Nuthatches go down tree trunks headfirst, treecreepers go up, if you can't see the bird clearly enough.
Nuthatches also scold you for being there loudly, like wrens and robins do..
If you have nuthatches and jays, keep a sharp eye out for goldcrests in hedges- they often like the same sort of territory,
and are often peeping to each other in pairs. So so tiny...