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Wilson Journal 
of Ornithology 
Published by the Wilson Ornithological Society 
VOL. 124, NO. 4 
December 2012 
PAGES 651-878 
The Wilson Journal of Ornithology 124(4):651-674, 2012 
HISTORY, STRUCTURE, EVOLUTION, BEHAVIOR. DISTRIBUTION, 
AND ECOLOGY OF THE EXTINCT HAWAIIAN GENUS CIRIDOPS 
(FRINGILLIDAE, CARDUELINI, DREPANIDINI) 
STORRS L. OLSON 1 
ABSTRACT.—The extinct drepunidine genus Ciridops is known from five historically taken specimens of Ciridops 
anna from the island of Hawaii, the last in 1892, and from fossil populations on Molokai, Oahu, and Kauai. The origins of 
the historical specimens and the taxonomic history of the genus are reviewed. The plumages of C. anna are interpreted as 
highly sexually dimorphic (red males vs. greenish females); the juvenile plumage of males included brownish feathers that 
appear to have been retained and mixed with the incoming definitive plumage. The thigh musculature and pelvic and 
hindlimb osteology show that the strong legs and feet of Ciridops were probably used to move plant debris in search of 
insects. The closest living analog may be the Yellowltead (Molioua uchrocephalu) of New Zealand. Analysis of stomach 
contents of the single fluid-preserved specimen of C. anna disclosed remains of insects that are widely distributed in 
Hawaiian forest ecosystems. The traditionally claimed association of Ciridops anna with palms of the genus Pritchurdia 
suggests that Ciridops may have fed ill the accumulated debris in the axils of palm leaves. Hie patchy distribution of fossils 
ot (iridops may result Iroin the birds being associated with nearly pure stands of Pritrhnrclki that were in turn patchily 
distributed. Vulnerability of Pritchurdia to introduced seed predators, including rats and humans, and to destruction of 
lowland habitats by cutting and burning, may have caused the prehistoric extinction of Ciridops on all islands except 
Hawaii. Received 2 March 2012. Accepted 25 May 2012. 
Among the most beautiful (Frontispiece, Fig. I) 
and enigmatic of the exuberant adaptive radiation 
of Hawaiian cardueltne finches of the tribe 
Drepanidini, is the extinct Ula-ai-hawane (Ciri¬ 
dops anna). This is among the rarest of birds, 
being known historically only from live study 
skins and remnants of a single skinned body 
preserved in alcohol. Although Ciridops was 
known historically only from the island of Hawaii, 
fossils show that it also occurred at least on 
Molokai. Oahu, and Kauai. Many new insights 
' Department of Vertebrate Zoology, National Museum of 
Natural History, Smithsonian Institution, P. O. Box 37012. 
Washington, D.C. 20013, USA; e-mail: olsons@si.edu 
into the structure and probable habits of the 
species of Ciridops have been gained through 
study of the fossil material and from new 
dissections of the one fluid specimen. Additional 
new information on the history and habits of C. 
anna comes from archival sources. This paper 
presents the new data and attempts to gather all 
previous knowledge regarding the genus Ciridops. 
reserving species-level revision of the fossil 
material for future studies. 
HISTORY AND DISPOSITION OF HISTORIC 
SPECIMENS OF CIRIDOPS ANNA 
The first published indication of the existence 
ol the bird that became Ciridops anna was in a 
651 
