In bright light, you run the risk of hitting the lowest ISO and overexposing your photo as the ISO can’t go any lower.
For shooting wildlife, we also often use Auto ISO. By setting a high shutter speed and wide aperture, the ISO is typically kept at a lower number. This can save you precious time fiddling with multiple settings. There are two things to be aware of though. In bright light, you run the risk of hitting the lowest ISO and overexposing your photo as the ISO can’t go any lower. In low light, you run the risk of your ISO overcompensating and going too high, making your photo grainy. If you use Auto ISO, keep an eye on the number and, if you see it creeping too low or high, switch back and adjust it manually to balance with the other settings. On some cameras you can set a maximum ISO which won’t be exceeded when shooting in Auto, so you don’t need to manually monitor it.