From the Winter 2024 issue of Living Bird magazine. Subscribe now.
When hordes of chickadees, finches, and woodpeckers descend on a backyard bird feeder, fights are bound to erupt: Sometimes getting a choice morsel means entering your position.
Minimizing conflict in these situations is good for birds, says Cornell Lab of Ornithology Research Associate Eliot Miller: “It takes energy to fight, and it can be dangerous, so it usually makes sense to avoid it. ”
In 2017, a team led by Miller used Project FeederWatch data to study such conflicts—moments when a bird moves toward a food source. The results, published in the journal Behavioral Ecologyhas yielded a dominance-hierarchy ranking for backyard birds: a guide to which species are most likely to hold their ground in one-on-one confrontations with other species, and which are more tend to be tail and fly.
Now, other scientists are picking up where Miller left off, using an ever-growing set of FeederWatch data to dig deeper into the behavior, social relationships, and physical characteristics that shape feeder conflict. of birds
Biologist Roslyn Dakin of Carleton University in Canada was inspired by Miller’s 2017 study to look at whether a bird’s social tendencies affect its place in the pecking order. For example, some birds, such as finches and House Sparrows, are social butterflies that often visit feeders in groups, while others, such as woodpeckers and nuthatches, are more likely lone wolves.
Working with Carleton PhD student Ilias Berberi, Dakin analyzed 6.1 million FeederWatch observations to determine the average group size at feeders for 68 species.
“What we realized when we entered [the FeederWatch data] is that it really opens up all kinds of opportunities that we wouldn’t have otherwise,” Dakin said. “It allows us to ask questions that we cannot ask through the observations of any scientist or even a small team of scientists because no one person can observe communities across continents.”
The team next looked at the 55,000 recorded one-on-one dominance interactions in the FeederWatch dataset to see if loner birds or social birds were better at displacing other birds. Their results, published in the journal Proceedings of the Royal Society B in February 2023, showed that birds such as the White-breasted Nuthatch and Red-bellied Woodpecker (lone wolves among the smallest birds in the students) are also among the most likely. to replace others. At the other end of the spectrum, social butterflies that often visit feeders in groups, such as American Goldfinches and House Sparrows, tend to flee the scene when faced with an enemy of similar stature.
But there’s a caveat: When these socially inclined birds came to eat in groups, their performance improved. For example, highly social Pine Siskin miss most encounters when they are alone, but when a group of five visit together, their individual interactions, on average, are twice as many. more successful.
Conversely, some birds that tend to be solitary wolves, such as Northern Cardinals, were less successful in feeder showdowns when they visited groups.
“We think that these effects may be driven by what the birds are paying attention to,” Dakin said. “So maybe when cardinals are present in a group, they pay attention to each other and may be more likely to be displaced by another species.”
Another study, published in 2024 in the journal Communication in Nature and led by Gavin Leighton, an assistant professor of biology at Buffalo State University, investigated what happens to the dominance hierarchy when a new face shows up at the bird feeder. Leighton and his team looked at about 1,600 interactions from more than 100 different bird species in the FeederWatch data and identified “syntopic” species—pairs of species which usually overlap in space and time—is less than expected. On the other hand, species that are not often found together fight more than expected when their paths cross.
For example, chickadees, goldfinches, and juncos seem to avoid scuffles even though they often rub shoulders at feeders. On the other hand, chickadees seem to spoil the fight with Yellow-rumped Warblers.
“It all comes down to energy,” Leighton said. “You don’t want to fight knowing you will lose. When birds meet regularly, they are more likely to learn whether they are the subordinate or the dominant. If you’re close to someone you know is likely to beat you, it’s more beneficial to just leave before anything else happens.”
Both Dakin and Leighton continue to use FeederWatch data to disentangle the social networks of bird feeders. Leighton is currently studying whether harsh weather makes it more likely that a subordinate species will resist an attack; Dakin is interested in how weather affects group size in bird feeders.
Emma Greig, the project leader for FeederWatch at the Cornell Lab, says she’s excited that the data is being used in new ways, and that thousands of FeederWatchers continue to report dominance interactions in their observations.
“We can use bird counts to infer things about behavior, but now we can also use people’s direct observations of behavioral interactions to learn how the birds to each other,” Greig said. “This is really amazing data.”
