This set of images were photographed during a recent Ray Hennessey field trip that I attended. I took a lot of photos of birds that morning. I am still reviewing each shot to find keepers.
The birds fly quickly between the branches of the low trees eating insects. When they stopped, I had just seconds to compose my photograph and push the shutter. I had the frame rate of the Fujifilm X-T2 set on continuous high with camera mode set to performance boost. The camera as shooting at 11 frames per second.

FujiFilm X-T2 + XF100-400mmF4.5-5.6 R LM OIS WR @ (400 mm, f/5.6, ISO2000), © Khürt L. Williams
You can learn more about Ray Hennessy's work and signup for his workshops on his website. You can learn more about the Prairie Warbler at the Audubon Society’s website.

Prairie Warbler —
FujiFilm X-T2 + XF100-400mmF4.5-5.6 R LM OIS WR @ (400 mm, f/5.6, ISO2000), © Khürt L. Williams
I think what you’ve got there is a prairie warbler. With the black mask and the rusty shoulder patch. (I’d peg it as a Townsend warbler if we were on the west coast.) check it out on the Cornell Ornithology site.
@irmina65 ??