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Mike and Elona Masson consider themselves “hawk people.”

Lifelong birdwatchers, they’re particularly fond of birds of prey and pay close attention to the raptors that visit their Santa Barbara backyard. In fact, when they get home, it’s not unusual to find their resident Red-shouldered Hawk feasting on a Band-tailed Pigeon or rodent. But as Elona stopped to record the bird tearing into its kill one February day in 2020, she noticed something peculiar: The hawk's meal wasn’t a kill at all—it was a fallen fruit.

“This bird was working on an avocado,” Elona says. “And we were just utterly dumbfounded by that, because he had his pupils dilated. He was looking at it with such ferocity, and it was a green avocado.”

Unbeknownst to the Massons, they were witnessing the first-known observation of a Red-shouldered Hawk eating avocado—or any fruit, for that matter. But it wasn’t the last: They saw the same behavior four times over the next four years, managing to record it twice. The pair disagree on whether they observed the same bird each time—according to Elona, there were differences in the feather coloration from visit to visit—but the food of choice was undeniable.  

After the fourth encounter, Elona decided to do some research to see if the bird’s diet was unusual for Red-tailed Hawks. Her search brought her to James Fitzsimons, an Australian researcher at Deakin University in Victoria, who had published a literature review on herbivory in raptors in 2021. The couple reached out and sent him their photos and videos of the hawk.

According to Fitzsimons, the Massons’ observations were particularly compelling. Many sightings of raptors eating fruit are incidental and lack photographic evidence. The Massons were able to capture multiple clear videos over the span of years, with the hawk showing undeniable intent: In one video, the bird even defended the avocado from a flock of pestering crows.

Fitzsimons offered to help the couple officially document the sighting and behavior. The resulting paper was this past May in the Wilson Journal of Ornithology, with the Massons as co-authors. The paper analyzes the hawk’s foraging behavior and briefly discusses the established research on the diet of Red-shouldered Hawks and herbivory, or the consumption of living plant matter, in other raptors. 

Since then, wildlife photographer Simon Arambula captured the unusual Red-shouldered behavior yet again, sharing on Facebook in September. According to Arambula's post, the sighting occurred about 60 miles away from Santa Barbara, in a different county, and with another local hawk.  

While it remains unlikely that Red-shouldered Hawks are full-fledged omnivores, these observations and other recent research only seem to be broadening the list of birds of prey that don’t exclusively eat meat. The Red-shouldered brings the current total to 33 raptors known to supplement their diet with plants—still a small sliver of hundreds of species but enough to suggest this avian behavior is more prominent than realized.

While raptors overwhelmingly focus on animal matter—from insects and fishes to rodents and even dead elephants—one exception has been known for a long time: the Palm-nut Vulture, with more than half its diet (58 to 92 percent) consisting of fruit and other plant matter. But Fitzsimons’ 2021 literature review identified 29 species of raptors that have been documented to feed on fruit and other plant matter, including both Black and Turkey Vultures, Black Kites, and Crested Caracaras. For the most part, the foods tend to fit the same profile as avocados and palm nuts: fruits high in lipids, which are chemically similar to raptors’ usual prey and might compensate for a lack of animal foods in hard times.

Fitzsimons, whose main area of study has to do with environmental science and landscape-scale conservation, says his decision to investigate frugivory in raptors was inspired by his co-author Jack Leighton’s observation of hundreds of Black Kites feeding on non-native avocado orchards in Australia. “It was reported as a little one-paragraph note in a magazine back in Australia, perhaps in the early 2010s,” Fitzsimons says. “But I thought it's quite significant. We should try and get [those findings] out a bit more.”

Avocados contain persin, a fungicidal substance which can prove highly toxic to birds. For domestic birds like budgies and canaries, as little as two grams can prove . Whether because raptors like the Red-shouldered Hawk are avoiding the pit and skin, where persin is more highly concentrated, or due to other factors like their size or physiology, Fitzsimons says it seems that these raptors aren't suffering any major ill effects.

While many of the examples covered by Fitzsimons and Leighton in the paper feature fatty fruits like oil palm and avocado, this isn’t always the case. The pair also described nine species that consumed berries, figs, and apples, and Ospreys have even been documented intentionally consuming algae and slime.

Since 2021, three other additional raptors have joined the list: the Roadside Hawk and the Lesser Yellow-headed Vulture, which both eat African oil palm, and the Eastern Screech-Owl. In 2023, researchers led by Arielle Fay witnessed an owl approach and appear to consume water oak acorns placed on a viewing platform for a separate study. The team their observations and noted that it wasn’t totally surprising for owls to consume foods outside of their usual diet, pointing to meat-eating deer and rabbits as another example. The behavior is known as opportunistic foraging, and it allows animals to take advantage of any available nutrients. “As is common in nature, there exist a multitude of exceptions to the rule,” the researchers wrote.

Or, as Mike Masson more simply puts it:  “Wild animals make choices, and sometimes they make rather interesting ones.”

According to Fitzsimons, the reason for the increase in observations of frugivory in raptors is unclear. It could be related to relatively recent ecological or habitat changes for the species, but more than likely, it’s simply the result of more monitoring with better equipment as birding has become mainstream. “It might be more common than we think, but we just don't know,” he says.