A printing error is causing people to accidentally call a phone-sex line, instead of getting information on ordering duck stamps.

The card carrier for the duck stamp mixed-up two numbers, so instead of spelling out 1-800-stamp-24, the number spells out 1-800-tramp-24.

People calling that second number are getting charged $1.99 a minute.

The U.S. Fish and Wildlife Service, which runs the duck stamp program, says it would cost around $300,000 to reprint the cards.

So the agency says it won't do that because that would take away needed funds for wildlife conservation.