Status of the California Condor and mortality factors affecting recovery. (Raptor Conservation).Abstract The California Condor Recovery Program (Program) is moving forward after the release of 116 California condors (Gymnogyps californianus Gymnogyps californianus see condor. ) to southern and central California Central California can refer to one of several divisions or regions of the U.S state of California:
Current status of recovery program In 1987, all remaining wild condors were brought into captivity to prevent their extinction and rebuild the population. By 1992, captive breeding captive breeding mating programs designed for use with animals kept in captivity. See also hand mating. at the Zoological Society of San Diego San Diego (săn dēā`gō), city (1990 pop. 1,110,549), seat of San Diego co., S Calif., on San Diego Bay; inc. 1850. San Diego includes the unincorporated communities of La Jolla and Spring Valley. Coronado is across the bay. and Los Angeles Zoo The Los Angeles Zoo founded in 1966, is a large zoo located in Los Angeles, California, USA. The Zoo, located in Los Angeles' Griffith Park, is home to 1,200 animals from around the world. increased the population to 52 birds and U.S. Fish and Wildlife Service (FWS) began releases of young condors to southern California Southern California, also colloquially known as SoCal, is the southern portion of the U.S. state of California. Centered on the cities of Los Angeles and San Diego, Southern California is home to nearly 24 million people and is the nation's second most populated region, . The Peregrine Fund began captive breeding in 1993 and releases to Arizona in 1996. Ventana Wilderness Society began releases in central California in 1997 to aid the recovery of the species. Captive breeding has brought the total population size to 161 birds as of February 1, 2001 (Jurek personal communication). The California Condor Recovery Program Plan (1996) calls for two geographically separate wild, self-sustaining populations each having 150 individuals, 15 breeding pairs Breeding pair is a pair of animals which cooperate to produce offspring. In contrast to any two copulating animals, the term breeding pair indicates some form of a bond between the individuals. For example, many birds mate for a breeding season or sometimes for life. and a positive rate of growth as well as a third population with 150 individuals in captivity in order to qualify for reclassification Reclassification The process of changing the class of mutual funds once certain requirements have been met. These requirements are generally placed on load mutual funds. Reclassification is not considered to be a taxable event. from endangered to threatened. As of February 1, 2001, 116 different condors have been released at three different geographic locations and despite heavy losses the wild population maintains a fairly evenly distributed age structure (Table 1). A total of 27 condors have been removed to captivity for possible re-release and another 43 birds have died or were presumed dead. A total of 46 condors remain in the wild--24 in California and 22 in Arizona. The oldest members of the reintroduced population are now entering maturity and therefore successful breeding may occur in the near future. In order to attain a self-sustaining population, controllable mortality factors must be identified and reduced. Mortality factors affecting recovery California condors are a long-lived k-selected species with low reproductive rates (Temple and Wallace 1989). Wild condor populations cannot sustain themselves with annual mortality rates exceeding five to 7.5% for adults and 13 to 15% for juveniles (Verner 1978; Meretsky et al. 2000). Up to the early twentieth century, the condor population plummeted due to losses primarily caused by shooting, poisoning, and museum collecting (FWS 1996). Throughout the remaining 1900s the condor continued to decline though the reasons were not entirely clear. Known causes of death in the reintroduced population include: power line collisions/electrocutions, coyote coyote (kī`ōt, kīō`tē) or prairie wolf, small, swift wolf, Canis latrans, native to W North America. It is found in deserts, prairies, open woodlands, and brush country; it is also called brush wolf. (Canis latrans) and golden eagle (Aquila chrysaetos Aquila chrysaetos majestic predator bird of Europe, Asia, North America. Called also golden eagle. ) predation predation Form of food getting in which one animal, the predator, eats an animal of another species, the prey, immediately after killing it or, in some cases, while it is still alive. Most predators are generalists; they eat a variety of prey species. , lead poisoning lead poisoning or plumbism (plŭm`bĭz'əm), intoxication of the system by organic compounds containing lead. , accidental drowning, shooting, ethylene glycol ethylene glycol: see glycol. ethylene glycol Simplest member of the glycol family, also called 1,2-ethanediol (HOCH2CH2OH). It is a colourless, oily liquid with a mild odour and sweet taste. poisoning, aspiration, cancer, and malnutrition (Jurek personal communication). Meretsky et al. 2000 determined that recent annual mortality rates of the reintroduced population are in excess of what is critical to maintain a self-sustaining population. In the following section, we will discuss current mortality factors to shed light on their impact on recovery efforts. Electrocution/collision Power line collisions and electrocutions represented a significant threat to the reintroduced population of condors during the first two years of release efforts. A total of 4 birds were lost to this hazard and the remaining individuals regularly perched on power poles power pole Noun Austral & NZ a pole carrying an overhead power line , which led to their return to captivity (Snyder and Snyder 2000). Beginning with the 1995 release cohort, a negative conditioning program was initiated to train condors from perching on power poles (Wallace personal communication). The results of this training appear to be promising. Prior to aversion training, 31% (four of 13) of the condors released died to collision and or electrocution electrocution Method of execution in which the condemned person is subjected to a heavy charge of electric current. The prisoner is shackled into a wired chair, and electrodes are fastened to the head and one leg so that the current will flow through the body. with power lines, while only 2% (two of 103) died of the same cause after the training was required for all releases. As a result, this threat was greatly reduced. The long-term effectiveness of this training, however, is unknown. Predation Coyotes and golden eagles combined killed eight young or inexperienced reintroduced condors. Although ravens and golden eagles are known threats to condor eggs and nestlings respectively (Snyder 1986), adult mortality from natural causes is virtually unknown (FWS 1996). The high rate of deaths to predation is likely a result of the reintroduced birds not having parental guidance or protection in the wild. Shooting Shooting greatly affected the original wild population since scores of condor deaths were attributed to this factor both done indiscriminately and for the purposes of museum collecting (Wilbur 1978). In the reintroduced population only two condors were shot and killed. While this threat may always loom over the recovery of this species, it does not, by itself, appear to be a significant problem at present. Lead poisoning Lead exposure and acute poisoning was first detected in the original wild population of California condors during the 1980s. Between 1984 and 1986 three condor deaths were attributed to lead poisoning and one bird showed a positive radiograph radiograph /ra·dio·graph/ (-graf?) the film produced by radiography. ra·di·o·graph n. for a bullet fragment in its digestive tract digestive tract n. See alimentary canal. Digestive tract The organs that perform digestion, or changing of food into a form that can be absorbed by the body. (Janssen et al. 1986). Other evidence of the lead threat within the range of the species includes studies on condors (Wiemeyer et al. 1988), turkey vultures (Cathartes aura Cathartes aura see vulture. ) and ravens (Corvus corax) (Wiemeyer et al. 1986b), and golden eagles (Pattee et al. 1990). Condors encounter lead bullet/ pellet fragments in their food supply, although the exact pathways are not well understood. Currently, lead rifle ammunition, in unrecovered carcasses and/or gut piles fed upon by the condor, may be the primary source of contamination. A single ingested in·gest tr.v. in·gest·ed, in·gest·ing, in·gests 1. To take into the body by the mouth for digestion or absorption. See Synonyms at eat. 2. lead fragment can be lethal (Risebrough personal communication). Four confirmed lead poisoning fatalities were documented among all reintroduced birds. To date, many of the reintroduced condors over the age of one year experienced elevated levels of lead in their blood at one time or another. Since 1997, 14 condors were successfully treated for acute lead toxicity using a technique called chelation therapy Chelation Therapy Definition Chelation therapy is an intravenous treatment designed to bind heavy metals in the body in order to treat heavy metal toxicity. . Without this intensive intervention effort, lead poisoning would easily account for the greatest number of deaths. So important is the lead threat resulting from spent ammunition in the condors' food supply that the California Condor Recovery Team is now recommending that FWS reduce lead contamination within condor range (Recovery Team Meeting February 14, 2001). Other causes The original wild population experienced some fatalities from drowning, leg-hold traps, and in one case a collision with a vertical pipe used as a surveyor marker (Koford 1953). No evidence exists to support any of these "other causes" playing a consistent role in the decline of the original wild population (Wilbur 1978). Accidental drowning (2), ethylene glycol poisoning (1), cancer (1), aspiration (1), and malnutrition (1) are each recorded causes of death in the reintroduced population. Although these causes combined may affect current recovery to some extent, individually they do not appear to be significant problems. Unknown causes and disappearances Out of 116 different condors released since the onset of the reintroduction Noun 1. reintroduction - an act of renewed introduction intro, introduction, presentation - formally making a person known to another or to the public program, a total of seven deaths of unknown causes and another 10 disappearances (presumed dead) occurred. These results undermine the ability of the Program to combat limiting factors. Management strategies The authors support strategies to (1) reduce the threat of lead to condors through public education, promotion of viable non-lead ammunition alternatives and enhanced food subsidy efforts, (2) to improve monitoring efforts utilizing aerial and satellite tracking, and (3) to operate facilities in the field for postrelease management. In the long run, measures taken to reduce the availability of lead in the condors' food supply represents the best chance for eventual full recovery. Ventana Wilderness Society supports public awareness efforts to openly discuss the problems of lead poisoning in wildlife, especially within the range of the California condor. Overall, the general public knows little of this problem. The use of viable, non-toxic ammunition should also be encouraged when possible. Non-toxic shotgun ammunition is already commercially available and non-toxic rifle ammunition, called Ultimet, may soon be available (Oltrogge personal communication). Until then, education is an important step that should be expanded. Currently, clean food subsidy is provided at all release sites. In addition, we support placing clean food at specific locations near known nest sites as they are discovered. In response to increasing losses to the reintroduced population and a growing number of unknown deaths and disappearances, Ventana Wilderness Society initiated an intensive (weekly) aerial tracking program for all condors in California beginning in fall of 2000 to augment the ongoing ground tracking effort. The authors also support the use of satellite telemetry telemetry Highly automated communications process by which data are collected from instruments located at remote or inaccessible points and transmitted to receiving equipment for measurement, monitoring, display, and recording. on key individuals, especially those actively feeding on their own to discover sources of lead contamination and other threats. Currently, condors are released both with and without post-release management facilities in the field depending on the release site. The authors support the use of post-release management facilities at condor release sites. Ventana Wilderness Society uses a "double-door," walk-in trap attached to post-release management facilities, that enables field managers to easily capture previously released condors. Routine evaluations of bloodlead levels can be achieved with minimal stress to individual condors and reduced staff effort. By increasing the level of monitoring both in terms of tracking and captures, field crews may be able to further reduce fatalities.
Table 1. California Condor releases, losses, and age structure
in wild (as of February 1, 2001). (a) "Total" includes one bird
(b) relocated to Arizona and therefore was released twice.
Southern Central
California California Arizona Total
No. released 48 22 47 117(a)
No. removed to captivity
or possible re-release 12 7 8 27
No. relocated 0 1(b) 0 1
No. died or presumed dead 26 0 17 43
No. 1-year-olds in wild 0 0 5 5
No. 2-year-olds in wild 1 5 1 7
No. 3-year-olds in wild 0 3 4 7
No. 4-year-olds in wild 2 6 2 10
No. 5-year-olds in wild 0 0 4 4
No. 6-year-olds in wild 7 0 6 13
Total in wild 10 14 22 46
Acknowledgements This manuscript was improved after review from Bruce Palmer
Bruce Palmer (September 9 1946 – October 1 2004) was a Canadian musician most famous for playing bass guitar in the influential folk-rock band Buffalo Springfield. , Dr. Robert Risebrough, Dr. Michael Wallace For individuals known as Mike Wallace, see . Michael Brunson Wallace is an attorney from Jackson, Mississippi. He was a controversial George W. Bush administration nominee to the United States Court of Appeals for the Fifth Circuit. , Salvatore Lucido, Piper Magallanes, and Carla Bundrick. Moose Peterson B. Moose Peterson is a well-known wildlife photographer whose work has been published in over 130 magazines world wide.[1] Moose was one of the first wildlife photographers to embrace digital SLRs, which were once thought unsuitable for wildlife and nature photography is a wildlife photographer dedicated to photographing the life history of California's threatened and endangered wildlife and wildplaces. His work covers all of the western US. He is currently looking to hook up with biologists working with interior grizzly bears grizzly bear or grizzly, large, powerful North American brown bear, characterized by gray-streaked, or grizzled, fur. Grizzlies are 6 to 8 ft (180–250 cm) long, stand 3 1-2 to 4 ft (105–120 cm) at the humped shoulder, and weigh up to and wolverines anywhere in the US/Canada to document the critter's biology and the research work being conducted. If you want incredible images for your project at no cost, contact him! Wildlife Research Photography PO Box 3628 Mammoth Lakes, CA 93546-3628 760-924-8632 www.moose395.net Literature cited California Condor Recovery Team Meeting. February 13-14, 2001. San Diego Wild Animal Park The San Diego Zoo's Wild Animal Park is a zoo in the San Pasqual Valley area of San Diego, California. It is one of the largest tourist attractions in the city and Southern California. , Escondido, California. Janssen, D.L., J.E. Oosterhuis, J.L. Allen, M.P. Anderson, D.G. Kelts, and S.N. Wiemeyer. 1986. Lead poisoning in free-ranging California Condors. J. Amer. Veter. Med. Assoc. 189:1115-1117. Koford, C.B. 1953. The California Condor. National Audubon Society The National Audubon Society is an American non-profit environmental organization dedicated to conservancy. Incorporated in 1905, it is one of the oldest of such organizations in the world. Resource Report No. 4:1-154. Meretsky, Vicky J., Noel F.R. Snyder, Steven R. Beissinger, David A. Clendenen, and James W. Wiley. 2000. Demography demography (dĭmŏg`rəfē), science of human population. Demography represents a fundamental approach to the understanding of human society. of the California Condor: Implications for Reestablishment. Conservation Biology conservation biology n. The branch of biology that deals with the effects of humans on the environment and with the conservation of biological diversity. . 11(1):957-967. Pattee, O.H., Bloom, P.H., Scott, J.M., and M.R. Smith. 1990. Lead hazards within the range of the California Condor. Condor 92:931-937. Snyder, N.F.R. 1986. California Condor recovery program. Pp 56-71 in S.E. Senner, C.M. White and J.R. Parrish, eds. Raptor Reserch Report No. 5: Raptor conservation in the next 50 years. Raptor Research Foundation, Provo, Utah. Snyder, N.F.R. and Helen Snyder. 2000. The California Condor: A saga of Natural History and Conservation. Academic Press. Temple, S.A., and M.P. Wallace. 1989. Raptors in the Modern World. Pp 247-251 in Meyburg, B.U. and R.D. Chancellor, eds. World Working Group Birds of Prey, Pica Press. U.S. Fish and Wildlife Service. 1996. California Condor Recovery Plan. 1996. Third Revision. Portland, Oregon. Verner, J. 1978. California condors: status of the recovery effort. Gen. Tech. Rep. PSW-28, U.S. Forest Service, Washington, D.C. Wiemeyer, S. N. Jurek, R. M. and J. R. Moore. 1986b. Environmental contaminants in surrogates, foods, and feces feces or excrement or stools Solid bodily waste discharged from the colon through the anus during defecation. Normal feces are 75% water. The rest is about 30% dead bacteria, 30% indigestible food matter, 10–20% cholesterol and other fats, of California condors (Gymnogyps californianus). Environ. Monit. Assess. 6:91-111. Wiemeyer, S.N., Scott, J.M., Anderson, M.P. Bloom, P.H. and C.J. Stafford. 1988. Environmental contaminants in California Condors. J. Wildl. Manag. 52:238-247. Wilbur, S.R. 1978. The California Condor, 1966-1976: a look at its past, present and future. US Fish and Wildlife Service North American North American named after North America. North American blastomycosis see North American blastomycosis. North American cattle tick see boophilusannulatus. Fauna 72:1 - 136. Kelly J. Sorenson Wildlife Restoration Coordinator and Assistant Director, Ventana Wilderness Society, P.O. 894, Carmel Valley, CA 93924; (831) 455-9514, (fax) (831) 455-2846; kellysorenson@ventanaws.org L. Joseph Burnett Condor Field Coordinator, Ventana Wilderness Society, P.O. 894, Carmel Valley, CA 93924; http://www.ventanaws.org James R. Davis Executive Director, Ventana Wilderness Society, P.O. 894, Carmel Valley, CA 93924; http://www.ventanaws.org |
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