Every year there's a day when the House Martins use the monument for a mass sit down. I still haven't got the answer as to what they are up to.
At one time there were about two Hundred House Martins either landed on or flying round, the Monument. Not one single Swallow or Sand Martin joined them.
The stone is obviously warm in the sunshine, so I wonder if they are just warming up, using it as a giant radiator. Many of them do have a preen, so it may be that the warmth brings feather lice and other parasites to the surface making the cleaning operation easier.
One of the features of Martins is their short, feathered legs and these can be seen in this picture. The brownish cap and dusky sides to the neck show that it is a juvenile.
As most were juveniles I had the fanciful notion that they were discussing the route that they were about to take on their epic voyage south, but I presume that they are genetically programmed to follow the right directions as indicated by the position of the sun, and if they move at night, the stars. There are lots of theories about how long haul migrants navigate, but however they do it they chat about it before they leave St Margaret's!
There was a sudden a scare and all the birds flew off, a quick look to the sky showed the reason to be a Sparrowhawk patrolling overhead.
The monument was now deserted and remained so for the nest few minutes. I suspect that they returned after I had gone.