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Simple Summary: Galápagos pink land iguanas (Conolophus marthae) are a critically endangered species endemic to Wolf Volcano, Galápagos. Among other conservation initiatives, a head-start program, involving the captive rearing of hatchlings prior to release in the wild, has been identified as a primary action needed to prevent the species' extinction. However, until this study began, the location of pink iguana nesting grounds was unknown, and no hatchlings and only a handful of juveniles and subadults had been observed. In an attempt to unveil the location of nesting grounds for C. marthae, we modeled the movement patterns of male and female iguanas tracked during the reproductive season. Based on the hypothesis that males and females might exhibit different movement patterns after the breeding season, we looked for females-specific migratory behavior. Thanks to this approach, we identified an area that females likely use to nest. Our results based on movement data alone led to the first-ever identification of pink iguana nests and hatchlings. Invasive alien species control is recognized worldwide as a priority action to preserve global biodiversity. However, a lack of general life history knowledge for threatened species can impede the effectiveness of conservation actions. Galápagos pink land iguanas (Conolophus marthae) are endemic to Wolf Volcano, Galápagos, Ecuador. These iguanas are threatened by invasive alien species, particularly feral cats, that may affect their small population size. To guarantee the long-term survival of C. marthae, the Galápagos National Park Directorate is considering, along with an ongoing campaign of feral cat control, the implementation of a head-start program. However, the success of this management strategy necessarily relies on the identification of pink iguana nesting grounds, which were still unknown at the onset of this study. We modeled the movement patterns of male and female iguanas during the reproductive season, using location data collected from custom-made remote tracking devices installed on adult pink iguanas in April 2021. We first calculated for each individual the vector of distances from its starting location, which was defined as net displacement. We then used net displacement as the response variable in a generalized additive mixed model with day of the year as the predictor. Based on the hypothesis that males and females may behaviorally differ after mating, we looked for female-specific migratory behavior suggesting females were moving toward nesting areas. The results obtained confirmed our hypothesis, as females exhibited a distinct migratory behavior, reaching a small plateau area inside of Wolf Volcano's caldera and ca. 400 m below the volcano's northern rim. Moreover, once inside the caldera, females displayed a more aggregated distribution pattern. The movement data obtained allowed Galápagos National Park rangers to locate individual pink iguana nests and subsequently to sight and collect the first observed hatchlings of the species. This work constitutes a necessary baseline to perform dedicated studies of pink iguana nests and emerging hatchling iguanas, which is an essential step toward the development of an effective head-start program. [ABSTRACT FROM AUTHOR]

Critically endangered Galápagos pink land iguanas, Conolophus marthae , are considered a rare and elusive species. These iguanas are endemic to Wolf Volcano, on Isabela Island (Galápagos), where they persist as a single, very small population on the northwestern slope of the volcano. In an attempt to unveil important information about their ecology and behavior we monitored and analyzed the movement data of a male C. marthae collected over a period of 159 days, from 25 September 2019 until 3 March 2020. We used a custom designed GPS-Wireless Sensor Node (WSN) to remotely track and describe the migration pattern of this individual. Using GPS location data and trajectory reconstruction we documented an altitudinal shift of more than 1000 m. These results not only agree with observations recorded while collecting data in the field but were also used to reconstruct and describe the individual's migratory behavior, and to document the potential path that this individual, and presumably others of this species, follow while searching for food or mates. The altitudinal shift described whether shared across individuals of the species or part of intraspecific variation, may be related to different factors. Here, we discuss alternative interpretations of this behavior. The urgent need to gather data on the species' ecology and develop an appropriate conservation strategy underlines the importance of this research. Although it is not possible to draw conclusions for an entire species based on results from one individual, this work represents a significant advancement for the conservation of this species, as it validates the importance of using cutting-edge remote-tracking technology to collect data on a very elusive species, and it reveals ecological traits not previously documented for these critically endangered iguanas. [ABSTRACT FROM AUTHOR]