best settings for birds & BIF?

Hi all. I am going to have my first attempt at bird shooting tomorrow, [Sat] both stationary, at least as stationary as they can be, & also in flight. The weather is set to be cloudy & overcast, & I will be at a wildfowl sanctuary. My kit will be 7D with Sigma 120-400 OS, & 70-200f/4 IS L. Although I am a relative newbie I have done most of my work in manual, but feel I may not have the luxury of time to work out settings for the unexpected shots. So my question is, what is the best mode to use? I will also be taking a tripod & wired remote. Any advice to make the day  a success would be very welcome. Cheers.

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lee uk.
There are old pilots, & there are bold pilots, but there are no old bold pilots.