(excerpt) "From the 1920s through the 1950s, we were the American duck business," said Doug Corwin, whose family owns Crescent Duck Farm in Aquebogue. Crescent is the last duck farm in Riverhead, where there once were dozens.

Through the 1950s, there were more than 70 duck farms on creeks and ponds throughout Brookhaven and the five East End towns. Today, according to Suffolk County official...