title: At-sea behavior varies with lunar phase in a nocturnal pelagic seabird, the swallow-tailed gull.
abstract: Strong and predictable environmental variability can reward flexible behaviors among animals. We used long-term records of activity data that cover several lunar cycles to investigate whether behavior at-sea of swallow-tailed gulls Creagrus furcatus, a nocturnal pelagic seabird, varied with lunar phase in the Galápagos Islands. A Bayesian hierarchical model showed that nighttime at-sea activity of 37 breeding swallow-tailed gulls was clearly associated with changes in moon phase. Proportion of nighttime spent on water was highest during darker periods of the lunar cycle, coinciding with the cycle of the diel vertical migration (DVM) that brings prey to the sea surface at night. Our data show that at-sea behavior of a tropical seabird can vary with environmental changes, including lunar phase.
authors.affiliation: Department of Migration and Immuno-Ecology, Max Planck Institute for Ornithology, Radolfzell, Baden-Württemberg, Germany. cruz.seb@gmail.com
authors.forename: Sebastian M
authors.initials: SM
authors.lastname: Cruz
authors.forename: Mevin
authors.initials: M
authors.lastname: Hooten
authors.forename: Kathryn P
authors.initials: KP
authors.lastname: Huyvaert
authors.forename: Carolina B
authors.initials: CB
authors.lastname: Proaño
authors.forename: David J
authors.initials: DJ
authors.lastname: Anderson
authors.forename: Vsevolod
authors.initials: V
authors.lastname: Afanasyev
authors.forename: Martin
authors.initials: M
authors.lastname: Wikelski
mesh_terms: D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal; D001947:Breeding; D046091:Charadriiformes; D004484:Ecuador; D008962:Models, Theoretical; D016081:Moon; D009792:Oceans and Seas; D012621:Seasons