lemongrove the mess appears to be sludgy grey stuff. I initially wondered if it was from the fat balls which are in the next feeder along, but in the past any residue from that was quickly gobbled up by the ground feeders. Mind you now I come to think of it the starlings seem to have deserted us lately. This much bigger residue has only recently appeared since I bought a new feeder, the one a local shop recommended, for sunflower hearts. It’s an area of about 12” in diameter, I’m not so bothered about the grass as merlot says it will regrow, more concerned about visiting rats! The day I spotted the sparrowhawk there were a few little feathers around on the ground and a noticeable dearth of gold finches! But they’re all back again, with various tits and today a nuthatch thrown in for good measure! I’m willing to sacrifice the grass for that treat!