The e-Duck Stamp would become a permanent part of federal law under legislation passed by the House Monday. Since 1934, migratory waterfowl hunters over the age of 16 have been required to buy the federal migratory bird hunting and conservation stamps, or duck stamps, at post offices or sporting goods stores. But four years ago, eight states joined a pilot program allowing them to sell temporary duck stamps through the Internet. The bill's sponsor, Rep. Rob Wittman, R-Va., said that program has been a success and it was time to make it federal law.