Neck extensions during a putative defense display and mounting during incubation with subsequent tail-fanning in the Chuck-will’s-widow ( Antrostomus carolinensis )

Abstract

Nightjars (Caprimulgidae) exhibit a wide range of behaviors that are often difficult to observe due to their nocturnal and crepuscular activity and cryptic coloration. Chuck-will’s-widows (Antrostomus carolinensis) are widely distributed in the Southeastern USA, yet detailed behavioral descriptions remain limited. Here, we document three previously undocumented behaviors of Chuck-will’s-widow during the breeding season in northern Alabama, in the context of capture and release and nest monitoring via trail camera. We report (1) a display consistent with defense behavior characterized by repeated, slow neck extensions combined with wing and tail spreading, after capture and release; (2) repeated mounting at a nest during incubation that may represent copulation; and (3) tail-fanning post-mounting. Our observations demonstrate the importance of targeted field observations and nest cameras for expanding the behavioral record of Chuck-will’s-widow and other cryptic nocturnal birds.