My husband noticed two hermit thrushes sitting on a post and on a bare rosebush in our yard just now.
One of them dropped to the ground and began rapidly shaking/vibrating one foot in the grass and soon enough caught a bug for the effort. Its whole body quivered with the effort. It repeated this leg vibrating technique a half dozen times with little result and then both flew away. Perhaps this is familiar to others here but I was delighted to both find them in the yard and to glimpse this behavior.
From Cornell’s All About Birds-
“Hermit Thrushes sometimes forage by “foot quivering,” where they shake bits of grass with their feet to get insects. They also typically begin to quiver their feet as they relax after seeing a flying predator. Some scientists think the quivering happens as the bird responds to conflicting impulses to resume foraging or continue taking cover.”
Randolph Center, VT