They're fairly trainable, but definitely not as cooperative as a domestic species of wyverns, yep! Additionally, if he were to raise one from an egg, it'd be a lot more receptive to commands.

As for things they could learn, though, you got it! Calling, stopping, and in the specific case of paradise wyverns, some light speech mimicry, and also: fetch! Anything you could teach a crow with time and patience, you can probably teach these guys.

(Also, on a whim: we've decided that resplendent pygmy drakes can be taught to hunt truffles. If Claude could use some mushrooms, they're good for that, as well!)