This tiny little Goldcrest seeking insects in a very rare display of sunshine is Europe's smallest bird. I have a pair visiting the garden and if you stand fairly still and only move slowly they will let you get very close. Sometimes if you can see which way they are working down the bushes, the trick is to get in front of them near the bushes and let them come to you, very often they will just ignore you giving you brilliant views.
They are related to the North American Kinglets.
