Try a monopod with a head like the Desmond (22 lb.) or Sirui (33 lb. capacity).
There are many to choose among, but the monopod itself should have a weight capacity similar to the head. A rough guideline is that monopod/head should be rated for about 3X the weight of your heaviest lens/camera combo.
Desmond DMH-2X1:
https://www.bhphotovideo.com/c/product/1345432-REG/desmond_dmh_2_x1_monopod_head_with_clamp.htmlSirui L-10:
https://www.bhphotovideo.com/c/product/892554-REG/Sirui_bsrl10_L_Series_Monopod_Tilt.htmlMonopod heads like these are pretty simple. They only have a single movement.... tilt. That's all you need with a monopod since you can rotate the whole rig for a panning action.
A monopod and monopod head would be about the lightest setup.
A gimbal head is the alternative and there is now even one specifically for use on a monopod. I haven't used it, not sure I'd like the way it sets the lens off to the side. But other folks like it.
https://www.bhphotovideo.com/c/product/1513932-REG/wimberley_mh_100_monogimbal_head.html Watch Steve's review:
https://www.youtube.com/watch?v=Fgj8bMviZOwSteve also has a video about using a full size gimbal head on a monopod, which makes for a pretty hefty rig:
https://www.youtube.com/watch?v=6wbQgQKqglcI have a monopod with an old ballhead on it. That works okay, but is best used with the head locked, which isn't ideal for birds in flight. It happens to be a single knob ballhead, too. One control knob locks or releases all the movements. The size of the ballhead matches the monopod pretty well, but I only use it with relatively light telephotos lenses (incl. a 300mm f/4 that weighs under 3 lb. and up to a 100-400mmm that weighs around 4.5 lb.)
The good thing about a monopod is that it can be relatively light and compact. A bad thing about one is that it can't just stand on it's own with the camera & lens installed, the way a tripod can. Basically you have to hold the rig all the time, until you disassemble and break it down. When I'm shooting sport and moving around a lot, a monopod works fine. But it's a PITA to use one in a blind where you might be sitting and waiting for hours, having to hold the rig upright the whole time to be ready when the action starts!
Bigger, heavier lenses may need a tripod and gimbal. Gimbal heads are designed to be used "loose" so that you can quickly move the camera and lens to follow moving subjects. Lens must have a tripod mounting ring and in nearly all cases must be fitted with an Arca-style plate. This allows the rig to be adjusted back and forth on the head, so that equilibrium can be achieved... which makes possible moving big heavy lenses around with a light touch.
There are several different types of gimbals. See
http://www.carolinawildphoto.com/gimbal_list.htm for a good, illustrated summary of the different types, as well as a partial list of models currently offered.
Wimberley sort of invented the gimbal head for still photography, around 30 years ago. They still offer an updated version of it (their WH-200), as well as three other gimbal options (incl. the monopod gimbal mentioned above):
https://www.tripodhead.com/index.cfmI use two different types of gimbals on tripods.
The one I have used the longest (20 years) and still use most frequently is the Wimberley Sidekick (SK-100) gimbal
adapter. The advantage of this is that it works in conjunction with a standard, heavy duty ballhead (which just needs to have an Arca-compatible QR platform). The adapter provides the tilt movement, while the ballhead it's used with provides the panning motion. It's able to handle lenses up to at least 500mm f/4 (8 lb. & the largest I use). I've seen people use it successfully with larger, heavier lenses.... although it's recommended a full size head like the WH-200 be used with 400mm f/2.8 and 600mm f/4 (which weigh around 10 lb.) The best thing about this is that the tripod can quickly and easily be converted back to "regular" use, simply by removing the gimbal adapter. Not tools, no fuss, only takes a few seconds.
On another tripod I have a
full size gimbal (bottom mount), a knock-off of the WH-200. There are MANY of these now, from a bunch of different manufacturers. Better ones like the Wimberley are no doubt more durable and smooth acting... But the cheap Chinese-made one (no name I can find) I use works surprisingly well. If/when the cheap gimbal stops working well, say if the bearings go bad and it's movements get rough, I'll probably replace it with something better. One of the "issues" with a full size gimbal head such as this is that it replaces any other head installed on the tripod and essentially dedicates it to "long telephoto use only" (there are quick release options, but those make for more parts, more joints to worry about getting loose, more weight and some added bulk).
With any gimbal a relatively heavy duty tripod is recommended. Mine are older Gitzo Series 3 Systematic models, which are rated for about 33 lb. (newer models are rated for 50 lb., I think).
The ballhead used with a gimbal adapter (such as the Sidekick and similar) also needs to be heavy duty and must have an Arc-style QR platform. Mine is a Kirk BH-1 rated for 50 lb. If only using it with light lenses (up to around 4 or 5 lb.), it might be possible to use a mid-duty ballhead, rated for around 30 lb. There are many different ballheads that will work.
Another accessory I use with both my gimbal heads is a leveling platform. This fits between the tripod and the head and makes for much faster setup on uneven ground. Rather than fiddling with leg lengths each time I move the tripod, it only takes a few seconds to loosen the leveler, adjust it and then re-tighten it. When camera and lens are still mounted on the gimbal and tripod, I think this is safer than making leg adjustments, too. In my case, the leveling platform takes the place of any center column on the tripod.... for best stability with big, long telephotos I don't want a center column anyway... but this means the tripod itself needs to be tall enough to bring the rig up to a comfortable working height.
These tripod setups are a lot heavier than a monopod, of course. I fact, each of the gimbal/tripod rigs I use aren't terribly compact and total up to around 8 or 9 lb. Some newer model tripods might be a little lighter and weight could be saved by not using a leveling platform. But it would be a big mistake, in my opinion, to try to use a too light weight tripod with insufficient load capacity.
Hope this helps!