I think that your red flags end the debate conclusively. After re-reading definitive information on the IBWP (and the same on the Pileated) I do not even have a minimal belief that the IBWP exists in the Cache and White River areas. The lingering assertion that we dealing with a "wary" remnant population is preposterous.
I assume that the believers are aware that genus Campephilus consists of at least 6 living representative species. It is easy to look up "Campephilus" and select a few websites that deal with photography of these woodpeckers. The remaining species of Campephilus, such as C. robustus, C. magellanic, and C. guatemalensis live in Central and South American forests.
None of these woodpeckers could be termed abundant. All have been exploited to some degree. Oddly enough, in these (surviving) subtropical and tropical forests we have PLENTY of good photographs. Recent ones. The reason we don't have good evidence of living populations of the Imperial Woodpecker, the Northern Ivory Billed Woodpecker, and the Cuban Ivory Billed Woodpecker is that the habitat was diminished such that populations could no longer reproduce. This genus was at it's northernmost limit in Northern Mexico, Cuba, and North America. The primal forests in these areas are gone. Thus, we no longer have good evidence for these species. I'm afraid they are extinct.
I am disturbed that no one has been doing good science and looking at other members of the genus (still living) to aid in their research. One reason is that folks would realize they are searching for a will o' the wisp. Campephilus woodpeckers appear to have been EASILY photographed across the genus. Those that we don't have good photographs for are extinct.
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