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Trip Report: March 20-26, 2016

As usual, much of this report will be focused on bark scaling. I found an unprecedented amount of fresh work this trip, a total of 29 trees, all sweet gums. I only counted live and freshly dead trees that appeared to have been scaled within the last year, and probably more recently than that, in most cases. As will be discussed, I was able to ascertain that 11 of these trees had been worked on no earlier than March 15th. I was selective about what I included in the count, relying on my years of experience looking at scaling and how its appearance changes over time and this passage from Tanner for the criteria:

Ivory bill sign shows as bare places on recently dead limbs and trees, where bark has been scaled off clean and to a considerable extent. Pileateds do some scaling too, but it is usually confined to smaller limbs and those longer dead. Freshness of the sign can be judged by any appearance of weathering, which will soon turn bare wood a grayish color. Extensive scaling of the bark from a tree which has died so recently that the bark is still tight, with a brownish or reddish color to the exposed wood showing that the work is fresh, is one good indication of the presence of ivorybills.

 

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Gray-hued old scaling

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More recent scaling below the fork and bleached older work at the top left

We had a number of visitors during my stay. Tom Foti joined me again on Tuesday and Wednesday, and Phil and Eric Vanbergen came along on Friday. I appreciate the Vanbergens’ help in collecting the data I’ll be discussing. It’s great to have such enthusiastic young people involved. Meanwhile, John Williams (Motiheal from ibwo.net) visited and spent four days in the field with Frank. Both John and Frank are planning to provide their own accounts, and those will be posted in the weeks ahead.

A general note about the week, leaf out progressed rapidly, and the change between Sunday the 20th and Saturday the 26th was dramatic. Nonetheless, I was able to find a good deal of feeding sign later in the week.

I arrived on the evening of Saturday, March 19th, and Frank and I spent the 20th in the northern sector. There had been severe flooding in the area earlier in the week; the waters had receded – we suspect by the 15th or 16th and certainly no earlier than the 15th. One of our trail cams, placed about 4’ above the ground, was completely overtopped, ruining the card and probably the camera as well. Such floods are exceedingly rare, perhaps a once in 500 year occurrence in the area. Fortunately, flooding tends to recede rapidly, but crossing both permanent and seasonal water bodies remained a much bigger challenge due to deep water and slick banks. The most stunning aspect of the flooding was the near total scouring of leaf litter in many parts of the search area, leaving bare soil and deposited silt visible. The landscape was transformed, and familiar spots looked radically different.

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Trail cam at lower right, about 4″ off the ground, was briefly but fully submerged

Frank often describes walking through the forest on dry leaf litter as “walking on cornflakes.” The absence of leaf litter limits the noise made by walking. This may be advantageous between now and late fall. Unfortunately, I anticipate being able to visit the area only once more before summer, probably in June.

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The forest floor was scoured of leaf litter and debris was hanging from branches in the understory

The flooding had another benefit this trip. The absence of leaf litter makes it much easier to find fresh bark chips on the ground and to determine with some degree of certainty when scaling has taken place. The flood waters receded no earlier than March 15, so all fresh chips found below trees where the leaf litter had been scoured were no more than a week old.

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When we reached the vicinity of the downed top, first discussed here, we heard a loud single knock. Frank’s initial reaction was that it might have been a gunshot, but we both agreed that the sound seemed to have come from a nearby source; we heard no other shots that day and saw only one vehicle, almost 2 miles away. Later in the morning we heard a couple of weak possible double knocks and later a very good sounding one.

We also found a little bit of scaling just north of the northern concentration discussed below. While some of it looked to be quite fresh, we did not find any bark chips.

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The scaling in the first of the above photographs is somewhat marginal, as only a single smaller upper limb is involved. While I’m unsure, I don’t think I counted either of these trees, as I only started keeping track later in the week; both examples came from very close to the northern cluster discussed below.

I was on alone on the 20th, and I returned to the same area. I found a good deal more scaling.

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In many cases, the scaling shows sign of progressing from treetops down, as Tanner described.

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And some of the trees, both large and small, showed signs of dying from the top down, also as Tanner described. IMGP1804IMGP1817

The detail of the small tree, scaled down to where small branches are still in leaf, is at the edge of a small pond around or in which I found five other trees with recent scaling on them, as well as two more with older work (not counted).

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Recent but not fresh work on a dying sweet gum

 

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Older scaling (not counted) with a little excavation on a dead sweet gum limb

There was new work on one of the trees I found last month, the larger one in the background, below. I found several other scaled trees in the immediate vicinity, including the one in the foreground, on which we’ve now deployed a camera, and much of that work was fresh too. I chose a spot for a stakeout and spent about an hour watching the treetops in this area of concentrated work. This location is 140 yards south of the small pond described above and is at the southern boundary of the cluster. During the stakeout, I heard a loud single knock that seemed to have come from the vicinity of the small pond.

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As I was leaving, I passed the pond again and found what appeared to be new scaling on one of the trees at its edge. There were fresh chips in floating in the water at the base.

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Tom Foti arrived on the morning of the 22nd. We spent the day in the one of the southern areas where we’ve found concentrations of bark scaling in past years and where there have been both possible visual and auditory encounters. We found several scaled trees in this area but did not see or hear anything.

I met up with Tom on the morning of the 23rd; I had decided overnight to be more methodical in my approach to documenting scaling. I’ve been so focused on what might be diagnostic that I haven’t attempted to quantify what I’ve found thus far and haven’t kept detailed location information. Thus, it seems like a good idea to start keeping better track. This should prove useful if we can document that ivorybills are present and that they are responsible for the bark removal.

Tom and I heard 6-8 likely kents at ~9:00 am, this at the downed top where we had the camera, the same location where Frank had his sighting last spring. The calls came from three directions, south, east, and west.

We headed south and met up with Frank and John in the core of the northern concentration, south of the pond. We did an extended playback series; John will have more to say about the specifics in his post. We all heard a nearby double knock during the playback; Tom, John, and I were sitting close together near the speaker and thought it was a single, but Frank, who was positioned closer to the source of the natural sound, called it as a double.

We found some very fresh bark chips (moist with sap) at the base of a 12” DBH dying sweet gum that has areas of scaling high on the bole. The tree (which is shown above) is only a few meters from the one found last month. We’ve deployed a camera aimed at this bole. Given the quantity of activity in the area and the evidence of return visits to feeding trees, we hope to get some hits before long.

We removed a piece of bark from a looser spot on a nearby downed tree (which had been fed on by woodpeckers both before and after it fell). Beneath the bark were Cerambycid larvae, pupae that I also suspect are also Cerambycids, and what I think may be a very young Elaterid larva. We placed some of these larvae and pupae on the piece of bark to illustrate. We suspect that Allen did the same for what became Plate 10 in Tanner.

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On the way out and not far from the cluster, I spotted what appears to be the start of a large, irregularly shaped cavity. We’ll monitor this and see whether there’s any further excavation.

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It rained heavily on the morning of the 24th. I spent part of the afternoon trying to take measurements but didn’t have much success, since I was using an ordinary tape measure.

On the 25th, Phil and Eric Vanbergen joined me and we took measurements in the two areas where there are concentrations of scaling, finding several more trees in the process. When I got back to Frank’s, the forester’s DBH measuring tape I ordered had arrived, making it possible for me to take measurements on my own.

I spent the 26th measuring suspected feeding trees in the southern area and found several more with recent work on them.

Except for feeding sign, I did not see or hear anything suggestive of ivorybills during my last three days in the area.

Now I’ll turn to some of the data I collected this week.

I counted 29 suspected recent feeding trees in the two areas, 13 in the northern sector and 16 in the southern. I did not count work that appeared to be more than a year old or work that was limited to very small branches.

The areas are 2.05 miles apart. The northern area was logged (probably partially) in 1905, although there may have been some later selective cutting. The southern area was logged in 1935. Forest composition is somewhat different between the two areas, with sweet gums seeming to be less predominant in the southern one. In the southern area, the scaled trees are in a narrow, almost linear strip with an area of .13 square miles/83.2 acres/33.67 hectares. The northern cluster is more compact and polygonal, with a total area of .03 square miles/19.2 acres/7.7 hectares. Within both areas, scaled trees were often found in groups of 2-6 – 11 out of 13 trees in the northern area and 11 out 16 in the southern. (This includes the cluster in and around the pond, which is perhaps 30 meters in diameter, but otherwise applies to trees that I estimated to be 20 meters apart or less.)

Scaled trees ranged from 6.5” dbh to over 5’ (estimated) for a gum with a split trunk, one stem live and the other dead. All but 3 inaccessible trees were measured.

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76% of the trees were alive, sometimes just barely, with scaling on dead or nearly dead limbs or boles. There was scaling on live parts of one or possibly two of the trees.

Though we have found scaling on boles of larger trees in the past, all trees scaled on boles were 12” DBH or less. While these measurements may not be meaningful absent a random sampling of trees in each sector for comparison, I thought the numbers might be of some interest even now, especially in light of the recent discussion of Tanner:

Both areas

3-12”                  20.7%

12.1-24”             24.1%

24.1-36″             44.9%

>36″                   10.3%

South

3-12″                  12.50%

12.1-24”              25.00%

24.1-36″              56.25%

>36”                       6.25%

North

3-12”                   30.8%

12.1-24”              23.00%

24.1-36”              30.8%

>36”                    15.4%

This is obviously a very small sample, but I think it’s interesting nonetheless. The three smallest trees in the northern sector were all in or near a pond that appears to have had its outflow blocked in recent years. They probably died due to the change in hydrology. But for that difference, there seems to be an even greater favoring of 25-36” DBH trees than found by Tanner, and this is so even in the less mature southern sector (again without data on overall composition). This year, feeding sign has been found exclusively on sweet gums. We’ve found a few scaled oaks over the years and more bitternut hickories; I suspect the latter are being fed upon at a high rate relative to abundance. We’ve discussed doing some random sampling for tree size and species, but given our limited resources, this may not be worthwhile or feasible at present.

Of course, none of this proves that ivorybills are in our area, but I think it’s another indication that they are. The best-case scenario is that the dramatic increase in scaling this year and in this season is related to there being young in a nest or nests.

 

 

 

 

 

 

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4 Comments on “Trip Report: March 20-26, 2016”

  1. Just curious, how often will you be monitoring the cavity you’ve shown… daily, weekly, less often? And do you know what species of tree it is in?

  2. Exciting stuff here, Mark. Great photos. Thanks for sharing!

  3. I think the tree is a black cherry. I am awaiting confirmation on that. If so, it’s a very rare species in the area. We’re down to two functioning cams and are going to get our old Reconyxes reconditioned. Frank will deploy one on his next visit, a couple of weeks from now.

  4. Single knocks are a warning call to others. I have heard them. I have also heard replies to them. As for the scalings, some appear to be similar to scalings I have seen in central Illinois. Others are different and quite interesting. Thank you for posting this.


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