(Eurasian) Nuthatch
Sitta europaea

Nuthatches are adept climbers and can be seen hanging upside down from branches or descending head-first down tree trunks. These are males, as told by the darker red rump and flanks.
 

  

1: Chard Reservoir, Somerset, 31/01/2007.
2-3: Chard Reservoir, Somerset, 03/03/2007.
4-5: Chard Reservoir, Somerset, 26/04/2006.