My cameras are lighter than yours (40D primary with a sigma 120-400) but birds in (high) flight and tripods rarely work together for me. This is partly because I'm too tall once the camera is tipped back.
For low-flying birds (as well as perched/static birds) I find a single locking control essential. And it's important that you support the camera/lens as close as possible to the centre of gravity. I've chosen a light ball head and mount via the lens bracket. Even unlocked you get quite a lot of steadying. Weight is an issue for me as I can be hiking all day with a full kit, so the light head (I have a slik and a manfrotto, there's no significant difference between them) is paired with manfrotto carbon legs. A head with separate pan/tip/tilt locks was infuriating especially because the hinges for tip and tilt were too far from the centre of gravity. I have only used a gimbal had with a scope. I liked it but not enough to buy one.
My spare tripod is an ancient aluminium thing, with the traditional single twist-arm lock. For moving subjects it gets in the way and takes my hand away from the camera controls (not just the trigger for which a cable release would be a solution).
You might choose a more upmarket head but I suggest that a single locking control (though you don't need to lock pan) and all pivots in a vertical line are essentials. Even if you're not expecting to walk far carrying your kit, this may change, so watch the weight. In heads you can get cheap and light, though they're obviously basic. In legs you have to pay to keep the weight down, so go for carbon upfront. I also don't find monopods much use for moving wildlife - with the head unlocked they move too much, with it locked you're too restricted. The exception is if you can clamp/strap them to something as in some hides.