The acrobatic blue tit

The blue tit prefers insects and spiders for its diet. But outside the breeding season, they also eat seeds and other vegetable-based foods. The birds are famed for their skill, as they can cling to the outermost branches and hang upside down when looking for food.

Blue tits are able to culturally transmit learning to other tit species. An example of this, dating from the 1920s, is the ability to open milk bottles with foil tops, to get at the cream underneath. Such behaviour has been suppressed recently by the gradual change of human dietary habits (low-fat or skimmed milk instead of full-fat), and the way of getting them (from a supermarket, instead of the milkman).

Thanks Wikipedia!