Ducks, which one?

I vote for the more colourful version, the first one would require more contrast to work.

I admit I've never much liked high-key portraits (I prefer deep moody shadows!), but there were some excellent high-key portraits here a while ago. My understanding of the genre is that you use enough light to blow out all the shadows, and usually saturate the background too.

In the studio you can take the time and adjust the lights to get this to your satisfaction, but by the lake it is more tricky. The nearest I've come to that is with the sun behind the subject and reflecting on the water in a blaze. Then you have the choice of exposing for the bright bits (with the ducks in deep shadow), or exposing for the shadow and pushing the bright bits all white for high key.
Either way you'd have more contrast than in your picture.

To make your ducks high-key, I'd add an extreme S-shaped tone map to salvage some contrast in the ducks, but I think it might be better to try again with bright sunlight behind the ducks.

The overall contrast between light and dark extremes is less because all the whites are burned out, but you still need a few stops of dynamic range there, otherwise weak contrast makes for a weak image ...
There are quite a few web sites about high-key but most are aimed at portraits. Reading rarely does any harm