Barad Ding's Eight Cats - Baldur's Gate 2 Side Quest
This quest begins by speaking with Barad Ding in the Hidden Refuge camp. The Hidden Refuge zone is part of the Enhanced Edition for Baldur's Gate 2 and can only be accessed after progressing far enough in Neera's Companion Quest. You will also have to recruit Neera into your party to access the Hidden Refuge.
Barad Ding asks you to hunt down all 8 of his cats which are currently roaming around the Wild Forest zone. This quest can be a bit annoying to complete since the Cats have a very big roaming radius in the areas that they are found. To make matters worse any Cats you capture can escape your inventory once captured.
Cats escaping out of your inventory seems to be completely random and it is not clear to me if they return to the location you first found them or patrol around the area where they escaped. What I typically like to do while completing this quest is to visit the Hidden Refuge each time I capture 3 or 4 Cats and unload them. The moment you enter the Hidden Refuge map any captured Cats will exit your inventory and return to Barad Ding.
Above you'll find a map which details each of the locations I found Cats when doing this quest. Much like I said earlier, keep in mind that these Cats roam around in a pretty wide area. I have done my best to watch the Cats and figure out how big their roam areas are but this is nothing more than an approximation and guesstimate on my part.
Once you have collected all 8 Cats return to Barad Dings and speak with him to complete the quest.