The term “pecking order” was coined a century ago by Norwegian scientist Thorleif Schjelderup-Ebbe to describe the dominance hierarchies he observed in domestic chickens. Individual birds with higher rankings pecked at individuals with lower status, thus gaining better access to food. Today, the term is often used to describe human social structures - someone rising in the office pecking order is building importance, prestige and power.
Interspecies bird pecking orders may be especially noticeable this time of year when we keep feeders stocked and watch birds from inside our warm homes. A 2017 paper used community science data from Project FeederWatch to study aggressive feeder interactions – when one bird displaced or chased another from a feeder perch. While the interactions can be complex, they found that in general, bigger birds win feeder battles. They also noted that some birds were more passive (doves), or more aggressive (warblers and hummingbirds) than their size would suggest. More recent research has focused on adherence to dominance hierarchies among birds familiar with one another and the impact of individual morphology and coloration on hierarchies.