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| Three inland reports and records of Ivory-billed Woodpeckers in South Carolina explained in text. |
"South Carolina - Sprunt and Chamberlain (1949) suggest that Ivory-billed Woodpecker was formerly common over much of the eastern part of the state but its virtual extinction was due to the encroachment of civilization.
The original range of Ivory-billed Woodpecker in South Carolina was the extent of the coastal plain bordered to the north by the fall line and extending to the Atlantic coast. This area was comprised of bottomland hardwood riverine systems surrounded by longleaf pine uplands intermixed with farms and plantations."
Recovery Plan for the Ivory-billed Woodpecker (Campephilus principalis) April, 2010Most, if not all Congaree National Park, SC's biology researchers are familiar with John Cely. In 2023, he wrote that Ivory-billed Woodpecker (Campephilus principalis; IBWO, IB) locality records extend as far inland as South Carolina’s Fall Line. He espoused that there is no ecological reason to exclude the Congaree River corridor, which lies well below the Fall Line, from the 19th-century IBWO range.
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| Cely, Page 1 2023 |
The Fall Line marks a sharp geological transition where the Piedmont’s hard, elevated bedrock gives way to the Coastal Plain’s soft, sandy sediments. While this boundary has substantial ecological implications for “the great chieftain of the woodpecker tribe” (Audubon), it was likely not an absolute barrier to IBWO dispersal or even nesting in landscapes of gradually increasing elevation above the Fall Line. IBWO density was probably lower above the Fall Line than below it across relevant states, because the line also delineates two distinct biotas.
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| Cely, Page 2 2023 |
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| Upon an ecological presentation here, there is no reason precontact Ivory-bills did not inhabit all of the land southeast of the Fall Line in SC. IBWOs likely inhabited some select areas above the Fall Line also (see map within). |
As a facultative omnivore but obligate feeder of larval Coleoptera during the breeding season, IBWO distribution would have been somewhat constrained by beetle density and community composition especially if female IBs exhibit site fidelity, which is suspected. Accordingly, breeding range and density should correlate with micro and macrohabitats supporting high biomass of cambium feeding Coleopteran larvae. This food limitation likely diminished post-fledging, when parents and altricial young became vagile as a group and could exploit resources at slightly higher latitudes and/or elevations. Proposed are only minor "incursions" of breeding north of the Fall Line; no proposal for large interstate expansion of the IBs historical range is presented or supported here.
In foothill regions, a historical symbiosis with beaver-driven hydrology may have further influenced IBWO occurrence, a hypothesis consistent with the observed pattern of reports and specimens declining with increasing altitude and latitude but not absent from these areas. Finally, seasonal differentiation in foraging strategy should be considered a potential evolutionary driver for precontact IBWOs.
Post-breeding resource availability may have made it advantageous for Campephilus principalis to avoid depleting select beetle families in lowland habitats. Fruits, nuts, and other insect taxa became more concentrated and accessible from early summer through early December, preceding the subsequent IBWO breeding season from early December to at least April.
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| Three notable locations with IBWO reports and records. 1. is referred to by Tanner, Cely and others. 2. summarizes years of modern work by many. 3. is based on reports with some suggestive modern videos. |
Many North American birds shift their movements seasonally with altitude, temperature, and food availability. A U.S. example is the American Dipper (Cinclus mexicanus), which moves to higher-elevation foraging and breeding areas in summer. A common type of seasonal movement is exhibited by the many neotropical migrants.
The Fall Line creates a somewhat sharp ecological divide in South Carolina in some areas. Above the line, rivers are faster and narrower, flowing over rocky, clay-rich soils. Below it, rivers slow and widen into floodplains with sandy soils. This transition produces distinct ecosystems and plant communities. The extensive floodplains, slower rivers, and warmer, sandier environments of the Coastal Plain support greater diversity of reptiles, amphibians, other lowland wildlife, and IBWOs.
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| SC data. Note the winter 10-degree lower average temperature difference between the two areas. Warm blooded animals like IBs face a large increase in energetic costs to survive cold nights. Average temperatures are impactful but extreme temperatures erect not only another barrier for IB breeding, but a lethal one at higher elevations. |
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| Record cold winter day in SC that shows the potentially fatal temperatures that warm-blooded, omnivores are exposed to. Note the 25 degree drop from the frigid coastal plain to the Appalachians. Cold Winter 1985 |
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| Zoogeographic limitations are often determined by the extremes and less so the averages. Birds can die in one night from these extremes. There is no evidence that Ivory-bills were a migratory species but seasonal movements were possible and may be the source of some historic higher elevation reports and records. |
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| Typical IBWO range map that roughly adheres to the Fall Line at least in SC. |
Consequently, IBWO breeding success and population density was likely higher below the Fall Line, correlating positively with warmer late-winter and early-spring temperatures and increased forest humidity relative to the Piedmont. The inner and outer Coastal Plain, both below the Fall Line, supported a denser, richer community of cambium feeding beetles than the drier, cooler upland forests above it.
The dominant cambium feeding beetles of stressed trees, early in senescence process that the IBWO is adapted to extract before any other Picidae do relatively well in higher temperature and humidity habitats.
Ecological correlates for an IBWO breeding area are forests that have concentrations of these insects:
Roundheaded Borers (Family Cerambycidae): Larvae of longhorned beetles. They have cylindrical bodies, are typically whitish-yellow, and some species are known as "sawyers" or "pine sawyers".
Bark Beetle Larvae (Family Curculionidae, Subfamily Scolytinae): Small, legless, white grubs that chew intricate, winding tunnels called galleries directly into the cambium.
Flatheaded Borers (Family Buprestidae): Larvae of metallic wood-boring beetles. They are legless, white, and feature a distinct broad, flat segment right behind their head.
Multiple studies report positive relationships between invertebrate biomass and temperature, humidity, and lower elevation.
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| General Humidity Chart, Coleopteran density, community diversity and biomass is positively correlated to humidity. |
However, beavers, which were abundant in the precontact era, may have partially altered this pattern by damming high-energy streams above the Fall Line. Beaver-induced tree mortality would have provided substantial, though spatially constrained, foraging substrate for breeding IBWOs along narrow, linear corridors bordering former stream channels that became ponds. Riverine wetlands, including small rivers, streams, and creeks, thus succeeded into a discontinuous series of lacustrine wetlands such as ponds, bogs, and swamps. These lacustrine systems create dynamic forest ecotones with elevated densities of stressed and standing dead trees.
These beaver-created gaps and increased habitat heterogeneity could benefit saproxylic invertebrates; a study in temperate forests found canopy openness and habitat heterogeneity being the main factors affecting saproxylic beetle diversity (Seibold et al., 2016).
These beaver-created gaps and increased habitat heterogeneity could benefit saproxylic invertebrates; a study in temperate forests found canopy openness and habitat heterogeneity being the main factors affecting saproxylic beetle diversity (Seibold et al., 2016).
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| Critical SC area that portrays an ecological approach to the IBWO breeding range represented by thick blue line. The feather like blue areas delineate precontact riparian/stream corridors likely dammed by beavers, these areas then supporting some IBs. The 3 red dots represent the 3 inland IBWO data points discussed in the text which were near the Fall Line. |
The adaptations of the Ivory-billed support the symbiosis between the IBWO and cambium feeding larvae. Morphology has capitulated to food source in the northern Campephilus clade. The ancestral species, likely in what is now Mexico, eventually speciated; it had the adaptations for efficient bark scaling. The unique physiology of the tropical genus was well suited to support the niche exclusion principal and fill an ecological gap in the northern latitudes of the genus' range during the Pleistocene Epoch, 1.1 MYA.
The unequivocal importance of cambium feeding insects is reflected by the Ivory-bills large, chisel-tipped bill that is ivory-colored and uniquely flattened at the tip. The bill has the utility of a chisel rather than the ice pick of the Dryocopus. The bird wedges and prys tight bark to expose larvae more efficiently than other North American bird species.
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| The cambium layer is critical for insects, therefore IBWOs; it is the most nutrient-rich, accessible and easily digestible part of a stressed or dying tree. |
Other adaptions include a reinforced skull and neck which generates the power to efficiently loosen adherent bark early in a tree's senescence phenology. The neck musculature supports prying without injury. The tail feathers, rectrices, are bowed for spring-like support, are strong, long and stiff. The feet and rectrices are a tripod against the trunk or branch.
Just about all woodpeckers have zygodactyl feet, two toes facing forward and two facing backward. This structural adaptation provides an iron grip on vertical bark surfaces, allowing the bird to lean back and swing its head with maximum leverage. The Campephilus woodpeckers advance this; they exhibit a functional pamprodactly-like arrangement that can rotate all four toes forward to cling to surfaces.The internal organs match the ecological niche. The gastrointestinal tracts of the Ivory-billed and the Pileated have distinct evolutionary modifications tailored to their different food items. The IBWO's tract is adapted for chemical degradation to maximize lipid and protein extraction of the larvae. Campephilus feature a highly vascularized proventriculus with dense glandular tissue. This robust initial chemical bath breakdowns the food and the bolus enters a moderately muscled ventriculus, which lacks the extreme grinding requirements of more generalized insectivores.
National Biodiversity Parks, Inc. (NBP) conducted multi-year point surveys for IBWO in coastal and inland South Carolina, both below and above the Fall Line. Several IB detections and one visual sighting occurred only in the central part of the state, approximately 35 mi south of the Fall Line, within the largest remaining expanse of old-growth bottomland hardwood forest east of the Mississippi River. All detections used methods authorized under federal permit.
In 2023, John Cely discussed several inland records relative to the Fall Line, a geologic and topographic feature often used to approximate the historical IBWO range in South Carolina. To this author’s knowledge, as of 7/12/2026, no specimens have been documented from the Congaree River, despite its entire stretch being below the Fall Line. The Congaree River is formed by the confluence of the Saluda and Broad Rivers. The Saluda basin originates at the Fall Line and once extended farther west. Construction of the Dreher Shoals Dam and creation of Lake Murray between 1927 and 1930 inundated ∼50,000 acres and displaced any IBWOs present. Prior to impoundment, the river was ∼220 ft above sea level and the area was sparsely settled.
Flooding altered hydrology, with backwater effects, a higher water table, reduced flow, and expansion of swamp and palustrine habitats. Any remaining IBWOs should have found forage along the new shoreline, while many hydrophytic trees died as water levels and the water table rose substantially.
Early in the 2020s, reports of one or more IBWOs emerged from a rural area in northwestern South Carolina with numerous large trees and several disjunct 500-acre patches of older second-growth forest within a fragmented matrix of roads, farms, clear-cuts, residences, timber stands, small parks, and wooded streams. The reports were accompanied by several low-quality cell phone images and videos, four or five which were suggestive of an IBWO and female IBWO.
To assess IBWO status in northwestern South Carolina, we analyzed aerial imagery to identify the largest contiguous, roadless forest blocks and consulted foresters and biologists regarding woodpecker activity, standing dead wood, seclusion, recent fires, and forest DBH. With targeted sampling we then conducted point surveys, transects, and bark-scaling inspections within a 50 × 100 mi area.
No definitive evidence of IBWO was observed or obtained although Lake Murray had a few trees that did not rule out IB claims from that fragmented area. Northwestern South Carolina and the Lake Murray region likely do not harbor a hidden IBWO metapopulation, although occasional seasonal or dispersing individuals or pairs may transit the area. In Congaree we did find one fresh cavity and a few feeding holes that could have been Ivory-billed sign.
This is consistent with conclusions of the South Carolina Ivory-billed Woodpecker Working Group (SCIBWWG) and NBP, though we consider the Working Group’s conclusion that breeding does not occur in Congaree National Park (CNP) to be unsupported with reports indicating the opposite may be true.
Over seven days in 2023, we surveyed a roughly C-shaped route that included the Broad River, multiple sites in Francis Marion and Sumter National Forests including the Long Cane Ranger District, Belfast WMA, The Territories, and several areas near Lake Murray. Bark scaling on pines was extensive and attributable to Pileated Woodpeckers (Dryocopus pileatus); scaling on stressed deciduous trees was minimal.
In summary, the IBWO range in South Carolina was very roughly constrained by the Fall Line and the inherent ecological implications. However, the pre-contact range was likely slightly larger than most published maps, based on an ecological model in which temperature and humidity are positive predictors of coleopteran biomass per unit area. Greater coleopteran biomass and diversity would be expected to increase IBWO fledging rates. The species likely bred to elevations of at least 200 m in an interdigitated pattern along inland streams commonly dammed by beavers, which maintained a continuous supply of stressed and standing dead wood that supported pertinent beetle communities and biomass.
Consistent with records emphasized by Tanner and Cely in South Carolina, NBP agrees with Cely (2023) that there is no ecological reason to exclude the Congaree River corridor from the 19th-century Ivory-billed Woodpecker's range, given its location well below the Fall Line. NBP teams also detected modern IBWOs in Congaree NP on multiple occasions, further supporting historical occupancy of the river corridor.
NBP's 2023 point surveys and hikes in select northwestern South Carolina sites yielded no definitive IBWO sighting, detections or sign. Our data infers but does not confirm the absence of an IBWO metapopulation in northwestern South Carolina; this area excludes Congaree National Park. Lake Murray reports had some supporting filed evidence but at best it may indicate possible dispersal from presently unknow secluded IB breeding area(s) in SC. Congaree NP is an obvious possibility and SCIBWWG (2013) assertions on no breeding there was and is premature.
More point surveys are needed in SC and elsewhere to produce data on the IB's modern persistence.
Bibliography
- "South Carolina Record Maximum Temperatures and Date". South Carolina State Climatology Office. South Carolina Department of Natural Resources. Retrieved 4 February 2010.
- "Map of South Carolina Record Maximum Temperatures and Year". South Carolina State Climatology Office. South Carolina Department of Natural Resources. Retrieved 4 February 2010.
- "South Carolina Record Minimum Temperatures and Date". South Carolina State Climatology Office. South Carolina Department of Natural Resources. Retrieved 4 February 2010.
- "Map of South Carolina Record Minimum Temperatures and Year". South Carolina State Climatology Office. South Carolina Department of Natural Resources. Retrieved 4 February 2010.
