Pacific Emerald Doves Chalcophaps longirostris socially signal with shoulder marking

Abstract

Pacific Emerald Doves Chalcophaps longirostris attracted to a constantly available artificial food resource within North Queensland upland tropical rainforest often simultaneously numbered up to six individuals, resulting in frequent aggressive interaction. Observing and photographing Pacific Emerald Doves near and at the food source showed that individuals approaching feeders with conspecifics already at the feeders fully exposed their white shoulder-patch and held the wing joint just slightly away from the body, possibly as a flight-intention movement. Birds more distant from the feeders, or approaching them in the absence of conspecifics, exposed but a small part of their shoulder-patch, holding the wing tight against the body with body contour feathers covering the edge of the wing to give the usual appearance of the species. Thus, exposing the entire white shoulder-patch, which makes it appear whiter, functions as a ‘fight or flee’ social signal previously undocumented in the species or in any of the other Chalcophaps species.