Avian Species at Crisis

"Declines in your common sparrow or other little brown bird may not receive the same attention as historic losses of bald eagles or Sandhill cranes, but they are going to have much more of an impact."
"We're overusing the world, so it's affecting everything."
Hillary Young, conservation biologist, University of California, Santa Barbara

"This approach of combining population abundance estimates across all [bird] species and looking for an overall trend is really unprecedented."
Scott Loss, conservation biologist, Oklahoma State University

"We were stunned by the result -- it's just staggering."
"It's not just these highly threatened birds that we're afraid are going to go on the endangered species list. It's across the board."
"Multiple, independent lines of evidence show a massive reduction in the abundance of birds. We expected to see continuing declines of threatened species. But for the first time, the results also showed pervasive losses among common birds across all habitats, including backyard birds."
Kenneth V. Rosenberg, conservation scientist, Cornell Lab of Ornithology and American Bird Conservancy, Cornell University

Wood thrush. Image by Michael Parr/American Bird Conservancy

Shocking statistics by any metric, leading experts to acknowledge the steep losses of over 500 species of birds, revealed through a new study. Birds whose presence we take for granted because they are so familiar to us, so much a part of our environment -- birds like robins and sparrows are facing an uncertain future -- and with their possible loss, so is humankind. The most important and oft-cited causes of a steep decline in the presence of birds species across North America include habitat loss and the widespread use of pesticides.

The natural ecosystem that we all are so dependent upon faces a dilemma without the presence of birds in their service to the balance of nature by controlling pests, pollinating flowers, spreading seeds and regenerating forest biosystems. Once birds indispensable to the health of an ecosystem disappear, those habitats that were their home will never recover their past health deprived of their presence. Avian populations are seen now to be threatened in a way never before imagined.

David Yarnold, president and chief executive of the National Audubon Society, was moved to characterize the new findings revealed by the study as "a full-blown crisis", based on news that the number of birds living in the United States and Canada has declined by 29 percent since 1970, with 2.9 billion fewer birds on the wing currently, than were present fifty years ago. "This is the loss of nature", added Kevin Gaston, a conservation biologist at University of Exeter.

The study arose out of the collaboration of a team of researchers drawn from universities, government agencies and non-profit organizations, combining old and new methods for counting bird species' presence. Professional ornithologists have for years been given assistance by volunteer, devoted amateur bird-watchers who regularly submit observations to databases, helping to carry out annual surveys of bird populations. The new study took advantage of those surveys to enable the estimate of populations of 529 species between the years 2006 and 2015.

A sparrow appears to be looking on in bewilderment as this goldfinch flies into the window of a vehicle parked in downtown Chatham, Ont.Ellwood Shreve/Chatham Daily News/Postmedia Network

The birdwatching records were utilized in estimation of the population of 76 percent of all bird species in the United States and Canada -- the most common varieties of avian species -- since 1970. Warblers were among the worst-impacted groups, their population declining by 617 million. Blackbirds similarly declined by 440 million. Starlings as well have dwindled in number by 83 million birds, representing a 49 percent decline. And nor is North America only impacted; Europe too is experiencing a similar loss of birds.

The study revealed the steep decline in bird populations without being designed to arrive at a determination that would explain the reason for their decline. Nonetheless reasons are explicable, such as habitat decline where grassland species, suffering the largest declines of any bird species, lost 717 million birds, in all likelihood caused by modern agriculture methodology and development of once-natural landscapes.

All is not entirely gloom. Some positive signs were found, with bald eagles thriving, falcon populations increasing by 33 percent and waterfowl too on the increase. In the last century many recovering bird species were almost exterminated by pesticides, hunting and other pressures. They were enabled to bounce back thanks to conservation measures undertaken at that time. In the current situation, the steep decline is such that halting its further trajectory would require an immense effort where habitats are defended, chemicals restricted, buildings redesigned.

Bird-rich habitats like the Great Lakes and the Colorado River Basin should be protected, according to the Audubon Society, to go a long way in ameliorating the crisis. The Migratory Bird Treaty Act should be fully restored and implemented. People should be convinced to keep their domestic cats within home interiors to provent their ravaging effect on small birds. The numbers of birds that die annually flying into windows could be reduced by measures to make the glass more visible.

A marsh wren wears a bit of cattail fluff near its nest at a slough east of Nanton, Ab.. Mike Drew/Calgary Sun/Postmedia Network

"These data are consistent with what we’re seeing elsewhere with other taxa showing massive declines, including insects and amphibians."
"It’s imperative to address immediate and ongoing threats, both because the domino effects can lead to the decay of ecosystems that humans depend on for our own health and livelihoods, and because people all over the world cherish birds in their own right."
"Can you imagine a world without birdsong?"
Peter Marra, senior scientist emeritus, former head, Smithsonian Migratory Bird Center, current director, Georgetown Environment Initiative, Georgetown University

Baltimore oriole. Image by Gary Mueller/Macaulay Library at Cornell Lab of Ornithology