Follow the Tripods link for frequently asked questions about tripods. Gitzo also makes fine tripods which are popular among professional photographers. The most expensive Velbon tripods are less expensive than the others listed here and may be an option for birders on a budget. A recent consolidation in the market now has Bogen owning or reselling Gitzo. However, the weight makes for a steady scope in the wind.
Some people find the heads too heavy, making the tripod assembly top heavy.
The quick release plate for the micro-fluid head is nice, especially for switching between scope and camera. The quick-release leg levers are handy, but take some strength to operate and have a reputation for coming loose. A few birders report tripod collapse as a result. The levers can catch twigs, hair, and binocular straps. Legs can open noisily if not careful.