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Old Material, New Light: More from the Archives Part 2

In late December 2014, I wrote what I’ve described as a speculative post titled, “Is There a Way to Recognize Ivory-billed Woodpecker Excavation? In that post, I relied on Tanner’s Plate 11,

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Tanner’s Plate 11, “Dead hackberry, fed upon frequently by Ivory-bills”. Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

a brief description from the monograph: “When Ivory-bills dig, they chisel into the sap and heartwood for borers like other woodpeckers, digging slightly conical holes that are usually circular in cross section (Plate 11)”, and online imagery showing the work of other Campephilus woodpeckers. Material found during my recent visits to Kroch library at Cornell lends some support to the ideas contained in that post, and so does T. Gilbert Pearson’s photograph of a tree that had been fed on by ivorybills. Holt:Pearson Tree

The archival material includes additional images of ivorybill excavation and a considerably more detailed description by Tanner in a document prepared for the Cuban search in the 1980s. The passage includes somewhat more detail on bark scaling than is found elsewhere, but more importantly it describes ivorybill excavations as “hard to distinguish from similar digging by the Red-bellied Woodpecker”.

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Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

This description may seem counterintuitive to some. Despite my own writing to the effect that ivorybill morphology may lead the species to dig less efficiently than pileateds and my references to targeted digging, I still had an underlying assumption that the size of the bird would correlate with the size of the dig and that ivorybill excavation would often resemble the familiar large furrows dug by PIWOs. While a couple of the holes in Plate 11 and in Pearson’s photograph may well involve the merging of more than one dig, it appears that ivorybill excavations are usually more targeted and that large furrows are not typical.

Also of interest for multiple reasons, including the observation of birds scaling very small limbs and of one feeding 5′ from the ground, are Tanner’s field notes from April 3rd, 1937.

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Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

I’ll let the remaining images of known and suspected ivorybill excavations speak for themselves and will conclude with a few from our search area that seem consistent with known ivorybill work. While I’m nowhere near as confident about this material as I am about scaling, I suspect that finding excavations that are consistent with what ivorybills are known to have done in conjunction with scaling is suggestive.

I hope this material will be useful for other searchers. All images from the Singer Tract below are courtesy of the Division of Rare and Manuscript Collections, Cornell University Library. Most of these images were published in Tanner’s dissertation but have not been widely disseminated.

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OakNest copy

Ash Roost

'35 Nest Tree copy

1935 Nest Tree, Red Maple

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detail

1935 Nest Tree and Detail from a Different Perspective

And now some examples from our search area that resemble the existing images of known ivorybill excavation. This is not something I’ve focused on, so I’ve probably missed other examples.

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IMGP1452

Image at bottom is a detail of the sweet gum snag above. I suspect that more than one species of woodpecker is involved.

There will be one or two more installments in this series, but the next post is likely to be a trip report, probably the last for this season.

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2 Comments on “Old Material, New Light: More from the Archives Part 2”

  1. Mark, do you recall what more Tanner had to say in the paper for the Cuban search regarding characteristics of Ivorybill roosting/nesting cavitites?

  2. I’m afraid not; I was a little hasty going through the papers, and I’ve kind of given up on cavities. Since basically any large cavity in Cuba would be likely ivorybill, it didn’t strike me as being that important. I now wish I’d read the document more carefully. It only struck me today that Tanner’s purpose in writing the monograph was rather different. As I said on Facebook, epitaph rather than guide.


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