Comparative ethology of the Ciconiidae

Abstract

1. This paper describes the ritualized and non-ritualized behavior patterns shown by the African Openbill Stork(Anastomus lamelligerus) and the Asian Openbill Stork(Anastomus oscitans), based on observations in Africa, India, Ceylon, and Thailand. 2. Except for their specialized feeding techniques (described in another paper), the Openbills generally resemble the other storks in their patterns of non-ritualized behavior. 3. Their repertoire of ritualized social behavior includes at least two displays away from the nest (Forward Threat, Upright Display) and at least seven displays at the nest (Forward Clattering Threat, Snap Display, Anxiety Stretch, Swaying Twig-Grasping, Advertising Sway, Up-Down, Copulation Clattering). Each of these displays is described. 4. Ritualized patterns of the young include the Begging Display, Nestling Defense Display, and an early ontogenic form of the Up-Down, shown by adults. 5. The social displays shown by the Openbills are rather simple in form, compared to homologous displays in other groups of storks. Only one display — the Advertising Sway — is unique to the genusAnastomus. 6. In their behavior the storks of the genusAnastomus most closely resemble the four “wood-storks” of the genusMycteria. Based on this behavioral evidence, I recommend the abolition of the subfamilies Mycteriinae and Ciconiinae and the erection of a tribe — Mycteriini — to include bothAnastomus andMycteria.