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The Seychelles magpie‐robin's (SMR) five island populations exhibit some of the lowest recorded levels of genetic diversity among endangered birds, and high levels of inbreeding. These populations collapsed during the 20th century, and the species was listed as Critically Endangered in the IUCN Red List in 1994. An assisted translocation‐for‐recovery program initiated in the 1990s increased the number of mature individuals, resulting in its downlisting to Endangered in 2005. Here, we explore the temporal genomic erosion of the SMR based on a dataset of 201 re‐sequenced whole genomes that span the past ~150 years. Our sample set includes individuals that predate the bottleneck by up to 100 years, as well as individuals from contemporary populations established during the species recovery program. Despite the SMR's recent demographic recovery, our data reveal a marked increase in both the genetic load and realized load in the extant populations when compared to the historical samples. Conservation management may have reduced the intensity of selection by increasing juvenile survival and relaxing intraspecific competition between individuals, resulting in the accumulation of loss‐of‐function mutations (i.e. severely deleterious variants) in the rapidly recovering population. In addition, we found a 3‐fold decrease in genetic diversity between temporal samples. While the low genetic diversity in modern populations may limit the species' adaptability to future environmental changes, future conservation efforts (including IUCN assessments) may also need to assess the threats posed by their high genetic load. Our computer simulations highlight the value of translocations for genetic rescue and show how this could halt genomic erosion in threatened species such as the SMR.

Introduced common mynas (Acridotheres tristis) can negatively impact native wildlife throughout the mynas’ non-indigenous range, and in Seychelles myna eradications have been attempted on some smaller islands to protect endemic and indigenous fauna. Initial attempts, relying on a quick knock-down of the population using toxicants, failed. Here we describe an eradication on North Island, Seychelles, that was accomplished by trapping, supported by shooting in the final stages. This eradication attempt was ultimately successful but took place in two stages spanning seven years and involved removing 1641 birds. During the second, successful, stage, morphometric data collected from caught mynas provided pointers to optimum times during the mynas’ annual cycle to target control activities. During both stages the trapping of non-target species interfered with the capture of mynas. The six main conclusions from this eradication are (i) eradication of mynas from small islands is feasible and achievable by trapping and shooting, without recourse to the use of toxicants; (ii) provision of adequate resources for the life of an eradication attempt, especially ensuring continuity of funding and staffing, is essential for the efficient removal of the whole population; (iii) knowledge of myna phenology can be used to target the optimal timing of an eradication attempt, (iv) post eradication, vigilance and capacity for immediate action must be maintained to remove any immigrant mynas, (v) further research on trap design is needed to minimise the capture of non-target species, and (vi) introduced endemic bird populations should be monitored to assess their responses to myna removal.

Long-term survey data can provide important information on temporal and spatial changes in bird populations and are needed for conservation management. We investigate population indices of seven landbird species using an 11-year dataset from the UNESCO World Heritage Site of Aldabra Atoll. We analysed the associations of location, season and habitat with abundance, assessed population trends, and examined the influence of monitoring circumstances on results. Populations of all species except for the Aldabra Drongo Dicrurus aldabranus increased over this period. Abundance was associated with season and habitat, and interactions were found between season and location that differed for each species. Bird count results were affected by the timing of monitoring, number of observers and weather conditions. We use the results to review the strengths and weaknesses of the current monitoring programme and make recommendations for improvements. Overall our results indicate no immediate cause for conservation concern for the Aldabra landbird species monitored.

Understanding the extent of morphological variation in the wild population of Aldabra giant tortoises is important for conservation, as morphological variation in captive populations has been interpreted as evidence for lingering genes from extinct tortoise lineages. If true, this could impact reintroduction programmes in the region. The population of giant tortoises on Aldabra Atoll is subdivided and distributed around several islands. Although pronounced morphological variation was recorded in the late 1960s, it was thought to be a temporary phenomenon. Early researchers also raised concerns over the future of the population, which was perceived to have exceeded its carrying capacity. We analyzed monthly monitoring data from 12 transects spanning a recent 15‐year period (1998–2012) during which animals from four subpopulations were counted, measured, and sexed. In addition, we analyzed survival data from individuals first tagged during the early 1970s. The population is stable with no sign of significant decline. Subpopulations differ in density, but these differences are mostly due to differences in the prevailing vegetation type. However, subpopulations differ greatly in both the size of animals and the degree of sexual dimorphism. Comparisons with historical data reveal that phenotypic differences among the subpopulations of tortoises on Aldabra have been apparent for the last 50 years with no sign of diminishing. We conclude that the giant tortoise population on Aldabra is subject to varying ecological selection pressures, giving rise to stable morphotypes in discrete subpopulations. We suggest therefore that (1) the presence of morphological differences among captive Aldabra tortoises does not alone provide convincing evidence of genes from other extinct species; and (2) Aldabra serves as an important example of how conservation and management in situ can add to the scientific value of populations and perhaps enable them to better adapt to future ecological pressures. In his quest to undermine the immutability of species Darwin famously cited the morphological variation displayed by the Galapagos giant tortoise, where distinctive morphotypes are found on different islands. Here we test whether the only other extant species of giant tortoise – the Aldabra giant tortoise – displays similar morphological variation. We find that it does and these differences have been apparent for around 50 years, despite the better‐connected nature of the subpopulations on Aldabra.

Invasive predators are a major driver of extinctions and continue to threaten native populations worldwide. Island eradications of (mostly mammalian) invasive predators have facilitated the (re)establishment of numerous island-endemic populations. Other invasive taxa, such as some predatory birds, could pose a more persistent threat due to their ability to fly and actively re-invade even remote and isolated islands. However, the impact of invasive predatory birds has been largely overlooked. We report on a novel sex-specific impact of an invasive-nest predator, the common myna (Acridotheres tristis), on a reintroduced population of Seychelles warblers (Acrocephalus sechellensis); translocated from Cousin Island to Denis Island in 2004. Regular post-translocation monitoring revealed that female mortality was 20% higher than males, leading to a 60–70% male-biased population sex-ratio between 2005–2015. This was attributed to mynas inflicting severe injuries to incubating female warblers while attempting to prey upon eggs in their nests. These effects likely contributed to the slower-than-expected population growth observed (relative to previous translocations of Seychelles warblers to other islands) over the same period. An eradication programme beginning in 2011 removed all mynas from Denis by 2015. Subsequently, we observed a balancing of sex-specific survival and the population sex-ratio of Seychelles warblers and, consequently, accelerated population growth. This study demonstrates the importance of assessing the threat posed by all invasive taxa (not just mammals) to island conservation. Furthermore, we show how extended monitoring is needed to identify problems, and develop solutions, post-translocation.