Source North Lancs Ringing Group (http://northlancsringinggroup.blogspot.com/2017/08/nest-box-statistics.html)

Nest Box Statistics

Further to my last post where the Group had 141 nest boxes occupied by Pied Flycatcher of which 121 were successful I now have data for the occupation rate of Blue and Great Tits in 24 of the woods we record they show some interesting differences.
The 11 woods at lower altitude mainly on the limestone where Ash is the dominant tree species and Pied Flycatchers do not nest Great tits outstrip Blue tits. In total in these woods we had 113 Great tits but only 62 Blue Tits. In contrast in the higher altitude woods with Oak dominant and where Pied Flycatchers also occur we recorded 143 Blue Tits but only 62 Great Tits.
To what extent this is due to the number and size of natural holes is difficult to assess. But the differences occur in comparatively new woods in both areas. Productivity was good as it was with Pied Flycatchers with very few nests lost to predation or dead young in the nest.
John