When they are paired up a loner comes in and invades the others space... Not a good idea if your the weaker one.. There's always a looser and sometimes it can get pretty ugly...
Nikon D700
,Nikon’s 200-400mm f4 G VR AF-S IF ED Zoom Lens. 1/1600s f/10.0 at 400.0mm iso500
full exif