Justification of Red List Category
After the removal of all surviving birds into captivity in 1987, an intensive conservation programme involving reintroduction and release of captive-bred birds has led to a very small but increasing population of this species in the wild. However, the population in the wild remains dependent on intensive conservation management efforts. The species consequently qualifies as Critically Endangered.
There are currently 106 adults in the wild that are old enough to breed, and 44 have produced viable offspring (J. Grantham in litt. 2010). Since mature individuals (as defined by IUCN) only includes individuals in the wild that are currently capable of reproduction, and re-introduced individuals must have produced viable offspring before they are counted as mature individuals, the current global population sensu IUCN is 44 mature individuals. The wild population currently numbers 231 individuals in total (California Condor Recovery Program 2012).
Wilbur (1978) states that the vulture population during the period 1920-1950 numbered more than 70 birds. Today, owing to an intensive captive-breeding and reintroduction programme, the world population comprises 446 individuals and is continuing to increase (Vulture Specialist Group 2017). However, this should be treated with caution as there are indications that without treatment for lead poisoning, mortality rates in the wild may exceed sustainable levels (Finkelstein et al. 2012). Despite the threat of lead poisoning, 2015 was the first year in which the number of successful fledglings was greater than the number of individuals that died in the wild (Silber 2016).
This species declined rapidly throughout its historic range from British Columbia to Baja California during the 19th century and reportedly disappeared from outside California, U.S.A., in 1937 (Wilbur and Kiff 1980, L. Kiff in litt. 2009). The population had dropped to an all-time low of just 22 birds by 1981, and in 1983 eggs were first taken from wild nests for captive-rearing; in 1987 the species became extinct in the wild when the last of the six wild individuals was captured to join a captive-breeding recovery programme involving 27 birds (Wilbur and Kiff 1980, Toops 2009). Due to intensive captive breeding efforts the population increased to 223 birds by August 2003, comprising 138 in captivity, and 85 reintroduced in California and northern Arizona (L. Kiff in litt. 2003). Breeding in the wild resumed in 2002, and by February 2009 56 nesting attempts had been recorded, from which at least 19 chicks have fledged and survived (L. Kiff in litt. 2009). In December 2003, birds were released at the Pinnacles National Monument in California, where one pair were observed raising chicks in 2009 (Moir 2009). Releases in New Mexico have been abandoned due to lack of funding, and release priorities have shifted to identifying sites and partnerships in southern Sierra Nevada, California (Chu et al. 2003). The regular movements of the Arizona birds are confined to Coconnino County (Arizona) and Kane County (Utah), although one individual wandered north to Flaming Gorge (Wyoming) and localities in Colorado before returning to the Grand Canyon area. The California birds occur regularly in San Bernardino, Los Angeles, Ventura, Kern, Santa Barbara, San Luis Obispo, Monterrey, San Benito, and probably Santa Cruz counties. By December 2006, there were 130 wild birds at five release sites (L. Kiff in litt. 2006, Graham 2006), including at least 44 that were over six years old, the earliest age at which the species breeds (L. Kiff in litt. 2005), and in February 2012, the total population stood at 173 individuals in captivity and 213 in the wild, primarily in southern and central California (Carpentier 2009, C. N. Parish in litt. 2012). In January 2010, the number of released birds that had produced viable offspring stood at 44, with another 60 birds of breeding age (J. Grantham in litt. 2010). By 2017, the total population has increased to 446 birds (Vulture Specialist Group 2017). The Arizona/Utah population now numbers 78 birds, with four birds released in 2017 and another 10 earmarked for release in 2018 (Vulture Specialist Group 2017).
The reintroduction programme continues and has expanded its geographic coverage, with six birds released into the Sierra de San Pedro Martir in Baja California, Mexico in 2002 (USFWS 2002). A release site in Baja was established in October 2003. The first chick born in Mexico for over 75 years hatched in April 2007. The Baja California birds are largely confined to the Sierra de San Pedro Martir (L. Kiff in litt. 2006), where efforts are ongoing to increase the population to an anticipated carrying capacity of c.20 pairs (Wallace 2005). It is hoped these birds will range widely enough to be effectively connected with birds in the southern U.S.A., and a bird from the Baja population was seen in San Diego County in April 2007. 2015 was an important year for the species in terms of its recovery in the wild as it was the first year when the number of individuals that died in the wild was less than the number of juveniles that fledged (Silber 2016). Second generation birds have recently matured to breeding age, but no population can be deemed sustainable, and without substantial reductions in the use of lead-based ammunition within the condor's range none are likely to become so (Finkelstein et al. 2012). The recovery programme for the species continues to address threats to the wild population, but lead contamination remains the greatest of these threats (C. Battistone in litt. 2016).
Its range includes rocky, open-country scrubland, coniferous forest and oak savanna. Cliffs, rocky outcrops or large trees are used as nest sites (USFWS 1996). It scavenges on the carcasses of large mammals and also feeds on the carcasses of small mammals, but perhaps only where there are sufficient numbers at one site (L. Kiff in litt. 2009). Released birds have become increasingly independent in finding food and may range more than 400 km from release sites (Anon. 1998), though the distance an individual ranges can vary depending on season and individuals released at different sites have shown significantly different home range sizes (Rivers et al. 2014), suggesting local ecological factors may play a role.
The drastic population decline during the 20th century is principally attributed to persecution and accidental ingestion of fragments from lead bullets and lead shot from carcasses (C. N. Parish in litt. 2012), resulting in lead poisoning. Lead poisoning remains a key threat for released birds (Kelly et al. 2014) and has caused many fatalities and resulted in the treatment of many more birds (Anon. 2001, Parish et al. 2007, Walters et al. 2010); 9 of 13 birds released at the Pinnacles National Monument in California had to be recaptured and tested for lead poisoning after feasting on a field of squirrel carcasses shot by hunters using lead-shot in 2006. It is particularly prone to the threat of lead-poisoning owing to its longevity and delayed-onset breeding strategy, and given the distances it travels to forage, meaning lead can build up in the blood to dangerous levels over many years having been ingested over a broad area (Hunt et al. 2007). Shooting and accidental poisoning continue to be the principal threats to condors and at current levels threaten the long-term sustainability of reintroduced populations (Cade 2007), but lead ammunition is being banned within the species's range in California and there are increasing indications that the federal government will gradually phase out the use of lead across the U.S. Despite efforts to reduce the threat of lead-poisoning, it is reported that over 90% of condors released in Arizona still test positive for lead (Toops 2009) and in January 2010 three birds were found to have died from lead-poisoning in northern Arizona. A study conducted in California, using samples collected in 2004-2009, suggests that around one third of condors in the region are experiencing toxicological effects from lead ammunition (Finkelstein et al. 2012). A study using samples collected between 1997 and 2011 showed that blood lead concentrations increased as birds became less reliant on provisioned food, as they became older and as their home range size increased (Kelly et al. 2014). In 2017, 69 of the 78 birds in the Arizona/Utah population showed high levels of lead exposure; despite a treatment, two individuals died from severe lead-poisoning (Vulture Specialist Group 2017). In preparation of a potential release at new sites in northern California, a study found that Common Ravens Corvus corax and Turkey Vultures Cathartes aura in the region still suffered from high lead contamination (West et al. 2017). Publicity and awareness raising campaigns appear to have successfully reduced persecution.
The population along the Central Pacific Californian coast also suffers from reduced eggshell thickness, consistent with the effects of the breakdown compounds of the pesticide DDT, compromising reproduction in the wild (Burnett et al. 2013). Apparently restricted to this population, it is thought that this is linked to feeding on the carcasses of predatory marine mammals that had been exposed to the pesticide from a specific point source during their lifetimes (Burnett et al. 2013, Kurle et al. 2016). The lack of additional DDT inputs suggests that these effects will decrease over time, though at present this is a further significant impediment to sustainable wild reproduction in this population. Ingested anthropogenic material was recently responsible for the deaths of two nestlings and strongly implicated in a number of other deaths. The dead condors were found to have swallowed glass fragments, wire, plastic cartridge cases, etc. (Mee et al. 2007). Two birds were shot in California in 2009. Both were alive as of April 2009, both being treated for lead poisoning (Anon. 2009). Puppet-reared birds may be more prone to exhibit problematic human-oriented behaviour such as tameness and vandalising property than parent-reared birds (Meretsky et al. 2000). However, there is no apparent difference in mortality between released birds that were puppet-reared and those which were parent-reared (Woods et al. 2007). In the early 1990s a number of captive-reared birds were lost owing to collisions with power-lines, but this behavioural problem has been addressed using a conditioning programme with fake power poles (L. Kiff in litt. 2005). The spread of west Nile virus is not anticipated to be a problem for the species as most birds are vaccinated (L. Kiff in litt. 2005). Overall survival of released birds has been high, although without the capture, treatment and re-release of lead contaminated birds it is likely that rates of mortality in the wild still exceed sustainable levels (Walters et al. 2010, L. Kiff in litt. 2009).
Conservation Actions Underway
CITES Appendix I and II. A large-scale, integrated captive-breeding and reintroduction programme, managed by the Peregrine Fund (at the World Center for Birds of Prey), Los Angeles Zoo, Oregon Zoo and San Diego Wild Animal Park is preventing extinction in the wild. The success of the scheme has seen an increase from one chick hatched in 1988 to an annual hatch of 25-30 birds in recent years (Wallace 2004). The genetic diversity of the population has been maintained through careful distribution and representation of founder genotypes at each captive-breeding facility and reintroduction site. Consequently the current population retains 99.5% of the likely heterozygosity of a wild panmictic population (Ralls and Ballou 2004). Aversion training to avoid powerlines and humans is practised (USFWS 1996). A total of 154 condors were released into the wild between 1992 and 2003 (Wallace 2004). Clean carcasses are provided for reintroduced birds to help prevent lead-poisoning, and community education programmes aim to minimise persecution (Wilbur and Kiff 1980, Anon. 1998). However, as the recovery of the species has continued, individuals are now ranging further than before and are less likely to take the food provided for them (Bakker et al. 2017). A huge step has been taken towards eliminating the threat of lead-poisoning with the signing in 2007 of the Ridley-Tree Condor Preservation Act, which requires the use of non-lead ammunition within the species's range in California and was implemented in 2008. As of February 2009, 99% of hunters were compliant with the act. The Arizona Game and Fish Department is now distributing safer lead-substitute bullets free of charge to hunters within the foraging range of the condors; similar programmes are being initiated in California (L. Kiff in litt. 2005) and Utah. Public awareness and engagement are continuing to increase, working toward the elimination of lead ammunition and the removal of lead-tainted carcasses from the field (Vulture Specialist Group 2017). By 2019, a California-wide ban of lead ammunition is scheduled to go into effect (West et al. 2017). Publicity measures include a website and near-weekly condor articles in local newspapers (D. Cooper and J. Grantham in litt. 2003). In 2008 an agreement was struck between the Tejon Ranch and five conservation organisations to preserve 240,000 acres of the 270,000 acre property as an open space in return for not opposing the development of the remaining land, providing a vast amount of foraging habitat for the condor (L. Kiff in litt. 2009). Legislation coming into force in early 2010 made it illegal for persons to enter a U.S. national park with a loaded firearm (Toops 2009).
Conservation Actions Proposed
Continue to monitor population trends. Continue the recovery plan to achieve two disjunct, self-sustaining populations of 150 individuals comprising 15 breeding pairs. Identify further potential release sites in southern New Mexico (Wilbur and Kiff 1980, USFWS 1996, Anon. 1998). Resume release programme in Mexico and establish new release sites in northern California. Maintain and increase the productivity of the captive population. Continue releases of captive-bred birds. Maintain suitable habitat (USFWS 1996, Anon. 1998). Continue supplemental feeding (Walters et al. 2010). Continue and expand information and education programmes (USFWS 1996, Anon. 1998, Walters et al. 2010). Continue supplying alternative lead-free ammunition to deer hunters. Advocate strongly for a ban on lead ammunition and lobby the Fish and Game Commission to ensure legislation is passed. Encourage the USFWS to promote the elimination of lead ammunition on land administered by other government agencies. Promote parent rearing of offspring (Walters et al. 2010).
117-134 cm. Huge and unmistakable. Black with white wing-linings and silvery panel on upper secondaries. Head naked and orange/red. Immatures with black head and underwing mottled dark. Soars on horizontal wings with primaries curled up. Hints Only likely to be seen near reintroduction sites, but expanding in range, occasionally 70-100 miles from release sites as observed in northern Arizona and southern Utah.
Text account compilers
Khwaja, N., Martin, R., Sharpe, C.J., Symes, A., Taylor, J., Temple, H., Wege, D., Westrip, J., Bird, J., Butchart, S., Ashpole, J, Benstead, P., Calvert, R., Harding, M., Hermes, C., Isherwood, I.
Grantham, J., Palmer, B., Cooper, D., Kiff, L., Battistone, C., Toone, W., Parish, C.
BirdLife International (2019) Species factsheet: Gymnogyps californianus. Downloaded from http://www.birdlife.org on 14/11/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 14/11/2019.