Great Crested Grebe #58

We had a couple of hours at Yarrow this afternoon. The light was poor, but with Great Crested Grebe humbugs, it wasn't a wasted journey. 
The pair had two chicks that were quite big - probably a few weeks old, but still small enough to climb onto Mum's back. Dad went off fishing and came back with this fish that he wouldn't give up for quite some time. I'm not sure if this is designed to teach them to work for their food or what?