About 6 years ago, I acquired a Sigma 70-300mm telephoto zoom lens and attempted to use it to photograph birds at Pearce Estate Park. Shooting chickadees with the lens at 200-300mm without a tripod was quite challenging. The little chickadee rarely stayed still. He kept flitting about and it was hard for me to keep the camera steady at that focal length. Every time the chickadee moved, I had to move as well. I think he found me curious and was toying with me. I count myself lucky that I was able to snap two photos of the chickadee that are more or less in focus.
I still have that lens, but I don’t think I’ve really used it since the day I shot these. I rarely have a need for such a long focal length. I’m much happier with a wide angle lens.