The Bald Eagle (Haliaeetus leucocephalus) is a rare example of a species humans managed to pull back from the brink of extinction by getting off our collective asses and doing some stuff.
Already decimated by hunting and habitat loss, the post WWII enthusiasm for spraying the chemical DDT on just about everything sent Bald Eagle populations into freefall. That is, until Rachel Carson published Silent Spring in 1962 and sensibly said, “Hey, maybe we shouldn’t go through pesticides like beer at a frat party. Maybe let’s use as little as needed?” We’re paraphrasing, of course, but, eventually, DDT was banned in the US, the Bald Eagle was placed on the Endangered Species list, and our national bird was on the road to recovery.
This is the story told about Bald Eagles and DDT. But a few out there question this narrative, claiming that DDT wasn’t a big problem for eagles and that banning it caused billions of unnecessary deaths because it prevented DDT’s continued use in the fight against malaria.
These claims are mostly nonsense, drudged up by folks who hate regulations, but looking into them makes for an interesting ride. Join the guys as they find out…DUN DUN DUN…what THEY don’t want you to know about Bald Eagles.
This episode was recorded on May 16, 2023 at the Hampton Brook Woods Wildlife Management Area in Hamburg, NY.
Episode Notes
Steve mentioned that the Osprey has the same specific epithet as the Bald Eagle’s generic name, and it turns out that he’s 99% correct. The Osprey’s scientific name is Pandion haliaetus (Pandion was a king of Athens in Greek mythology), and the Bald Eagle’s is Haliaeetus leucocephalus. Every source we could find points to the etymology of both “haliaeetus” and “haliaetus” as “sea eagle”. For some reason that we could not discover, the “Haliaeetus” in the Bald Eagle’s name has an additional “e”. We want to know why! If you can figure it out and provide solid sources, let us know and we’ll send you a Field Guides sticker.
Bill wondered if he was correct when he referred to the first part of a scientific name as the “generic epithet”. Steve said he said he usually refers to it as the “general epithet”. But according to the California Academy of Sciences: “A scientific name consists of two words: the generic name and the specific epithet. The generic name is the genus to which the species belongs, and the specific epithet refers to the species within that genus. For example, in the name Homo sapiens, Homo is the genus and sapiens is the specific epithet.” So, if we want to be precise, both Bill and Steve were partly wrong.
Steve asked if Rachel Carson was a scientist. She was. She had a master’s degree in Zoology and was a marine biologist with the U.S. Bureau of Fisheries.
Steve wondered if there are any bird species with ranges restricted to the lower 48 US States. Bill could not find any, but, while searching, he did find a brief but fascinating article about bird species endemic to the lower 48. Here’s a brief excerpt:
In the United States, the continental Lower 48 states encompass ~3 million square miles, and host 15 fully endemic bird species out of the ~560 regularly-occurring residents or breeders.
A review of US endemics reveals some interesting facts. Four (4) members of the corvid (crows and jays) family are endemic, of which 3 are also endemic to the state in which they reside. The sparrow and finch families each have 3 endemics, while the grouse family has 2. Blackbirds (Icteridae), woodpeckers, and chickadees have 1 each. More than half of the endemics (8 of them), can be found in Florida.
Links
The Story of Benjamin Franklin, the Bald Eagle, and the Turkey
A great comparison of Bald Eagles and Golden Eagles, courtesy of the Cornell Lab of Ornithology
Video of DDT spraying in San Antonio, TX in 1946
Steve mentioned a book about how birds got their names, but he was confused. He was thinking of How Plants Got Their Names by L.H. Bailey. In our search for the bird name book, however, we did find Birds: What's in a Name?: from Accipiter to Zoothera, The Origin of Bird Names, which we immediately added to our Amazon wish list.
DDT, Eggshells, and Me by Ronald Bailey at Reason.com, an article that provided a valuable overview of eggshell thinning research.
Skeptoid Podcast #230: DDT: Secret Life of a Pesticide
A general fact check on the Skeptoid episode, including links to more thorough, point-by-point fact checks, such as the ScienceBlogs fact check of the Skeptoid episode Part One and Part Two
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Photo Credit
This month’s Bald Eagle photo is courtesy of friend of the podcast/wildlife photographer Dan Mlodozeniec. Check out his work on Instagram. Also, check out our Snowy Owl episode that Dan co-hosted!
Our Sponsors
Always Wandering Art - Thank you to Always Wandering Art for last month’s episode artwork and for the artwork for many other episodes, as well!
Works Cited
Bailey, R. (2004) DDT, Eggshells, and Me. Available at: https://reason.com/2004/01/07/ddt-eggshells-and-me/ (Accessed: 12 April 2023).
Bitman, J., Cecil, H.C., Harris, S.J. and Fries, G.F., 1969. DDT induces a decrease in eggshell calcium. Nature, 224, pp.44-46.
Friederici, Peter. (2012) Is DDT Here to Stay? Available at: https://www.audubon.org/magazine/may-june-2012/is-ddt-here-stay (Accessed: 12 April 2023).
Hickey, J.J. and Anderson, D.W., 1968. Chlorinated hydrocarbons and eggshell changes in raptorial and fish-eating birds. Science, 162(3850), pp.271-273.
Lincer, J.L., 1975. DDE-induced eggshell-thinning in the American kestrel: a comparison of the field situation and laboratory results. Journal of Applied Ecology, pp.781-793.
Ratcliffe, D.A., 1967. Decrease in eggshell weight in certain birds of prey. Nature, 215(5097), pp.208-210.
Souder, W., 2012. Silent Spring didn't condemn millions to death. Available at: https://www.newscientist.com/article/dn22245-silent-spring-didnt-condemn-millions-to-death/ (Accessed: 21 April 2023).
US Fish and Wildlife Service, 2020. Final report: Bald eagle population size: 2020 update. Division of Migratory Bird Management, US Fish and Wildlife Service, Washington, DC.