Blue tit egg laying

We have a bird box with a camera and a metal plate on the entrance suitable for blue tits.  Last year we had a successful brood, initially with seven eggs, from which four chicks fledged.

This year, for the past three or four weeks a female blue tit has been very busy first collecting moss, and then several days collecting feathers.  Usually she has slept in the box overnight and been away most of the day, except when returning with materials.  Then on Friday last I noticed that she was spending a lot of time in the box around lunchtime, looking somewhat agitated.  On Friday morning there had been no eggs, so imagine my astonishment when I glanced in later that day to find SIX eggs in the nest depression!!  On Saturday she added a seventh, and she is now sitting for long periods.

I thought that the usual style was for one egg a day, so found this behaviour really unusual - does anybody have any comments?

Thanks

Andrew

  • Since I have been watching blue tits in my nest box with a camera over the last ten years or so, the initial egg lay has always been at least 3 or more. The final eggs may be laid singly and generally the most eggs are laid in the first batch.
    This year in one day our nest had 12 eggs laid in one day but we have subsequently found that we have two females sharing the nest and incubating the eggs together at the same time! Now we have 18 eggs! Even so, this means that they laid an average of six eggs each on that first day. the second day there were 3 more eggs and an additional 3 on the third day. Exciting times ahead.
    Mike