The bright lights of big cities help blackbirds thrive

Cut out for city life?

Arterra/UIG via Getty

By Julianna Photopoulos

Light pollution is a problem for many animals, but at least one bird seems to welcome it. European blackbirds choose to nest near street lights, and appear to thrive as a result.

“This might be because it protects them from predation by species that don’t like it bright at night,” says Anja Russ at the Helmholtz Centre for Environmental Research in Leipzig, Germany.

Her team studied the effects of street lights on the European blackbird (Turdus merula), a forest species that has adapted to city life. “Its breeding attempts in urban areas can be dated back in Germany to almost 200 years ago,” says her colleague, Reinhard Klenke.

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The team found that the city birds laid their eggs almost a week earlier than blackbirds in dark areas such as forests, and were more likely to successfully rear hatchlings.

The results are surprising given that other studies have found that lighting harms wildlife. “We usually think that light at night will have detrimental effects,” says biologist Brett Seymoure at Colorado State University in Fort Collins.

However, it’s not clear whether light really is the key factor, he says. To be sure of this, the team would need to artificially light forest sites and darken urban sites to see how it affects blackbirds.

Deterred by noise

While street lighting may not be all bad, it seems that noise can be as bad for birds as it is for us. A study in Brazil found that noise reduces the richness and diversity of birds in city parks.

“Birds rely on sound for communication and finding prey,” says Vinícius Goulart of the University of Salford in the UK. “Some sensitive species will leave the area even with what we consider as low noise levels.”

Goulart and his colleagues collected data on bird species and both continuous and transient noise pollution in eight green areas in Belo Horizonte, Brazil, between 2009 and 2010.

Their findings come as no surprise. “We think these are good habitats and we conserve them, but in reality some are being inundated with noise that is decreasing their quality for animals living there,” says Rachel Buxton at Colorado State University.

“The number of threatened species is increasing every year — mostly due to human actions — so it is essential to properly mitigate these impacts made by us,” says Goulart.

Journal references: Journal of Avian Biology, DOI: 10.1111/jav.01210; Ibis, DOI: 10.1111/ibi.12481