My wife and I acquired the Wand of Finding memento recently. After putting it in a quickslot, we tried using it on various creatures - chickens, pony guar, rats, bog rats, etc - in the Deshaan area but it didn't work for either of us. I saw a video of someone using it on a pony guar, so went back out and tried again on another pony guar, and it still had no effect. We just get the message that the target is invalid.
I contacted support, and they said it should work on small, non-aggressive creatures; otherwise it's a bug. So here we are, bug report filed