Having had some lucky success with my tamron 70 -200 getting a bird or two. Have started to look at lenses with a bit more reach. Camera nikon 810.

Of recent the nikon 200-500 has impressed me with some great images, and good value for price. The new 300f4 pf vr has had some good reviews too, and thought it might go well with a 1.4 tele converter? price is the issue with the latter, but more versatility thought? Any other things to consider?....... some thoughts please? Cheers.