Calling?

The peregrine on the tower this evening was sitting on a ledge I've not seen used as a perch before.

This is on the NW corner of the tower.

He (assuming this is CR) was calling every few seconds.

Does this mean that he is lonely, or that there is a second bird he is calling to?

(An update - Alice was at Bishop's Cleeve at this time - info from Bob Telford)