torchy,i have the same problem with my 4 1/2 acre pond in south louisiana.no creek,no ditchs just rain water.i can tell you what i was told by the wildlife & fisheries people,birds have eggs in there feathers and when they visit your pond they drop in your water and some birds eat eggs and pass them threw there system and say still make it.hard to believe but i guess it's possible.i've talked to a couple people about this and i keep getting the same answers.it's pretty common for my pond to have 1 are 2 big white birds around the pond and often i have wild ducks come in and stay for several days.
