Are junior boobies always losers?

Among blue-footed boobies, a picked-on little brother or sister stays wimpy for days after being moved to a new home, even when its new nest mate is small. Likewise, the bullying sib continues to bully, even when it's outweighed in a new family.

Boobies offer a great way to test for persisting effects of winning and losing conflicts, according to Hugh Drummond and Cristina Canales from the National Autonomous University of Mexico in Mexico City. The first chick to hatch torments the second one, attacking it every day of the three- to four-month nestling period.

The researchers broke up these sibling rivalries, resettling youngsters in nests that had previously held only one chick. Despite having a size advantage, the former under-chick showed much less aggressive behavior than its foster sibling. The transplanted booby continued to lose scraps for about 10 days.

The former bullies, even though they were smaller than their new nest mates, continued to peck and threaten aggressively. Even after 6 days, half the bullies were still trouncing their nest mates. The experiment marks the first test in vertebrates for winner and loser effects in sibling spats, the researchers report in the June Animal Behaviour.