Urbanization Makes Life ‘Hard’ For Songbirds
New research reveals the downsides of suburban development and its impact on the lives of songbirds.
According to the research, the rise of suburban development has wreaked havoc on the lives of songbirds, making them susceptible to divorce, and missing their best chances for successful reproduction.
John Marzluff, head author of the study and a professor of wildlife science in the University of Washington’s School of Environmental and Forest Sciences, said, “The hidden cost of suburban development for these birds is that we force them to do things that natural selection wouldn’t have them do otherwise.”
Marzluff added, “Because development requires that these birds move, we force them to abandon the places they selected and go elsewhere, which often entails finding new mates when they wouldn’t have otherwise.”
This research was published Dec. 28 in the journal PLOS ONE.
“Avoider” Birds Are Greatly Affected
One of the most affected kinds of birds due to urbanization are what we called the “avoiders.” These birds are affected by urban sprawl, forcing them out of their territory, forcing divorce and hampering their ability to find new mates and reproduce successfully, even after relocating.
Two avoider species are the Pacific wren and Swainson’s thrush, which are known to be generally shy of humans. These birds dwell and reproduce successfully within their native habitat, better than in manicured suburban yards.
The sad thing is, when forced to move, the avoider birds largely failed to reproduce again for at least one year after relocating.
The Study
The intensive study allowed researchers to identify and monitor hundreds of individually marked songbirds from six common species found in Seattle-area suburbs.
For about 10 years, Marzluff and a number of graduate students tracked bird activity in three types of landscapes: forested preserves, already developed suburban neighborhoods and neighborhoods transitioning from forest to subdivision. By placing bands around the birds’ legs and mapping sightings of mated pairs and nest locations, the researchers were able to tell when a bird relocated, broke up from its mate or stayed put year to year.
The result in general yielded negative impacts to the natural activities of the songbirds. The researchers found out that as forested areas increasingly are converted to suburbs, songbirds birds are forced to look for new places to build their nests, breed and raise fledglings.
