According to an article in BB this month Marsh and Willow Tits may have dropped in numbers due to fragmentation of woodlands preventing re-colonisation and increased predation by GSWPs
For more details get BB
:)
S
There are certainly a few sites around us that has lost them in the last few years in fact I can only think of one site fairly close by that has both Marsh and Willow tits on a regular basis.