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Grackles adapt to urban life better than any other animal species

Have you ever wondered why some animals seem to love hanging out in urban areas while others steer clear? You’ve got grackles buzzing around on power lines, squirrels raiding trash cans, and pigeons strutting through bustling parks. Meanwhile, bears, wolves, and creatures of that nature keep their distance from urban life.

A new study from the Max Planck Institute for Evolutionary Anthropology reveals the secret to success in the urban jungle: a knack for dealing with risks. Turns out, those critters brave enough to roll the dice might be the ones cashing in on our love of city life.

Learning to live in the city

“For animals, living alongside humans is ‘risky business,’” said Dr. Alex Breen, one of the lead researchers. The study looked specifically at urban life among sleek black birds known as grackles. They wanted to discover what makes these birds such successful city-dwellers.

Let’s not forget that cities are unpredictable places. Imagine a hungry grackle. Sure, it might scavenge a tasty morsel from a sidewalk cafe, but those same streets are also filled with unpredictable humans, chaotic traffic, and maybe a few unfriendly dogs.

To figure out how grackles deal with this uncertainty, the researchers observed how quickly the birds learned where to find hidden snacks. Then, they switched up the locations and watched how fast the grackles figured out the change.

Male grackles are urban risk takers

The experts discovered that male grackles learned the new food locations faster than the females. In the grackle world, males are the pioneers.

They’re the ones scouting out new territories, venturing beyond familiar grounds to discover fresh opportunities. This drive to explore makes them ideal candidates for leading the urban invasion.

Imagine a group of grackles encountering a sprawling city and tackling urban life for the first time. The females, likely more cautious by nature, might hang back in the safety of nearby trees or fields.

The males, however, compelled by their pioneering spirit, would be the ones venturing into the unknown. They’d be the first to navigate the maze of buildings, dodge traffic, and deal with the unpredictable behavior of humans.

Grackles identify the safe urban spots

Here’s where the ability to learn quickly from successes and failures becomes crucial. A male grackle who stumbles upon a reliable source of food in a new city neighborhood needs to remember that location.

This “risk-sensitive learning” allows him to exploit this newfound bounty and potentially share it with others in the group.

Conversely, a male grackle who explores a risky location and encounters danger, perhaps a close call with a car or a territorial cat, will be more likely to avoid that area in the future. This ability to learn from negative experiences helps grackles navigate urban life and establish safe and successful city colonies.

Dr. Deffner, another researcher from the study, explained: “Unlike females, males exhibit pronounced risk-sensitive learning.” They pay close attention to successful food sources and are less likely to just wing it and try a new spot.

It’s a “better safe than sorry” approach that turns out to be pretty helpful when exploring uncertain environments.

Grackles winning strategy for the urban jungle

To further understand how learning impacts survival in urban environments, the researchers took their study into the digital realm.

They designed a computer simulation that mimicked the challenges and unpredictability of a city. This virtual world included fluctuating food sources, potential dangers, and other elements that animals would encounter in an urban setting.

Within this simulation, they introduced virtual creatures programmed with different learning strategies. Some were bold risk-takers, while others were more cautious and methodical.

Over many simulated generations, the researchers observed which learning strategies led to the highest survival and reproduction rates.

The results were striking. Time and time again, the cautious, risk-averse virtual creatures outperformed their bolder counterparts. These successful virtual creatures employed strategies that closely resembled the real-world learning patterns observed in male grackles.

“Our study offers compelling evidence for how and why at least grackles are thriving in unpredictable urban environments,” said Dr. Breen.

Urban life takes guts

So the next time you see a pigeon waddling down the sidewalk or a squirrel digging through a dumpster, remember, they’re taking calculated risks to survive alongside us. A little caution goes a long way when you’re navigating the ever-changing, sometimes chaotic world created by humans.

And if you’re interested in learning more or building your own models of how animals thrive in cities, the researchers have even created an online resource for scientists and curious minds alike. “We hope this open-science resource proves useful to others,” said Dr. Deffner.

It looks like animals are learning some pretty impressive tricks to share our spaces, and scientists are only just starting to uncover their secrets.

More about the urban-friendly grackles

Grackles are fascinating birds that belong to the Quiscalus genus, which is part of the larger family of New World blackbirds. Here are some key points about grackles:

Habitat and distribution

Grackles are found across North America, from the high plains to urban centers. Their ability to thrive in a wide range of environments, including cities, makes them a common sight in many areas. They are highly adaptable and can live in environments ranging from open woodlands to agricultural lands and urban parks.

Diet and foraging behavior

Grackles have a varied diet that includes insects, seeds, grains, fruits, and even small vertebrates and eggs from other birds. Their opportunistic feeding habits allow them to take advantage of different food sources throughout the year.

When it comes to urban life, grackles also forage in trash bins and around outdoor eating areas, showcasing their adaptability.

Social behavior

Grackles can be very social birds, often seen in large flocks, especially outside of the breeding season. These flocks can include thousands of birds and are known for their impressive, synchronized flights. During the breeding season, however, they can become more territorial, with males displaying aggressive behaviors to defend their nesting sites.


Grackles are noted for their wide range of vocalizations, which include whistles, caws, and other sounds that can be surprisingly melodic. Their calls serve a variety of purposes, such as attracting mates, signaling danger, and communicating with others in their flock.


Grackles are nest builders, with females usually taking the lead in constructing nests out of twigs, grass, and other materials. These nests are often located in trees or bushes. Females lay between 4 to 7 eggs, which they incubate for about two weeks. The young are then cared for by both parents until they fledge.

Interaction with humans

Grackles have a mixed relationship with humans. On one hand, people admire them for their adaptability and their role in controlling insect populations. On the other, they can be considered as pests, especially in agricultural areas where they eat crops, and in urban areas where their large flocks create noise and mess.

The study is published in the journal ELife.


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