By Frank La Sorte and Kyle Horton
Millions of birds travel between their breeding and wintering grounds during spring and autumn migration, creating one of the greatest spectacles of the natural world. These journeys often span incredible distances. For example, the Blackpoll warbler, which weighs less than half an ounce, may travel up to 1,500 miles between its nesting grounds in Canada and its wintering grounds in the Caribbean and South America.
Blackpoll warbler. PJTurgeon / Wikipedia<p>We used this information to determine how the number of migratory bird species varies based on each city's level of <a href="https://www.britannica.com/science/light-pollution" target="_blank" rel="noopener noreferrer">light pollution</a> – brightening of the night sky caused by artificial light sources, such as buildings and streetlights. We also explored how species numbers vary based on the quantity of tree canopy cover and impervious surface, such as concrete and asphalt, within each city. Our findings show that cities can help migrating birds by planting more trees and reducing light pollution, especially during spring and autumn migration.</p>
Declining Bird Populations<p>Urban areas contain numerous dangers for migratory birds. The biggest threat is the risk of <a href="https://doi.org/10.1650/CONDOR-13-090.1" target="_blank">colliding with buildings or communication towers</a>. Many migratory bird populations have <a href="http://dx.doi.org/10.1126/science.aaw1313" target="_blank">declined over the past 50 years</a>, and it is possible that light pollution from cities is contributing to these losses.</p><p>Scientists widely agree that light pollution can <a href="https://doi.org/10.1073/pnas.1708574114" target="_blank">severely disorient migratory birds</a> and make it hard for them to navigate. Studies have shown that birds will cluster around brightly lit structures, much like insects flying around a porch light at night. Cities are the <a href="https://doi.org/10.1002/fee.2029" target="_blank" rel="noopener noreferrer">primary source of light pollution for migratory birds</a>, and these species tend to be more abundant within cities <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13792" target="_blank" rel="noopener noreferrer">during migration</a>, especially in <a href="https://doi.org/10.1016/j.landurbplan.2020.103892" target="_blank" rel="noopener noreferrer">city parks</a>.</p>
Composite image of the continental U.S. at night from satellite photos. NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center
The Power of Citizen Science<p>It's not easy to observe and document bird migration, especially for species that migrate at night. The main challenge is that many of these species are very small, which limits scientists' ability to use electronic tracking devices.</p><p>With the growth of the internet and other information technologies, new data resources are becoming available that are making it possible to overcome some of these challenges. <a href="https://doi.org/10.1038/d41586-018-07106-5" target="_blank">Citizen science initiatives</a> in which volunteers use online portals to enter their observations of the natural world have become an important resource for researchers.</p><p>One such initiative, <a href="https://ebird.org/home" target="_blank" rel="noopener noreferrer">eBird</a>, allows bird-watchers around the globe to share their observations from any location and time. This has produced one of the <a href="https://doi.org/10.1111/ecog.04632" target="_blank" rel="noopener noreferrer">largest ecological citizen-science databases in the world</a>. To date, eBird contains over 922 million bird observations compiled by over 617,000 participants.</p>
Light Pollution Both Attracts and Repels Migratory Birds<p>Migratory bird species have evolved to use certain migration routes and types of habitat, such as forests, grasslands or marshes. While humans may enjoy seeing migratory birds appear in urban areas, it's generally not good for bird populations. In addition to the many hazards that exist in urban areas, cities typically lack the food resources and cover that birds need during migration or when raising their young. As scientists, we're concerned when we see evidence that migratory birds are being drawn away from their traditional migration routes and natural habitats.</p><p>Through our analysis of eBird data, we found that cities contained the greatest numbers of migratory bird species during spring and autumn migration. Higher levels of light pollution were associated with more species during migration – evidence that light pollution attracts migratory birds to cities across the U.S. This is cause for concern, as it shows that the influence of light pollution on migratory behavior is strong enough to increase the number of species that would normally be found in urban areas.</p><p>In contrast, we found that higher levels of light pollution were associated with fewer migratory bird species during the summer and winter. This is likely due to the scarcity of suitable habitat in cities, such as large forest patches, in combination with the adverse affects of light pollution on bird behavior and health. In addition, during these seasons, migratory birds are active only during the day and their populations are largely stationary, creating few opportunities for light pollution to attract them to urban areas.</p>
Trees and Pavement<p>We found that tree canopy cover was associated with more migratory bird species during spring migration and the summer. Trees provide important habitat for migratory birds during migration and the breeding season, so the presence of trees can have a strong effect on the number of migratory bird species that occur in cities.</p><p>Finally, we found that higher levels of impervious surface were associated with more migratory bird species during the winter. This result is somewhat surprising. It could be a product of the <a href="https://www.epa.gov/heatislands" target="_blank">urban heat island effect</a> – the fact that structures and paved surfaces in cities absorb and reemit more of the sun's heat than natural surfaces. Replacing vegetation with buildings, roads and parking lots can therefore make cities significantly warmer than surrounding lands. This effect could reduce cold stress on birds and increase food resources, such as insect populations, during the winter.</p><p>Our research adds to our understanding of how conditions in cities can both help and hurt migratory bird populations. We hope that our findings will inform urban planning initiatives and strategies to reduce the harmful effects of cities on migratory birds through such measures as <a href="https://www.arborday.org/programs/treecityusa/index.cfm" target="_blank" rel="noopener noreferrer">planting more trees</a> and initiating <a href="https://aeroecolab.com/uslights" target="_blank" rel="noopener noreferrer">lights-out programs</a>. Efforts to make it easier for migratory birds to complete their incredible journeys will help maintain their populations into the future.</p><p><em><span style="background-color: initial;"><a href="https://theconversation.com/profiles/frank-la-sorte-1191494" target="_blank">Frank La Sorte</a> is a r</span>esearch associate at the </em><em>Cornell Lab of Ornithology, Cornell University. <a href="https://theconversation.com/profiles/kyle-horton-1191498" target="_blank">Kyle Horton</a> is an assistant professor of Fish, Wildlife, and Conservation Biology at the Colorado State University.</em></p><p><em></em><em>Disclosure statement: Frank La Sorte receives funding from The Wolf Creek Charitable Foundation and the National Science Foundation (DBI-1939187). K</em><em>yle Horton does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</em></p><p><em>Reposted with permission from <a href="https://theconversation.com/cities-can-help-migrating-birds-on-their-way-by-planting-more-trees-and-turning-lights-off-at-night-152573" target="_blank">The Conversation</a>. </em></p>
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EcoWatch Daily Newsletter
By Trina Hamilton and Winifred Curran
There are many indexes that aim to rank how green cities are. But what does it actually mean for a city to be green or sustainable?
More and more homeowners in Raleigh, NC, have embraced renewable energy like solar power. This popular option allows residents to fuel their homes cleanly and effectively, minimizing their home's environmental footprint while lowering their monthly utility bills. What are the best solar companies in Raleigh, NC? We'll show you the top options, plus provide important information on solar panel systems, federal tax credits, and more.
As cities in the developing world continue to grow, so do their traffic safety concerns. Latin America, for instance, now sees three times as many deaths from traffic crashes as Europe, the vast majority of which occur in cities. Vulnerable road users are particularly at risk: Older pedestrians and cyclists can account for up to 45 percent of pedestrian fatalities and up to 70 percent of cyclist fatalities globally.
Improving developing cities’ traffic safety is a critical task for ensuring that these growing urban centers become safe, equitable places to live. A key part of achieving this safety? Sustainable urban design.
The connection between safety and justice is a major theme of the upcoming World Urban Forum (WUF7), organized by UN-HABITAT, which this year focuses on “urban equity in development—cities for life.” At the event, EMBARQ experts will host a Cities Safer by Design for All networking session. The event will convene key experts and explore ways that urban design can improve safety—and in turn, justice—in developing cities around the world.
At the Intersection of Safety, Justice and Urban Design
Disadvantaged communities are disproportionately impacted by shortsighted urban design choices, whether it’s the poor—who are forced to live on the city’s periphery—or the disabled, who face mobility obstacles every day. Smart urban design principles can improve these citizens’ quality of life while also boosting a city’s overall safety.
For example, implementing urban design principles like transit-oriented development (TOD), which encourage mixed commercial and residential land use, compact layout, access to high-quality mass transport, and pedestrian-friendly streets, is an important step towards creating livable cities for all communities. Cities built in this way provide opportunities for walking, bicycling, and using transport instead of relying on a car—an expense many cannot afford. Furthermore, promoting sustainable urban design components like bike lanes and pedestrian walkways can have significant traffic safety benefits through reducing exposure—such as by preventing the need for vehicle travel altogether—and risk—by limiting vehicle speeds and prioritizing pedestrian and bicyclist safety.
Connecting urban design to safety is a concept that’s still under-utilized by most local officials and even urban planners. But some cities are beginning to emerge as leaders in this space:
Mexico City, Mexico
In order to combat its history of urban sprawl, Mexico City is enhancing its sustainable transport systems and revitalizing public spaces. The newest corridor of the Metrobús bus rapid transit (BRT) system took a complete streets approach, which aims to design streets that account for all road users, providing safe infrastructure for transport, cars, cyclists and pedestrians. One shining example of the transformation along Avenida Eduardo Molina is the city’s decision to change a dangerous and confusing intersection design that forced cars and buses to switch from the right side of the road to the left at the stoplight. EMBARQ research finds that streets with such confusing designs, called counter-flow intersections, have 82 percent more severe and fatal crashes than other streets.
Mexico City has also introduced new “pocket parks” or “parklets,” which repurpose street space previously allotted to cars to create new public spaces for socialization and interaction. These spaces help to calm traffic, reduce street-crossing distances for pedestrians, and provide protected areas for recreation. The city has built five in the last year, and expects to build as many as 150 in the coming years.
Rio de Janeiro, Brazil
As a host to both the 2014 World Cup and the 2016 Olympic Games, Rio de Janeiro is using these mega events as a catalyst to make significant improvements to its design. One of Rio’s flagship projects is the Morar Carioca initiative, which pledges $ 3.76 billion to improve accessibility, health, education, and the environment in the city’s favelas.
Favelas pose an interesting challenge for city officials, as they house the city’s poorest residents and are often cut off from city services. Furthermore, EMBARQ Brazil’s household travel survey revealed that 90 percent of residents travel on foot while inside favelas, yet 70 percent use public transport when outside favelas. In short, proximity to transport is key to ensuring that these residents have access to jobs and opportunities within the city.
With this in mind, Morar Carioca is the one of the first favela improvement initiatives in Rio to emphasize connecting these communities to the city via new BRT lines like the TransCarioca, which will also connect the core of the city to the Olympic Village in 2016. Systems like TransCarioca will provide vital access to jobs and opportunities in the city center and help ensure that favela residents are not cut off from the benefits of urban life.
Bangalore is one of the fastest-growing cities in India, with almost 10 million residents. The majority of this population relies on public transport—most notably bus and metro—for mobility, so it’s imperative that these services meet the needs of all residents. Bangalore, like many Indian cities, is also home to many making a living through the informal economy—such as street vendors and auto-rickshaw drivers—who rely on pedestrian traffic and transit hubs to make their living. While Bangalore’s bus and metro stations are hubs of economic activity, they are also currently hubs of congestion and chaos. Previous attempts to ease congestion and improve safety around these areas have privileged cars over pedestrians and transport users. They’ve also squelched the informal economy, harming the city’s poorest residents.
To reverse this trend, EMBARQ India is working with local authorities to make transport hubs safer for cars, cyclists, and pedestrians while retaining the vitality of the informal economic sector. New station area plans for Bangalore’s Namma Metro prioritize safe access to transport hubs and reorganize public space around these hubs. The redesigned stations promote safer links to other transport modes like auto-rickshaws and buses, provide space for vendors, and improve the quality of the public space and public transit experience for all. With the plans now under development, city officials intend to implement the new station designs over the next two years, improving accessibility and safety in some of the most crowded parts of the city.
Putting Urban Design and Safety on the International Agenda
It’s time to change the narrative about urban design. It’s not about building more roads or luxury apartment complexes; it’s about creating cities that are safer, more livable and healthier for a growing number of residents. As this year’s WUF7 tagline explains, “A safe city is a just and equitable city.”
Discussions at the WUF7 can play an important role in shifting the urban design narrative. While the week-long conference emphasizes civil society participation, the official dialogues will feed into the ongoing discussions of the Open Working Group on Sustainable Development Goals, clarifying issues related to urban prosperity. These include such broad topics as sustainable cities and human settlements, infrastructure, and economic growth. The WUF7 presents an opportunity for organizations from around the world to insert real examples, bring this agenda to life, and explicitly tie equity to the urban development narrative. In short, the WUF7 discussions are a key way of ensuring that safe and equitable cities are a first-level objective of the U.N.’s emerging SDGs, which are set to be released in 2015.
Every minute of every day, new cities are being built and existing cities are constantly evolving. Smart design can help ensure that these cities are built for people—not cars.
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