This spring I monitored a nest that has always been active with bluebirds. This year a house sparrow decided to take over the nest. These two birds were at it for weeks over the nest. The sparrow would just sit in the hole and the bluebird would land and watch it. There were fights when the sparrow left the nest. Made for some interesting images.
Nikon D500 Nikon 200-500, ISO 640, F8 and 1/500th.
Comments and critiques please. Not a real fine art bird image but it does capture some interesting behavior.