Object Play in the Royal Tern

Play behavior has been documented in a variety of bird species, especially among the families Corvidae and Psittacidae (Ficken 1977, Ortega and Beckoff 1987, Dia-mond and Bond 2003, Burghardt 2005, Emery and Clayton 2015, Kaplan 2020). Play behaviors are often classified into three categories: locomotor play, object play, and social play. Object play, the manipulation of an object for no apparent survival func- tion (e.g., foraging or reproduction), has been reported in at least nine species of terns (Sterninae): the Sooty ( Onychoprion fuscatus ; Feare 1975), Gull-billed ( Gelochelidon nilotica ; Sabne et al. 1997, Molina et al. 2020), Caspian ( Hydroprogne caspia ; King 1981, Cuthbert and Wires 2020), Inca ( Larosterna inca ; Ashmole and Tover 1968), Roseate ( Sterna dougallii ; Shealer and Kress 1994), Common ( S. hirundo ; Arnold et al. 2020), Arctic ( S. paradisaea ; Hatch et al. 2020), River ( S. aurantia ; Kasambe 2011), and Sandwich ( Thalasseus sandvicensis ; Hollom 1955, Shealer et al. 2020). In this note we report the first documented instance of object play in the Royal Tern ( Thalasseus maximus ).