Jackdaws

We have triangular vent-holes in the barn walls, and every year jackdaws drop twigs through them non-stop for several weeks.  In some years we have removed two six-foot trailer loads of twigs from inside the barn.  So we blocked them up.

But jackdaws are extremely persistent and determined.  Once they have decided where they will nest they generally stick to it for life.  So we had a pair last year who tried to build a nest in one of the blocked vents.  They managed a huge heap of twigs and sheep wool on the ground and about three twigs in the vent.  On which they laid two eggs and successfully fledged the chicks.

They're back!  Twice as much stuff on the ground outside the barn, but nothing in the vent.  They were still at it yesterday but today I think they have finally given up.  I cleared the heap away this afternoon and found two eggs in it - one broken and this one, which is cracked.  I have put it next to a hen egg for comparison.