We video-recorded an adult Least Bell’s Vireo (Vireo bellii pusillus) puncture-ejecting one of its own eggs. The behavior was detected during analysis of footage from 25 vireo nests that we videotaped continuously along the San Luis Rey River near Bonsall, California, in 2000 (Peterson 2002, Sharp 2002). The ejection occurred at 0622 on 21 July 2000 in a nest containing two 5-day-old vireo nestlings (both fledged on 27 July) and the unhatched vireo egg. Prior to ejection, one adult stood in the nest cup and the other was perched on the main branch that supported the nest. The former adult flew away, and the latter moved to the edge of the nest, looked into it, pecked the unhatched egg three times with its closed bill, stopped, and looked into the nest again. This cycle of striking the egg three to five times then looking into the nest was repeated over 44 seconds, during which the adult pecked the egg 27 times. Following the last strike, the adult grasped the egg with its bill on either side of the hole it had created and flew away from the nest with the egg. A vireo returned to the nest 9 seconds later, looked into the nest, but did not lower its head into the nest cup. We could not confirm the adult’s sex, and they did not vocalize during the time observed. This report is the first of puncture-ejection of an egg by a Least Bell’s Vireo.