Have you seen young tits?
In any case, the volunteers of NESTKAST (national network for STUDIES at nest KAST brothers). They are celebrating their tenth anniversary with an extensive report of the breeding season of 2018. It reflects an impressive amount of work. In the mild, very sunny spring, Great Tit and Blue Tit accelerated their breeding process to anticipate the caterpillar peak. Among others, the Starling and Collared Redstart breed very successfully.
Read more about the NESTKAST working group on the Sovon website