Not Just Sparrows and Pigeons: Cities Harbor 20 Percent of World’s Bird Species

By Andrea Alfano
April 29, 2014
Cedar Waxwings Cedar Waxwings are a colorful species commonly found in North American cities, and one of the species tracked by Celebrate Urban Birds. Photo by Derek Bridges via Birdshare.

Rock Pigeons, House Sparrows, and European Starlings are widely known as “city birds,” and with good reason. These three species (plus Barn Swallow) occur in more than 80 percent of cities according to the first-ever global study of biodiversity in urban areas, published earlier this year in Proceedings of the Royal Society B. But there’s more to cities than this narrow cast of avian urbanites: cities also retain more of their region’s native diversity than previously thought, according to the study’s analyses of bird and plant census data. So take heart, your next city stroll has much more to offer than just a few ubiquitous species.

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In fact, at least 2,041 species—20 percent of all known bird species—live in the world’s cities, according to the research. Unlike previous studies, which have focused on single cities or regions, this study spanned six continents, compiling data on birds from 54 cities and plants from 110 cities. The researchers themselves hailed from North America, Europe, Australia, and South Africa.

House Sparrows are one of the most successful species to adapt to living in urban environments, but a surprising 20 percent of the world’s species can be found in urban areas. Photo courtesy of Madhusudan Katti.

“One of the big paradigms of urban ecology is that the biota of the world’s cities is homogenized,” said lead author Myla Aronson, a researcher at Rutgers University and a Cornell University alum. “But we showed that at the global scale, cities are primarily retaining the unique composition of their geographic location.”

This means that although there are a few species that can truly be considered ubiquitous “city birds,” they are in the minority—a finding that wouldn’t have been possible without the global scope of this study. In fact, the list of species that you can find across 80 percent of the world’s cities amounts to just the four species mentioned above. The full list of birds found in cities includes nearly three-quarters of all bird families. Cities even provide habitat for rare species, including a total of 36 bird species identified by the IUCN Red List as threatened with extinction, the study said.

For many people, this remarkable diversity is often overshadowed by the notion that humans have almost entirely forced nature out of cities. A recent study by a different group showed that many urbanites fail to notice increases in biodiversity even when they happen.

“If you’re not particularly connected with nature, it’s easy to just not see what’s there,” said Karen Purcell, project leader for a Cornell Lab project called Celebrate Urban Birds. Purcell aims to change this “biodiversity blindness” by encouraging people to learn about and look for just 16 bird species that are commonly found in cities. It’s intended as a manageable introduction to the amazing diversity that can be found in cities.

Formerly on the endangered species list, Peregrine Falcons are increasingly common in cities and are one of 16 species tracked by our Celebrate Urban Birds citizen-science project. Photo courtesy of Laura Erickson.

For many city-dwellers, knowledge of just these few species leads them to become more aware of urban biodiversity in general, and encourages them to take pride in their city’s non-human life in addition to its human culture.

“We want to get that bug into people to watch,” said Purcell.

Urbanites are right to realize that cities are by no means ideal habitats for birds. Many species still manage to survive in them, but only around 8 percent as many species are found in cities as in the non-urban areas surrounding them. That’s why part of the goal of Celebrate Urban Birds is to inspire people living in cities to take action to support their urban biodiversity.

“Providing native vegetation is something that not only city planners can do, but that people can also do on a smaller scale,” said Frank La Sorte, a researcher at the Cornell Lab and an author of the urbanization study.

Cities with the least amount of urban land cover have the highest densities of bird species, according to the study. Parks and community gardens filled with native plants play an important role in maintaining bird species, but providing even small patches of vegetation, like hanging basket plants or container gardens, can help to attract birds to urban areas.

As of now, cities cover only 3 percent of the Earth’s terrestrial surface, but this doesn’t mean that the effects of urban greening efforts are insignificant. It’s not only the size of a city that affects biodiversity—location is important too.

“People tend to settle in regions that are already very species-rich because these are often the best areas in terms of climate and agricultural activities,” said La Sorte.

Cities may only take up 3 percent of the Earth’s land cover, but they are currently home to more than half of the world’s human population. This makes increasing awareness of biodiversity in cities even more crucial, because people can’t care about or protect things that they don’t notice. But actions as simple as participating in a citizen science project like Celebrate Urban Birds can open one’s eyes to biodiversity for a lifetime

“Once you see, you don’t ever stop seeing,” said Purcell.

For more on biodiversity in urban areas:


  • THESE birds are NOT sparrows,pigeons or Starlings!!
    look at the yellow tip at the end of its tail…

  • Trudi Poquette

    Thank you

  • Hi there, very good article! This is exactly what I see in urban areas in Germany too. There is an amazing bird diversity in gardens, yards, parks, city trees – almost everywhere. Only most people don’t realize. Everybody’s in a hurry, only few know about bird species, songs and names. It’s a pitty! That’s why I started “Let’s bird” on Information is in German but the videos speak for themselves. It’s so easy to watch birds – almost everywhere and anytime: Have a break – watch a bird!

  • Hugh

    thanks for commenting – you’re right, the birds in the top picture are Cedar Waxwings—a fairly common North American city bird that is surprisingly easy to overlook. They are identified in the photo credit line at the end of the post. – Hugh

  • Mary Ann Andrukiewicz

    Coming from a “city” area I was always aware of the “city birds”. I don’t live in a city anymore but still get a delight when I visit any city and identify their “city birds”. It’s a pity more people don’t open their eyes and take in and appreciate whatever nature is around them. Nice article, thanks.

  • Pradyot Bhanja

    Excellent !!

  • We are very lucky in Toronto, Ontario Canada to have a very beautiful 400 acre park in the city called High Park. It is well known for a rare Black Oak Savannah habitat that supports a wide biodiversity of plants and wildlife including resident and migratory birds.

    Your article brings out some important issues, especially about people having to learn to protect nature. Our park also has a great deal of recreational activity like bike trails, a swimming pool, a restaurant, a zoo and a huge off-leash dog area. Many residents love to be in nature but only when it is a backdrop for other activities, mostly those that have a very destructive impact on plants and wildlife including birds. Getting people to appreciate nature for its own sake and understanding how they can help not hurt wildlife is a real challenge.

    We have created a website to show people how citizens can help the city with habitat restoration and to display photos and articles on all of the natural treasures of High Park. Please visit us at For raptor enthusiasts there is a group called Hawk Watch that counts sping and fall migrations.

  • Boyd Winsor

    As a boy I studied with keen interest any bird I could especially house sparrows who would entertain by getting puddle baths or dust baths. I don’t see them anymore and wonder why they disapeared.

  • Greg Nemeth

    Birds are giving their best effort to survive. Humans need to be much more respectful of wildlife and its remaining hatitat especially prime flora and faua habitat. Wetlands and its adjacent surroundings. With Spring upon us lets do something different and let more fields of weeds mature. Weeds are the natural landscape. Specie numbers will increase with more weed fields. What will you do for our wildlife that can make a difference?


  • Letting wildflowers and some “weeds” mature is fine as long as they are not invasive species. These plants, imported from outside the natural ecosystem found in each area have no predators so they can take over and become a monoculture, crowding out the native plants that provide food and shelter for wildlife and not providing those features themselves. Garlic Mustard also has a substance that poisons the soil for other plants and Dog Strangling Vine (pale swallowwort) tricks Monarch butterflies into laying eggs on them (they are like milkweed) but the larvae will die.

    An awful lot of habitat restoration and protection is removing the really harmful invasives.

  • Eva

    I adore birds! I listen to them, I record them so I can listen again later, I search for their names, and wherever I go and hear an unfamiliar bird song I can’t get it out of my head and need to find which species it is. I want to get a decent camera and lens so I can photograph them. They are so mystical, eerie almost, especially the smaller ones. I am absolutely enchanted by the small birds with their heavenly songs! Even the tiny sweet sparrows are adorable, especially when they gather by the dozens, hidden in bushes and sing together, making such a racket :)