Northern watersnakes are aquatic-feeding generalists that will usually eat whatever is available. Fishes are their predominant prey item followed by amphibians. I have a book on North American watersnakes which lists confirmed prey items for northerns and "bird" is at the end listed under Other. So it's not likely they are going to pluck hummingbirds out of the air, as there are probably easier and more plentiful meals nearby to be had. Hope this helps.

We have been told by some relatives that live on the river that the fish jump up and can catch a hummer. Never thought of that happening!

Try 'Robert Kemp' Cannas - red flowers that hummers love, medium height, and would like the moist conditions around your watergardens.

Thanks everyone!