its defo only one bird, they have nested there for three years and theres always been a pair, they nest in januery and rear 2 or 3 rounds.
ive had the pigeons on my hand feeding them, but i wont let them in the loft. im sure they would have come in if i allowed it. this year its just 1 bird, the nest is empty most of the day. thats my concern. its tempting to take the eggs, but as mentioned before, its nature.