The Migration is between Tanzania and Kenya (Central Africa) while South Africa as in the name is in Southern Africa some thousands of kilometers away.

June through to August are considered to be the best times for game viewing in Southern Africa. It is winter when the bush is dry and not as dense, the temperatures are in the mid 20's Celsius. Animals are more visible as they will generally only look for shade at midday. As there is little surface water they will use waterholes and other permanent water sources.

Cape Town has winter rains while Durban has summer rains but being coastal cities they can experience rains at any time of the year as well. Rain storms in Southern Africa general only last for a few hours and then the sky clears but it is possible to have a few days of cloudy and overcast conditions.

In South Africa and Botswana you have to go through security and all your hand luggage and any other items will be put through an x-ray machine. Will only physically check items if they have a problem with the images they are receiving. You have to go through a metal detector and you may be frisked.

I never set up back button focusing on my 7DII. Always used standard shutter button until I read about the benefits of back button focusing. Then discovered that that if I used "AF On" button the camera focused and I could still use the standard shutter button to focus as well. Electronic remote devices have also worked without a problem.

Herewith 2 shots of a Red-billed Oxpecker at the eye of an old male Buffalo and it then moved down to his nose

The oxpeckers in addition to eating ticks and parasites on the animals they also eat dry and dead skin tissue, blood and other body tissue and fluid. They can help animals by keeping wounds clean but can also slow the healing process down by keeping the wounds open.

The birds that you see riding on the back of the animals are Oxpecters.

Sorry meant on the right

If you use the on board flash and hold the camera in the portrait position then the lens barrel will obstruct the spread of the light and that is why you have that shadow on the left.