Some feeding adaptations and postures of the yellow white-eye (Zosterops senegalensis)

Abstract

Yellow white-eyes were observed in the Kivu Highlands of the Eastern Zaire both in the field and in an aviary.

Some feeding adaptations are described, among them the ability to reach most points of the feeding ground among twigs and leaves by clinging in almost every body position even to weak supports and by hovering, ‘Zirkeln’ (enlarging of crevices by introduction of the closed bill which then opens and presses its edges apart), intake of liquids by licking and examination of shallow cavities with the tip of the tongue.

Some aspects of the flock structure, clumping and allopreening are discussed.

The agonistic behaviour patterns are described. While fighting is still of a relatively general passerine pattern, threat and submissive postures are partly ritualized. Threat postures consist of bill-opening, pivoting, wing-dropping and bill-clattering, each of them manifesting increasing aggressive tendencies in this order. Submission is expressed by becoming motionless and, in higher intensity, by fluffing, whereby certain plumage areas, crown and back, are already fluffed maximally in low intensity displays and re-direct the aggressive tendencies of an eventual partner towards allopreening.

Only a few observations were made on courtship behaviour. Horizontal wing-quivering is the usual approach of males to their potential mates whose aggressive tendencies are cut off by the offer of the male's head and neck plumage for allopreening.

The described postures are compared with what is known of comparable behaviour of other Zosterops species.