Chemistry research provides scientific understanding that has been and continues to be essential to insuring the California condor’s survival. In this post, I offer a brief look at some of these contributions from chemistry.
Because of concern about the impact of pesticides on birds, scientists with California’s state goverment collect and preserve dead birds. So, in a 1969 book, Eldridge Hunt could report these findings of a chemical analysis:
A California condor killed accidentally had 18 ppm DDT and 80 ppm DDE deposited in its fat.
But Hunt went on to note that the effects on birds of the pesticide DDT and its byproduct DDE were not understood.
Two decades later, researchers had made progress developing that understanding. In the 1986 volume of Current Ornithology, Richard Risebrough wrote:
We can now conclude that the continued use of DDT in North America at the levels applied during the mid-sixties would have caused continuing reproductive impairment of a considerable number of … birds….
It … appears that the California condor would have been the first species to become extinct as a result of DDT use, had the use of this chemical … not ended in time.
An especially important piece of research is described in a 2005 article by Mauricio Dujowich and colleagues in the Journal of Zoo and Wildlife Medicine. These authors provide details about the chemistry of California condor blood with the goal of serving the veterinarians who care for the birds. The article gives the blood concentrations of glucose, sodium, cholesterol, and many other substances in condors of different ages (the concentrations change as the birds mature). With such information, veterinarians can know whether the results of a particular condor’s blood analysis are “normal” or suggest a health problem.
Writing in the journal Endrocrinology in 2015, authors Rachel Felton and colleagues return to the impact of DDT on California condors. DDT is still a concern because DDT dumped into the ocean decades ago continues to find its way into marine animals, some of which wash up onto beaches after they die and are then consumed by condors. So these researchers studied DDT’s potential to chemically disrupt the endocrine (hormonal) system of condors.
The journal Environmental Science and Technology, published by the American Chemical Society, deserves appreciation for all of its publishing on the topic of chemistry and the California condor. This journal has published articles such as:
Ammunition Is the Principal Source of Lead Accumulated by California Condors Re-Introduced to the Wild
Terrestrial Scavenging of Marine Mammals: Cross-Ecosystem Contaminant Transfer and Potential Risks to Endangered California Condors (Gymnogyps californianus)
The journal has also published critical comments about articles and responses to those comments. This formal scientific debate is what leads scientists to better understanding of the world that humans and condors live in.
Further, Environmental Science and Technology has published news items and editorials that inform a (somewhat) broader audience about chemistry and condors:
Condors Are Shot Full of Lead
Lead Ammunition and Illegal Poisoning: Further International Agreements Are Needed to Preserve Vultures and the Crucial Sanitary Service They Provide
Finally, I note that the citations below are evidence of an important change in scientific research that has been occurring during my life time. The first names of the authors of the more recent items include Rachel, Molly, Carolyn, Vicky, and Myra. This change is worth celebrating, as is the work of all scientists engaged in chemistry research concerning the California condor.
Hunt, Eldridge G. 1969. Pesticide residues in fish and wildlife of California.” In Peregrine Falcon Populations: Their Biology and Decline. University of Wisconsin Press.
Risebrough, Robert W. 1986. Pesticides and bird populations. Current Ornithology.
Dujowich, Mauricio, and others. 2005. Hematologic and biochemical reference ranges for captive California condors (Gymnogyps californianus). Journal of Zoo and Wildlife Medicine. December.
Felton, Rachel G, and others. 2015. Identification of California condor estrogen receptors 1 and 2 and their activation by endocrine disrupting chemicals. Endocrinology. December.
Church, Molly E, and others. 2006. Ammunition is the principal source of lead accumulated by California condors re-introduced to the wild. Environmental Science and Technology. October 1.
Saba, Don. 2008. Comment on ‘Ammunition is the principal source of lead accumulated by California condors re-introduced to the wild’. Environmental Science and Technology. March 1.
Church, Molly E, and others. 2008. Response to comment on ‘Ammunition is the principal source of lead accumulated by California condors re-introduced to the wild’. Environmental Science and Technology. January 31.
Kurle, Carolyn M, and others. 2016. Terrestrial scavenging of marine mammals: cross-ecosystem contaminant transfer and potential risks to endangered California condors (Gymnogyps californianus). Environmental Science and Technology. August 8.
Meretsky, Vicky J, and Noel F R Snyder. 2017. Comment on ‘Terrestrial scavenging of marine mammals: cross-ecosystem contaminant transfer and potential risks to endangered California condors (Gymnogyps californianus)’. Environmental Science and Technology. May 2.
Finkelstein, Myra E, and others. 2017. Reply to comment on ‘Terrestrial scavenging of marine mammals: cross-ecosystem contaminant transfer and potential risks to endangered California condors (Gymnogyps californianus)’. Environmental Science & Technology. May 2.
Thacker, Paul D. 2006. Condors are shot full of lead. Environmental Science and Technology. October 1.
Margalida, Antoni, and others. 2013. Lead ammunition and illegal poisoning: further international agreements are needed to preserve vultures and the crucial sanitary service they provide. Environmental Science and Technology. June 4.