The classic examples of wildlife harvesting having positive affects for the
conservation of the species appear to be the "big game" animals in Zimbabwe
(at least I think that's where its happening) where landholders appear to
have a quota allocated each year to tender out to "big game hunters" the
harvesting of a number of "game" animals. This might amount to one
elephant, two buffalo and three eland in a particular year, for example.
This, as I understand it, is assessed each year and it set up to be fully
sustainable. Landholders are therefore encouraged to tolerate, or actively
encourage, the conservation of these large animals. The income offsets any
loss of income associated with not clearing land or damage to crops etc.
Another classic example is crocodile farming in northern Australia. The
pros and cons of such activities, particularly that of tendering out big
game hunting, could be argued forever and I really don't want to advocate
such a discussion here - it is merely an example that I am aware of and not
necessarily one that I support.
To be highly commended are the efforts to encourage indigenous people in
Papua New Guinea, and elsewhere, to take up intensive insect farming
therefore retaining rainforest. This is far preferable to the less
sustainable income sources that logging companies provide.
I have, however, yet to see anyone argue for any real positive outcomes
arising from the harvesting of bird species, such as Red-tailed Black