Family Ibises, Spoonbills (Threskiornithidae)

Critically Endangered

White-shouldered Ibis (Pseudibis davisoni)


French: Ibis de Davison German: Weißschulteribis Spanish: Ibis de Davison

Geronticus Davisoni

A. O. Hume

, 1875,

Pakchan estuary, Tenasserim, south Myanmar


Closely related to P. papillosa, with which often considered conspecific. Differs from latter, however, in having no papillose red mid-crown to hindneck (3) but possessing instead a bluish-white band of bare skin from hindneck and nape forward around throat (3)#R; it is also larger (effect size for bill of male 2.89; score 2). Monotypic.


Once widespread from Myanmar to SW China and S to Indochina and Borneo, range now much reduced; small remaining population now focused on N Cambodia, with tiny additional numbers in adjacent S Laos and, disjunctly, in S Borneo (mainly along R Mahakam)#R.

Descriptive notes

60–85 cm. Large, dark ibis with distinctive blue bare mid hindcrown and nape down to upper hindneck, spreading round and becoming bold white below ear-coverts to upper... read more


Territorial birds utter loud, hoarse screaming “errrrrrh” or “errrrrroh” and moaning “errh errh... read more


Similar preferences to those exhibited by T. gigantea, at least in Indochina. Marshes,... read more

Food and feeding

Very little known until recently. Old records indicate main food includes grasshoppers, cicadas and grain, with recent unsubstantiated... read more


Copulation observed Feb in Borneo, with egg-laying in late Aug and mid Dec suggesting main season there is Sept–Dec; season Feb... read more


Presumably sedentary, but on Borneo most rivers exhibit large fluctuations (short-term and seasonal... read more

Status and conservation

CRITICALLY ENDANGERED. BirdLife International estimate the world population at just 650 mature individuals (based on a global population estimate of 731–856 birds... read more

Recommended citation

Matheu, E., del Hoyo, J., Kirwan, G.M. & Garcia, E.F.J. (2018). White-shouldered Ibis (Pseudibis davisoni). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 16 December 2018).