The unusual length of the green-rumped parrotlet's nestling period is believed to be caused, or at least influenced, by the low levels of available nutrients and minerals for young found in typical green-rumped parrotlet habitat. Because of the difference in hatching time, not all chicks are the same size when they are young. Research has been done on resource allocation between different chick sizes by green-rumped parrotlet parents. It was shown that male parents tend to feed larger chicks more often, while females are far more likely to feed smaller individuals first because of their begging habits - smaller chicks tend to beg more, while larger chicks are more submissive. This effect has also been observed in other parrot species.