Hi Rowly, glad to hear everything is going well. When it comes to brooding time, you may be surprised to find that the brooding instinct will probably kick in after the hens have been laying eggs for a while. It almost seems that the early eggs are practice and at a point in time they begin to accumulate eggs for brooding. The nesting cylinders are very effective lures (even for wild ducks). As far as numbers are concerned, with 17 acres you are no where near overpopulation. Your bigger issue will probably be roosting capacity on your island. The birds will leave the island to seek relief on their own and will be subject to predation at that point. Duck books will quote large numbers per acre, but I don't think going above 10 or so is a good idea if you want a healthy margin. If your pond is receiving fresh water constantly, it also could support more birds. At this point you should be seeing some adult type activity such as courting and showing off - they do mature early.
Jim
