Getting its grub

The adult pied wagtail spends its day running about the lawn picking up food and delivering it, often deeply down the throat, to its young.  Often it is a beak full of flies, other times it is a fairly large 'grub'.

During the winter we take part in a 'garden bird survey' and have never seen wagtails in the garden although they are plentiful enough in the yard, feeding presumably on the flies around the stables.