Kidike Sanctuary is home to a spectacular colony of Pemba flying foxes, a large bat indigenous to Pemba (called popo in Swahili). About 4000 individuals hang in a patch of trees, often taking to the air, clearly visible during the day, undisturbed by local people thanks to the proximity of a local burial site. There's a small (and tumbledown) viewing platform so you can see more clearly.
Kidike is near Kangagani village, 2km east of the new main road between Chake Chake and Wete. If you have a vehicle, turn off the main road about 10km northeast of Chake (or drop here if you're on public transport). Go through Kangagani village and the sanctuary is across some fields on your right. A guide/guardian will probably meet you and collect your entrance fee. If he's not around, his phone number is scrawled on the wall of an unused building at the edge of the sanctuary.