Mysterious bird behaviour

QI would be grateful if you could explain some mysterious behaviour. Over the past year we have had a Dunnock peck at the handle of our French doors to the patio. This has happened often through the day and it does not appear to be seasonal. It’s very mysterious behaviour and I cannot think of a reason for it. Nigel Young, Neston

AIt’s hard to be sure, but this is a behavior noted in several species of small birds. There are a few possibilities. One is that it is picking tiny mites, spiders and insects off the handle or doors. Another is that it is territorial behavior of some sort, although this more often involves pecking at the window itself (and its own reflection). Finally, as it sounds rather tame (being willing to come that close to the house), it could be reminding you to refill your feeders!