The Ivory-billed Woodpecker ( Campephilus principalis ) is or was one of the largest woodpeckers in the world, at roughly 20 inches in length and 30 inches in wingspan.

The American Birding Association ( ABA ) lists the Ivory-billed Woodpecker as a Class 6 species, a category the ABA defines as " definitely or probably extinct.

Reports of at least one male Ivory-billed Woodpecker in Arkansas in 2004 were investigated and subsequently published in April 2005 by a team led by the Cornell Lab of Ornithology ( Fitzpatrick et al., 2005 ).

A $ 10, 000 reward was offered in June 2006 for information leading to the discovery of an Ivory-billed Woodpecker nest, roost or feeding site.

In December 2008, the Cornell Lab of Ornithology announced a reward of $ 50, 000 to the person who can lead a project biologist to a living Ivory-billed Woodpecker.

Despite these high-profile reports from Arkansas and Florida and sporadic reports elsewhere in the historic range of the species since the 1940s, there is no conclusive evidence for the continued existence of the Ivory-billed Woodpecker ; i. e., there are no unambiguous photographs, videos, specimens or DNA samples from feathers or feces of the Ivory-billed.

Ornithologists have traditionally recognized two subspecies of this bird: the American Ivory-billed, the more famous of the two, and the Cuban Ivory-billed Woodpecker.

There is some controversy over whether the Cuban Ivory-billed Woodpecker is more appropriately recognized as a separate species.

A recent study compared DNA samples taken from specimens of both Ivory-billed birds along with the Imperial Woodpecker, a larger but otherwise very similar bird.

The Ivory-billed Woodpecker ranks among the largest woodpeckers in the world and the largest in the United States.

The Ivory-billed Woodpecker is sometimes referred to as the Grail Bird, the Lord God Bird, or the Good God Bird, all based on the exclamations of awed onlookers.

At that time, the Ivory-billed Woodpecker ranged from east Texas to North Carolina, and from southern Illinois to Florida and Cuba.

The Ivory-billed Woodpecker feeds mainly on the larvae of wood-boring beetles, but also eats seeds, fruit, and other insects.

The Ivory-billed Woodpecker is thought to pair for life.

By 1944 the last known Ivory-billed Woodpecker, a female, was gone from the cut-over tract ( Smithsonian p 98 ).

Ivory-billed Woodpecker sighting analysis is considered by some to be a good example of cryptozoology's potential application in modern zoology.

A comparison of the Ivory-billed Woodpecker ( bottom ) with the Pileated Woodpecker ( top )

In the afternoon of 27 January 2002, after ten days, a rapping sound similar to the " double knock " made by the Ivory-billed Woodpecker was heard and recorded.

The expedition was inconclusive, however, as it was determined that the recorded sounds were likely gunshot echoes rather than the distinctive double rap of the Ivory-billed Woodpecker.

Since 2002, most of the attention in the search for the Ivory-billed Woodpecker has turned away from the Pearl River region, although several unconfirmed sightings have been reported there since February 2006, see video clips.

A group of seventeen authors headed by the Cornell Lab of Ornithology reported the discovery of at least one Ivory-billed Woodpecker, a male, in the Big Woods area of Arkansas in 2004 and 2005, publishing the report in the journal Science on 28 April 2005 ( Fitzpatrick et al., 2005 ).

" Before this study, it was thought that the Cuban Ivory-billed were descended from mainland woodpeckers, either introduced to Cuba by Native Americans or accidentals that flew to the island themselves.

A large woodpecker was videotaped on 25 April 2004 ; its size, wing pattern at rest and in flight, and white plumage on its back between the wings were cited as evidence that the woodpecker sighted was an Ivory-billed Woodpecker.

Doubt was also cast on some of the auditory evidence ( ARU recordings of double-raps ) for the presence of Ivory-billed Woodpeckers in Arkansas and Florida.

In October 2009, Cornell scientists announced that their search for the Ivory-billed Woodpecker in North America was being suspended.

The Ivory-billed Woodpecker is ( or was ) slightly smaller at 50 cm ( 20 inches ) and a weight of 500 g ( 1. 1 lb ).

There was once hope that Ivory-billed woodpeckers might survive here, but this now seems unlikely.

The male had a red-sided crest, but was otherwise black, apart from the inner primaries, which were white-tipped, white secondaries, and a white scapular stripe which unlike in the Ivory-billed Woodpecker did not extend on the neck.

His book about the experience, The Grail Bird: Hot on the Trail of the Ivory-billed Woodpecker ( ISBN 0-618-45693-7 ) was published in May 2005.

His notes on his time in Texas, published in The Ibis ( 1865 – 66 ) are a leading source of information for the period and include mention of several interesting birds including the extinct ( or almost extinct ) Ivory-billed Woodpecker, the almost extinct Eskimo Curlew and the endangered Whooping Crane.

The Ivory-billed is the type species for the genus Campephilus, a group of large American woodpeckers.

“ We will continue to accept and investigate credible reports of Ivory-billed Woodpeckers, and to promote protection and restoration of the old growth conditions upon which this magnificent species depended across the entire southeastern United States .”

Two species of woodpeckers, the Ivory-billed Woodpecker and the Imperial Woodpecker, have been considered extinct for about 30 years ( there has been some controversy recently whether these species still exist ).

Its ability to survive in many wooded habitat types has allowed this species to survive human habitation of North America much better than the more specialized Ivory-billed Woodpecker.

As one of the first three searchers to report seeing and identifying the species, he played an instrumental role in the 2004 / 2005 Arkansas reports of the Ivory-billed Woodpecker.

The Ivory-billed has a total length of and, based on very scant information, weighs about.

The photos, taken with a cheap Instamatic camera, show what appears to be a male Ivory-billed perched on the trunks of two different trees in the Atchafalaya Basin of Louisiana.

In March, 2007 the Florida Ornithological Society Records Committee voted unanimously not to accept the 2005-06 reports of the Ivory-billed Woodpecker on the Choctawhatchee River :< ref >

Chrysocolaptes on the other hand appears to be a rather close relative of Campephilus, the genus of the famous Ivory-billed Woodpecker ( C. principalis ).

In April, an announcement is made that the Ivory-billed Woodpecker has been rediscovered in North America ; in July, doubt is cast on this claim.

* In April, Louisiana State University student David Kulivan sees a pair of Ivory-billed Woodpeckers in the Pearl River Wildlife Management Area on the Louisiana / Mississippi border.