Yesterday morning, after I'd parked my car further down the driveway than usual, I noticed that the car roof had been showered with frass overnight. Sure enough, a quick glance up to the cherry tree showed some heavy defoliation high up in the canopy. Later when I got home from work, a quick search with bins revealed a large number of larvae in several groups. I got the ladders out and lopped off a branch with some larvae to check them out and rear through. Turned out to be Buff-tip - another new breeding species for the garden list.