An evolved spatial memory bias in a nectar-feeding bird?

Studies have shown that nectar-feeding birds more easily learn to avoid a previously rewarding location (to win-shift) than to return to such a location (to win-stay). This pattern has been interpreted as evidence of an evolved adaptation to the fact that nectar is a depleting resource; however, such a conclusion requires ruling out the possibility that this tendency is a consequence of the experience of individual birds, and is more compelling if performance in the memory task reveals sensitivity to detailed features of the spatiotemporal distribution of nectar in the environment. We tested the tendency of captive-reared Regent honeyeaters, Xanthomyza phrygia, a species of nectar-feeding bird, to win-shift or win-stay at different intervisit intervals. The birds generally avoided rewarding locations after a short retention interval (10 min), but returned to these locations after a long retention interval (3 h). This behaviour tracks the replenishment rate of the flowers exploited by this species in the wild, even though the subjects were born and reared in captivity.