Scientists studying winter flocks of golden-crowned sparrows at the UC Santa Cruz Arboretum have discovered surprisingly complex social behavior in these small migratory birds. A new study reveals that the sparrows have different ways to assess dominance status depending on whether the interaction is with a familiar bird or a stranger.
Scientists studying winter flocks of golden-crowned sparrows at the UC Santa Cruz Arboretum have discovered surprisingly complex social behavior in these small migratory birds. A new study reveals that the sparrows have different ways to assess dominance status depending on whether the interaction is with a familiar bird or a stranger.
Previous studies by the UC Santa Cruz researchers showed that the patches of yellow and black plumage on the birds' heads serve as "badges of status," signals that correlate with fighting ability and allow birds to figure out who is dominant without having to fight. Birds with bold crown coloring are dominant over those with duller crown colors, regardless of whether the bold colors are natural or painted on by the researchers. Those were the findings of two studies published in 2011 and 2013, in which the researchers staged confrontations by placing two birds captured in different locations together in an aviary.
"To show that birds are using badges of status, you have to pit birds against each other that have never met to make sure they do not have prior information about fighting ability," explained Bruce Lyon, professor of ecology and evolutionary biology at UC Santa Cruz.
Lyon's lab has now been studying the Arboretum's golden-crowned sparrows for 15 years. The plumage studies have been led by Alexis Chaine, a former graduate student in the lab who is now at the National Center for Scientific Research (CNRS) station in Moulis, France.
Read more at University of California - Santa Cruz
Image: Golden-crowned sparrows with bold crown coloring are dominant over those with duller crown colors. (Credit: Bruce Lyon)
