Year in review: The post-pigeon century

Buildings, cars and cats take toll on birds

eastern meadowlark

GOOD NEWS, BAD NEWS  While eastern meadowlarks remain too abundant to classify as threatened, the population of the birds has decreased by about three percent per year since 1968, a 2014 report found.

Alastair Rae/Wikimedia Commons  (CC BY-SA 2.0)

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News of bird troubles received an eerie emphasis in 2014 when biologists marked the 100th anniversary of the death of the last known passenger pigeon.

For the occasion, the slim, coffee-and-cream-colored taxidermy mount of that final pigeon, named Martha, came out of storage at the National Museum of Natural History in Washington, D.C. (SN: 8/23/14, p. 28). Visitors puzzled anew at how a species once numbering several billion birds vanished in decades.

Readers of the 2014 State of the Birds report from government and private sources may wonder about perils to today’s abundant birds. Among the report’s somber assessments is a list of 33 “common birds in steep decline” (SN: 11/1/14, p. 4). Common grackles, eastern meadowlarks and northern bobwhites, among others, are still too abundant to classify as threatened. Yet each has lost more than half its population during the last 40 years.

“I am more concerned than ever about our state of the birds,” says Peter Marra of the Smithsonian Migratory Bird Center in Washington, D.C. “I think we need to move faster than ever to understand the declines and to try and stop them.”

Today’s biggest threat to birds is habitat loss, the report says. Papers by Marra and collaborators also calculated the tolls of more direct — and possibly more controllable — ways that humankind causes bird deaths.

Between 365 million and 988 million birds in the United States each year die crashing into windows and buildings, Marra and colleagues estimated (SN: 3/22/14, p. 8). Other bird killers include automobiles, smashing up to 200 million birds annually, and wind turbines, taking an estimated 234,000. Not even buildings, however, approached the death toll for birds caught by cats, estimated by Marra and colleagues at 1.3 billion to 4.0 billion (SN: 2/23/13, p. 14).

Estimates of birds killed in U.S. each year
IN DANGER Although habitat loss is the top killer of birds in the United States, other human-related sources — and cats — also cause billions of bird deaths annually. Source: State of the Birds Report 2014

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.