Yellow-bellied Sapsucker Gleaning from Leaves

Also yesterday morning, a female Yellow-bellied Sapsucker was gleaning something from the gray-green leaves and branches of some privet at the edge of the woods. She was very pretty, with a rich lemon-yellow breast, pure white throat and crimson crown. She raked the branches and leaves of the shrub through her bill, and once flew up and appeared to hawk a flying insect from the air. I could not tell if she was getting insects or maybe water or some kind of plant excretions from the privet.