> $9 million an owl Quoting the figure that way is really strange. The relevant thing isn't the cost per owl alive now but either the cost per owl potentially

> $9 million an owl Quoting the figure that way is really strange. The relevant thing isn't the cost per owl alive now but either the cost per owl potentially alive now and in the future (probably with some discount rate) or the cost for the species considered as a whole. Imagine three alternative worlds. One is ours. One has 10x as many spotted owls currently alive. One has 1/10 as many. In all of them, the owls will (all) go extinct unless we spend $46bn. Does it really make sense to say that in one case the cost is $900k/owl, in another it's $9M/owl, and in another it's $90M/owl? Is there any plausible belief about the value of these owls that would say we should be willing to pay 100x more to prevent extinction in the case where there are 50k of them rather than 500? (It would probably make sense to pay some more when the population is larger. Larger population now means (a) probably larger populations in the future if extinction is averted and (b) better prospects that avoiding extinction now really will avoid extinction for longer. But I don't see any reason to think that either of these is simply proportional to the present population, or anything like it.)