DOI: 10.5061/dryad.dbrv15f65
title: Data and code to analyze reproductive rates of California Condors in the first two decades of reintroduction in California

description: In the first comprehensive assessment of the reproductive rates of
 critically endangered California Condors (Gymnogyps californianus)
 recovering from complete extirpation in the wild, we analyzed 20 years
 (1999–2018) of data from condor flocks in southern and central California.
 We found that several anthropogenic threats affected reproductive rates:
 (1) coastal space use by female condors was associated with lower hatch
 probability, presumably due to marine mammal foraging and associated DDE
 exposure, (2) trash ingestion by chicks decreased fledging probability
 prior to implementation of trash management in 2007, and (3) all parent
 deaths during rearing resulted in chick or early fledgling deaths, and
 most parental deaths were due to lead poisoning. We also detected several
 effects on reproductive rates of the complex individual-based management
 of condors, which involves ongoing releases of captive-bred individuals
 and health interventions including treatment of lead poisoning.
 Recruitment rates were lower for new release sites, which we attribute to
 a lack of individual- and flock-level experience. In addition, the number
 of free-flying days in the wild was positively associated with female and
 male recruitment and with female rebreeding probabilities, indicating that
 removing individuals from the wild may reduce their breeding success.
 Finally, probabilities of recruitment, rebreeding, and fledging all
 increased with age, and given the age distribution skew of the recovering
 flocks towards younger individuals, overall reproductive success was lower
 than would be expected at the stable age distribution. Thus, reproductive
 rates should increase over time as the mean age of California Condors
 increases if current and emerging threats to reproduction, including the
 loss of breeders due to lead poisoning, can be addressed.
description: Observations consisted of near-daily attempts to locate each
 individual visually or by telemetry signal. Starting in 2002 in the
 southern flock and 2008 in the central flock, observations at cameras
 established at proffered feeding stations were also recorded and included
 in our data. Given the intensive monitoring, we believe that essentially
 all breeding attempts that produced an egg were detected. Nests were
 monitored visually and nesting phenology was inferred based on parental
 behavior, or where possible, observations of eggs and chicks, including
 regular nest entries at most nests. Starting in 2012, webcams were
 installed at a subset of remote nests. Additional details on the
 collection of daily condor data are available through the U.S. Fish and
 Wildlife Service (https://ecos.fws.gov/ecp/species/8193). Data are summarized as described in the associated paper, “Anthropogenic threats and young age skew lower fertility in the first two decades of reintroduction for critically endangered California Condors in California”
description: Data and code compiled in R.<br>R Core Team (2022). R: A
 language and environment for statistical computing. R Foundation for
 Statistical Computing, Vienna, Austria. URL
 https://www.R-project.org/.