Bob Burnett from Barefoot mining. 
The three categories are: 
Elephants: large, easy to target. 

Wild horses: midsize, often in herds but might just be a few. Harder to target because they run fast and change direction quickly. 

Rabbits: small, usu individual miners, hard to see them and, thus, the hardest to target. Lots of them, multiply quickly, and disappear into the grasses/underground dens in a flash. 

 Thanks (and @PentaSophia ). Such categorisations are pretty helpful because they emphasise the dynamics. Thinking too statically seems like a common mistake. 

 Welcome back!