Field observations of defecations and antagonistic interactions of dark-bellied brent geese on Schiermonnikoog island. For details, see main manuscript. observation ID: incremental index colorcode: color ring code of observed individual date: date time: local time observer: observer initials sex: sex of observed individual partner: partner of observed individual observation ID partner: observation ID of simultaneously observed partner bird young: number of accompanying juveniles group size: estimate of foraging groups size position in group: approximate position in group (center or edge) start: start time of dropping and interaction observation bout dropping1: timing of 1st defecation dropping2: timing of 2nd consecutive defecation dropping3: timing of 3nd consecutive defecation droppingX: timing of Xth consecutive defecation stop: end time of dropping and interaction observation bout win: number of winning antagonistic interactions between start time (start) and end time (stop) draw: number of draws between start time (start) and end time (stop) lose: number of losing antagonistic interactions between start time (start) and end time (stop) abdomen time: total time that the observer had the abdomen in sight # droppings: total number of droppings excreted during observation bout