Both Canon and Nikon have announcements of interest to tour participants.
Canon has announced a replacement for their popular 100–400 f5.6 zoom lens. The 100–400 is the go-to lens for Canon photographers for photographing birds in flight. The new lens is reported to be significantly sharper wide open and have an improved Image Stablization system offering 4 stops rather than 2 stops of improvement. The older lens was a great lens and it looks like the new one is even better.
Nikon has announced a new 300 f/4 prime lens. Notable improvements include the addition of Vibration Reduction, a reduction in weight by nearly 50% and Nano coating of the lens elements. I've used the older 300 f/4 for many shoots and have loved the results with and without a 1.4 teleconverter. Addition of VR for much of the work on the boat is a big plus as is the redcution in weight.