Egrets are beautiful and elegant aquatic birds, about half the size of a swan. You can often find them in the shallows as they slowly brood in the water looking for fish and aquarians. They are very shy and will fly away as soon as they spot you, which they are able to do from very far away. It pays to be patient because they are likely to return to the same spot after a while.
The photos you see here were shot at dusk with a Nikon D780 and 200-500 f/5.6 with the TC-14E teleconverter. I learned that although the continuous autofocus (AF-C) works, the 3d focus tracking is not available on this camera due to the aperture being too small (the teleconverter turns the f/5.6 into a f/8 aperture). This makes focusing very accurately challenging, especially at the long end of the lens (700 mm) because the depth of field is very narrow. Surely a D500 or D850, which have better autofocus modules, would be better in this situation.
On the other hand the low noise at high ISO on the D780 enables shooting these fast-moving birds possible at dusk. It is better to use a high ISO such as 6400 and get a good exposure then try to avoid noise by keeping the ISO low and underexposing. This allows for high shutter speeds in the 1/500 – 1/1000s range. On the other hand the image stabilization (VR) on the 200-500 lens is beyond excellent. It is entirely possible to use shutter speeds as much as 4 – 5 EV lower than what would be required without VR. It is entirely possible use a shutter speed of e.g. 1/100s at 700 mm with this lens with a little technique and practice.