Yellow-rumped Warblers sometimes hang out in large flocks, but the flock in the park this morning numbered two or maybe three. They move so fast, and hide so well in the shrubbery and rocks, that they defy an accurate count even of this small number. I saw one of them foraging on the ground on the edge of the area set aside as a Burrowing Owl preserve. She was quite shy and quickly vanished, but allowed me to take a casual snapshot or two. Later I saw two (or three) darting on and between the rocks on the north edge of the preserve.
The Cornell bird lab website has these “Cool Facts” about Yellow-rumped Warblers:
- The Yellow-rumped Warbler is the only warbler able to digest the waxes found in bayberries and wax myrtles. Its ability to use these fruits allows it to winter farther north than other warblers, sometimes as far north as Newfoundland.
- Male Yellow-rumped Warblers tend to forage higher in trees than females do.
- Yellow-rumped Warblers 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. Other places Yellow-rumped Warblers have been spotted foraging include picking at insects on washed-up seaweed at the beach, skimming insects from the surface of rivers and the ocean, picking them out of spiderwebs, and grabbing them off piles of manure.
- When Yellow-rumped Warblers find themselves foraging with other warbler species, they typically let Palm, Magnolia and Black-throated Green warblers do as they wish, but they assert themselves over Pine and Blackburnian warblers.