Chemoreception and the Selection of Green Plants as Nest Fumigants by Starlings

Abstract

Although once controversial, it is now well-established that many avian species use volatile chemical cues. This is the case even though birds lack a vomeronasal organ (Portmann, 1961). Chemoreception is not restricted to those species with anatomically well-developed olfactory and/or trigeminal systems. Songbirds and other birds (e.g., pigeons) with relatively undeveloped olfactory anatomy nonetheless use volatile cues for a variety of purposes, including feeding (Archer and Glen, 1969; Stager, 1967; Snyder and Peterson, 1979; Wenzel, 1968), homing (Benvenuti et al., 1973; Grubb, 1974; Papi et al., 1973; Wallraff, 1980), and, possibly, communication (Frings and Jumber, 1954). Because comprehensive reviews of these topics are available (e.g., Kare and Mason, 1985; Wenzel, 1973, 1980), we choose not to review them here. Instead, we will suggest that some birds may use chemical cues for a quite different purpose. We will present natural history, and behavioral, chemical, and electrophysiological data consistent with the hypothesis that birds that reuse nest sites use green plants as nest fumigants, and that they choose plants for incorporation into the nest on the basis of chemical cues. This use of green vegetation represents the first documented case of an air-breathing vertebrate using the chemical defenses of another organism for its own purposes.