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What Makes the California Condor a Vulnerable Species?

Source: https://www.flickr.com/photos/39422575@N02/14838390698/in/photolist-oBdCAo-obYEhT-x4U7RM-Vj7dre-ovbZ7Y-otTi94-otFvK9-cP9Zr3-osN1xA-otAcUM-otTw6r-wLDwB1-x4V48H-otTiep-ownRWa-otThtg-oum6UY-otgZiz-ou45BM-Vj6gnr-otFind-ow3FYD-ov8NuT-ovaBPa-otStZb-otkAUp-odoAK6-osN1mo-orSitN-owpeEg-otkK88-ov3Mie-ormAeS-otgVYu-otSvFv-ouzQ1G-otxfMh-vdDWpo-ornCaJ-otjPz6-owaUry-otUsCT-otTsgH-otReTY-otb4XW-ouNmLW-UHRVQq-wSpxv8-oteJ99-ovc2WB

A recent Desert USA article on Cathartes aura, more commonly known as the turkey vulture, made us wonder: Why is it that the noble turkey vulture is so ubiquitous tin North America and especially the southwest deserts, while the iconic California condor (Gymnogyps californicus) has struggled against extinction? Both bird species are Falconiformes, or diurnal birds of prey, and are members of the Cathartidae family of New World vultures and condors. Both breed in the caves and cavities of cliff faces. Both scavenge carcasses.

California Birds: Their Status and Distribution by Arnold SmallUnfortunately, while turkey vultures remain a relatively common sight in California skies, the California condor has experienced population decline such that it even went extinct in the wild in 1987, with a captive population of only 27 adults and eight captive-bred chicks. According to Arnold Small’s California Birds: Their Status and Distribution, “These 35 condors were housed at the Los Angeles Zoo and San Diego Wild Animal Park, as part of the condor recovery program’s captive breeding program, which would eventually result in the releasing of condors back into the wild.”

 

As a result of those efforts, The IUCN Red List of Threatened Species reports a total wild population of 231 individuals as of 2012, which is certainly a success worth celebrating. Nevertheless, the species remains on the list of “critically endangered” species—just a single ranking up from “extinct in the wild.” In fact, their position is so tenuous that in Birds of Prey of the West Field Guide, author Stan Tekiela recommends checking for  a colored wing tag to distinguish between California condors and turkey vultures because, “Every California condor is marked with a numbered, colored wing tag on each wing.”

As with many cases of species decline, the reason behind one species faring more poorly than the other is likely a multifaceted one. For instance, the fact that the turkey vulture inhabits a much wider range than the California condor would be one factor in favor of its survival. While contemporary sources list the California condor as inhabiting only limited areas of the central California Coast and the Grand Canyon region of Arizona and Utah, even their historic range was primarily in the coastal mountains from southern Biritsh Columbia to northern Baja California, compared turkey vulture whose range spans North America.

Factors attributed to the decline of the California condor cited by Small include shooting, lead poisoning from ingested fragments of bullets in scavenged carcasses, habitat encroachment and disturbance, the consumption of baited poison meant for rodents and coyotes, and egg shell thinning from DDT exposure. But according to the “All About Birds” blog at the Cornell Lab of Ornithology, DDT exposure and lead poisoning have similarly affected turkey vultures, and it’s likely the other factors would have, as well.  Yet, the blog goes on to say, “Migrating [turkey vulture] flocks can number in the thousands.”

Source: https://www.flickr.com/photos/internetarchivebookimages/19177546380/in/photolist-vdDWpo-ornCaJ-otjPz6-owaUry-otUsCT-otTsgH-otReTY-otb4XW-ouNmLW-UHRVQq-wSpxv8-oteJ99-ovc2WB-obWGFK-otFuV3-otCbdX-ouScZb-oTH3y8-orys7q-ouRQdo-otF897-orA58b-otAmGv-tAKyW7-otwZf5-otrvjt-x4mc92-otCani-ovCq4c-ovdPgH-ovcM5k-x4Vsst-odpP5K-V4D4C7-wLLg5A-ovDmfZ-otAY7W-GiPZsL-otpu7x-RQVMX9-GiQkBo-otSPhQ-ovDqmz-V7ryyZ-V4DMZm-x3ALuA-otro8w-x4VnCi-otogkb-orpp8YSo is a smaller range the primary distinction between the success rates of these species?  According to the Ventana Wildlife Society, no. Their website details the way a long life-cycle with a slow reproductive rate is a major factor distinguishing the vulnerability of the California condor. “Condors, like any species with this reproductive strategy, cannot withstand persistent high mortality rates.” In fact, in the 1980’s when concern about the species was mounting, mortality rates were so high that the birds were not living long enough to begin their reproductive stage and their lifespan was mis-gauged by more than forty years.

And turkey vultures? They begin to breed at a much younger age and have multiple chicks per nest, compared to the single-chick strategy of condors. Therefore, what we’re looking at is not necessarily lower mortality rates amongst condors, so much as significantly higher reproductive rates amongst vultures.

For more information about condors, vultures, and other North American and southwest birds, visit or call Sunbelt Publications in El Cajon, CA.  We publish, distribute, wholesale, and retail a plethora of guides and texts about Californian and North American Birds, including: