Flock

Once you’ve charmed one of each Cosmet, you’ll need to keep charming a few dozen more to earn Expert status. They’re located in a number of places, but if you use the feeders (available after completing the story when you retrieve Jane’s Feedbag) that are near the starting hill (where Jane, Nadiya, and Reg are located), you’ll attract at least one or two each time. There are multiple feeders near the top of the hill, and even with the cooldown times needed, I was able to circuit them one after another and rarely had wait for long to use it again. The one directly between Jane and Nadiya would sometimes attract three at once.

In between uses of the feeders, there are usually a couple of Cosmets roaming the grass one the hill. Between the feeders and the randoms, it only took about twenty minutes to max this out.