Hi there I have had 2 x Bluetits started building a nest in my box complete with camera we were wondering why does the female take nest material out when she’s took so long filling it ???

It is possible it is another female blue tit that has taken over the box so she may remove the other female's nesting materials in favour of her own.

We are also seeing this behaviour. I have the RSPB sparrow terrace up since Feb last year.

A bluetit roosted in one of the boxes over winter.

Lots of checking the box out through spring.

Now there is a pair of bluetits keep filling the box with moss.

The female brings most of the material. Male brings some occasionally. The male also occasionally has brought her insects and catapillars and fed them to her.

Then she empties it again and moves to one of the other boxes. Fills that and then empties it again. Seems like a huge amount of wasted effort!

I'm not sure if it's confusion and she can't tell between the three entrance holes or if she knows they're three different boxes but is trying to decide which one to use.

As far as we can tell it's the same female because she has some quite tatty feathers that we can identify her by.

Hopefully at some point she will stop emptying / trying all three boxes and commit to one.

Not sure. Its my first time observing any of this.

Here is the state right now...

I am seeing the same thing. Blue tits busy bring nesting material in but now suddenly I now keep seeing the female busy removing material out. She just drops it outside the box. We also have more than one box up which they guard even though they are 40 ft apart. I also have great tits nesting in a box only 20ft away from them but no fighting between them, intact they share the same perching tree with no issues.
I may take down other box to see what happens.

Yes, mine are doing this too, taking moss out of the box. I was worried they might have decided to use a different nest site and were raiding their supplies from this one, is that a possibility anyone?