Many visitors have the bad habit of feeding ducks bread crumbs. Ducks and other waterbirds already used to it join and fight over a piece. Among the regulars there are rosy-billed pochard, three type of coots, common gallinules. The scene told by Carlos includes brown-hooded gulls which descended to steal bread crumbs caught by rosy-billed pochards. Steal a prey obtained by another is a frequent habit in gulls. In this incident the rosy-billed pochard tried to swallow a piece of bread but it couldn't. The gull insisted so hard that it got tired and pecked at the pochard's back. At this point the pochard released the piece. Though in these photos there is no proof of the minor injury, it is clear how the gull harrasses the pochard and the pochard's elusive maneuvres.