You can read more about those hippos and everything else about Xudum, as I have just posted a full report on our stay:
http://luxurytravelblog.net/The_Silv...0_Entry_1.html
Early-mid autumn is the perfect time to go to the Okavango, so if you want to go this year, start thinking about it now!
The birdlife is particularly interesting, as you can see from the pictures I have posted below.