First time travelers to Africa. My understanding is the two major iconic wildebeest crossings are at the Grumeti and Mara rivers, with the Mara being the major of the two (I think there's another river in Northern Massai Mara too). The Grumeti crossings are located in Western Serengeti in Tanzania. My question is, do the animals cross the Mara river in a) Kenya only or b) Kenya AND Tanzania? From looking at a map, the Mara river is located in both countries, but unsure if the animals actually cross the river at any parts in Tanzania. The second part of my question is what are the 'typical' time frames when the herds will have moved to Kenya in that it would not make sense to be on the TZ side of the Serengeti as you won't see enough. Or, are the herds large/long enough that there will always be some remaining herds in TZ. Would hate to travel to the TZ Serengeti only to find out the animals have left the country. Also, given the difficulty in crossing borders, its not like we can just hop over.
I've asked multiple tour operators and the response has been conflicting with some saying "they don't cross in TZ, only Massai Mara (KE)" vs "they cross in TZ every day in August". While the timing and number of animals crossings is guesswork, I would think it's either a fact or not whether the animals can cross in TZ or not. I've done quite a bit of research in this matter and I completely understand the disclaimers of nature is unpredictable and 'it depends'.
The context of my question (and dilemma I'm having while planning) is:
Our only time windows to visit E. Africa for 7-10 days is late Aug, late May, or possibly early July 2016.
We know we'd like to do the N. circuit in TZ to the see the crater and neighboring parks.
If we're going to be in E Africa at the time of the river crossings, it only makes sense to make an effort to attempt see it (completely understand we may not end up seeing it but gotta try, right?)!
I read up about crossing KE/TZ borders and sounds too time consuming and pricey; we want to avoid that as much as possible. Our itinerary preference would be just do the Northern circuit and see the herds and river crossing in TZ. However, I've asked the TOs about our time frames and just got too varied of an answer to make a decision. We're not opposed to going to Massai Mara if it comes down to it, but with the conflicting answers, its making it hard to plan or book any flights.
For late May, most TOs said the migration does not have Grumeti river crossings- Is this generally correct? We know this is the low season.
For late Aug, this is where I get the most varied answer. We are likely going to travel at this time so would like a better idea of how to best plan an itinerary.
For late July, sounds like staying in TZ only so I don't have to worry about planning to Kenay. Are there any river crossings at this time of year?
Any insight is much appreciated, thanks ahead of time!