Stonechat

Went for a stroll along Donabate beach this afternoon and this Stonechat was chirping noisily at me  --- he has a nest nearby and he is distracting me from it.  I also saw a gull repeatedly dropping something onto the sand (see extras). I know they often drop shellfish and mussels onto rocks, to try and break them open and get at a meal, but this guy was dropping his potential lunch onto sand, from about 15' or 20' up, and it wasn't clear this was going to have any effect! I couldn't make out what it was (perhaps a whelk?), but bouncing it off sand wasn't going to have a huge effect. Maybe the gull is not very bright, or maybe he was after something other than breaking a shell?