Insightful study shows how lighting in cities affects the route and survival of migratory birds
Did you know that artificial light attracts migratory birds towards cities and this can be fatal for them? This is according to a study published in Nature Communications by researchers at Colorado State University. Using weather radar data, this study is the largest of its kind and shows that artificial light is a leading indicator of where birds land during their migrations. Surprisingly, light pollution emerged as the second most important predictor of bird roosting density, surpassed only by altitude.
Bird migration is a critical and risky phase in a bird’s life. During their journey, which can extend from hundreds to thousands of kilometers, birds can lose up to half of their body mass. Finding a good place to rest and recharge your batteries is essential to survival. However, cities with their buildings, fewer habitats, food shortages, more people and cats are not the best resting place for birds. Although urban parks can be suitable resting places, birds can face competition for limited resources.
This research provides the first continental maps of migration stopping points in the contiguous United States. Understanding these standstill patterns can help develop conservation plans. While cities pose numerous risks to migratory birds, they also provide them with opportunities to rest and feed.
The study highlights a conservation dilemma: Should urban centers be retained as important stopping points or should they be targeted by lights-off campaigns? Researchers are working with nonprofit and government organizations to answer both questions. Light pollution affects not only birds but also humans, as it disrupts human circadian rhythms and can lead to health problems such as depression, insomnia, cardiovascular disease and cancer.
Tools like BirdCast, a collaborative project between CSU, the Cornell Laboratory of Ornithology and the University of Massachusetts, provide migration forecasts and real-time maps from weather radar data. These systems help identify the most important nights for reducing light pollution. In addition, it is recommended to apply window stickers and reduce the brightness and changing light colors to avoid collisions. Bright white or blue light is the worst for wildlife, while warmer hues like red, orange and yellow are less attractive.
REFERENCES
Artificial light at night is an important indicator of the stopover density of bird migrations in Nature Communications.
