“Basically, the best you can afford”
Fast focusing camera bodies with a high frame rate will work the best; like the Canon 1Dx MkII or the Nikon D5. The Canon 7D MkII and the Nikon D500 are great value for money options and will also do the job.
Long focal length and fast focusing lenses are a must. Isak recommends prime lenses like the 600mm f/4, a 500mm f/4 or 400mm f/2.8. The new generation of zoom lenses is also great, like the Canon 100-400mm f/5.6, the Nikon 80-400mm f/5.6, the Sigma and Tamron 150-600mm lenses.
Isak also suggests a sturdy tripod like the Benro A2682TB1, gimbal or fluid head, a monopod, off-camera flash and a camera bag with more space than you think you’ll use. You will also need larger and faster memory card than you think you’ll need “and a picnic basket with a flask of coffee.”