you're sitting on the edge of the Udzungwa Mountains forest near Mang'ula as it gets dark. you're sitting on your own by a tree. from the forest above you animals come out at night - small deer, elephants and apes. the voices in the middle distance are your children playing. further away there is traffic on the Ifakara road. in between, a tractor is finishing ploughing the deep black soil. some birds close up. hornbills are making the raucous call you hear as they come back into the forest from the mango tree in the field. during the day that mango tree has given a pool of shade. people who congregated there have gone home now. in the course of the next half hour, the sounds of day, already becoming less marked, will gradually lessen, to be replaced by the sounds of night, as if these two sets of sounds were on two sliders. the call of a common bulbul Pycnonotus barbatus stands out clearly. the trucks on the road are probably sugar beet trucks, carrying cane from the fields to the crushing plant