Bark Scaling Gallery 2009-2015

I’ve collected examples of bark scaling that we think is suggestive of or diagnostic for Ivory-billed Woodpecker from various pages on the site that include a good deal of analysis (although I’ve included a more analytical addendum at the bottom of this page.) I think the images speak for themselves, and many aspects of the gestalt we rely on in the field should be apparent. Most of the work (other than that described as old) was on recently dead trees or dead parts of living ones, although the hickory (also shown on the homepage) was wet with sap when we found it and apparently died soon after. The bark on that tree was so tight that it could only be removed with a hatchet. When examination was possible, bark was tight and could either only be removed with an implement or was very difficult to remove by hand; twigs and sometimes leaves still attached. The downed trees shown had all fallen and died recently, probably within no more than six months; twigs were still attached on all of them and leaves on most. Also in most cases where examination was possible, very large bark chips were found at the base of the tree, some as long as my forearm, several inches across, with many a quarter inch thick.

In Tanner’s description of ivorybill feeding preferences, the kind of wood they “habitually feed upon” had been dead for “only for a year or two”, while Pileateds prefer longer dead snags. (p. 51). While I think Tanner overemphasized freshly dead trees as a food source (as Plates 9-11 suggest), I’m confident that the vast majority, if not all, of the work shown here falls well within those parameters, or indeed involves trees that died considerably more recently, as the presence of leaves suggests.

Tanner was fairly cryptic about identifying criteria for bark scaling, but he relied on it as the strongest indicator of ivorybill presence. From his notes: “This leaves patches of exposed wood, usually with a reddish tinge because of the frass, on limbs and trunk where the bark is otherwise hard and tight.” He also wrote that IBWO scaling is more extensive than Pileated, calling Pileated scaling “spotty” by comparison. In the monograph, he wrote that Pileated scaling is mostly “on loose bark and was never as cleanly done or extensive as the work of the Ivory-bills” and the ivorybill ” . . . is capable of easily scaling away heavy bark that other woodpeckers could not loosen. Even the Pileated is not able to remove hard, tight bark with anything like the speed of the Ivory-bill.” His observations suggested that scaling comprised 23% of Pileated foraging behavior. A more recent and probably more relevant study from central Louisiana showed Pileateds scaling a mere 7% of the time (Newell, 2010).

Over the past eight years, I have visited many locations where ivorybills have been reported and have studied bark scaling in areas outside the historic range. I have found an abundance of the types of work shown below only in two Louisiana locations. In our current search area, we’ve often found this scaling in concentrated pockets.

For a more in depth discussion of many of these images, our hypothesis about bark scaling, the field observations, and scientific literature that informs it, visit the posts tagged “cavities and feeding sign”, this one and this one in particular.

Updates to this page will be posted above the original images included in the gallery, most recent first. The original gallery is in chronological order, November 2009 – February 2015.

Update: March 2015:

We found an abundance of recent feeding sign on sweet gums, both standing and downed, as well as some older work we think of as diagnostic on dead hickories. This is discussed in detail in Part 1 of the trip report. Many of those images (some with exposure adjusted) are included here. Several others were not included in that post.


OldHickory3 oldhickory2

Extensive scaling on an older hickory snag. Work goes from near the base to near the top. Atypically, some of the work at the base appears to be more recent than the rest.

Extensive mostly older scaling on a hickory snag. Work goes from near the base to near the top. Atypically, some of the work at the base appears to be more recent than the rest. Presence of twigs indicates the tree is still in the stage of decay Tanner described as preferred by ivorybills.

ScaledSGUnscaledOak3:15

Scaling on sweet gum amid unscaled oak blowdown.

BigSGLimb

Extensive somewhat older scaling on recently dead sweet gum limb.

HackedupTop

Top of sapling that looked as if it had been chopped by a hatchet and cut almost halfway through.

HackedGum2

Detail of work on sweet gum sapling that had a chopped up look. Note that the wood was hard and showed no signs of rot.

LittleGumTopLittleGumMiddle

LittleGumBottom

Small sweet gum almost entirely stripped of bark

BillMarks?

The lateral scratches above the reverse L-shaped depression appear to be bill marks. This is the sweet gum sapling shown immediately above.

ExitTunnelExpanded

Detail of an expanded exit tunnel near the base of the scaled sapling shown above. Another possible bill mark is visible at the lower right.

March15Limb

Extensive high branch scaling on recently dead sweet gum

Extensive high branch scaling on recently dead sweet gum

Topzoomed

Detail of extensive high branch scaling. March 2015

 End of update.

Sweet Gum Scaling, East-Central Louisiana, 2009

Sweet gum scaling, East-Central Louisiana, 2009

Twin scaled honey locust trunks, 2009 possible sighting and suggestive trail cam photo in this immediate vicinity.

Twin scaled honey locust trunks, 2009 possible sighting, Nov. 2009 and suggestive trail cam photo taken a week later in this immediate vicinity.

Trail cam photo with scaled tree in the foreground, Nov. 2009.

Trail cam photo with scaled tree in the foreground, Nov. 2009.

Scaling on three month old oak slash.

Scaling on three month old oak slash,  2009.

Scaling on freshly dead oak, East-Central Louisiana, January 2010

Scaling on freshly dead oak, East-Central Louisiana, January 2010

Extensive Scaling High on a Living Oak, Louisiana, March 2012

Extensive Scaling High on a Living Oak, Louisiana, March 2012

Detail of extensive scaling on oak

Detail of extensive scaling on oak

Heavily scaled young oak with suspected IBWO work extending from the base to well up on the trunk. Large bark chips are visible around the base of the tree

Heavily scaled, recently dead, young oak or sweet gum with suspected IBWO work extending from the base to well up on the trunk. There was what appeared to be older scaling higher up; twigs and a few leaves were attached. Large bark chips are visible around the base. Louisiana, May 2012.

young oak

Detail of scaling on young oak or sweet gum, showing apparent damage from lateral strikes.

Lateral strike marks in the cambium

Second detail showing lateral strike marks in the cambium and intact sapwood

Sweet gum scaling, Louisiana, 2012.

Sweet gum scaling, Louisiana, 2012.

Detail of Sweet gum scaling.

Detail of Sweet gum scaling.

Extensive Scaling on Live Willow Oak, March 2012

Extensive Scaling on Live Willow Oak, March 2012

Scaling on dying hickory, Louisiana, May 2013

Scaling on dying hickory, Louisiana, May 2013

Extensive scaling on a sweet gum, 2013

Extensive scaling on a sweet gum, 2013

Oak1

Scaled oak, November, 2013. Twigs and possibly a very few leaves attached suggest tree died within approximately one year.

Scaled oak, 2013.

Lower part of scaled oak, 2013.

Scaled sweet gum, 2013. Photo by Steve Pagans

Scaled sweet gum, 2013. Photo by Steve Pagans

Hickory3

Extensive scaling on hickory, 2013.

Top of scaled hickory.

Top of scaled hickory.

Scaled hickory, 2013. Photo by Steve Pagans.

Scaled hickory, 2013. Photo by Steve Pagans.

More scaling, same hickory, 2013. Photo by Steve Pagans.

Scaling, same hickory, 2013. Photo by Steve Pagans.

Same hickory, 2013. Photo by Steve Pagans.

More scaling, same hickory, 2013. Photo by Steve Pagans.

Scaled hickory, 2013

Scaled hickory, 2013. This work appeared to be somewhat less recent, and the snag seemed to be longer dead; some of the bark had loosened, but it remained tight around some of the scaled areas.

Another hickory, 2013

Another hickory, 2013

Same scaled hickory with large bark chip, 2013

Same scaled hickory with large bark chip, 2013

Heavily scaled, downed sweet gum, 2014. Photo by Patricia Johnson.

Heavily scaled, downed sweet gum, 2014. Photo by Patricia Johnson

Detail of scaling on downed sweet gum, 2014.

Detail of scaling on downed sweet gum, 2014.

Detail of scaling on downed sweet gum

Detail of scaling on downed sweet gum

Old scaling with large exit tunnels

Old scaling with large exit tunnels, 2014.

Old scaling on hickory, 2015

Old scaling on hickory, 2015.

Scaling on recently dead, downed sweet gum, 2015

Scaling on recently dead, downed sweet gum, 2015

Heavily scaled, recently dead downed sweet gum.

Heavily scaled, recently dead downed sweet gum, 2015.

Limb of another recently dead, downed sweet gum, 2015.

Limb of another recently dead, downed sweet gum, 2015. Note attached leaves and hanging slabs of bark.

Detail of hanging bark. 2015

Detail of hanging bark, 2015. This is reminiscent of Tanner’s Plate 8.

An additional insight followed the initial creation of this page, and this seems like the appropriate place to include it. There appear to be two types of work in these images, both consistent in many respects with what is known about ivorybill feeding.

One is scaling on what appear to be cerambycid-infested trees. Cerambycids are known to be a preferred ivorybill prey species, and we found adults of a known prey species (Hesperandra or Parandra polita) under the bark of one of the scaled hickories. This type of scaling reveals numerous, large exit tunnels and virtually no frass. This work is found on boles and large branches, and I suspect that it may have to be done very rapidly and efficiently because the window of time for capturing larvae as they dig their exit tunnels before creating a sealed chamber and pupating is likely quite narrow. This seems suggestive of IBWO, since efficient scaling and a high degree of specialization in terms of targeting this particular prey at the right time, when the larvae are at their most nutritious, are consistent with both morphology and known behavior; for a Pileated, the time and effort involved would likely exceed the reward. The long temporal gap between or lack of return visits to these feeding trees might also point in this direction.

This type of scaling seems to involve the first infestation with and maturation of cerambycid larvae. The last time I visited the hickory that appears on the home page, approximately 18 months after finding it, there was no new scaling (the bark was of course quite loose) and a little bit of apparent Red-bellied excavation. There did not appear to be any new exit tunnels either. The same is true for the sweet gum shown just below it.

The second category involves trees that are predominantly infested with larvae that live just under the bark. These generally have shallow galleries and few or no exit tunnels; frass is often visible when the work is fresh. We’ve found this work on boles of smaller trees and on the boles and tops of downed, but very recently dead sweet gums – twigs attached (in all) and leaves attached (in most) instances. The reddish tinge from the frass that Tanner described is visible in some of the images above. I suspect this type of scaling is less dependent on season.



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