P.S. A full-size tripod would be recommended. My first tripod, and a good value for money, is Manfrotto 055 series aluminum, of which there are a zillion available used. For stationary shots at nests, any head will do. For follow shots on a tripod, a gimbal head will be best. Jobu junior gimbal (used) is an excellent one for a camera + lens weighing ~ 3 kg or under (local bird photographer). Or, if the photographer already has a good tripod and very good full size ball head, a "Side-kick" type half-gimbal (Wimberly, Custom Brackets, and maybe others) is good. Flip ball head stem into slot at 90 degrees, oriented with Arca-Swiss clamp long axis vertical - fasten half-gimbal to clamp - leave pan function on ball head loose - effective gimbal action for lens+camera ~3 kg. Ball head by itself is terrible for following birds in flight.
People shooting shore birds often use a ground pod and ball mount or gimbal mount, to get on the bird's level (yes, that means photographer is lying in mud or sand). This could be a DIY project: 1 cheap aluminum 12" frying pan with rounded sides from Goodwill, 1 wood block ~ 4" tall, one 3/8" (or 1/4") bolt. Drill hole through pan, and through block, insert bolt through pan and block, cut bolt so that bolt sticks out above the block no more than 1/4", polish cut edge of bolt, screw your head onto the bolt so head is snug against the wood. If you have the tools, that's about USD 10. of materials - or you can buy the "Skimmer" for USD 100.. Another supercheap way to shoot at ground level, or out the car window or roof, is the store-bought or home-made sandbag, filled with sand, plastic beans, or rice. Piece of insulation foam cut to fit car window can work too.
That being said, I still shoot hand-held 90% of the time, mostly because I like walking, and I like the freedom of shooting birds-in-flight handheld - no worry about not being able to get overhead shots. Monopod with simple tilt head is a good thing to have on hand if I want to sit and wait, also a folding 3 leg stool (full size Walkstool, made in Sweden, is most comfortable and sturdy, but a USD 15. stool will do also)
The other approach is to go with the superzoom bridge cameras no tripod needed - these are hugely popular with birders - look at the Sony 10X IV - rave reviews from many birders, apparently handles birds-in-flight well.
