I report observations consistent with the interpretation that a Chestnut-collared Longspur (Calcarius ornatus) fledgling from a first brood begged for and received food from its parents at a their second brood nest. All five nestlings in the second brood subsequently died and starvation appeared to be the major factor contributing to their deaths. This is the first reported case of apparent between-brood sibling competition in a passerine species and it fits the criteria of a parent-offspring conflict.
