Sounds like a great team and a lot of fun!
Ideally it should be illegal to buy wild caught ones (imho)
Yes it should be. However many are used for medicine, food source, souvenirs etc. Wikipedia has quite an article on them
I wonder if Canada Geese could be used the same way. I could show researchers a seemingly endless supply of the filthy pests! You think ducks are bad? Ducks aren't even in the same league!
They have so many ponds & food sources here in crop fields that they stay here year around. Not all, but the vast majority does, anyway. They make such a mess at the local park that the town hired a guy with a dog, a kayak, and a remote-control toy boat to run them off. If the birds are on shore he sends the dog to chase them off. If they're on the water, he sends the boat in to run them off. If that fails, he gets the kayak out and heads into them. The whole idea, of course, is to harass the geese so much that they go somewhere quieter.
Here in Israel we use falcons for this job, in air filds where wild bird can be a threat. If there was a guy with a trained eagle I can guarantee you that they would fly and not come back!