Audubon Christmas Bird Count issue: Eagles did not prosper during the ‘time of DDT’

August 26, 2015

Still photo captured from the film,

Still photo captured from the film, “Christmas Bird Count,” by Chan Robbins; photo shows a group counting birds, probably in the 1940s or 1950s. Audubon’s Christmas Bird Count got its start in 1900.

In the notoriously wrong and misleading “100 things you should know about DDT” posted by pro-DDT, anti-wildlife Steven Milloy of “Competitive Enterprise Institute” and Fox News fame, based on the foggy rant of Dr. Gordon Edwards, we get these two misleading claims:

69. After 15 years of heavy and widespread usage of DDT, Audubon Society ornithologists counted 25 percent more eagles per observer in 1960 than during the pre-DDT 1941 bird census. [Marvin, PH. 1964 Birds on the rise. Bull Entomol Soc Amer 10(3):184-186; Wurster, CF. 1969 Congressional Record S4599, May 5, 1969; Anon. 1942. The 42nd Annual Christmas Bird Census. Audubon Magazine 44:1-75 (Jan/Feb 1942; Cruickshank, AD (Editor). 1961. The 61st Annual Christmas Bird Census. Audubon Field Notes 15(2):84-300; White-Stevens, R.. 1972. Statistical analyses of Audubon Christmas Bird censuses. Letter to New York Times, August 15, 1972]

99. The Audubon Society’s annual bird census in 1960 reported that at least 26 kinds of birds became more numerous during 1941 – 1960. [See Anon. 1942. The 42nd annual Christmas bird census.” Audubon Magazine 44;1-75 (Jan/Feb 1942), and Cruicjshank, AD (editor) 1961. The 61st annual Christmas bird census. Audubon Field Notes 15(2); 84-300]

100. Statistical analysis of the Audubon data bore out the perceived increases. [White-Stevens, R. 1972. Statistical analyses of Audubon Christmas bird censuses. Letter to New York Times, August 15, 1972]

Those claims are false with regard to bald eagles.

The careful citations offered by Milloy and Edwards simply do not exist; if the source exists, the source does not say what is claimed by these guys.  (Don’t take my word for it; go see for yourself.)

Audubon never suggested, in any forum, that their famous Christmas Bird Count had shown increases in eagles. Most other species showed no increases, either. I spent a couple of days at the library of Southern Methodist University reviewing every issue of Audubon Magazine from 1941 through 1974, and found not a single article suggesting anything other than declining eagle populations in the lower 48 states (Alaska eagles were not untouched by DDT, but were not so seriously affected; and as you will see below, the first counts of Alaska’s eagles did not occur until after 1950, so the addition of numbers from Alaska counts do not indicate an increase in U.S. population of eagles.)

I also reviewed each bird count, usually published in a separate booklet with the March issue of Audubon in that time. While raw numbers increased, that was clearly due to increases in people observing. At no point did any ornithologist or Audubon member suggest eagles were in recovery, from 1941 through 1972.

That’s a long explanation, unsuitable for quick discussion on blogs, and wholly too much for a 140-character Tweet. My experience with Milloy and his followers is that they will say my analysis somehow errs, though they cannot offer any real analysis from any other source that isn’t just a misreading of the raw bird count.

I wrote the Audubon Society, and asked them to respond to the claim. At first the press office thought the claims so bizarre that they didn’t think a reply necessary.  I sent them a half-dozen links to other documents that cited Milloy and Edwards.  Delta Willis at Audubon took the claims to officials of the bird count.

Geoff LeBaron, Director of Audubon’s Christmas Bird Count sent the following reply (posted without correction).

See also the footnote from Audubon Chief Scientist Gary Langham appended to the end of the e-mail.

LeBaron, Geoff
Sent: Friday, May 10, 2013 10:21 AM
To: Willis, Delta; Langham, Gary; Dale, Kathy
Subject: RE: DDT and effects on birds, and Audubon Christmas bird count

Hello Delta,

From the 1930s through 1970s there was a tremendous growth in the number of Christmas Bird Counts, from 203 total counts in the 30th CBC to 1320 counts in 80th CBC.  The number of observers on those counts rose from 679 in 30th to 32,322 in the 80th Count.  That is a tremendous increase in effort as well as geographic coverage, and more people in more areas are going to count more Bald Eagles, even if the populations are [were] declining.

A second major factor is that during that period many CBCs were started with the specific goal of censusing wintering Bald Eagles.  Thus we were targeting the areas where eagles were wintering, and thus tallying a much greater percentage of the total population.

Thirdly, there were only two individual CBCs conducted in Alaska prior to the late 1950s.  Bald Eagle populations never suffered dramatically in Alaska [from DDT?], and their numbers were always much higher there.  Since the late 1950s there has been a tremendous growth in the number of counts in Alaska—again, with some of these counts targeting areas where wintering eagles congregate even in the thousands.  These counts added in Alaska can contribute greatly to the total number of Bald Eagles in each season’s CBC.

Thus even while Bald Eagle populations were plummeting in the lower 48 states (outside of Florida) CBC [Citizen Science] efforts were greatly increasing, and in fact targeting monitoring Bald Eagles.  That is why both the raw number of eagles and the numbers when weighted for observer effort went up when you pull CBC data for Bald Eagle during the decades of heavy DDT use.

It’s still educational to look at raptor numbers in CBC data in the years following the banning of the use of DDT in the US.  Many species of raptors show a rapid rebound in numbers after the mid-1970s…and Bald Eagles also dramatically increased.

Per Dr. Gary Langham, Audubon Chief Scientist:   Audubon scientists are careful to include levels of participation and geographic coverage in all analyses. Fortunately, we have tracked both of these aspects since the CBC was started and so it is straightforward to adjust for their impacts.

Bird counts do not show that eagles were out of trouble during DDT years, roughly 1946 through 1972; especially they do not show that bald eagle populations increased.

More:

Explanation of the Christmas Bird Count in four minutes, by Chan Robbins.

Chandler Robbins, founder of the Audubon Christimas Bird Count, screen capture from Audubon film

Chandler Robbins, founder of the Audubon Christimas Bird Count, screen capture from Audubon film “Christmas Bird Count.”

Nota bene: Yes, this has sat in my “to be published” box for too long. It was scheduled for publication, but it appears I had not hit the “publish at scheduled time” button. My apologies to readers, and especially to Audubon’s scientists and press people.


Red-breasted sapsucker in Yosemite

May 6, 2015

I really like this close-up of a woodpecker; from Twitter.

Wonder how long birds live? Red-breasted sapsuckers can live at least 7 years! Photo by Ann & Rob Simpson #Yosemite

Wonder how long birds live? Red-breasted sapsuckers can live at least 7 years! Photo by Ann & Rob Simpson #Yosemite


Snow Friday

February 27, 2015

It was clear this morning, but the snow started just before 9. It’s predicted to warm up enough that the stuff from the skies will be wet, but the ground will be stay frozen. Ice storm.

Businesses and schools shut down about noon.

Two male house finches, probably in their first year, try to eat enough to stay warm on a snowy day in Dallas. Photo by Ed Darrell

Two male house finches, probably in their first year, try to eat enough to stay warm on a snowy day in Dallas. Photo by Ed Darrell

Something about snow makes the birds hungry.  A tube feeder we filled last night emptied by noon.

At home we refill the feeders as best we can.

Rewards are high.  We’ve had six species in the yard at any time, all morning, and at least eight species total.

  • Blue jays

    A sparrow -- a chipping sparrow juvenile? -- acting as scout to find food; it was joined by at least two companions after dusting snow off of seeds in the feeder, and finding them suitable.

    A sparrow — a chipping sparrow juvenile? — acting as scout to find food; it was joined by at least two companions after dusting snow off of seeds in the feeder, and finding them suitable.

  • Cardinals
  • Two species of junco
  • House finches
  • Gold finches
  • White-winged doves
  • A sparrow (juvenile chipping sparrow?)
  • Chickadees
  • Wrens (probably Carolina, but they won’t come close to the house)

It would be nice if our downy woodpecker friends would visit, but they’ve been scarce most of the fall.

Where are the titmice?

As usual, we have some vireo or other (Bell’s, I think), but it knows us well enough to be able to sing to get us excited, but appear only when humans are not looking.

How are things in your yard?

We get the goldfinches in winter, with their winter colors; some of the males may be anticipating spring a bit.

We get the goldfinches in winter, with their winter colors; some of the males may be anticipating spring a bit.

Female cardinal and male house finch await their turn at the small bird feeder.

Female cardinal and male house finch await their turn at the small bird feeder.

 


Vulture surfing crows

September 21, 2014

Frans de Waal posted this on Facebook a while back.

Wouldn’t it be great to be able to join the crows in vulture surfing?  Doesn’t that look like fun?

A crow, surfing on a vulture. Place, time, and photographer unknown to me.  Via Frans de Waal.

A crow, surfing on a vulture. Place, time, and photographer unknown to me. Via Frans de Waal.

You’ll not convince me easily that the crows don’t know what they’re doing, and don’t have loads of fun doing it.


Eye to eye with a black vulture

May 26, 2014

Great photo out of a group at the University of George studying carrion-eating birds.  They capture vultures — black vultures are a current project.

Close up of an eye of a black vulture.  Photo by Megan Winzeler, at a University of Georgia research project.

Close up of an eye of a black vulture. Photo by Megan Winzeler, at a University of Georgia research project. Note the photographer, reflected in the bird’s eye.

This bird has the unromantic name of BLVU202.

“The last thing the old prospector would see . . .”


Night heron in the Ding Darling NWR, by Errickson

May 22, 2014

Love this photo for many reasons.

U. S. Department of Interior on Twitter:  Amazing photo of a night heron in J.N.

U. S. Department of Interior on Twitter: Amazing photo of a night heron in J.N. “Ding” Darling NWR by intern Libby Errickson. @USFWSSoutheast #Florida pic.twitter.com/PA04nE4hhD

Let me count the ways I love it:

  • It’s a great photo, of a beautiful bird — a pose you won’t see often.
  • An intern took it.  Management of our great natural treasures, the Wildlife Refuges, the National Parks, the National Monuments, is flat enough that an intern can get great experience, and spend a lifetime — and score a great picture that the poobahs in Washington like and promote.  It’s a career photo; let’s hope Libby Errickson has (or had) a great internship, and this is just the first of many career photos or studies or whatever.
  • At a time when federal management of public lands is under fire, generally unjustifiably, simply for doing a good job but not having billionaires running their press operations, this is one more small example of something done right, for a long time.  The J. N. “Ding” Darling National Wildlife Refuge is one of the oldest in the U.S.  It was created by Executive Order from President Harry Truman in 1945, and is now one of more than 500 units of National Wildlife Refuges under the management of the U.S. Fish and Wildlife Service, and other federal agencies.
  • Bonus:  Ding Darling was a political cartoonist, and a conservationist.  His pen, in pictures and words, convinced authorities to stop the sale and development of Sanibel Island in the Gulf of Mexico, preserving unique and valuable bird habitat.  This refuge celebrates one of our greatest political cartoonists.  It was renamed from Sanibel to Ding Darling NWR in 1967.  If you ask me, we don’t honor our political cartoonists enough.

More:

Video on the refuge, from the Ding Darling Society:


Annals of DDT: Rachel Carson was right, DDT hurts birds

April 6, 2014

Coming up on World Malaria Day 2014, and U.S. Congressional elections, we’ll start seeing repeated false attacks on Rachel Carson as the right’s most-favored representative of environmentalism, and those attacks will include calls to “end the ban” on DDT to roll back the “increase in malaria caused by the ban. ” Facts are that DDT was never banned in Asia nor Africa (not even under a 2001 anti-pollution treaty); Rachel Carson called for no ban on DDT, but instead urged use of “integrated pest management” (IPM)  to combat disease vectors, and IPM used broadly since 1999 has slashed malaria death totals and infections even more; and malaria deaths and infections started a downward trend in the 1960s that continues today, mostly without DDT.
This is one in an occasional series of posts to correct these hoax claims, with citations to information that readers may check for themselves. Much of this post appeared here earlier, in much longer form.

Rachel Carson was very careful in her 1962 book Silent Spring.  She offered more than 50 pages of citations to science papers and hard research to support what she wrote — a “don’t take my word for it, check it out for yourself” kind of honesty.

Still, today, there is an organized effort with broad success on the internet to smear Rachel Carson and hide the science she wrote about.  Standard from adherents to this insurgent anti-science movement include are claims that Carson’s book was wrong.  The title comes from a prologue of the book in which Carson described a spring in some future year, a spring which was unheralded by the songs and chatterings of birds.  Carson argued that, if humans do not stop to think about secondary effects of chemicals used, especially as pesticides, whole regions might be devoid of birds, dead from DDT poisoning.

Carson cited research from the U.S. Department of Agriculture and the U.S. Fish and Wildlife Service about just how deadly DDT could be to entire ecosystems.  She was particularly alarmed by research done at Midwestern universities, where DDT sprayed to save American elm trees from Dutch elm blight, quickly killed off most birds who came in contact with the stuff.  Dutch elm blight is spread by beetles, the targets of DDT in those sprayings.

In the 1950s, ornithologists, wildlife managers and bird watchers documented the pending demise of entire species of birds, especially raptors at the top of local food chains.  Audubon bird watchers throughout the eastern U.S. noted that migrations consisted of older birds only, with young and maturing birds appearing to have disappeared. Older birds mated, built nests, and laid eggs. Usually the eggs did not hatch, with chicks dying before the end of gestation.  In the few cases where young hatched, they generally died before they could migrate even one year.

Especially for the American bald eagle, this was a great disappointment. Eagles had been plentiful when European colonists migrated to North America, starting after Columbus’s voyages, 1492-1494.  By 1900, however, eagles had been hunted almost to extinction — well, they were extinct in some states.  Colonists, then farmers and ranchers, saw eagles as pests.  They ate fish the colonists wanted to catch for themselves.  Eagles would sometimes take a farmer’s chicken.  Cases of eagles taking larger prey are sparse to non-existent prior to the latter 20th century — but farmers claimed they did.  And so the birds were hunted mercilessly, simply to shoot them.

In 1911 the federal government tried to solve a many-states-wide problem, with a law protecting eagles from hunting.  It did little good.  In 1941 Congress passed a new law, with criminal penalties for people who poached eagles.  The decline of adult numbers slowed dramatically.  But that problem with hatching fledges stopped the recovery, at least so far as young birds who could replace those who died of old age or accidents.

Carson’s critics argue that eagles were never really in decline.  Steven Milloy and Gordon Edwards invented a fantastic tale that the Audubon Society annual Christmas Bird Count actually recorded an increase in eagle numbers, a false claim that Audubon certainly never made, based on a twisted misapplication of bird count methods.  USFWS and others noted the decline of eagles speeding up through the 1950s and 1960s.

Carson’s critics then will say that what plagued eagles was hunting and poaching, and not DDT.  While that was true prior to 1941, that was not the case after World War II when the laws were enforced well.

When studies indicated that DDT would stop birds from successfully breeding, Carson cited them. Her critics claim those studies were in error.

Double-crested cormorant chicks, dead in their nest from DDT-DDE poisoning; nest in the Columbia River estuary, in Oregon. US Fish and Wildlife photo.

Double-crested cormorant chicks, dead in their nest from DDT-DDE poisoning; nest in the Columbia River estuary, in Oregon. U.S. Fish and Wildlife photo. 1999 report.

But they were not.  In fact, not a single study cited by Carson in Silent Spring has ever been refuted by later peer-reviewed research, nor pulled back for any reason.  A decade after Carson’s death, researchers discovered that residual DDT in birds, especially eagles and other raptors, prevented the females from forming competent shells on the eggs they laid.  Even when the DDT doses were not high enough to kill the chicks outright, the shells could not survive the mother’s sitting on them.  The shells broke, and the chicks inside died.

DDT was a scourge to the American bald eagle, the brown pelican, the peregrine falcon, and osprey — and probably many other birds.

Healthy pelican egg on the left, and a DDT-affected pelican egg on the right.  Image from VCE Environmental Science.

Healthy pelican egg on the left, and a DDT-affected pelican egg on the right. Image from VCE Environmental Science.

Discover magazine carried an article about DDT and Carson’s book in November 2007Discover said that, since 1962 when Carson’s book was published, more than 1,000 peer-reviewed publications support Carson’s conclusions, a record remarkable in any branch of science.

In fact, Carson may have underestimated the impact of DDT on birds, says Michael Fry, an avian toxicologist and director of the American Bird Conservancy’s pesticides and birds program. She was not aware that DDT—or rather its metabolite, DDE—causes eggshell thinning because the data were not published until the late 1960s and early 1970s. It was eggshell thinning that devastated fish-eating birds and birds of prey, says Fry, and this effect is well documented in a report (pdf) on DDT published in 2002 by the Department of Health and Human Services’ Agency for Toxic Substances and Disease Registry (ATSDR). The report, which cites over 1,000 references, also describes how DDT and its breakdown products accumulate in the tissues of animals high up on terrestrial and aquatic food chains—a process that induced reproductive and neurological defects in birds and fish.

History also supports the scientists.  President John F. Kennedy tasked the President’s Science Advisory Council to check out Carson’s book, to see whether it was accurate, and whether the government should start down the path of careful study and careful regulation of pesticides as she suggested.  In May 1963 the PSAC reported back that Carson was dead right on every issue, except, maybe for one.  PSAC said Carson wasn’t alarmist enough, that immediate action against pesticides was justified, rather than waiting for later studies or delaying for any other reason. (The full text of the report may be obtained here.)

Rachel Carson was right.  DDT kills birds.  DDT threatened several species with extinction.

Carson’s science citations were verified by a select panel of the nation’s top biologists including entomologists, certified as scientifically accurate.   Since she published, more than 1,000 peer-reviewed studies have been performed that verify her findings on DDT’s harms to birds.

I have never found a contrary study published in any peer-review science journal, based on research.


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