Largest Woodpecker Research Articles

Statistics, Probability, and a Failed Conservation Policy

Many sightings of the Ivory-billed Woodpecker (Campephilus principalis) have been reported during the past several decades, but nobody has managed to obtain the clear photo that is regarded as the standard form of evidence for documenting birds. Despite reports of sightings by teams of ornithologists working independently in Arkansas and Florida, doubts cast on the persistence of this iconic species have impeded the establishment of a meaningful conservation program. An analysis of the expected waiting time for obtaining a photo provides insights into why the policy of insisting upon ideal evidence has failed for this species. Concepts in statistics and probability are used to analyze video footage that was obtained during encounters with birds that were identified in the field as Ivory-billed Woodpeckers. One of the videos shows a series of events that are consistent with that species and are believed to be inconsistent with every other species of the region. Another video shows a large bird in flight with the distinctive wing motion of a large woodpecker. Only two large woodpeckers occur in the region, and the flap rate is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker (Dryocopus pileatus). Supplemental materials for this article are available online.

Using a Drone to Search for the Ivory-Billed Woodpecker (Campephilus principalis)

During the past several decades, there have been many reports of sightings of the ivory-billed woodpecker (Campephilus principalis), but nobody has managed to obtain a clear photo, which is regarded as the standard form of evidence for documenting birds. A study was conducted in the Pearl River swamp in southeastern Louisiana to test the feasibility of searching for this elusive species and surveying its habitat using a DJI Phantom 3 Professional drone with a 4K video camera. Drone images are of much higher quality than images that were previously obtained at much greater expense during flights in a Cessna 172. The approach was found to be effective for searching for and inspecting trees that are potential foraging sites for woodpeckers and that might be suitable for nest and roost cavities. Large woodpeckers in flight are identifiable in video footage obtained from an altitude of 40 m, which was found to be sufficient to reliably avoid collisions with trees in the study area.

Periodic and transient motions of large woodpeckers

Two types of periodic and transient motions of large woodpeckers are considered. A drumming woodpecker may be modeled as a harmonic oscillator with a periodic forcing function. The transient behavior that occurs after the forcing is turned off suggests that the double knocks of Campephilus woodpeckers may be modeled in terms of a harmonic oscillator with an impulsive forcing, and this hypothesis is consistent with audio and video recordings. Wingbeats are another type of periodic and transient motion of large woodpeckers. A model for the flap rate in cruising flight is applied to the Pileated Woodpecker (Dryocopus pileatus) and the Ivory-billed Woodpecker (Campephilus principalis). During a brief transient just after taking off, the wing motion and flap rate of a large woodpecker may not be the same as in cruising flight. These concepts are relevant to videos that contain evidence for the persistence of the Ivory-billed Woodpecker.

Effects of Radio-Transmitter Methods on Pileated Woodpeckers: An Improved Technique for Large Woodpeckers

Abstract We captured and radio-marked 64 Dryocopus pileatus (Pileated Woodpecker) in bottomland hardwood forests from February 2007 to June 2010. At least 12 (35.3%) of the first 34 birds radio-tagged died within 43 d of capture ( = 8.2 d). Thus, we adjusted our radio-attachment techniques adaptively from a figure-eight harness to a tail-mount, and reduced handling times to minimize stress on woodpeckers. In 2009 and 2010, after the change in attachment type and modified handling protocol including a reduction of handling time (from ca. 1 h to 30 min), all 30 radio-marked birds (100%) survived the entire field season (≥3 mo). These data suggested that Pileated Woodpeckers, and perhaps other large woodpeckers, have an increased risk of death when tagged with figure eight harnesses, handled for longer periods and more obtrusively, and captured on days with relatively cold temperatures. We submit that future telemetry on this species or other large woodpeckers should not employ the figure-eight harnesses and...

Film documentation of the probably extinct Imperial Woodpecker (Campephilus imperialis)

ABSTRACT. The Imperial Woodpecker (Campephilus imperialis) of Mexico—the largest woodpecker in the world—probably became extinct in the late 20th century, without known documentation of the species in life. We describe a recently discovered 16-mm color film of an Imperial Woodpecker taken in 1956 by William L. Rhein. The film documents climbing strides, launches, flights, and foraging of one female Imperial Woodpecker. For perches and foraging the woodpecker used dead or recently dead Durango Pines (Pinus durangensis). Trunks of perch and foraging trees were of the largest diameters available in this tree species. After allowing for possible inaccuracies in the frame speed of the film, we found that the Imperial Woodpecker had slow climbing strides and a fast wingflap rate compared with other woodpeckers. Following landmarks documented during the 1956 expedition, we identified and surveyed the film site in 2010. The site was in coniferous forest in lightly undulating terrain at 2,700–2,900 m elevation. In...

Bottomland Ghost: Southern Encounters and Obsessions with the Ivory-Billed Woodpecker

[ILLUSTRATION OMITTED] Among birders in the South, the Ivory-billed Woodpecker is a haunting presence whose status is debated at ornithological meetings, in popular media outlets and leading scientific journals, and on birding web sites such as the Ivory-bill Researchers Forum. The woodpecker conjures up images of deep and fore boding bottomland forests, of John James Audubon exploring and painting the South, and of a wild southern landscape home to wolves, panthers, and innumerable species of birds, long before the southern forests were felled to create fields for cotton and soybeans. The ivory-bill's nicknames--the Lord God Bird, the Log God Bird, and King of the Woodpeckers--indicate the esteem that birders, naturalists, and others hold for this majestic species. (1) Until the announcement in 2005 of the rediscovery of the ivory-bill at the Cache River National Wildlife Refuge in Arkansas, and even more recent reports from the Florida Panhandle, there had not been a broadly accepted ivory-bill sighting for sixty years. Had the bird survived? If so, where? The authenticity of the few photos of the bird that have surfaced has been debated by the ornithological and birding communities, as have many reported sightings. Some of the sightings seemed valid enough to make hardened skeptics think twice about the ivory-bill's status, but even after the Arkansas sightings--including a successful filming of the bird by the Cornell Lab of Ornithology-led search team in 2004--consensus on the bird's survival remains as elusive as the bird itself. (2) In a competitive birding world full of large egos, rediscovery is the ultimate achievement for a member of the birding tribe, and the ivory-bill is the Holy Grail among birders. There also exists a distinct hierarchy in the birding world, and reports of rare birds made by hunters and fishers rank low in the birding caste system. Furthermore, skepticism of ivory-bill sightings has also hardened because logging has greatly altered the woodpecker's southern bottomland forest habitat. Many believed the ivory-bill depended on huge expanses of virgin bottomland forest, but by the end of World War II, almost no virgin bottomland forest remained in the South. (3) It was easy to believe the ivory-bill had long since disappeared with its habitat. So why has the ivory-bill drawn so much attention that it lands on the front page of the New York Times? Is it the beauty of the bird? Is it because it is the largest woodpecker in the United States, slightly larger than a crow? Is it its association with a more environmentally pristine South? Does the ivory-bill garner attention because it is another uniquely southern feature, such as a bottle tree or juke joint, that fascinates outsiders? Or do the reasons for our fascination run deeper? Is it because the ivory-bill seemed to rise from the dead? Indeed, the ivory-bill has gained a mythical identity among birders and ornithologists--it is a ghost bird, appearing and vanishing, allowing no more than glimpses and leaving nothing but stories. Although reports of the woodpecker have met with skepticism, I have no doubt that the bird survives. My own research on the ivory-bill in Louisiana began well before the Arkansas team released its findings. I sought to discover why stories of the ivory-bill persisted and why people kept reporting ivory-bills when, according to many in the scientific community, the ivory-bill had been extinct since the 1940s. The last documented sightings came from Madison Parish in northeast Louisiana in the early 1940s, photographed by the godfather of ivory-bill research, ornithologist James Tanner of Cornell. But over the past sixty years, many people--especially hunters, fishers, and locals--have claimed to have seen the ivory-bill in the Santee Swamp in South Carolina, the Florida Panhandle, and the Atchafalaya Basin in Louisiana. Numerous people with no apparent birding agenda, most not seeking publicity for their sightings, truly believed they had seen ivory-bills. …

Reproductive correlates of eggshell thickness in European woodpeckers

Woodpeckers excavate their own nesting holes, have small eggs relative to their body size and many species have small clutches. Based on data from the eight European woodpecker species it was found that the mean thickness of eggshells increases with egg volume, whereas large woodpeckers lay smaller eggs with thinner eggshell relative to their body mass. It is speculated that woodpeckers minimize their reproductive costs by laying energy-poor eggs that are relatively cheap to produce, and with their low adult mortality rates, increase their lifetime reproductive success.

Ingestion of Snow and Ice by Pileated Woodpeckers and Northern Flickers

Although on occasion pileated woodpeckers (Dryocopus pileatus) and northern flickers (Colaptes auratus) drink water from puddles or other sources (Kilham 1983; Bull and Jackson 1995; Moore 1995), obtaining water by eating snow and ice is apparently unreported for these species (see Bent 1939, Bull and Jackson 1995, Moore 1995). Here I report on observations of a female pileated woodpecker eating snow and a female northern flicker eating ice, and speculate on the significance of this behavior by birds living in areas where water in a liquid phase may be unavailable for several days or weeks. On 13 January 1978 I was walking in Hellgate Canyon, just east of Missoula, Missoula Co., Montana (46° 52' N, 113° 59' W). At 1300 MST I watched a female pileated woodpecker swoop down from a wooden power line pole to a snow-covered log about 30 m from me; about 6 cm of granular snow covered the surface of the log and most of the ground. In the next 60 sec the woodpecker ate 9 bill-loads of snow (scooping up each load while keeping the side of its head nearly parallel to the snow surface). The bird then flew back to the pole before flying into the woods out of view. Although the site where the observations took place was near the Clark Fork River, most of this reach of the river was frozen at the time, and accessible free water in a liquid phase appeared rare. Ambient temperature at the time was-1°C. For several days preceding and following the day of the observations, the daily maximum was 5% of total body weight for medium-sized and large woodpeckers, and much greater for smaller passerines (see discussions in Bartholomew and Cade 1963; West and Norton 1975; Marsh and Dawson 1989). Heating fro-

The Decline and Present Status of the Imperial Woodpecker of Mexico

THE largest woodpecker in the world, Camnpephilus imperialis, is appropriately known as the Imperial Woodpecker (Figure 1). It has frequently been called the Mexican Ivory-billed Woodpecker because of its close relationship to the Ivory-billed Woodpecker of the United States, C. principalis, but this name causes confusion because of other Mexican woodpeckers, especially Phloeoceastes guatemalensis, which are often called ivory-billed woodpeckers. The Imperial WVoodpecker's most widely used common name in Mexico is pitoreal. In the western part of the State of Durango I found that this name was also used for Phloeoceastes guatemalensis. Indian names for the Imperial Woodpecker include the Naihuatl name cuauhtotomomi (Miller, 1957) and the Tarahumar name cumecocari (C. W. Pennington, Univ. of Utah, letter). The most complete description of the appearance and habits of the Imperial Woodpecker, based on observations of the species, is Nelson's (1898). In 1962 my son David Tanner and I went to Mexico in search of the Imperial Woodpecker. My primary objective was to compare this species with the American Ivory-bill, which I had studied intensively (1942). We were not successful in finding the woodpeckers, but we did learn something about the present status of the species and about the cause of its decrease. The trip was supported by grants from the Frank M. Chapman Fund, American Museum of Natural History, and from the International Committee for Bird Preservation.

Nesting Habits of the Woodpeckers and the Vultures in Mississippi

OBSERVATIONS on the nesting and laying of the Woodpeckers (Picidae) and the Vultures (Cathartidoe) have shown several very interesting phenomena. The following will be an effort to bring out the rather peculiar and often unexpected actions on the part of these birds without any attempt to go into detail or record the many familiar nesting habits that are well known to all ornithologists. The notes are taken entirely from my data that were made while collecting and observing in the field in the east central and southwest portions of Mississippi. Ceophlceus pileatus. PILEATED WOODPECKER.-This bird has become rare in many parts of Mississippi but is still rather common in certain portions. During three seasons seventeen nests were watched in Adams County. In the vicinity where observations were made every small woods had its pair of these large woodpeckers. The individuals of this species seemed to occupy very small feeding areas. Of the seven nests that were found in 1902 five pairs of the birds were located in their respective woods during the previous December and January. Whenever a pair was once seen feeding in a wood during the winter the same pair could always be found very close to that place. At the beginning of the nesting season they would invariably make their burrow in some dead but sound tree near the edge of the brake. From continued observation it appeared certain that whenever a pair were found in a small wood during the winter they were sure to nest there the following spring. The burrow is very large and requires in most cases about one month for construction, being commenced in this locality about the latter part of February. But it was found very difficult to note the exact length of tiine consumed in burrowing, as the birds try so many parts of the same tree before striking one to suit their taste. The nest tree and other dead trees close at hand were often scarred from top to bottom. In two cases they began a nest, then seemed to start one in another place, and then returned