Saturday, September 29, 2018

Extinction is Silent, Unless It Chirps

Dodo skeleton and model at Oxford University

[I owe a series of brief research essays over the next year in fulfillment of my Audubon Birding Certificate, sponsored by the good folks at Joppa Flats on Plum Island.  Essay #1 was about food waste and birds.  This essay addresses extinction.  Future topics should be happier.]

The first Dodo was described by a Dutch sailor in 1598.  The last confirmed sighting was in 1662.  It took humankind exactly 64 years to wipe a million-year-old species off the face of the earth.  Likewise, there were five billion Passenger Pigeons in North America two hundred years ago. Audubon himself observed a flock that passed for three days numbering perhaps two billion.  Thanks to hunting and habitat conversion, the last Passenger Pigeon, Martha, died in the Cincinnati Zoo in 1914.[1]

Here’s the extraordinary thing: As good as human beings have been historically at wiping out our fellow species, we are even better at it today.

Our newest technique is the wholesale destruction of biological diversity, an “existential” threat equivalent to a pandemic or meteor strike.  Scientists believe we are well into the earth’s sixth great extinction, this one caused by human consumption.  For example, the Living Planet Index (LPI) measures the state of the world's biological diversity based on population trends of vertebrate, including the health of 3,706 species.  In 2016, the LPI showed a 58% decline between 1970 and 2012 meaning, on average, that animal populations are half the size they were four decades ago.[2]  A 2017 research paper attempts to frame the problem in terms of relative pace.  Almost 200 species of vertebrates (that we can confirm) have gone extinct in the last 100 years.  Measured against the “background” extinction rate prevailing in the last two million years, those 200 species should have taken 10,000 years to disappear.[3]  This pace suggests that the earth could lose 30 percent to 50 percent of all species by 2050.[4]

The Alagoas foliage-gleaner, now extinct. 
Because birds are visible, ubiquitous, and sometimes iconic (like the Dodo), they have become a bellwether for tracking extinction.  Globally, 12 percent of nearly 10,000 species are headed for extinction in our lifetimes while 192 species are at “extremely high risk” of extinction.[5]  In the US, a 2009 report found that 251 species out of 800 are of conservation concern.[6]  Habitat conversion is the single greatest factor, but invasive species, hunting-trapping, and capture by collectors all play a part in this tragedy.  There are, for example, eight birds that are confirmed extinct this decade alone.  Five are in South America and four of those in Brazil—all attributed to deforestation.[7]

Birds that reproduce slowly or sit near the top of the food chain (and can be threatened by everything along the chain, from pesticides to toxic waste to animal vaccines) are at special risk.  The Peregrine Fund released a study earlier this year that measured 557 raptor species, finding that 52 percent have declining global populations and 18 percent are threatened with extinction.[8]

In September 2017, Mass Audubon published its third “State of the Birds” report, showing that 43 percent of 143 species (modeled so far) are projected to be highly vulnerable to global warming. “The results speak to a chaotic near-future for some of our most iconic species, like Black-capped Chickadee, Rose-breasted Grosbeak, and Yellow-bellied Sapsucker,” the report noted. “Many of our coastal nesting species, like Piping Plover and Roseate Tern also show vulnerability to the changing climate.”[9]

Northern Harrier (EBS)
What would a birding trip on Plum Island look like in 2050 if we lose all the species currently listed by the state of Massachusetts as endangered (E), threatened (T), or special concern (S)?[10]  How about: no Barn (S), Long-eared (S), or Short-eared Owls (E).  Warblers?  No Golden-Winged (E), Northern Parula (T), Blackpoll (S), or Mourning (S).  For Sparrows, we’d miss the Grasshopper (T) and Vesper (T).  For Terns, no Common (S), Roseate (E), Arctic (S), or Least (S).  No more Whip-poor-will (S) or Sedge Wren (E).  No Bald Eagle (T), Northern Harrier (T), or Peregrine Falcon (T).  And our 2050 field trip would not be able to find a single Common Loon (S), Pied-billed Grebe (E), Leach’s Storm-petrel (E), American Bittern (E), Least Bittern (E), King Rail (T), Common Moorhen (S), Piping Plover (T), or Upland Sandpiper (E).  Such loss would not only be a tragedy, but could fundamentally alter the State’s ecosystem.

In 1889, Le Grand T. Meyer warned of the imminent extinction of birds.[11]  The Pinnated Grouse[12] and Quail were once common game birds east of the Mississippi, he wrote, and are now nearly extinct in New England and the mid-Atlantic.  The hunting of Geese and Ducks is no longer profitable, the result of greedy “Pot-Hunters.”  Next, Meyer reported on a woman who wore a dress with “patches of three thousand Brazilian Hummingbirds” and another with a hat that included the heads of 21 Quail.  In South Carolina, 3,000 Roseate Terns were killed for a single New York milliner.  So, he said, fashion was also to blame.  Finally, Meyer credited the Amateur Naturalists who indiscriminately slaughtered birds to adorn their “collectors cabinet” as a primary cause of extinction.

Thanks to groups like the Audubon Society, every trend in Meyer’s nineteenth-century avian holocaust has been slowed or reversed.  The founding of Ducks Unlimited in 1937, for example, has resulted in the restoration of more than 13 million acres of wetlands.[13] A visit to the Stage Island Pool on Plum Island to see dozens of Egret hunting—and having to stop the car on the way there to let a flock of Wild Turkey pass—are two indications of the enormous good accomplished by Audubon.  Mass Audubon’s 2017 report suggests that future efforts to rebuild ecosystems and protect biodiversity should be focused on the further creation of science-based models, and on outreach to federal, state, municipal, and public partners.  Press coverage and a robust public conversation are also critical to success.  As environmentalist Paul Hawken wrote, “biological diversity is messy . . . but extinction is silent, and it has no voice other than our own.”

Egrets at Stage Island Pool, 2018 (EBS)

[1] Gerardo Ceballos, Anne H. Ehrlich and Paul R. Ehrlich, The Annihilation of Nature: Human Extinction of Birds and Mammals, Baltimore: John Hopkins University Press, 2015, pp. 31-35.
[2] “Living Planet Index,” 2014, Zoological Society of London and WWF, Web September 27, 2018,
[3][3] Gerardo Ceballos, Paul R. Ehrlich and Rodolfo Dirzo, “Biological Annihilation Via the Ongoing Sixth Mass Extinction Signaled By Vertebrate Population Losses and Declines,” PNAS open access, May 23, 2017, Web September 27, 2018,
[4] “The Extinction Crisis,” Center for Biological Diversity, Web September 27, 2018,
[5] “The Extinction Crisis,” Center for Biological Diversity, Web September 27, 2018,
[6] “The Extinction Crisis,” Center for Biological Diversity, Web September 27, 2018,
[7] Patrick Barkham, “Eight Bird Species are First Confirmed Avian Extinctions This Decade,” The Guardian, September 4, 2018, Web September 27, 2018,
[8] “Astonishing Research Shows More Than Half of the World’s Species of Birds of Prey Have Declining Global Populations,” The Peregrine Fund, September 6, 2018,
[9] “Conservation Science Annual Report, 2017,” Mass Audubon, Web September 28, 2018,
[10] “List of Endangered, Threatened, and Special Concern Species,”, Commonwealth of Massachusetts, 2018, Web September 27, 2018,
[11] Le Grant T. Meyer, “Extinction of Our Birds,” The Ornithologists’ and Oologists’ Semi-Annual, Wilson Bulletin, Volume 1, Issue 1 (January-February) 1889, pp. 28-29.
[12] The Pinnated Grouse is the Greater Prairie Chicken.  Its numbers are still under pressure due to habitat loss.
[13] Gerardo Ceballos, Anne H. Ehrlich and Paul R. Ehrlich, The Annihilation of Nature: Human Extinction of Birds and Mammals, Baltimore: John Hopkins University Press, 2015, p 169.