Trouble In Paradise: Songbirds Divorce, Fail To Reproduce In Face Of Suburban Development


The travails of development are hitting the birds hard. According to a new study, songbirds profound in urban areas are on the run, as the spread and developmental expansion of suburbs are leading to their loss of habitats, partners, and reproductive rates.

When forced to pack up, the songbirds lose mates, privacy, and habitat required for successful reproduction. In the relocation process, its life goes in complete disarray in terms of finding a place and mate.

As suburbs develop, birds that live at the tether end of urban sprawls are the worst hit. After being forced out of the urban centers, they have to find new places to build nests, breed, and raise progeny.

The new research published in PLOS ONE highlights the problems faced by a group of songbirds known as "avoiders."

Plight Of Avoider Birds

Forced out of their territory, the "avoiders" divorce mates and undergo hard times with new mates and many other hurdles cropping up in the matter of reproducing successfully, even after relocating.

"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," said lead author John Marzluff, wildlife science professor at the University of Washington's School of Environmental and Forest Sciences.

As for specific examples, Pacific wren and Swainson's thrush are the two avoiders found in the Pacific Northwest. They are shy of humans and seek ground cover and fallen trees, shrubs, and ferns for breeding.

They are worst hit, and when forced out, avoiders fail to reproduce for at least one year after the relocation.

In short, it means losing a home and transiting to a new home take away half of the bird's breeding years.

 "To conserve some of these rarer species in an increasingly urban planet is going to require more knowledge of how birds disperse. I expect that as we look more closely, we will find birds that are compromised because of us," Marzluff added.

The study also highlighted another group of songbirds known as "adapters" or "exploiters." They are not uncomfortable with human presence. The species covers song sparrow, dark-eyed junco, and Bewick's wren.

These birds living in backyards and birdhouses are not negatively hit in the matter of reproduction from the waves of urban development as compared to avoiders.

The study has been noted for its exhaustive data collection, spread over 10 years, with birds being tracked in landscapes such as developed suburban neighborhoods, forested preserves, and neighborhoods converted from forest to subdivisions.

Arctic Warming Hits Birds

Meanwhile, the vulnerability of northern birds in a warming climate has been unveiled in a new study published in the journal Ecological Applications.

It urges conservationists to pay added attention to northern species affected by global changes.

The study was put together by researchers from the United States and Finland. They identified various species of birds breeding in subarctic and Arctic regions and the effects of climate change on them.

"By carrying out this type of analysis, we have been able to predict what species are most at risk and why," said ecologist Anouschka Hof.

The study tracked the breeding behaviors and habitat characteristics of 180 species and assessed how rising temperatures and shifting vegetation types affect their behaviors. The researchers used climate forecast models in the study.

The study said key characteristics of bird species threatened gravely by climate change are those with skewed geographical distribution, niche habitat requirements, and limited reproduction.

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