Behavior

Walking, Hopping, Climbing, Etc

Hitched up tree surfaces in a manner similar to other woodpeckers; Tanner (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close : 57) described movement on tree surfaces as springing upward, shifting position of feet toward the end of each leap; also described their movements as "quick and vigorous, almost nervous." Occasionally came to ground in recently burned areas, there moving about "hopping like a flicker" (Allen 1939b Allen, A. A. (1939b). "Ivory-billed Woodpecker." In Life histories of North American woodpeckers., edited by A. C. Bent, 1-12. U.S. Natl. Mus. Bull. 174. Close : 8).

Sutton (Sutton 1936a Sutton, G. M. (1936a). Birds in the wilderness. New York: MacMillan Co. Close ; illustration in Dennis 1967b Dennis, J. V. (1967b). The Ivory-bill flies still. Audubon 69 (6):38-44. Close : 43) sketched Ivory-billeds from life in ne. Louisiana in 1935, noting specifically how the longest toe, digit 3, was held outward horizontally with respect to the bird's movement up a tree trunk. Ivory-billed held its legs somewhat outward as it hitched up tree surfaces, much as described for Magellanic Woodpecker (Campephilus magellanicus; Short 1970c Short, L. L. (1970c). The habits and relationships of the Magellanic Woodpecker. Wilson Bulletin 82:115-129. Close ). Such movement is shown in movie footage taken by Allen and Kellogg in 1935 in Louisiana (a portion of which can be seen in the movie At the Crossroads: the Story of America's Endangered Species; Stouffer 1988 Stouffer, M. (1988). Marty Stouffer's Wild America. New York: Times Books. Close ).

Flight

Audubon (Audubon 1842 Audubon, J. J. (1842). Birds of America. Vol. 4. J. B. Chevalier, Philadelphia, Pennsylvania, USA. Close : 215-216) provides a detailed description:

"The flight of this bird is graceful in the extreme, although seldom prolonged to more than a few hundred yards at a time, unless when it has to cross a large river, which it does in deep undulations, opening its wings at first to their full extent, and nearly closing them to renew the propelling impulse. The transit from one tree to another, even should the distance be as much as a hundred yards, is performed by a single sweep, and the bird appears as if merely swinging itself from the top of the one tree to that of the other, forming an elegant curved line."

Tanner (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close ) specifically noted flight behavior so that he could describe it in detail: strong, direct flight with steady wing beats. When traveling any distance, flew above the trees, thus avoiding navigation among branches. As with other birds, flight ended with a quick, upward swoop, using wings to brake.

Thus Ivory-billed flight apparently varied with functional circumstances: glides and swoops for shorter distances; "rapid strokes after the manner of a crow or duck" (Christy 1943 Christy, B. (1943). The vanishing Ivory-bill. Audubon Magazine 45 (2):99-102. Close : 102) for powered flight between slightly more distant points; and perhaps a more relaxed flight with long undulations for long-distance flight.

The Great Slaty Woodpecker of Southeast Asia is similar in size to the Ivory-billed and shows many behavioral and ecological similarities that may be a function of the size of the birds. Flight of the Great Slaty Woodpecker has been described as taking place high above the trees, perhaps to move freely without the problem of obstructing understory, "often over long distance between successive foraging patches," and "less dipping than in other woodpeckers and almost crow-like" (Winkler et al. 1995 Winkler, H., D. A. Christie, and D. Nurney (1995). Woodpeckers: A Guide to the Woodpeckers of the World. Houghton Mifflin, Boston, MA, USA. Close : 393).

Swimming And Diving

Not known to occur.

Preening, Head-Scratching, Stretching, Bathing, Anting, Etc

In Florida, Allen and Kellogg (Allen and Kellogg 1937 Allen, A. A. and P. P. Kellogg. (1937). Recent observations on the Ivory-billed Woodpecker. Auk 54:164-184. Close ) observed Ivory-billeds preening in early morning while perched on the trunk of a tall pine stub.

Sleeping, Roosting, Sunbathing

Individual roosted in a tree cavity that it probably excavated. In general, late to emerge from roost in morning, sometimes after "sun had lighted the treetops" (Tanner 1941 Tanner, J. T. (1941). Three years with the Ivory-billed Woodpecker, America's rarest bird. Audubon Magazine 43 (1):5-14. Close : 57). Upon emergence, often climbed to top of roost tree to preen and stretch before calling and joining its mate (Tanner 1941 Tanner, J. T. (1941). Three years with the Ivory-billed Woodpecker, America's rarest bird. Audubon Magazine 43 (1):5-14. Close ).

Began leaving feeding area to head toward roost site by late afternoon, dallying near roost site until quietly entering to roost at dusk (Tanner 1941 Tanner, J. T. (1941). Three years with the Ivory-billed Woodpecker, America's rarest bird. Audubon Magazine 43 (1):5-14. Close ). Although Audubon (Audubon 1842 Audubon, J. J. (1842). Birds of America. Vol. 4. J. B. Chevalier, Philadelphia, Pennsylvania, USA. Close : 218) noted that he had "frequently observed the male and female retire to rest for the night, into the same hole in which they had long before reared their young," and Lamb (Lamb 1957 Lamb, G. R. (1957). The Ivory-billed Woodpecker in Cuba. Pan-American Section, Int. Comm. Bird Preserv., Res. Rep. 1. Close ) reported a male and female sharing a roost cavity in Cuba, as with other woodpeckers it is quite unlikely that adult Ivory-billeds shared a roost cavity (Tanner 1941 Tanner, J. T. (1941). Three years with the Ivory-billed Woodpecker, America's rarest bird. Audubon Magazine 43 (1):5-14. Close , JAJ). Tanner (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close ) occasionally found pair members using different cavities in the same tree; he did not find individuals using old nest cavities as roost sites.

Daily Time Budget

No quantitative information. Fed until about 10:00, then became quiet and almost ceased feeding in midday (Tanner 1941 Tanner, J. T. (1941). Three years with the Ivory-billed Woodpecker, America's rarest bird. Audubon Magazine 43 (1):5-14. Close ).

None noted.

Tanner (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close ) looked at maximum numbers of Ivory-billeds found by collectors in some swamps, as well as maximum numbers he estimated to be present in the Singer Tract; from this, he estimated maximum density of about 1 pair/15.5 km²(6 mi²)-in contrast to his estimates of 6 pairs of Pileated Woodpeckers/2.6 km²(1 mi²) and 21 pairs of Red-bellied Woodpeckers (Melanerpes carolinus)/2.6 km²(1 mi²).

We do not know how Ivory-billed home range might vary with habitat quality or population density, but in poor foraging habitat (younger forests), a Red-cockaded Woodpecker's (Dryobates borealis) home range can be >5 times that in optimum habitat (Jackson 1994b Jackson, J. A. 1994. Red-cockaded Woodpecker (Picoides borealis). In The Birds of North America, No. 85 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington D.C.: The American Ornithologists' Union. Close ).

Mating System And Sex Ratio

Apparently monogamous, possibly mated for life (Short 1982 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ), but no compelling data.

Pair Bond

Courtship Displays. Allen and Kellogg (Allen and Kellogg 1937 Allen, A. A. and P. P. Kellogg. (1937). Recent observations on the Ivory-billed Woodpecker. Auk 54:164-184. Close ) observed a pair in early morning that flew to a dead pine stub, perched near one another (male above female), both preened, then as female approached the male, they clasped bills. Allen (Allen 1939b Allen, A. A. (1939b). "Ivory-billed Woodpecker." In Life histories of North American woodpeckers., edited by A. C. Bent, 1-12. U.S. Natl. Mus. Bull. 174. Close ) considered these behaviors part of a courtship display.

Copulatory Displays. No information.

Mate-Guarding. No information.

Duration of Pair Bond. Pairs seen together year-round; no information on duration of bond (Short 1982 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ).

Extra-Pair Mating Behavior

No information.

Degree Of Sociality

Largest number reported seen at one time was 11, 4 of which were foraging in the same baldcypress tree in winter, probably in late 1870s-1880s near Florida's Gulf coast (Scott 1903 Scott, W. E. D. (1903). The story of a bird lover. New York: Macmillan. Close ). Audubon, in his journal entry of 14 Dec 1820, noted 5 Ivory-billeds feeding together. His classic painting of 3 adult-plumaged Ivory-billeds feeding amicably (see cover page) together reinforces an emphasis on sociality. In Louisiana, Lowery (Lowery 1935 Lowery, G. H. (1935). The Ivory-billed Woodpecker in Louisiana. Proc. Louisiana Acad. Sci. 2:84-86. Close : 86) watched 2 males and 2 females feeding on the same dead tree. He wrote: "In manner and disposition the birds are very quarrelsome, although only in a vocal way." Such is also true of the highly social Red-cockaded (Jackson 1994b Jackson, J. A. 1994. Red-cockaded Woodpecker (Picoides borealis). In The Birds of North America, No. 85 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington D.C.: The American Ornithologists' Union. Close ) and Acorn (Melanerpes formicivorus; Koenig and Mumme 1987 Koenig, W. D., and R. L. Mumme (1987). Population Ecology of the Cooperatively Breeding Acorn Woodpecker. Princeton University Press, Princeton, NJ, USA. Close ) woodpeckers.

Similar sociality noted in Cuba. Dennis (Dennis 1948a Dennis, J. V. (1948a). A last remnant of Ivory-billed Woodpeckers in Cuba. Auk 65:497-507. Close ) observed a group of 3 Ivory-billeds, 2 of which were incubating at a nest. Gundlach (Gundlach 1876 Gundlach, J. (1876). Contribucion a la ornitologia Cubana. Habana: La Antilla. Close , Gundlach 1893 Gundlach, J. (1893). Ornitología Cubana. Impressa La Habana, Cuba. Close ) also observed groups of up to 3.

In Red-cockaded Woodpecker, largest group sizes are found in the best habitats; as habitat quality de-clines, so do group size and breeding success (Conner et al. 2001a Conner, R. N., D. C. Rudolph and J. R. Walters. (2001a). The Red-cockaded Woodpecker: Surviving in a fire-maintained ecosystem. Austin: Univ. of Texas Press. Close ). Potentially this happened to the Ivory-billed, hastening its decline toward extinction.

Perhaps other parallels with cooperatively breeding Red-cockaded Woodpecker (Jackson 1994b Jackson, J. A. 1994. Red-cockaded Woodpecker (Picoides borealis). In The Birds of North America, No. 85 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington D.C.: The American Ornithologists' Union. Close ) and also the Acorn Woodpecker (Koenig and Mumme 1987 Koenig, W. D., and R. L. Mumme (1987). Population Ecology of the Cooperatively Breeding Acorn Woodpecker. Princeton University Press, Princeton, NJ, USA. Close ). These species depend on a concentrated resource, adequate for sharing, with group effort benefiting the individual. For Red-cockaded Woodpecker, the resource is long-lasting cavities exca-vated into living pines; for Acorn Woodpecker, stored acorns. Ivory-billed social behavior might be linked to a long juvenile dependency (see Breeding, below), and to patchy distribution of the large cerambycid beetles they seem to favor. Discovery and access to beetles probably facilitated by group effort.

Play

No information.

Nonpredatory Interspecific Interactions

Tanner (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close ) observed Ivory-billeds chasing Pileated Wood-peckers, but also often saw them foraging near one another without apparent interaction.

Many species-including Eastern Bluebirds (Sialia sialis), Wood Ducks (Aix sponsa), gray squirrels (Sciurus carolinensis), opossums (Didelphis virginianus), and honeybees (Apis melifera)-probably took advantage of Ivory-billed Woodpecker cavities, but usually could not compete for one that was actively used by Ivory-billed. Honeybee might have been an important exception since it is not native to North America and thus Ivory-billed experience with honeybees was relatively recent.

Tanner (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close ) felt that the Ivory-billed Woodpecker had no real competitors for food and noted that it and Pileated rarely interacted with one another. But he was observing Ivory-billeds that had, until shortly before he began working in the Singer Tract, been living in an old-growth forest under more or less natural conditions. Ivory-billeds and Pileateds had coexisted for millennia, each with its own specializations, but with some areas of niche overlap. As a result of forest fragmentation and removal of dead wood and older trees, the realized niche of the Ivory-billed likely narrowed, perhaps narrowing or even eliminating foraging opportunities at which it ex-celled.

Competition with Pileated Woodpecker for cavity sites and for food resources is a potential problem that Short (Short 1982 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ) considered serious. Human impacts on southern forests seem to have favored Pileated populations while negatively impacting Ivory-billed populations. Short (Short 1982 Short, L. L. (1982). Woodpeckers of the World. Monograph Series 4, Delaware Museum of Natural History, Greenville, DE, USA. Close ) was pessimistic about chances for establishing a viable Ivory-billed population in the presence of Pileated Woodpeckers.

Kilham (Kilham 1977d Kilham, L. (1977d). Nesting behavior of Pale-billed Woodpeckers in Guatemala. Auk 94:773-774. Close ) suggested that other sympatric pairs of Campephilus/Dryocopus species (Pale-billed, Crimson-crested [C. melanoleucos], and Lineated [D. lineatus]) might minimize competition for nest sites by nesting at different times. Ivory-billed sometimes nested much earlier than Pileated (see Breeding: phenology, below, and Bull and Jackson 1995 Bull, E. L., and J. A. Jackson. 1995. Pileated Woodpecker (Dryocopus pileatus). In The Birds of North America, No. 148 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington D.C. Close ), perhaps thereby reducing competition between these species.

Kinds Of Predators

Despite large size and formidable bill, adult Ivory-billed probably had few predators. In general, probably same ones faced by the Pileated Woodpecker (Bull and Jackson 1995 Bull, E. L., and J. A. Jackson. 1995. Pileated Woodpecker (Dryocopus pileatus). In The Birds of North America, No. 148 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington D.C. Close ): e.g., cavity entrance of an Ivory-billed nest or roost is large enough that an adept raccoon (Procyon lotor) could reach in; rat snakes (Elaphe obsoleta and E. guttata) potentially predators on eggs and nestlings and a large rat snake might take an adult (see, for example, Jackson and Dakin 1982 Jackson, J. A. and O. H. Dakin. (1982). An encounter between a nesting Barn Owl and a gray rat snake. Raptor Research 16:60-61. Close ).

Great Horned (Bubo virginianus) and Barred (Strix varia) owls are potential predators, especially on young just out of the nest and before they begin roosting in cavities. Tanner (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close ) recorded Ivory-billed responses to Cooper's and Red-shouldered hawks that were consistent with efforts to drive off a potential predator, but he also felt such predators were not a serious problem. A Cuban Crow (Corvus nasicus) was seen chasing what was believed to be a male Ivory-billed, and Stygian Owl (Asio stygius) was considered a potential predator on Cuban Ivory-billed (Short and Horne 1990 Short, L. L. and J. F. M. Horne. (1990). "The Ivory-billed Woodpecker: the costs of specialization." In Conservation and management of woodpecker populations., edited by A. Carlson and G. Auln, 93-98. Uppsala, Sweden: Rep. 17, Swedish Univ. of Agric. Sci., Dep. Wildl. Ecol. Close ). Cuban Crow also reported as possibly robbing an Ivory-billed nest (Lamb 1957 Lamb, G. R. (1957). The Ivory-billed Woodpecker in Cuba. Pan-American Section, Int. Comm. Bird Preserv., Res. Rep. 1. Close ). In both the U.S. and Cuba, major predator on Ivory-billeds was probably humans (see Conservation and management: effects of human activity, below).

Manner Of Predation

No predation known.

Response To Predators

Two adult Ivory-billeds flew toward a Cooper's Hawk that perched within 30 m of their nest with young, the male giving "an almost continual cackling scold" (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close : 54). When the hawk flew, they chased it from the area. A female with a fledgling may have responded to the presence of a Red-shouldered Hawk by giving a warning note and flying closer to the perched juvenile: on other occasions, Ivory-billeds responded to other raptors or vultures (Cathartidae) by quickly moving to the opposite side of a tree (Tanner 1942bb Tanner, J. T. (1942b). The Ivory-billed Woodpecker. National Audubon Society Research Report 1. National Audubon Society, New York, New York. Close ).