The remnant wild population of California Condors (Gymnogyps californianus) of the 1980s exhibited a rapid population decline caused by high mortality rates among adult and immature birds. The most prominent mortality factor was lead poisoning resulting from ingestion of bullet fragments in carcasses. Successful captive breeding has allowed many birds to be released to the wild since 1992, based originally on an assumption that exposure to lead could be prevented by food subsidy. The mortality of released birds, however, has generally exceeded levels needed for population stability calculated from simple population models. Collision with overhead wires was the most frequent cause of death in releases before 1994. Lead poisoning again surfaced as a problem starting in 1997 as older birds began feeding on carcasses outside the subsidy program. Although poisonings have been treated successfully by chelation therapy in recaptured birds, food subsidy is proving an ineffective solution to lead exposure. The best long‐term solution appears to be either the creation of large reserves where hunting is prohibited or the restriction of hunting to nontoxic ammunition in release areas. Until sources of lead contamination are effectively countered, releases cannot be expected to result in viable populations. In addition, problems involving human‐oriented behavior have resulted in the permanent removal of many released birds from the wild. The most promising reduction in human‐oriented behavior has been achieved in one release of aversively conditioned, parent‐reared birds. Rigorous evaluation of the factors reducing attraction to humans and human structures has been hampered by confounding of techniques in releases. Behavioral problems could be more quickly overcome by adoption of a comprehensive experimental approach.

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The long-term goal of any species reestablishment program should be the creation of self-sustaining wild populations that replicate as closely as possible the behavior and ecology of original wild populations. We analyzed current reestablishment efforts for the California Condor ( Gymnogyps californianus ) by identifying and discussing both demographic and behavioral problems inhibiting success (Meretsky et al. 2000). We then suggested solutions to these problems. Our demographic model was developed with the clear objective of evaluating the demography of the historic condor population and developing benchmarks for evaluating long-term survival rates of reintroduced birds. Our goal was not, as contended by Beres and Starfield (2001; this issue), a campaign against double clutching of captive pairs; contrary to their allegations, our comments on the implications of multiple clutching for production of parent-reared birds did not stem from results of our demographic modeling. We did not present any chain of arguments resembling that attributed to us in their third paragraph, and our approach does promote practical management decisions leading to self-sustaining and properly behaving populations.Unfortunately, the alternative condor model offered by Beres and Starfield (which is too incompletely presented to allow an examination of its internal consistency or to evaluate its behavior under alternative assumptions) addresses neither of the primary release problems identified in our paper-demographic unsustainability and failure to achieve appropriate species-typical behavior. Instead, their modeling exercise is evidently driven entirely by an assumption that whatever strategy produces the most condors for release in a given period of time should be used in reestablishment efforts. Such an approach ignores the fact that different rearing procedures can have profound effects on the quality of behavior exhibited by released populations and the fact that rate of production of releasable condors is no guide to the sustainability of released populations. Their analysis is entirely focused on a single process-double clutching-and thus cannot provide management suggestions for countering the major problems that have arisen in the program: unsustainability of the wild population and behavioral problems of released birds. Problems with SustainabilityThe primary problem we discussed in our paper was the excessive mortality rates seen in most releases, rates that far exceeded the 10% annual rate that we calculated would likely produce sustainable populations under normal reproductive conditions. Beres and Starfield assume that mortality rates in future generations of released birds will be lower than those currently observed in the released populations. In contrast, we predicted that mortality rates were likely to increase to approach the disastrous mortality rate of the historical wild population (26.6% annually) because of increasing vulnerability of the released birds to lead poisoning, the primary known stress factor for th...