While it may appear that this female Cerulean Warbler is feeding on plant matter, it is actually picking small insects from the tree using its small, sharp beak, a form of foraging known as foliage gleaning. The term gleaning can also refer to birds feeding on invertebrates from other substrates, including mites or ticks on the backs of other animals.

This video accompanies Chapter 8, Avian Food and Foraging, Handbook of Bird Biology, 3rd Edition from the Cornell Lab of Ornithology and Wiley Publishing.

Recorded by Benjamin M Clock, Macaulay Library