Unusual nesting sites

[david2004]

Earlier this year I was disappointed to find that for the fourth year running, no House Martins had used the specialist nestboxes provided. I kept checking, and nothing. Then suddenly one morning I was in the garden and saw a Blue Tit emerging from it! I had seen a few curious birds go up to it, but then fly off.
I continued to watch every day and some very health babies were hatched. They left early in June and are regular visitors to my bird table.

Has anyone else found birds nesting in unusual places?

Tp

[Tero]

How does the Martin box differ from a Blue Tit box?

[david2004]

How does the Martin box differ from a Blue Tit box?
It's different because House Martin's nests are mud in a shape of a closed cup and I bought artificial versions of those, and Blue tits nest in traditional nestboxes with normal nest materials.