Torrent ducks

What's your desert island bird?

I think this may be mine. 

I found this family group (and later their ducklings) navigating the tumbling glacial waters of a mountain stream in the southern Patagonian Andes. 

As a whole, we don't think of ducks as exhibiting much ecological diversity, but once you've seen torrent ducks hunting in water you can't even stay afloat in, let alone swim or stand up in, you'll never look at a mallard the same way....