Snake biologist here, I know I am late to this thread but a snake showing up at your pond means that it is thriving. Water snakes are not really huge into egg-eating, in my experience. They certainly will not bother adult ducks. They like to eat fish and frogs, generally. Sounds like you've made peace with the fellow, which is awesome. They are very cool to have around and some people even feed them little fish snacks! They are quite intelligent and seem to learn that people might feed them.
As far as snakes to "watch out" for, ratsnakes tend to be coop raiders. Kingsnakes might as well, though not as frequently. If any of these dudes show up, it's pretty simple to move them a couple of miles away and you should be set. Venomous snakes don't generally bother people too much if you leave them be, but I recommend calling a snake removal service if you are not comfortable having them around. Sometimes, just a local snake enthusiast will do it for free to save a snake's life.
Falcon500 is correct, it's much nicer to have this safe guy occupy this niche rather than a more problematic cottonmouth, who also loves fish, frogs, and water.
As far as snakes to "watch out" for, ratsnakes tend to be coop raiders. Kingsnakes might as well, though not as frequently. If any of these dudes show up, it's pretty simple to move them a couple of miles away and you should be set. Venomous snakes don't generally bother people too much if you leave them be, but I recommend calling a snake removal service if you are not comfortable having them around. Sometimes, just a local snake enthusiast will do it for free to save a snake's life.
Falcon500 is correct, it's much nicer to have this safe guy occupy this niche rather than a more problematic cottonmouth, who also loves fish, frogs, and water.