Eagle and crows.
Eagle and crows.
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Whether it’s following the yearly Yankees/Red Sox rivalries or even rooting for a favorite political candidate, we Mainers seem to relish hearty competition. But have you considered the daily tussles at your bird feeders when mixed-species flocks compete for the food you place there? Feeding birds has two basic rationales: 1) to provide birds with life-sustaining food throughout harsh winter conditions or periods of food scarcities; 2) to enjoy interesting bird activity around our yards. In truth, most birds would likely survive without our handouts, but the secondary rationale of curious enjoyment of birds is always valid.

Birds are not static creatures that occupy isolated single- species realms. We should remember that bird feeding stations typically draw diverse species into closer-than-usual contacts with one another. In many cases, there are predictable outcomes to competitive matchups. Members of the same species, such as nuthatches, will often compete strongly for food dominance. Some of the most intense avian rivalries are hashed out among the seeds and suet, says Eliot Miller, a researcher at the Cornell Lab of Ornithology and author of a new feeder-hierarchy study. “Feeders are these arenas where birds gather and fight,” he says. “There’s an increased rate of aggression to some degree.”

Through computerized analysis of thousands of feeder observations from Project Feeder Watch, a volunteer science count that runs from November to April, Miller compared 136 common North American species to reveal where they belong in Nature’s pecking order. Some mildly surprising results were uncovered in the process. For instance, despite their diminutive stature, Downy Woodpeckers ranked relatively high in the dominance scale of smaller birds, being feared by a number of species — is it possibly that formidable woodpecker bill?

Perhaps it’s less surprising that gutsy little hummingbirds fare well against many sizes of competitors. Around the vicinity of my summer nectar feeders, I’ve witnessed their routing attacks on a host of birds ranging from titmice, wrens, sparrows and up to larger robin-sized birds. Hummers also battle mightily against bees and other winged insects vying for sap drippings at sapsucker wells. With their hyperbolic body metabolism, hummers need to feed regularly — a biological factor that could invigorate their aggressive feeding behaviors.

Now let’s explore some head-to-head results from Feeder Watch participants: 

Black-capped Chickadee vs. American Goldfinch: Although the goldfinch has a slight size advantage, the perky, athletic chickadee is more aggressive and usually gets the prime spot at the feeder.

European Starling vs. Blue Jay: Both species are naturally spunky and aggressive in food gathering practices. While the bullying jays are highly intelligent and weigh a bit more, starlings are equally successful competitors, known for their colonizing skills and ability to thrive in novel environments. Miller has noticed that introduced species like starlings often don’t fit neatly into the predicted pattern. The starling and jay are perfectly matched and their competitive interactions frequently end in a draw.

Common Raven vs. American Crow: On the surface, this pairing would logically favor the bulky raven that is far superior in size to any crow. This situation would hold true on a strictly individual basis, but when crows act in a group, the story is different. When crows work together, they can prevail against a solitary raven. A “murder of crows” wins the day to push their bigger rivals away from the prize. And against even higher competitive stakes, I watched a group of six crows agitate and eventually displace an adult Bald Eagle from its riverside meal.

I urge my readers to become consistent feeder watchers and make your own observational conclusions. Joining Project Feeder Watch (easy to do online) will also enhance your bird enjoyment while increasing scientific understanding of birds.