Does Size Matter? It Depends Whether You’re a Pigeon or a Parakeet

Pugnacious pigeons. Cantankerous canaries. Sparring starlings.

When birds flock together, feathers often fly. Even though knock-down-drag-out fights are rare, birds frequently squabble to establish their place in the pecking order. 

The biggest bullies usually get the highest quality food and cushiest living arrangements. But being the bossiest bird doesn’t mean life is always easy. Sometimes, staying on top is a never-ending struggle. 

Henpecked and Chicken-Hearted

Norwegian zoologist Thorleif Schjelderup-Ebbe coined the phrase “pecking order” in the early 1920s to describe the skirmishes between his barnyard chickens. He noticed how social rankings were established when one member of the flock confronted another. The bird who backed down got demoted while the winner moved up a rung on the social ladder. 

Schjelderup-Ebbe dubbed this ranking system a pecking order because the higher-ranking chickens would peck at the lower-ranking birds whenever they overstepped their boundaries. In addition to getting first dibs at the food, the top-ranked chickens often received preferential mating status, prime perches, and superior nesting boxes.

While individual traits like age, personality, and social experience contribute to chickens’ social standing, body size often determines who rules the roost. Heavier birds are usually stronger and better at pushing around their peers. 

Big-Bodied Bullies

Chickens aren’t the only birds with a pecking order. Homing pigeons also form hierarchies, and the beefiest bullies are usually the top birds. In fact, being big is so important to pigeons’ rankings that scientists can upend the social order by temporarily making wimpier birds into burly bodybuilders. 

While studying a captive flock of homing pigeons, researchers found that hierarchical rank significantly correlated with body mass. The larger birds were more aggressive, and they held the top spots in the pecking order. 

The scientists knew that pigeons’ body mass could change throughout the year due to breeding, molting, and migration, so they wondered what would happen if the smaller birds suddenly became bigger. To find out, they attached weighted backpacks to the pigeons in the lower 50% of the hierarchy. 

Buoyed by their newly enhanced physique, these once-submissive pigeons instantly became combative and fought their way up the ranks—leaving the ousted leaders flummoxed by the sudden personality changes. When the weights were removed, the hierarchy returned to its previous structure. 

Scientists aren’t sure why the augmented birds became more aggressive. Perhaps the added bulk boosted their confidence. Or, maybe carrying around extra weight made the birds hungry and more willing to fight for food. Since only male pigeons displayed hostile behavior, their aggression may also be linked to mating competition. 

Food Fights at the Feeder

Pecking orders aren’t limited to birds of the same species. If you’ve ever owned a backyard bird feeder, you may have noticed that some birds are pushier than others when it comes to getting snacks. Scientists who studied these inter-species hierarchies found that big birds often, but not always, get first dibs.

In separate studies, researchers in the U.S. and U.K. used network analysis and a variation of the Elo rating system (a method for assigning rankings to international chess players) to rank different bird species based on the outcomes of confrontations at backyard feeders. They assigned each species a score based on their wins and losses against other birds.

In both studies, the largest birds—which included blue jays in the U.S. and sparrows and greenfinches in the U.K.—monopolized the food. Whenever these heavyset hooligans came to the feeder, the smaller birds moved aside and waited for the leftovers. 

Although body size mattered, a few scrappy birds refused to be pigeonholed by their physiques. Woodpeckers, warblers, orioles, and hummingbirds all ranked higher than expected based on body weight alone. 

Follow-up studies suggest that beak length might explain why these underdogs often prevail. It seems that well-endowed birds with larger bills relative to body size win more battles than predicted. 

When binging at the birdfeeder, it also helps to bring along some BFFs—best feathered friends. If individual birds from a social species appear at a feeder by themselves, they tend to win fewer fights than expected for their body mass. But when these social species show up with a group, they are more likely to score victories—even if their buddies don’t join in the fight. 

The Struggle is Real

While being big allows some birds to dominate their peers, it isn’t the only way to soar to the top of the social standings. Hierarchies in monk parakeets aren’t based on body size or other physical attributes. For these scrappy birds, tenacity is key, and their constant quarreling results in lots of social drama.

Native to South America, monk parakeets form multifamily nests that house up to 200 birds. The parakeets are chummy with their friends, but they can be grumpy toward other flock members—often shoving each other off perches and swiping adversaries with their beaks.  

The birds typically avoid conflicts with flock-mates ranked much higher or lower than themselves. Instead, they focus their attacks on parakeets who are similar in ranking since these neighbors provide the easiest opportunities for moving up the social ladder. 

But the incessant scuffles are more than political posturing. Rankings in monk parakeet communities are tenuous, and a recent study found that birds who take sabbaticals face devastating demotions.

To better understand the parakeets’ complex hierarchical system, researchers removed birds of different levels of social standing from a captive flock, holding them in isolation for eight days before reuniting them with the larger group. When the birds returned from their involuntary vacations, their rankings plummeted, forcing them to fight their way back from the bottom of the social ladder.

The highest ranked parakeets suffered the harshest homecomings. Unwilling to relinquish their superior status, the flock’s newly established bigwigs frequently attacked these returning birds.

Whether fighting for food or wrestling for mates, life among feathered friends can be far from friendly. For many birds, hanging on to their spot in the status quo is a daily grind. And while being big comes with perks, it doesn’t guarantee the top rank in the pecking order.

If you would like to read more about unusual animal behaviors, check out this article about crabs.