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Bits and Pieces Part 4: Rethinking Range and “Suitable Habitat”

Part 1.

Part 2.

Part 3.

Bottom line upfront: In pre-contact and early colonial times and into the 19th century, Ivory-billed Woodpeckers inhabited a more varied and expansive range than most people realize. The range probably reached from the southern tip of Florida to central Ohio, with the 40th parallel as the approximate northern limit, westward to St. Louis and perhaps along the Missouri River. As discussed in the previous post, the western limit of the range appears to have been somewhere around the 96 or 97th Meridian, in the southwest, and probably somewhat farther east at the northwestern edge, if unproven historic reports from the Kansas City area are valid. Outside of coastal areas, distribution appears to have followed riparian corridors to its outer limits, and there are no records from elevations of over ~1000′.

A couple of maps may be useful for additional information about forest, bioregion, and habitat types and may help with visualization along with my map of records from unexpected habitats.

This is a new avenue of exploration for me, and I’m not personally familiar with many of the areas involved. I need to do additional research on areas within Tanner’s range map, along the coasts and in Florida, to be sure my characterizations are accurate. I’m leaving some of these locations on the master map for now (but removing them from the graphic below which includes extralimital and edge of range records). The master map is thus subject to change, so view it with the caveat that the notations may be incomplete or inaccurate. This post will address locations that are outside the confines of Tanner’s 1942 range map, although he accepted some of these records in 1989.

 

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As in the previous post, my analysis relies on records accompanied by reported physical evidence (even if that evidence has been lost) and to Native American sites where remains found are deemed unlikely to have been trade items. I relied on the US Fish and Wildlife Service’s Recovery Plan, Appendix E, Tanner, Jackson, and a few additional sources.

Before undertaking a whirlwind tour of the locations involved, I thought I should return to the mythology discussed in the previous post. I chose my words poorly in describing that mythology: “To a large extent these beliefs treat the Singer Tract as a model – a vast tract of “virgin” bottomland forest dominated by oaks and sweetgums, with abundant, moss-draped cypress for atmosphere (although ivorybills seem to have avoided cypress in the Tract).”

In fairness to Tanner, he didn’t characterize cypress as being abundant in the Tract. (It was not.) And his overall view was that cypress-tupelo swamps were not good ivorybill habitat. Audubon, with his romantic, indeed gothic, language is the father of the cypress myth.

I wish, kind reader, it were in my power to present to your mind’s eye the favourite resort of the Ivory-billed Woodpecker. Would that I could describe the extent of those deep morasses, overshadowed by millions of gigantic dark cypresses, spreading their sturdy moss-covered branches, as if to admonish intruding man to pause and reflect on the many difficulties which he must encounter, should he persist in venturing farther into their almost inaccessible recesses, extending for miles before him, where he should be interrupted by huge projecting branches, here and there the massy trunk of a fallen and decaying tree, and thousands of creeping and twining plants of numberless species! Would that I could represent to you the dangerous nature of the ground, its oozing, spongy, and miry disposition, although covered with a beautiful but treacherous carpeting, composed of the richest mosses, flags, and water-lilies, no sooner receiving the pressure of the foot than it yields and endangers the very life of the adventurer, whilst here and there, as he approaches an opening, that proves merely a lake of black muddy water, his ear is assailed by the dismal croaking of innumerable frogs, the hissing of serpents, or the bellowing of alligators! Would that I could give you an idea of the sultry pestiferous atmosphere that nearly suffocates the intruder during the meridian heat of our dogdays, in those gloomy and horrible swamps! But the attempt to picture these scenes would be vain. Nothing short of ocular demonstration can impress any adequate idea of them. 

Hasbrouck (1891) perpetuated the emphasis on cypress and very low-lying locations:

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Hasbrouck’s explanation of the Missouri extralimital records is odd. The locations given are well outside bald cypress range.

That aside, the myth discussed in the previous post is a composite. The emphasis on cypress originates with Audubon and Hasbrouck, and the emphasis on large tracts, old growth, oaks, sweetgums, and tree size is largely drawn from Tanner.

Here are the extralimital records:

Reedy River, South Carolina: Nest with eggs reportedly collected in 1896 and later lost. The location is in the Piedmont, south of Greenville, at an elevation of approximately 900′. The Reedy flows into the Salad, which flows into the Congaree. This report is listed in the Recovery Plan because it was accepted by Sprunt as “definitive” but is considered highly questionable.

Etowah Mounds, Georgia: Pre-contact site, elevation approximately 700′. Presumably not trade goods “but requires further discussion” per the Recovery Plan. The Etowah River is at the northern end of the Alabama River watershed.

Between Martinsburg, West Virginia and Winchester, Virginia: Specimen reportedly collected by Wilson ca. 1810. Elevation at Winchester is 725′ and at Martinsburg is 453′. This would appear to be in the Potomac watershed.

Moundsville, West Virginia: Two lower mandibles found in a pre-contact (early Common Era, 0-200) midden. Potentially trade goods. Elevation 696′. The location is on the Ohio River.

Philo, Ohio: Near the Muskingum River. Tarsometatarsus found in pre-contact midden, dates from ca. 1100-1500. Elevation 735′.

Sciotto County, Ohio: Same as above. Elevation of the site is 1050′, but the nearby Sciotto River is lower. The site is about 10 miles from the Ohio, and the elevation at the confluence is 533′.

Ross County, Ohio: Same as above. Also on the Sciotto River but farther upstream. Elevation 863′

Near Troy, Ohio: Near the Miami River, March 1804 sight record by Gerard Hopkins, a Quaker envoy to the Miami and Pottwatomi. The report includes a description, “. . . resembling the red headed woodcock of Maryland, except that its head is black and its bill ivory. ” (Leese 2001). Omitted from the map because it doesn’t involve a specimen, but included here because it adds weight to the archaeological records.

Franklin County, Indiana: Report of a specimen, 1869, now lost. Elevation at least 490′. Probably along the Whitewater River, an Ohio tributary. There are a number of early reports from Indiana, but no other reported specimens and no archaeological records. In light of Audubon’s collection at Henderson, KY (just across the Ohio River) as well as the Ohio records, it seems likely that ivorybills were present in parts of Indiana into the 19th century.

Henderson, Kentucky: Female specimen collected by Audubon in July 1810 and used as a model for his first painting of the species. Elevation 400′. This record does not appear in the Recovery Plan or Jackson, and it seems to have been overlooked by researchers. Audubon’s own notation describes the location as “Red Banks”, on the Ohio River at the northernmost limit of the cypress-tupelo association, well upstream from the confluence with the Mississippi. Article by R. Haven Wiley in Kentucky Warbler, May 1970.

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Stanford, Kentucky: Pair reported, with one specimen collected by a Colonel Fleming, 1790. Record accepted by Tanner in 1989. Elevation 942′. The Dix River, which flows into the Kentucky and thence the Ohio, is nearby.

Cahokia Mounds, Illinois: East of the confluence of the Mississippi and the Missouri, 1500s or earlier, tarsometatarsus. Elevation 490′.

Forest Park, Missouri or Vicinity: West of the confluence of  the Mississippi and Missouri. Specimen collected 1896 and in the collection of the Colorado Museum of Natural History. Elevation approximately 500′.

I find it interesting that Ohio is the state with the most pre-contact records involving likely food items – 3 out of a total of 4-6.

With regard to Missouri and the Missouri River watershed, Hasbrouck accepted reports from Fayette and Kansas City, and given the overall picture, this does not seem implausible. In addition, there were persistent reports from the vicinity of Lake of the Ozarks, in the Missouri River watershed, until the end of the 1940s; Tanner received information about Missouri reports from local Audubon society officers but apparently disregarded it. There’s no way to assess the validity of these old, anecdotal claims and no evidence to support them, but given this perspective on the historic range, they may be somewhat less far-fetched than it seems at first glance.

I’m heading for Louisiana soon. More after I return – a trip report and probably two additional installments.

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Not So ‘Virgin’ Forest: The Singer Tract Myth Debunked

Update: This post includes hard data about the extent of old growth in the Singer Tract (scroll down past all photographs) and in ivorybill home ranges. The general points made below remain valid, although some of the wording is perhaps too strong; Tanner overestimated the amount of old growth in the Tract ( at “over 80%” v. 72% in fact), and the Mack’s Bayou home range was predominantly second growth.

This post is a companion to the previous one and to others discussing habitat conditions in the Singer Tract. Those posts reference Richard Pough’s 1944 report to the Audubon Society. Pough, whose study was never published, noted that much of the Singer Tract had actually been under cultivation prior to the Civil War. But it’s worth taking a closer look at just how much.

Tanner characterized the Singer Tract as “the largest tract of virgin timber in the Mississippi Delta,” contending that it contained “120 square miles of virgin forest in 1934”. He also wrote that the largest plantation “had about 3000 acres under cultivation,” while suggesting that “some of the early settlers along the Tensas River cleared land along the river banks for cotton fields.” Thus, the myth of the Singer Tract as virgin forest was born.

It’s not clear where Tanner got his information, but some of his characterizations are not supported by the historical record; the language about “early settlers” almost seems disingenuous when one looks at the history of Madison Parish. (Rootsweb has many pages devoted to this subject, and I’ve drawn heavily on them for this analysis.) As should become evident, there was a great deal of human activity in and around the Singer Tract, especially prior to the Civil War. I will suggest that most, perhaps virtually all, of the arable land in the parish, had been cleared for agricultural purposes and that the Singer Tract was a mix of second growth and remnant old growth, most of which was in the lower-lying, wetter areas that Tanner deemed to be less suitable for ivorybills.

A 1937 Masters thesis in economics by Robert L. Moncrief, “The Economic Development of the Tallulah Territory”, provides a great deal of information about the parish and its history. In the post-Columbian era, the area was very sparsely settled until the 1830s. Madison Parish was established in 1839, and in 1840, steamboats began plying the Tensas River. A major population influx began in 1836, and the population kept growing until the Civil War, going from 5,142 in 1840 to 14,133 in 1860. The war led to a dramatic decline to a mere 8,600 in 1870. Over the next couple of decades, the numbers grew again to 14,135 in 1890. Changing economic conditions and the boll weevil outbreak caused another decline that was only reversed between 1920 and 1940, when the number of residents reached 14,826. By 2010, it had fallen to 12,093.

Cotton and the quality of the soil drove this influx. By 1850, there were 27 landowners in the parish who owned more than $20,000 (over $590,000 in 2015 dollars) worth of real estate. The largest holding was valued at $140,000 (well over $4,000,000 in today’s dollars).

According to Moncrief, “the newcomers cleared away the heavy forests and planted the new ground in the favored crop then, as now –– cotton. They cleared all the lands fronting water courses (which are the highest and most desirable lands for cultivation in this region) to form a continuous line of plantations along the streams.” Streams in this context refers not just to the Tensas but also to the smaller non-navigable bayous. Cotton raised along the smaller streams was brought down to the Tensas in flat-bottomed boats.

Moncrief’s thesis also includes figures for cotton and corn production in Madison Parish. Cotton production peaked at over 46,000 bales in 1858. (Pough was apparently incorrect in stating it was over 100,000 bales; he may have combined the total with that of an adjoining parish.) It had fallen to 1,830 by the end of the war. Production recovered between 1870 and 1875 and reached a postwar/pre-boll weevil peak of 25,981 bales in 1890, about the same level of production as in 1936. Corn production peaked at 618,620 bushels in 1859, falling dramatically after the war, peaking at 836,000 bushels in 1909, and then falling to 320,000 by 1936. My crude, back of the envelope estimate based on  yields of 5 bales per acre for cotton and 15 bushels per acre for corn, suggests that between a quarter and a third of the total acreage in the Parish was under commercial cultivation prior to the war.

While Moncrief’s paper evokes Tanner by describing the Singer Tract as 81,102 acres (126 square miles) of virgin timber, it also notes, “The tract includes several abandoned and grown up plantations, which after the Civil War, reverted to the state and were later sold to the present owners.” The ruins of one plantation house are still standing, deep within the Tensas National Wildlife Refuge.

While it was adjacent to and not strictly part of the Singer Tract, the story of the Frisby Plantation is illustrative. The plantation was established in the early 1850s with land acquisitions taking place over the next decade. Norman Frisby, the founder, was murdered by his nephew by marriage in an 1863 in a dispute over property. When Frisby’s widow was forced to sell the plantation in 1870, it totaled 19,479 acres, and its crops generated over $77,000 in revenue (the equivalent of $1.36 million in 2015). Tanner visited the site of the plantation and photographed one of its old fields. I haven’t been able to pinpoint the location of the old house; one 19th century survey survey seems to place it in Tensas Parish, near Fool’s River. Another account (from the history of the Sharkey Plantation discussed below) says it borders Disharoon (or Dishroom) Bend, much closer to the core of the Singer Tract. As shown on this overlay of 1875 land ownership on a modern map, the Frisby holdings included parcels adjacent to Mack’s Bayou and on Dishroom Bend.

The maps help flesh out the story. An earlier and incomplete parish-wide map of patentees shows that many parcels in the Singer Tract were purchased well before Frisby started acquiring land in the 1850s. Lands purchased in the 1840s include parcels along John’s and Mack’s Bayous, which makes sense since frontlands along streams were most desirable. This history of the Sharkey Plantation reveals that land sales began in the heart of Tanner’s search area during the 1840s. The author explains that the Sharkey plantation and others like it were more like communities, with a cluster of families (and presumably their slaves) living in close proximity, near a watercourse.  The 1875 map shows that much of the Singer Tract remained in private hands even after many parcels were abandoned during the Civil War.

Perhaps even more telling is this hand drawn map of Madison and Carroll Parishes from 1862. It shows the locations of towns, roads, ferry crossings, and plantations in the Singer Tract area. While it is incomplete and John’s Bayou is not shown, Sharkey Road is there, cutting in a southwesterly direction from the Richmond-Carthage road, crossing Alligator Bayou, and the Swearingen parcel. Another road crosses the heart of the Mack’s Bayou home range and the Tensas itself. The map delineates abandoned plantations and appears to show that, except for those abandoned areas, some cotton was being grown in every division of the Singer Tract. However limited the agricultural activity may have been in these sectors, the area was hardly a primeval wilderness; habitat had been fragmented; and old growth conditions were likely restricted for the most part to areas unsuitable for farming.

This passage from an 1885 article from the New Orleans Times-Picayune sheds some additional light on conditions in the area both before and after the Civil War. “But little has been said about Tensas River and Joe’s Bayou as, but little interest is there as compared with former years. Before the war there was a continuous planting interest all along those two streams but overflows and the war left them to grow up into weeds and bushes. In 1870 Mason, and later Loyd bought cattle from other parts of the country and carried them to those bayou places for pasturage, wherein a few years they made large sums of money. This was in the neighborhood of Quebec, which before the war was a flourishing little city, shipping 7090 bales of cotton. It was at the junction of the Tensas River and the railroad. It is now a waste place and to pass there on the railroad you would never know that a town had been there.” (In The Race to Save the Lord God Bird, p.76 Hoose plays into the virgin forest myth by claiming that railroads “finally reached the Tensas River sometime around 1900.”) Quebec was just a few miles outside the tract, near Bayou Despair, where Tanner listed a pair from 1934-1936.

The Rootsweb pages provide a couple of additional and important pieces of information.

Theodore Roosevelt visited Madison Parish in 1907.  Roosevelt’s descriptions provide added detail about conditions in and around the Singer Tract several decades after the Civil War. According to Roosevelt:

“Beyond the end of cultivation towers the great forest. Wherever the water stands in pools, and by the edges of the lakes and bayous, the giant cypress loom aloft, rivalled in size by some of the red gums and white oaks. In stature, in towering majesty, they are unsurpassed by any trees of our eastern forests; lordlier kings of the green-leaved world are not to be found until we reach the sequoias and redwoods of the Sierras. Among them grow many other trees–hackberry, thorn, honeylocust, tupelo, pecan, and ash. In the cypress sloughs the singular knees of the trees stand two or three feet above the black ooze. Palmettos grow thickly in places. The canebrakes stretch along the slight rises of ground, often extending for miles, forming one of the most striking and interesting features of the country. They choke out other growths, the feathery, graceful canes standing in ranks, tall, slender, serried, each but a few inches from his brother, and springing to a height of fifteen or twenty feet. They look like bamboos; they are well-nigh impenetrable to a man on horseback; even on foot they make difficult walking unless free use is made of the heavy bush-knife. It is impossible to see through them for more than fifteen or twenty paces, and often for not half that distance. Bears make their lairs in them, and they are the refuge for hunted things. Outside of them, in the swamp, bushes of many kinds grow thick among the tall trees, and vines and creepers climb the trunks and hang in trailing festoons from the branches. Here, likewise, the bush-knife is in constant play, as the skilled horsemen thread their way, often at a gallop, in and out among the great tree trunks, and through the dense, tangled, thorny undergrowth.”

The most salient point here is that Roosevelt’s “great forest” applied to low-lying areas in which there was standing water (something that Hoose glosses over). Roosevelt also saw three Ivory-billed Woodpeckers:

“The most notable birds and those which most interested me were the great ivory-billed woodpeckers. Of these I saw three, all of them in groves of giant cypress; their brilliant white bills contrasted finely with the black of their general plumage. They were noisy but wary, and they seemed to me to set off the wildness of the swamp as much as any of the beasts of the chase.”

 

A photograph from the hunt is here. Tanner seems to have been unaware of the Roosevelt encounter. Roosevelt’s visit came just 17 years into cotton farming’s second decline and 52 years after the end of the Civil War. Habitat conditions are likely to have been poorer in general than when Tanner was there 3 decades later. The relative ease with which Roosevelt saw three ivorybills (despite their wariness) suggests they were not uncommon in 1907 and calls Tanner’s assumptions (pp. 48-50) about fire, tree death, and population influxes between 1911 and 1930 into question.

There’s another gem in the Rootsweb pages. It’s not directly on topic, but it relates to Tanner’s later dogmatism. In arguing for extinction and dismissing post-Singer Tract reports, many of which involved birds being flushed from tree stumps or other locations near the ground, Tanner characterized this behavior as being characteristic of pileateds not ivorybills.

Rootsweb has a newspaper account of  T. Gilbert Pearson‘s  visit to the Singer Tract in 1932. Pearson (who was President of the Audubon Society at the time) was the first ornithologist to confirm the presence of ivorybills in the Tract. He saw, “The birds . . . feeding on stumps of rotting trees, the tops of which had been broken off. A favorite place for feeding is also on dead limbs at or near the tops of the very tall sweet gum trees found abundantly in this region.”

The evidence that relates directly to Tanner’s study area and its immediate environs suggests that claims about “virgin forest” and IBWO dependency on old-growth are based on flawed premises. The Singer Tract was no doubt a remarkable place, a huge area of contiguous and relatively undisturbed forest, but it’s clear that much of it was not old growth or “virgin”.

It’s more useful to think about what the Singer Tract is likely to have offered Ivory-billed Woodpeckers – some measure of seclusion, enough big trees for roosting and nesting, and an abundance of standing and fallen deadwood. The myth that the Ivory-billed Woodpecker required vast tracts of “virgin” forest may be emotionally compelling, but it’s not based on evidence; it’s time to put it to rest.

I’m looking forward to spending a week in the field starting just after Christmas.


Habitat Conditions in the Singer Tract

Late last year, I wrote a post entitled “More Minutiae – Habitat Quality and Population Density in the Singer Tract”. I had to follow up with a couple of corrections and elaborations based on insights others shared with me. In the interest of providing more clarity and coherence, I thought I’d do a new piece combining the three posts and expanding on them a bit. I won’t delete the originals, but this one reflects what I think is a more accurate understanding of the material involved.

Mack's Bayou Ivorybill nest tree. Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

Mack’s Bayou nest tree. Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

The initial post was inspired by the image above and the caption describing it as the “Third ivorybills’ nest”, one I had looked at but not closely until last year. When I did examine it carefully, I was struck by how open the surrounding area seemed to be. Then I started going through archival photographs and scrutinizing them a little more closely.

In browsing through the Louisiana Digital Library’s collection of Singer Tract photographs, I came across an image that I had missed, one of the bridge over John’s Bayou taken in 1940. Tanner (p.32) includes an ivorybill sighting from this immediate vicinity, just northwest of the bridge. What I find interesting about the photograph is that the forest along the road appears to be fairly even-aged and does not have the characteristics typically associated with old growth. It is similar to what can be found in many parts of Louisiana today. An image from along Sharkey Road taken in 1937 shows similar characteristics, although another shot from 1939 (probably taken east of the bridge) shows more impressive looking habitat.

Richard Pough wrote a follow-up report to the Audubon Society on the Singer Tract in 1944. It’s a very interesting document that raises some questions about Tanner’s work. Pough explicitly accepted “Tanner’s premises as to the feeding habits and habitat preferences of the ivory-bill”, but he also noted “[n]othing in Mr. Tanner’s study indicates that Ivory-billed Woodpeckers show any preference or marked dependence on trees of great size such as one would find only in a virgin forest. He found them doing 14% of their feeding on trees 3”-12” in diameter and 64% on trees under 24” in diameter.”

Pough pointed out that “Maps of the area as of 1846 showed much of the Tensas River in plantations and many cleared fields back from the river on some of the interior ridges. This development continued for another 20 years until the Civil War, by which time Madison Parish was producing 110,000 bales of cotton a year. As the Parish has never produced over 30,000 bales since the Civil War, one gets some idea of how much land is now occupied by second growth forest of approximately 80 years age.”

Pough found only one ivorybill, a female. He assumed, relying on Tanner, that this was the only one left in the Tract. He may well have been mistaken, since Gus Willett, game warden in the Tract, wrote Tanner about seeing a pair in November 1948 (although the exact location is unclear). Correction, Willett did not write the letter, although the report reached Tanner, as discussed here.

The lone bird Pough saw was either the John’s Bayou female or one of its offspring. According to Pough, this bird was probably not feeding in virgin forest, and his report specifically suggests that Tanner might have been mistaken about the maturity of some of the habitat in the John’s Bayou area. In 1941, Tanner had written that the remaining John’s Bayou birds were roosting and feeding in “virgin” timber. Pough’s description of this area (and it seems to be the same patch) suggests it was likely cultivated pre-Civil War. It was devoid of big sweet gums, which Pough deemed to be the best indicator of old growth conditions, but had many dying Nuttall oaks 12-20 inches in diameter. Nonetheless, Pough relied on  Tanner’s premises to conclude that “only a relatively small portion of the total area of the Singer Tract supported a forest suitable as habitat for these birds.”

To return to the material in the earlier blog posts, much of the discussion focused on home ranges and the distribution of nest sites.

This map, drawn by Tanner after the 1935 expedition, lists three nests – designated as nests II, III, and IV –within a mile or two of each other and in the vicinity of John’s Bayou. Nest II is the famous “Elm Rock” nest. The map also shows a tree which is designated “Nest (?) III Squirrel” (also mentioned in Bales, “two miles to the south of the first nest” and fifty feet up p. 45). This was outside the area Tanner designated as prime in 1941 (p. 91); it is approximately a half-mile from the John’s Bayou bridge.

I’ve discussed this issue in depth with someone who’s very familiar with Tanner’s notes. I’m now persuaded Tanner concluded that nests III and IV from 1935 were not nests after all and that he assigned the birds involved to Titepaper (Nest III) and Bayou Despair (Nest IV). Nest IV is apparently one that Kuhn found but was unable to re-locate. Why Tanner changed his mind about it remains a mystery.

It’s very difficult to piece together this fragmentary information, and the monograph muddies the waters a bit by presenting the home ranges of the birds as being quite discreet, perhaps a good deal more than they were in fact. I suspect that Tanner decided the cavities were actually roosts, (although neither one is mentioned in the monograph). If so, they would have been well outside the home ranges Tanner identified and closer to the core of the John’s Bayou range than to the core of Titepaper or Bayou Despair.

Nests I and V were located near Mack’s Bayou. Nest I is dated May 14, ’34 on the map, and Nest V is dated May 10, ’35. The ’35 nest failed. It is the one referenced above. Allen and Kellogg described it as being 45’ feet up, in a pin oak snag, in a natural clearing, although it has been suggested that the snag may have been a remnant large tree in area that had been cleared prior to the Civil War. The nest designated Nest I and dated May 14, 1934 appears to be the one Tanner described on p. 81 of the monograph, “located within 100 yards of the second nest found in 1935”; however, in the monograph, he gave the date as May 13, 1933.

It’s worth pointing out that the Mack’s Bayou nests were in an area that Tanner designated as “best” for ivory bills (even if it’s not clear whether it was truly old growth). Nonetheless, nests failed in 1933 and 1935, and the adult birds had disappeared by 1938, apparently after producing one fledgling in 1936 or 1937. This was before the logging began.

My intention in writing those initial posts was to get a clearer handle on population densities and habitat requirements in the Singer Tract. In retrospect, I’m not sure that’s possible, since Tanner’s observations were almost entirely limited to one family of birds in a population that was dwindling for unknown reasons. At the very least, Tanner’s statement that 7 pairs of birds required 120 square miles of virgin forest in 1934 is based on an inflated estimate of the amount of old growth in the Tract and his minimum estimate of 6.25 square miles per pair also rests on that flawed premise.

Pough observed, “ . . . the ivorybill problem puzzles me exceedingly, and I do not feel that Tanner’s report begins to explain the reasons for the drastic decline in this species.” As the 2014-2015 search season approaches, I can only hope that the question of how the species persisted will puzzle people exceedingly in future years.


How The Ivory-billed Woodpecker Might Have Survived

I have been corresponding with Christopher Carlisle, a Mississippi birder who has recently started searching for ivorybills in the Pascagoula watershed. These exchanges, along with a post on IBWO.net about the Choctawhatchee, led me to start thinking, in a somewhat more methodical fashion, about habitat conditions and how the ivorybill might have survived and to consider the significant differences between the old Project Coyote search area and the new one.

I suspect there may have been three behaviors, probably operating separately and together, that made survival possible and detection and documentation difficult. These behaviors are consistent with the historical record, which suggests the species was considerably more adaptable than the simplified reading of Tanner that treats “virgin” or old growth timber as essential. Tanner’s own views on this issue became considerably more dogmatic over time, but even his early surveys of possible habitat in the southeast were influenced by this belief, which I’d suggest was more cultural than scientific, since Tanner was a product of an era in which frontier mythology profoundly influenced American thinking. Tanner’s description of the Singer Tract and especially his ivorybills are reminiscent of Edward S. Curtis’s Native Americans, magnificent, worthy of honor, but ultimately doomed and incapable of adapting.

The reality about Native Americans was considerably more complex of course, and the same goes for the Singer Tract. It was by no means a vast tract of virgin forest in the 1930s; much of it had been under cultivation prior to the Civil War, less than a century prior to Tanner’s seasons there. In pre-Columbian times, the southeast had a significant indigenous population, with perhaps as many as 5.2 million people in the Mississippi Valley alone. Thus, much of what was deemed to be “virgin” forest in the 20th-century was quite likely agricultural land in the pre-Columbian era. As I see it, Tanner’s preconceptions about what constituted “suitable habitat” led him to be somewhat cavalier, even in the early days – dismissing areas based on very brief visits, most often due to lack of “virgin” forest. As a result of this prejudice, Tanner may have underestimated the IBWO population.

This is not to negate the argument that IBWOs are more specialized than PIWOs; their morphology clearly places them in a different ecological niche, and their considerably more limited historic range also points to a higher degree of specialization. The fact that IBWOs do not regurgitate may place limits on behavior and home range during breeding season. The specialization, however, has far more to do with foraging behavior than with habitat requirements.

The IBWO.net post suggested (and implied some direct knowledge) that Geoff Hill and the Auburn team focused too heavily on the main channel of the Choctawhatchee. A person calling himself “Ranger Mike” wrote:

“During the last expedition by Auburn here on the Choctawhatchee River Basin I noticed two things that in my amateur opinion could have been better-First every time I saw researchers, or others who hunted and fished the area saw them, they were far to close to the main river. I am well aware of how hard it is access the flood plain areas, but the birds will likely be closer to the banks in the floodplains where there are very large old growth long leaf interspersed with the large cypress and gum that has been missed by logging due to its inaccessibility. This transition zone will be good habitat, and in my very significant time in these in both work and hunting/fishing has produced some interesting sightings and sign, with nothing of interest in the more frequently traveled areas. Second, I don’t think much time was spent on East Island. Its a very remote and promising area, but I think it was avoided because it would have required traversing by foot instead of floating around in kayaks or canoes.”

While I have not verified this account with anyone on the Auburn team, the general observation makes sense and is consistent in some respects with what Tanner observed in the Singer Tract. Nesting habitat was primarily located along tributary streams, not the Tensas River itself.

Edited to add: I have never been to the Choctawhatchee, and so have no first-hand knowledge with which to assess Ranger Mike’s comment. My intention was not to criticize Dr. Hill or the search efforts but to highlight a possible survival scenario. Since posting, I’ve heard from a couple of people with more knowledge of the area; one emailer stated that East Island is “way overlooked”, so if anyone’s interested in revisiting the Choctawhatchee, that might be a place to start.

The two Project Coyote search areas are quite different in character and forest composition. The current search area is secluded, very mature and surrounded by a good deal of contiguous lower quality habitat. It is part of a major watershed but is somewhat distant from the main river system, in the floodplain of a tributary. The old search area was on a small parcel of private land, about 3/5 of a mile distant from a medium-sized WMA, with bean fields in between. There are a number of larger WMAs in the surrounding area. The habitat in this area is mostly if not all of lower quality than in the new area and is discontinuous. Frank Wiley described it as “pearls on a string”. Assuming that ivorybills are or were present in both areas, it seems likely that the differences in habitat require different behaviors, and this may in turn point to how the species managed to persist post-Singer Tract. The following may be the behaviors that made survival possible.

Survival Strategy 1. Seek seclusion in remnant stands of mature forest and areas that were selectively logged, with substantial tracts of contiguous lower quality habitat associated; core habitats provide sufficient food supply during breeding season, and surrounding areas, pine plantations, younger upland hardwood forests and the like, might provide additional food sources the rest of the year. Examples of this type of area may include the Choctawhatchee, possibly other Florida rivers, the Carolinas, and the Pearl.

Survival Strategy 2. Expand home range substantially to forage in degraded habitat, using forested corridors to move around whenever possible but traversing open fields when necessary. This would entail having roosts and possibly nest sites near field edges in some instances, as appeared to be the case in the old Project Coyote search area, near Patterson, LA , a few other Louisiana locations, and possibly Wattensaw WMA in Arkansas. This idea is in part inspired by the November ’48 report to Tanner from Gus Willett, Singer Tract warden, saying that he saw a pair of ivorybills at “North Lake #1” and that the “birds are moving over a much larger area than formerly.” This is the last letter to Tanner pertaining to the Singer Tract, and it points to the likelihood that the widely circulated story of Don Eckelberry’s encounter with the last female IBWO is just another facet of the mythology that surrounds the species.

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Suspected recent nest cavity found by Frank Wiley near the edge of a bean field, East-Central Louisiana, 2009.

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Black and white image of tree in which suspected nest cavity was found. Compare with the appearance of this nest tree from the Singer Tract.

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Close up of suspected roost cavity in a willow at the edge of a bean field. This cavity was in the tree where we obtained a Reconyx image of a possible ivorybill, discussed here.

Survival Strategy 3. The IBWO can function as a “disaster species”, as Dennis and others have argued, having a high degree of mobility when necessary. “Disaster” in this context could be a slow motion sort of disaster as in the Singer Tract, where sweet gums were undergoing a die-off, so this could include elements of either 1 or 2.

Strategy 1 would help explain some of the difficulty finding, relocating, and documenting the species, since these are remote and inaccessible locations and sightings would most often take place outside of core habitats. Strategy 2 might also help explain why detection is so difficult. These areas are sparsely populated, birds would only be in the open briefly, and would not stay in one place for long, except during nesting season. And as Frank Wiley pointed out, the main human activity during nesting season is turkey hunting, and David Kullivan notwithstanding, turkey hunters are unlikely to see ivorybills, in part because of where they’re focused and in part because their methods would be likely to be disruptive and cause any birds in the vicinity to flee.