There is no question but that Tanner focused on areas of large, relatively unaltered forest and dismissed many areas out of hand. Let me quote him: "Good guides were exceptional, and the best service that most of them could perform was understanding from my descriptions the type of forest I wanted to investigate and then leading me to the best territory."
It is true that reports of ivory-bills decreased dramatically in each part of its range as the virgin forests there were cut. Tanner's assumption, clearly, was that the birds did long survive the cutting.
If I may use the pine snake example again - Pine snakes were often reported in the virgin longleaf forests of western Louisiana. As these forests were ruthlessly mowed down, reports of pine snakes dropped sharply and herpetologists feared they were going extinct. The assumption, seemingly supported by the trend, was that they needed these forests to survive. Today the La. pine snake is the most difficult to find large snake in North America. Even in parts of Kisatchie N.F. that have fairly mature, frequently burned, second-growth longleaf they have never recovered and are extremely rare. I have never seen one dead or alive despite many thousands of hours in those forests. But in fact, there is one area that produces them regularly. It does not have mature longleaf, in fact there is very little longleaf there. If you looked at the area you would not give it a second look. It is "crappy" second-growth paper company land.
How was this population of pine snakes discovered? By making a connection to local people. The local people didn't read the books saying where pine snakes were supposed to be and where they weren't. Neither did the pine snakes. Similarly, local people can help us find ivory-bills. But we have to be willing to listen.
