In social animals, when conspecific individuals use limited resources differently jealousy will occur. To address whether jealousy is an environmental variable underlying negative evolutionary responses to superior phenotypes, we investigated jealous behaviours in the azure-winged magpie, Cyanopica cyanus, under natural and experimental conditions. Within a triad composed of a feeder, a target and three differently-ranked third-party individuals, the target was fed exclusively to experimentally imitate a scene of uneven resource distribution. Three jealousy-type behaviours were exhibited by the third-party (i.e., raiding and assaulting the target, ingratiating themselves with the feeder) and target (expelling and flaunting the worm to third-party, ingratiating itself with the feeder), respectively, that were significantly affected by their social ranks. It suggests that uneven distribution of limited resources should account for the occurrence of jealous behaviours, and that jealousy may function as a reverse evolutionary force to neutralize the potentially too quick diffusion of superior phenotypic traits.