Monday, December 19, 2016

Inconvenient Data On Bald Eagles

The National Audubon Society's 117th annual Christmas Bird Count is in full swing.

The annual annual "Christmas Bird Count," is mostly an unscientific "bird feeder" bird count done when those birds which are at greatest risk of decline (i.e. neo-tropical migrants including most grassland birds) are actually down south in Mexico, the Caribbean, and Central and South America.

In short, this is the wrong time of year to count birds that are truly at risk!

That said, the 117-years worth of data collected by the "Christmas Bird Count" does have some use, if for no other reason than to prove that one of the biggest fables told about Bald Eagles is more than a small lie.

What's the fable? Simple: that the Bald Eagles was pushed to the edge of extinction by DDT.

Only one problem:  It's not  true. 

In fact, Bald Eagles were pushed to the edge of extinction by bullets and leg hold traps long before DDT showed up on the scene.

The TRUE story here is a common one in American wildlife: as guns became more accurate, cheaper, and more powerful between 1850 and 1900, game laws did not keep up.

The result was a true wildlife massacre.

We not only shot out all of the buffalo that once grazed on the East Coast, we also shot out all the passenger pigeons, Canada geese, beaver, elk, wolves, deer, mountain lions and yes, eagles, osprey and no small number of hawks.

Eagles, osprey and hawks were also decimated by the use of pole traps -- leghold traps set on the top of poles placed around fishing nets and barn yards. Nothing kills hawks and eagles faster, or more efficiently, than a pole trap.

Native Americans did their fair share of shooting eagles too; it takes a lot of feathers to make a bonnet for the tourist trade, and there was no shortage of bonnets being made and shipped east to museums, collectors, and other wealthy patrons.

The graph above (click here to see full-sized graph) shows Bald Eagle populations as tracked by the National Audubon Society's Christmas Bird Count, which has tracked bird populations in the U.S. since 1900.

As you can see, by 1900 -- more than 40 years before DDT was invented -- Bald Eagle populations were vanishingly low. The same is true for Osprey -- another bird unlikely to be misidentified by a dedicated bird watcher.

Ironically, Bald Eagle populations climbed between 1940 and 1970, when DDT was in full use in the U.S.

The reason for this is fairly simple: the Bald Eagle Protection Act of 1940 made it illegal to shoot Bald Eagles. This protection was further expanded when the Endangered Species Act was passed in 1973.

Left to their own devices, and protected from unregulated shooting and trapping, Bald Eagle populations took flight and have now soared. Today, there are about about 8,000 nesting pairs of Bald Eagles in the Lower Forty-Eight, and the Bald Eagle was de-listed from the Endangered Species Act in 2007 (but still protected).

Another American success story. Add that to the rostrum of success we have achieved through a marriage between hunters and conservationists: the return of the white tail deer, moose, elk, cougar, beaver, Canadian geese, wood ducks, and wolves.
To be clear:  I am NOT saying that the ban on DDT was not good for birds (it was!), only that the notion that Bald Eagles were specifically driven off the map by DDT is simply not true, and obscures an important story about the value of the Bald Eagle Protection Act of 1940, and the Endangered Species Act of 1973.

It also says something about the National Audubon Society that they have not told this true story about the history of the Bald Eagle and the Christmas Bird Count.

And why have they not told this story?  

I think it's because most of the folks who work for the National Audubon Society do not know much about birds, data, or science.  

This is an organization, headquartered in Manhattan, that produces a pretty magazine, but that it has lost its way and has wrapped itself in a history that is largely a fabrication.

The simple truth is the National Audubon Society was an obstructionist when it came to Condor recovery, it bungled the protection of Hawk Mountain, and it was not a leader in the push to bad DDT and "save" the Bald Eagle.

In fact, the Bald Eagle was in deep trouble long before DDT was invented, and awareness of the impact of DDT on birds was not raised by the National Audubon Society, but by Rachel Carson in the pages of New Yorker magazine.  

National Audubon Society specifically rejected an opportunity to lead the fight to ban DDT, which was why the Environmental Defense Fund was created.  

As for the reintroduction of Peregrine Falcons, here too the National Audubon Society had no role -- that was done by a relatively small group of fanatical falconers and hawkers who spent weeks and months hacking captive and incubator-raised birds back to the wild.  Audubon and the other big environmental organizations had nothing to do with it.

With little success or leadership to show for in its long history, the National Audubon Society has invented two lies:  that the "citizen science" of the Christmas Bird Count yields important data, and that the organization had a leadership role in protecting the Bald Eagle from the ravages of DDT.

In fact, neither story is true, and ironically it is the Bald Eagle Data collected by the Christmas Bird Count that illuminates how little of the other data is useful, and how little DDT had to do with the decline, and near-loss, of the Bald Eagle.


PipedreamFarm said...

Sampling (who participated in the bird count and where they lived) had no influence on the data plotted?

Lucas Machias said...

They are common here now and you have to wonder what they live on in winter.

They are a very big bird.

PBurns said...

Bald eagles mostly live on fish, same as Osprey. So long as the rivers and ponds do not ice over for very long, they can do OK. They winter over in Alaska in massive numbers, hanging out at canaries and along rivers and creeks where the speed of the water prevent ice-over, and they fish the ocean as well.

Audubon data is adjusted by obserservations per hour of observation, which weights both the number of observers and the duration. I do not think there is a geographic adjustment, but if there were it would go the other way as bald eagles are not commonly found out west far from water (they are a fishing eagle).

Keith Smith said...

What are some good conservation groups? Every group I've ever joined seems to eventually become a waste of time and/or money.

PBurns said...

Trout Unlimited is run by Chris Wood and is worthy of support.

ABC, the American Bird Conservancy does more with less than Audubon.

The Teddy Roosevelt Conservation Partnership is a public-use of public-lands place, that I think does good work. They are a very pro-conservation hook and bullet organization.

Lots of local conservancy groups that may not seem glamorous, but which are critical to real land and riparian protection in your area.

One group that never gets enough credit is the Fish and Wildlife Service and the local Department of Natural Resource folks. Get on their mailing lists, buy them a coffee, and write a letter to the editor reminding everyone that "THIS LAND IS YOUR LAND" and you thank these stewards for taking care of it so well.

Karen Carroll said...

There is a trend of bald eagles being found with high levels of lead in their systems, and dying from it. Two sources: Offal (gut) piles out of field dressed deer left by gun hunters who use lead for deer hunting. The offal has lead fragments that are ingested by the scavenging eagles. Second and I think a larger problem is lead weights in fishing tackle. Arizona hunters are well aware of secondary lead poisoning and have an over 90% compliance with either burying or removing offal piles when hunting. Awareness is out there of this issue.