The ivorybill controversy began to heat up when James Tanner dismissed reports by John Dennis in Texas in the 1960s. Although Tanner was involved in the only detailed study of the species, his work (as a graduate student at Cornell) only involved a few birds under limited conditions at one site. It is hard to imagine how anyone could be regarded as an authority on any species on the basis of such a limited study, but Tanner's opinions on the ivorybill were treated as gospel decades later. It is unfortunate that Tanner's comments were not looked at more closely. With proper oversight (which is still sorely lacking), the controversy might have been avoided and the conservation of this species might have commenced decades ago.



The image above is a scan from an article by David Nevin, "The irresistible, elusive allure of the ivorybill," that appeared in Smithsonian magazine in February 1974. In the left column, note that Tanner raised his eyebrows at the claim that ivorybills were observed near an area that had been logged in Cuba. It seems unusual that Tanner tried to extrapolate his limited study in bottomland hardwood forest in Louisiana to the subspecies that prefers upland pine forest in Cuba. It also seems unusual that he cast doubts on a report from the vicinity of an area that had been logged since it was well-documented that Don Eckleberry repeatedly observed a female ivorybill returning to a roost hole in a logged area of the Singer Tract (where Tanner did his study) in 1944. In the right column of the Smithsonian scan, note that Tanner considered it "very unusual for an ivorybill, very unusual" that Dennis reported seeing an ivorybill on the ground. Tanner was apparently not aware (or had forgotten) that the caption of the photo below by Arthur Allen (Tanner's advisor at Cornell) mentions that a female ivorybill was on the ground at the time.



In the letter below to Hardy, who was analyzing an audio recording obtained by Dennis, Tanner asked what a Pine Warbler was doing in the same habitat as an ivorybill. Once again, we only need to refer to Allen's photo above, which shows an ivorybill in pine forest (the preferred habitat of Pine Warbler). The location where I have had several sightings and obtained two videos in Louisiana has both pines and Pine Warblers. There have also been recent sightings in similar habitat in Florida. At both of these sites, there have been multiple reports of ivorybills flushing from the ground. In the letter to Hardy, Tanner asked why an ivorybill could be recorded but not seen and followed. This comment indicates the limitations of Tanner's experience with this species. He studied a few ivorybills that were found by others and that had become somewhat acclimated to the presence of humans. No nests or roosts have been discovered since 1944, but nearly all reports have been of birds that were extremely wary. Tanner searched for ivorybills but never found them. In contrast, Dennis discovered this species in Cuba and obtained photos that were published in the Auk in 1948. With this track record of success, it is hard to understand why he was not taken more seriously when he later reported this species in Florida and Texas.