First of ..... WELCOME to the frustrating and expensive world of bird photography!
Now to your post ...... I am not a fan of the new RF600mm or the RF800mm lenses. They are Canon's idea on how to get folks into inexpensive long lenses. The f/11 aperture just does not work for me. My daily bird "kit" is the R5 camera body and the new RF100-500mm lens. I also have a version II Canon 500mm f/4 prime lens for the days when the light is really really bad. There are lots of good camera and lens combinations for bird photography
My suggestions
- Shoot often and a lot .... backyard birds will as subjects work too
- Shoot on a tripod or good monopod when you can .... but you will find yourself being in handheld situations a lot as well
- Shoot in manual or shutter priority .... keep your shutter speed up as high as the light will allow
- When shooting handheld lock you elbows into your ribs or your sides .... makes things "sturdier"
-Do not let the camera and lens wander out in front of you .... if you have to move your eye forward to the viewfinder your arms are not tight against your body
- Do not get caught with "Buck Fever" ...... in other words do not throw your camera up and press the shutter "praying and spraying"
- Find a location to shoot gulls or other slow flying birds with regularity .... a beach, a lake, some shopping center parking lots and most all landfills have Gull populations. Be patient and learn how to lock focus on the birds head / eye .... Be smooth / Shooting birds in flight is rhythmical ..... think about panning when photographing a fast moving car going by
Message me (if you want) or ask questions here and I will try to help