Oh yes, calls can fly. Here are two references, not great, but I only have a couple minutes between classes right now..
http://www.terrascritters.com/xbantamcallducksx.htm under general call duck info
http://www.feathersite.com/Poultry/Ducks/BRKDucks.html
in the section about mallard-derived breeds.
http://www.terrascritters.com/xbantamcallducksx.htm under general call duck info
http://www.feathersite.com/Poultry/Ducks/BRKDucks.html
in the section about mallard-derived breeds.