Hey all, I'm the new one here! You can call me Alexander or Alex. I'm married with 3 sons. I recently got back into photography and enjoying it. Actually I'm finding it very addicting! I started with a D700, now I have Nikon D810 and considering the D850 or Sony A7rIII. Not sure yet.
Welcome to BPN! A great place to learn and grow as a nature photographer.
The D810 is a remarkably competent camera, and is almost assuredly not holding you back. Consider spending the money on glass, and time in the field. That latter is what will really improve your skills!