WASHINGTON (AP) - The popular "duck stamp" program, which has generated some $700 million for wildlife habitat preservation since its inception in 1934, will go electronic on a trial basis under legislation approved by Congress Monday.

The measure passed by the House would set up a three-year pilot program in 15 states enabling hunters, conservationists and stamp collectors to purchase their duck stamps over the phone or Internet. The vote was 358-4.

"Hunters will be able to spend more time enjoying nature rather than waiting in lines to purchase their duck stamp," Sen. Mike Crapo, R-Idaho, said in an earlier statement. The bill has already cleared the Senate.

Under the 1934 law, all migratory waterfowl hunters 16 years of age or older must buy a federal migratory bird hunting and conservation stamp annually.

Revenue from the stamps, different from hunting licenses, have been used to preserve some 5.2 million acres of migratory waterfowl habitat.

Rep. Greg Walden, R-Ore., said 122 million stamps have been sold. He said that if the three-year pilot program proves successful, Congress could act to make the electronic sales permanent.