Gleaning (birds) World flycatchers, Tyrant flycatchers, babblers, Old World warblers, New World warblers, Vireos and some hummingbirds and cuckoos. Many birds make use of multiple feeding strategies, depending on the availability of different sources of food and opportunities of the moment. Foliage gleaning, the strategy of gleaning over the leaves and branches of trees and shrubs, can involve a variety of styles and maneuvers. Some birds, such as the common chiffchaff of Eurasia and the Wilson's warbler of North America, feed actively and appear energetic. Some will even hover in the air near a leaf or twig while gleaning from it; this
The Life of Birds matter had been covered before by Attenborough within "Life on Earth", in an episode entitled "Lords of the Air", but now he was free to expand on it. However, by his own confession, despite being especially fascinated by one family, the birds of paradise, Attenborough was not an expert in ornithology. Nevertheless, the notion of an entire series devoted to the creatures excited him, as he would be able to not only communicate his findings to the viewing audience, but further his own knowledge as well. From the outset, the production team were determined that the sound of birds calling