Lead Poisoning and the Reintroduction of the California Condor in Northern Arizona

Abstract

Since 1996, The Peregrine Fund has released California condors (Gymnogyps californianus) in the Grand Canyon region of northern Arizona with the goal of establishing a self-sustaining population, disjunct from other released populations in California and Baja California. A free-ranging population of more than 60 individuals now ranges within northern Arizona and southern Utah and has produced 9 wild young. The most frequent cause of death is lead poisoning from the ingestion of lead bullet fragments and shotgun pellets in the remains of gun-killed animals. In response, the Arizona Game and Fish Department has effectively reduced lead occurrence within the foraging range of the condors through hunter education and the promotion of nonlead ammunition. Most hunters have participated in the program. Throughout the course of the reintroduction effort, veterinary science and application have played essential roles in diagnosing fatalities and treating lead-exposed condors, a species with such a low natural reproductive rate that every adult is significant to the population.

Assessment of lead exposure in Spanish imperial eagle (Aquila adalberti) from spent ammunition in central Spain

“…Some countries, including Norway, Denmark and the Netherlands, have extended the ban to all hunted species (Mateo 2009). However lead ammunition is still employed worldwide in large and small game in upland hunting even though lead toxicosis is an important cause of concern for conservation of scavenging raptors, such as the white-tailed sea eagle (Kenntner et al 2001;Helander et al 2009), bald eagle (Redig et al 2009) and California condor (Hunt et al 2009b). In cases such as the Spanish imperial eagle, in which there is confirmation of lead exposure from spent ammunition, even if the exposure to lead is low in certain areas, such as our study area, death of adults of these threatened birds, even in small numbers, may have consequences on the recovery of their populations (Pain et al 2009).…”

Dropping dead: causes and consequences of vulture population declines worldwide

“…Lead poisoning through the ingestion of pellets or fragments of lead‐based bullets in hunter‐killed carcasses is a serious threat to some vulture populations, most notably the California condor. Lead poisoning has been implicated as the leading cause of death in the Arizona population of the condor (∼40% of the worldwide population), and it had been estimated that without the intensive intervention of veterinarians, this population would not be self‐sustaining in the wild 29,84–86 . However, in 2005 the Arizona Game and Fish Department implemented a hunter‐education campaign and provided free, nonlead ammunition for hunters in condor habitats.…”

“…Shooting and intentional poisoning are the two main forms of persecution. Shooting vultures has long been documented in the United States, Europe, and North Africa, where the activity appears to be largely for sport 22,28,29,61 . Documented cases of intentional poisoning of vultures have been noted as being in retaliation for the suspected killing of newborn lambs, to disguise the locations of poachers’ activities, and to obtain vulture parts for traditional medicine 65,72,87,89,90 .…”

“…Lead poisoning has been implicated as the leading cause of death in the Arizona population of the condor (∼40% of the worldwide population), and it had been estimated that without the intensive intervention of veterinarians, this population would not be self-sustaining in the wild. 29,[84][85][86] However, in 2005 the Arizona Game and Fish Department implemented a hunter-education campaign and provided free, nonlead ammunition for hunters in condor habitats. With >80% participation by hunters, the severity of lead exposure during 2007 was low and there were no lead-related condor deaths.…”

“…Shooting vultures has long been documented in the United States, Europe, and North Africa, where the activity appears to be largely for sport. 22,28,29,61 Documented cases of intentional poisoning of vultures have been noted as being in retaliation for the suspected killing of newborn lambs, to disguise the locations of poachers' activities, and to obtain vulture parts for traditional medicine. 65,72,87,89,90 The acquisition of vulture parts for traditional medicine has been documented in West and southern Africa 72,91-93 and is suspected in parts of East Africa (N. Baker, pers.…”