City lights setting traps for migrating birdsLeave a Comment
Researchers found an increasing density of migratory birds as they get closer to cities due to light pollution, which is increasing with more LED use;
They also found that suburban areas, such as people’s backyards and city parks, ….harbor some of the highest densities of birds in the northeast, potentially increasing their risk of mortality due to domestic cat predation.
19 Jan 2018 University of Delaware read full ScienceDaily article here
A new study has examined how light pollution lures birds into urban areas during fall migration, a trend that poses risk for the fowl that often fly into buildings and has increased with the addition of brighter LED lights. The researchers were interested in seeing what factors shape the birds’ distributions and why they occur in certain areas.
We found an increasing density of birds the closer you get to these cities. The effect goes out about 200 kilometers [about 125 miles]. We estimate that these flying birds can see a city on the horizon up to several hundred kilometers away. Essentially, there is no place in the northeastern United States where they can’t see the sky glow of a city.”
…The researchers also found that suburban areas, such as people’s backyards and city parks, such as Fairmount Park in Philadelphia, harbor some of the highest densities of birds in the northeast.
…”Domestic cats could be the largest anthropogenic source of mortality for birds. If birds are being drawn into these heavily developed areas, it may be increasing their risk of mortality from anthropogenic sources and it may also be that the resources in those habitats are going to be depleted much faster because of competition with other birds.”
Another concern: light pollution created in these cities has been increasing in recent years with the advent of LED lights, which are much brighter than the incandescent lights they replaced. “The transition of street lighting from incandescent to LED continues to increase the amount of light pollution”….
James D. McLaren, Jeffrey J. Buler, Tim Schreckengost, Jaclyn A. Smolinsky, Matthew Boone, E. Emiel van Loon, Deanna K. Dawson, Eric L. Walters. Artificial light at night confounds broad-scale habitat use by migrating birds. Ecology Letters, 2018; DOI: 10.1111/ele.12902