Yellow-rumped Warblers

Yellow-rumped Warblers are impressive in the sheer numbers with which they flood the continent each fall. Shrubs and trees fill with the streaky brown-and-yellow birds.
The Yellow-rumped Warbler is the only warbler able to digest the waxes found in bayberries and wax myrtles. They are perhaps the most versatile foragers of all warblers. They're the warbler you're most likely to see fluttering out from a tree to catch a flying insect, and they're also quick to switch over to eating berries in fall. There are two separate races, "Audubon's" (western) and "Myrtle" (eastern).
"A large flock was encountered eating wax myrtle berries in Burkes Garden on October 17, 2015. The registered count was 24, but many were flying away that could not officially be counted."