational tool that begins the process by informing visitors that Hawaii is unlike the rest of United States and that there are additional requirements to maintain Hawaii's unique environments," she said.

Any person who defaces the Plants and Animals Declaration form, gives false information or fails to declare restricted items may be guilty of a misdemeanor, which could be punishable by a maximum penalty of $25,000 and/or up to one year imprisonment. Intentionally smuggling a snake or other prohibited or restricted items could result in a maximum penalty of $200,000 and/or imprisonment of up to five years.

The 2000-2001 Maui study acknowledges mixed results. Passengers who don't properly fill out the forms face penalties, but generally, most of the items they brought in during the time period weren't an environmental threat, the study concludes.

"While passengers may pose a low risk of entry of pests into the islands, passengers are undoubtedly the high-risk component or pathway for smuggling," it concludes.

The Hawaii Legislature wants to know more. A concurrent resolution asks if the forms need to be modified, or if the money to print, collect and process them could be better spent elsewhere. The state Department of Agriculture and the Hawaii Tourism Authority are tasked with producing a report before the Jan. 15 start of the regular legislative session.

State Sen. Lorraine Inouye is a Democrat who chairs the Senate Transportation Committee, which includes oversight of the state's airports. She's also a participant in the Hawaii Invasive Species Council.

The state has recently hired a consultant to coordinate state and federal endangered species permitting with a special emphasis on long-term planning for airport operations, Inouye says.

There's also a multi-agency program funded by the state Department of Transportation to monitor and trap invasive species at six airports, and the Department of Health has vector control traps to control and monitor mosquitoes, rats and mice, she says. Those two programs alone cost more than $500,000 annually.