Justification of Red List Category
Claims for this species's persistence in USA have emerged since 2004 although the evidence remains highly controversial. It may also survive in south-eastern Cuba, but there have been no confirmed records since 1987 despite many searches. If extant, the global population is likely to be tiny, and for these reasons it is treated as Critically Endangered.
Given the lack of confirmed sightings since 1944 any remaining population within the USA is likely to be tiny. A tiny population may also remain in Cuba, despite lack of recent sightings. Its total population, if extant, is likely to number fewer than 50 individuals and mature individuals.
It is not possible to determine trends within any remaining population of the Ivory-billed Woodpecker should it remain extant, and as such, the direction of current trends remain unknown. Despite historical declines, this species's habitat throughout the southeastern U.S.A. is currently recovering as previously cut forests mature (Collins et al. 2019, G. Hill in litt. 2020), however habitat loss and potential hunting in Cuba may pose a threat to any remaining individuals within the Cuban subpopulation.
Campephilus principalis formerly occurred at low densities throughout the south-east U.S.A. (nominate principalis) and Cuba (subspecies bairdii). Sixty years after the last confirmed North American record in north-eastern Louisiana in 1944, the species was reported to have been rediscovered in 2004 in the Big Woods region of eastern Arkansas (Fitzpatrick et al. 2005). Evidence for the rediscovery comes in the form of seven sightings, a short poor-quality video, over 100 sound recordings indicative of this species from automatic recording stations, and a number of additional "possible encounters" (Charif et al. 2005, Dalton 2005, Fitzpatrick et al. 2005, M. Lammertink in litt. 2005, 2006). The sound and video recordings have been analysed in detail, and the identity of the recorded birds has been debated between Ivory-billed Woodpecker and other sources, including the Pileated Woodpecker Dryocopus pileatus (Fitzpatrick et al. 2005, Sibley et al. 2006, Fitzpatrick et al. 2006, Sibley et al. 2007, Collinson 2007, Fitzpatrick et al. 2007). The U.S. Fish and Wildlife Service concluded that the recordings provided compelling evidence for the presence of Ivory-billed Woodpecker in 2004, and that search efforts were warranted (USFWS 2010). However, intensive searches until 2009 did not find conclusive evidence for the continued presence of the species in the Big Woods region. There were also unconfirmed reports by researchers working in forests along the Choctawhatchee River in Florida, reporting 14 sightings and 309 double knock and kent calls during 2005-2006. Additional sightings and calls were compiled in the 2006-2007 field season, but no incontrovertible evidence was obtained (Hill et al. 2006). Similarly, video and sound recordings made during 2006 and 2008 in Louisiana suggest characteristics of the species (Collins 2011, 2017). A search in the coastal mangrove forests and inland hammock forests of south Florida in 2009 failed to find any sign of the species (Gold 2009), but south Florida has large areas of potential habitat and there is a relatively high frequency of plausible reports from there in recent decades (M. Lammertink in litt. 2012). Between the last confirmed sightings in 1944 and the 2000s records discussed above, there were more than 20 reports from within its historic range (Jackson 2002, Roberts et al. 2010) and Michaels (2015) suggests there have been many more unconfirmed sightings, including records from several years after the last official sighting in 1944.
The species may survive in Cuba, although searches have not found any new records subsequent to those of the late 1980s (M. Lammertink in litt. 2004). The best hope lies in the Alejandro de Humboldt National Park, an area in which despite regular bird inventories being taken some sections have been only sparsely searched (M. Lammertink in litt. 2012). Calls potentially of this species were heard in 1998 in the Sierra Maestra in south-east Cuba (D. S. Lee verbally 1998, G. M. Kirwan in litt. 1999), in an area from which there had been no historical records and at an elevation higher than the known altitudinal range of the species. Follow-up searches in the area found poor habitat and no indications of presence of the species (M. Lammertink in litt. 2004). With the lack of recent confirmed records and no evidence of large woodpecker activity (M. Lammertink in litt. 2012), this subspecies also may well be extinct.
A recent statistical analysis of physical evidence and independent expert opinion, as part of a study into the burden of proof required for controversial sightings of possibly extinct species, supported the view that this species is very likely extinct (Roberts et al. 2010). Similarly, use of statistical methods for estimating the probability of species persistence from collection dates of museum specimens, along with quantitative stopping rules for terminating the search for missing or allegedly extinct species (based on survey data for counts of co-occurring species that are encountered in the search for a target species) suggest there is virtually no chance that the species remains extant within its historical range in the southeastern United States (Gotelli et al. 2012). In addition, a Bayesian method accounting for sightings of uncertain validity was applied to certain and uncertain sightings over the period 1897-2010, and results indicated substantial support for extinction (Solow et al. 2012). Nevertheless, other statistical studies have shown that, when considering the specific natural history traits of large woodpeckers, small numbers of Ivory-billed Woodpecker may have persisted up to the present (Mattsson et al. 2008), and that very large search efforts are needed to detect small populations (Scott et al. 2008). Collins (2019) suggests that video evidence obtained in recent years displays behavioral and morphological traits consistent only with those of the Ivory-billed Woodpecker and that the species likely remains extant, although clear, definitive photographic evidence of the species remains elusive. Any remnant population in either the U.S.A. or Cuba is likely to be tiny.
It was originally found in bottomland hardwood in the U.S.A. and in Cuba, where it also resided in montane (pine, mixed and broadleaf) forests. Historic accounts indicate that it has a very large home range and occurs naturally at low densities, suggesting that large contiguous tracts of mature woodland would be required to support a viable population (Jackson 2002). The Big Woods area comprises several distinct types of swamp and bottomland hardwood forests (Fitzpatrick et al. 2005), covering a total area of c.220,000 ha. In Cuba, extensive habitat loss and degradation in the lowlands mean that any remaining population may be restricted to intact montane Pinus cubensis forests. The primary requirement is for dead trees, which harbour wood-boring beetle larvae, its preferred food source. It forages by stripping bark from dead trees, using its bill like a carpenter's chisel, and also takes fruit, nuts and seeds (Jackson 2002). The breeding season is between March and June in Cuba, and between February and May in the U.S.A.
Logging and clearance for agriculture have been suggested as a primary cause of the species's past decline however, the regions where the species is purported to remain in the U.S.A. are currently undergoing a net increase in habitat as a result of re-forestry and the ongoing maturation of previously cut forests (Collins 2019, G. Hill in litt. 2020). Hunting has also been implicated in the rapid population decline, and it has been proposed that this was the primary cause of its decline, with habitat destruction playing a secondary role, but this theory is contentious (Snyder 2007, Hill 2008, M. Lammertink in litt. 2012).
Conservation Actions Underway
After the reported rediscovery in February 2004, intensive surveys involving dozens of observers, automatic cameras and recording equipment have been carried out in the Big Woods area (Fitzpatrick et al. 2005). Searches have also continued in other parts of the south-east U.S.A. that have historic records of the species, with specific searches taking place in 28 locations across that area in 2004-2009 (Hill et al. 2006, Rohrbaugh et al. 2007, M. Lammertink in litt. 2012). An endangered species recovery team of c. 50 members has been appointed (Jackson 2006). Between October 2003 and September 2013 the U.S. Fish and Wildlife Service (USFWS) spent $20.3 million on efforts to document and protect the species, including through habitat protection and acquisition ($13.2 million spent on land acquisitions) (Jackson 2015). In October 2009, the search for the species in the U.S.A. was suspended because the most promising areas, including most of Arkansas's Big Woods, had already been surveyed to some extent (Dalton 2010, M. Lammertink in litt. 2012). USFWS published a recovery plan in April 2010 (Dalton 2010, USFWS 2010). Part of the Big Woods area falls within the Cache River and White River national wildlife refuges. In Cuba there have been a number of searches for the species, and further searches were planned for 2010 and 2011 (BirdLife International unpubl. data).
48-53 cm. Huge black-and-white woodpecker. Mainly black with large white wing-patch, 'braces' on mantle and stripe on side of neck from lower edge of ear-coverts to mantle. White underwing-coverts separated by black from white secondaries. In flight, resembles a duck and does not undulate. Similar spp. On Cuba unmistakable. In U.S.A., Pileated Woodpecker Dryocopus pileatus is smaller and has dark bill, white neck-stripe across the cheeks to bill, white supercilium and throat, lacks white stripes on mantle and large white wing-patch (small patch at base of primaries sometimes visible). In flight, lacks white secondaries and has more extensive, white underwings. Voice Single or double note drum, toy-trumpet-like kent calls sometimes as a fast series or as a double note call (emphasis on the first).
Text account compilers
Ashpole, J, Benstead, P., Bird, J., Butcher, G., Calvert, R., Hill, G., Khwaja, N., Kirkconnell, A., Kirwan, G.M., Lammertink, M., Lee, D.S., Sharpe, C.J., Symes, A., Taylor, J., Temple, H. & Westrip, J.R.S.
BirdLife International (2021) Species factsheet: Campephilus principalis. Downloaded from http://www.birdlife.org on 21/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/10/2021.