Duck question, need an explanation!

Two years ago I went out to our marsh early one morning to try to photograph some ducks with my crummy little point and shoot (before I had a DSLR). I was laying in the grass and shortly after sunset a small group of ringnecks began swimming past me but there wasn't enough light for I good photo so I switched the flash on. As soon as I took a picture they began getting kind of excited and starting swimming around a little quicker. I took another picture and they began to swim towards me! I kept taking pictures and they eventually came within 10 feet of me. These birds are definitely anybody that would be coming into human contact and I don't know what else could have been on their minds. Has anyone else had similar experiences or was this a freak occasion? thank you.

I have no idea what the birds are thinking but I had a similar experience a few years ago. I was trying to photograph an Elegant Trogon with flash. It was quite a ways out but I wanted to try anyway, since I couldn't get closer. When the flash went off, the trogon flew straight at me and landed on branch within 5 feet of me! Too close to focus with the big lens and I didn't even get a shot.

For what it's worth, I read in a photography magazine recently that some animals will charge you or come towards you when using a flash. The light is an attraction. The article addressed not using a flash around Elk or Moose because they will charge. I read Outdoor Photographer, Popular Photography and Imaging, and American Photo so I am not sure which of these the article was in.

Animals are frequently curious about things that don't fit patterns that they recognize as a threat. I've had mule deer bucks watching me from 20 yards off while I was stacking alfalfa bails, but if you tried to sneak up on that buck in the woods, it would be tough to get within 50 yards of him. I heard of a guy who saw a white tail buck regularly when he was mowing his lawn, but couldn't get any where near him during hunting season. Canada Geese won't get off your dock if you live on a lake in a residential area, but are extremely wary when they're hunted. Geese avoid hunters but ignore golfers. The critters seem to have developed a rather sophisticated threat analysis profile. I've often wondered if any goose hunters have ever tried wearing loud golf clothes and standing out in the open rather than wearing camouflage and trying to hide in blinds.

In my neighborhood, Bluebirds have learned that the sound of the lawnmower will provide them with a wealth of insects to eat. Whenever I mow the lawn, the Bluebirds come from all over, and will fly within feet of me. Try to sneak up on one with a camera though.