Eggs - pipe watch No 1

I spotted this rusty iron pipe last year and for some reason had a look only to find baby birds waiting for mum to feed them.

Passed it again today and had a peek - low and behold mummy bird has laid her clutch in the same pipe again.

I waited for ages to see what sort of bird had laid the eggs but I think our presence was scaring her off so gave up and will come back for another look next time we pass.

I am going to attempt a series of blips hopefully from when they hatch to when they have fledged! Watch this space.

If any of you knowledgeable bird blippers can tell me who laid the eggs that would be useful.