Long Lens Support - Tripod, Mono or Both?

Got my 500 today and my Gitzo should arrive tomorrow. I was thinking about licking up a monopod to use interchangably with my Sidekick but wasn't sure it was necessary or beneficial. Any of you guys use both and why? Do you find that you like one better than the other?

Very much depends on what you use it for. Monopods are a good choice for things like motorsports, where quick changes of angle are required. For sitting in a hide for hours or even days/weeks at a time a tripod is very much easier.

How about walking for birds, both in flight and stationary, as well as general wildlife when not in a blind?

For on the move I'd probably use a monopod.

Sounds like you want a monopod. I'd suggest a QR as well, so you can switch around quickly as well.

A tripod is heavier, bulkier, costs more and is meant for a more stationary approach. Plus, depending on the lens you'll ideally want a gimbal mount... Which definitely adds to the overall weight/bulk/cost.

Honestly, for BIF I prefer shooting freehand. Kick the IS into mode 2 (panning) and go to town. Most birds (in my area at least) tend to move pretty quickly and they don't always have predictable flight paths...