SPECIES

Ivory-billed Woodpecker Campephilus principalis Scientific name definitions

Jerome A. Jackson
Version: 1.0 — Published March 4, 2020
Text last updated January 1, 2002

Plumages, Molts, and Structure

Molts

Hatchlings

No specimens, descriptions available, but likely similar to other neonate woodpeckers (JAJ): naked with no conspicuous pterylae. Long neck, large head, closed eyes.

Juvenile Plumage

Attained while in nest cavity; no data on early development. Juvenile plumage of male and female alike, with no red in crest of male; overall Juvenile plumage closely resembled plumage of Definitive Basic female except crest shorter; contour feathers more loosely webbed and less iridescent than those of Basic I plumage. Juvenile also has white tips on all primaries (Tanner 1942bb). At fledging, tail is “squared” (Tanner 1942bb), a result of the central rectrices being slower to develop. Among specimens of juveniles I have examined, none with a description of gonads; probable that some specimens of juveniles are sexed incorrectly (sexes alike in appearance). A specimen labeled as a juvenile female (Museum of Comparative Zoology [MCZ] #242972) taken in the Florida Panhandle by A. T. Wayne on 15 Apr 1892 seems to be a bird shortly out of the nest. As in juveniles of other woodpecker species, plumage is dull, soft, more loosely webbed as a result of fewer barbs, and primary 10 is exceptionally long (85 mm) and broad. On this specimen, each primary has a white tip, increasing in size from P10 to P1. On birds ap-parently longer out of the nest, these white tips often missing, apparently as a result of wear. Sheaths were still present at the base of R1, but R1 was still the longest rectrix, though apparently the last Juvenile rectrix to complete growth.

Basic I Plumage

Basic I plumage similar to Definitive Basic, though less iridescent; crest of both sexes shorter than in Definitive Basic; male develops red crest gradually, beginning with a few red feathers. Audubon (Audubon 1842: 217) suggests that “towards autumn the males have a slight line of red on the head, and do not attain their richness of plumage until spring.” Tanner (Tanner 1942bb: 79) noted that the first scarlet feather of his young, banded male appeared at 2.5 mo.

Among the 204 specimens I examined, I found only 8 molting juveniles. Of these, only 2 showed any red on the head and were labeled males; remaining 6 had no red and were labeled females. I suspect at least some of these were mis-sexed as a result of the absence of red in Juvenile plumage. Prebasic I molt is similar to Definitive Basic (see below), except that juveniles appear not to molt secondaries in the Prebasic I molt. The following describes the state of molt for one juvenile male examined:

14 Jul 1876, juvenile male, Wekiva Creek (Seminole Co.?), FL, (Field Mus. #41865), P1–P5 new, P6 7/10 in; P7–P10 old and with large white tips; r2, R3, R5, R6 in; R1 80% in, R4 50% in; all older feathers of head black, about 20+ new feathers are red and about half inch.

Definitive Basic Plumage

Male. Overall color glossy blue-black, glossed with green below (Baird 1858a), rectrices and remiges less glossy. Nasal tufts overlaying bill white. Head with prominent crest. Front edge of crest black (extending almost to tip of crest); remainder of crest scarlet red. Red feathers longer than black feathers in most U.S. birds, but black feathers longer than red feathers in many Cuban birds. Basal third of red feathers also white, such that when feathers are erected, bird might display a white spot (JAJ). No author has mentioned this, but it is clearly illustrated by Wilson (Wilson 1811). A white stripe beginning somewhat below eye (or slightly anterior to eye in some Florida and many Cuban specimens) extends back to neck, down side of neck, and then through outer rows of scapulars. White stripe ends on distal outer scapulars, where it meets inner edge of large white patch present on folded tertials and secondaries (see below). All secondaries and tertials white, and P1–P5 show extensive white distally; P6 rarely shows white distally (Ridgway 1910). Together these white feathers form a prominent white patch on wing. Tips of loosely webbed feathers that surround cloaca often white, though these not conspicuous. Undersurface of wing black except secondaries and distal portions of inner primaries white, and all underwing coverts white (Baird 1858a). Together these areas form 2 large white patches on leading and trail-ing portions of open under-wing surface; rectrices pointed. Tail graduated. Many specimens also have irregular white markings near tip in outer web of outermost rectrix, R5.

Female. Similar to male, except crest entirely black, and crest somewhat recurved, but not nearly as recurved as in Imperial Woodpecker.

No previous studies of molt in the Ivory-billed, thus I include here a minimum of information gleaned from specimens I have examined. Because of the fragile and rare nature of the specimens, examination of them for molt was difficult, and detailed study of molt not possible. Most specimens examined appeared to have been collected during nesting season in late winter/early spring, a time when molt would not be expected. Many had no data. Of the 204 specimens examined, I detected evidence of molt in 27 adults (13 males, 14 females). I am certain that I missed evidence of molt on some specimens because initially I was not looking for it. As with other woodpeckers, Ivory-billed appears to have had a single annual molt that occurred primarily in summer and fall. Progression of molt in general is similar to that for most other North American woodpeckers (Pyle and Howell 1995), beginning in adults shortly after nesting and ending by late fall. In Definitive Basic molt, replacement of primaries begins with the innermost and continues sequentially outward. Replacement of secondaries seems to begin both distally with S1 and proximally with S8. Rectrix molt proceeds centrifugally in adults, beginning with r2, with R1 lost only after other new rectrices are grown. Molt of primaries, secondaries, rectrices, and body feathers seems to begin more or less concurrently, though in Denver Museum of Natural History (DMNH) specimen #36511 (see below), rectrix molt seemed to begin first. Extreme dates of molting birds (assuming dates on specimen labels are correct) and examples of details I noted include:

12 Apr 1894, adult male, Jefferson Co., FL (DMNH #36511), r2 right and left missing; no other evidence of molt.

20 May 1905, adult male, Lafayette Co., FL (MCZ #253498), P1, P2 new; P3—80% in; R1 old, r2—70% in, R3—20% in; some sheathed body feathers.

20 Dec 1907, adult female, Orange Co., FL (Field Museum #139, 362), P10 right and left still with sheath at base, molt otherwise completed.

Adaptive Significance Of Plumage

Strong black-and-white pattern of the Ivory-billed may be disruptive. Melanin of black plumage provides greater strength in the very abrasive environment associated with tree surfaces.

Aberrant Plumages

A. T. Wayne reported a specimen of an adult male he collected in Jefferson Co., FL, on 19 Feb 1894, had “the ends of all the longer primaries (except the 3rd and 4th) pure white,” and that an adult female collected nearby was similar (Wayne 1905a: 414). Wayne did not indicate catalog numbers for these birds, but male seems to be Charleston Museum #30.147.512 collected on same date at that locality, and female may be Charleston Museum #30.147.511, collected on Cow Creek near Aucilla River, Jefferson Co., on 15 Feb 1894. Male also has white at tip of R6 and white in inner and outer vanes of R5, more white than in other specimens; female has a small spot of white in outer vane of R5, an amount of occasional occurrence. I did not note an exceptional amount of white in primaries of the female other than a small spot of white on the outer vane of P3. A male (USNM #197910) from Iberville Parish, LA, has red of the crest extending farther down neck than on most specimens, into black feathers of neck such that some black feathers have red tips.

Bare Parts

Bill And Gape

Hatchling: no description, but likely as in other woodpeckers: pink skin, prominent shiny white egg tooth with accessory shiny white covering on bill-tip, prominent light-colored oral flanges. Fledgling: bill a “chalky white” (Tanner 1942bb). Adult: bill “ivory” (Tanner 1942bb).

Bill incredibly robust; its straightness and broad and deep base contribute to its strength. About 7.6 cm long and tapering to a chisel-tip on both upper and lower halves; bill thus can serve not only as a wood chisel, but also as probe, dagger, and pincers all wrapped into one tool -- a Swiss Army Knife for the primeval forest. Slit-like nostrils are back near the skull and are hidden beneath whitish, bristle-like feathers that stretch forward. These feathers, as in other woodpeckers, filter out chips and dust as individual excavates.

Iris

Nestling and juvenile: dark brown to dark sepia (Tanner 1942bb); Field Museum specimen #41865, a juvenile male collected in Jul, by C. B. Cory, has “eye bright yellow” written on original label. Adult: pale lemon yellow, as evidenced by color photo taken by Tanner; by description of Allen (Allen 1939b), who saw the birds in both Florida and Louisiana; and by description and painting by Audubon. However, Ivory-billed eye color is subject of some confusion. Short (Short 1982: 449) described it as being “white to creamy-white.” Wilson (Wilson 1811), who once kept a live Ivory-billed, de-scribed its eyes as “vivid yellow.” Col. William J. Fleming, who shot an Ivory-billed in Kentucky in 1780, described iris of dead bird as being bright yellow (Mckinley 1958). George Miksch Sutton, who studied and sketched Ivory-billed Woodpeckers in Louisiana, made statement about his first observation of an Ivory-billed that “what struck me most was the rich whiteness of his beak and the staring whiteness of his eye” (Sutton 1936a: 195)—yet he painted the eyes a pale yellow. Mark Catesby had given the Ivory-billed eyes that graded in color from red at the outside to yellow—in general an orange appearance, and the eminent artist Francis Lee Jaques painted the Ivory-billed with reddish-brown eyes (in Howell 1932). At the Buffalo Museum of Natural History in New York, I found 2 specimens with red glass eyes mounted in a display. While this variant description of eye color is minor, and understandable since many artists work from specimens with only cotton for eyes, the possible extinction of the species means that these published illustrations and descriptions could perpetuate an inaccuracy.

Fledgling Ivory-billeds have dark eyes, evidenced by Tanner's black-and-white photos of a young male shortly before it fledged. Tanner (Tanner 1942bb) described its eyes as “dark sepia.” We have no idea what sort of intermediate colors an Ivory-billed's eyes might show during the transition to adulthood. We also have no idea whether there might be inter- or intra-populational variation in eye color. Maybe there's a bit of truth in all of the art and taxidermy!

Legs And Feet

No description of hatchling, but likely as in other woodpeckers: pink legs and toes, large pink heel pads, and white claws on toes. Adult legs and feet bluish gray (Audubon 1842); claws black, as seen on specimens (JAJ); notes on the label associated with a loose tail of an Ivory-billed at the USNM (no catalog number; taken in Florida on 16 Feb 1898) indicate: “feet light gray, large scutellar paler & somewhat yellowish gray, claws horn gray.”

Long toes give species a broad, solid grip on tree surfaces, with the third and longest toe normally reaching out to the side, providing stability as well as grip. Each toe equipped with a large, very curved (almost a semicircle), sharp claw. Tip of each claw contacts surface perpendicularly, thus effecting best possible grasp of a difficult surface.

Measurements

Linear Measurements

Largest woodpecker known to have lived in North America north of Mexico. Appendix 1 provides standard anatomical measurements from specimens examined from numerous collections. Based on measurements taken, males from the 2 largest samples (n. Florida/Georgia and s. Florida) averaged only slightly larger than females in wing chord, and length of culmen from distal edge of nostril. This pattern also apparent for most other samples. Sample from Texas and Louisiana differed as a result of overall smaller measurements for a single male specimen taken in Jul (possibly a juvenile misidentified as an adult). Females exceeded males in tail length in 4 out of 7 samples, but many specimens had an exceedingly worn tail. A woodpecker tail wears greatly over the course of a year as a result of abrasion with tree surfaces, and inadequate numbers of Ivory-billed specimens are available to compare birds in fresh plumage. Cursory evaluation of data from various regional samples suggests the species varies geographically in size, larger to the north, smaller to the south, and smallest in Cuba.

In addition to measurements in Appendix 1, however, are some measurements no longer possible to obtain—total length and wingspan measured on fresh specimens. In the course of examining Ivory-billed specimens, I noted 5 (2 adult males, 3 adult females) for which these measurements were given on the original specimen label. All 5 birds were from Florida, the largest male from n. Florida, the remainder from s. Florida. Total length of the 2 males averaged 50.2 cm (50.8, 49.5), and for 3 females 47.8 cm (45.7, 48.3, 49.5). Wingspan of 2 males averaged 79.2 cm (79.7, 78.7); for 2 females, 77.5 cm (78.7, 76.2).

An extraordinary aberrant specimen of a female Ivory-billed was collected in Cuba by Juan Gundlach and described by Cory (Cory 1886). The bird had an overgrown upper bill such that it could not wear normally and hence grew out, curving downward to a length of about 43 cm (JAJ). In mid-nineteenth century, Gundlach (F. García pers. comm.) discovered the adult-plumaged bird along with an adult male and female Ivory-billed. He was curious as to how the aberrant bird fed, followed the trio for 3 d, observing that the aberrant bird could probe into arboreal termite nests to feed, but that it was also being fed by the other 2 adults. Then he collected all 3. The specimens are in the collections of the Instituto de Ecología y Sistemática, in Havana, Cuba (adult male #2226, adult female #11, aberrant female #5999).

Mass

Few data. Catesby (Catesby 1731) stated the mass to be 20 oz. (567 g). The label with a study skin of a male collected in Hernando Co., FL, on 17 Jan 1877 (MCZ # 35888 fide Tanner 1942bb) indicates that the bird weighed 1 lb (454 g). Hahn (Hahn 1963) lists this specimen as being at the MCZ, but I did not find it among those in the collection there; MCZ # 35889 is a female Ivory-billed taken in Hernando Co., FL, 18 Mar 1876. W. J. Fleming (in Mckinley 1958) noted that an Ivory-billed shot in Kentucky “weighed upwards of 1 lb” (454 g).

Recommended Citation

Jackson, J. A. (2020). Ivory-billed Woodpecker (Campephilus principalis), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.ivbwoo.01