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[EN] Species baseline information is required for effective biodiversity conservation. Here we provide sound ecological data to support effective conservation of the Principe Scops-owl, Otus bikegila Melo, Freitas, Verbelen, Costa, Pereira, Fuchs, Sangster, Correia, de Lima & Crottini 2022, discovered in 2016. We mapped the observed and potential distribution, inferred habitat associations, estimated population size, and assessed the International Union for Conservation of Nature (IUCN) Red List category for this species. Surveys were carried out across Príncipe Island during the long and short dry seasons, recording owl presence in sampling points along transects. These data were used to model distribution, revealing that the Principe Scops-owl is restricted to 34.4 km2 in the south of the island, inside the Príncipe Obô Natural Park. Most records were in lower altitude native forest. Remoteness was the most important variable to explain presence at island level, followed by land use, which showed that the species is restricted to forest, clearly depending on native forest. Distance sampling using different models suggested a population density ranging between 33.4 individuals/km2 (95% CI: 23.6–47.2) and 46.4 individuals/km2 (95% CI: 29.3–73.6), which extrapolates to an estimated population size ranging from 1,149 individuals (95% CI: 813–1,623) to 1,597 individuals (95% CI: 1,007–2,533). We propose that the species is classified as “Critically Endangered” due to the small extent of occurrence, coupled with occurrence in a single location and inferred continuing declines in the extent of occurrence, area of occupancy, number of mature individuals and area, extent, and quality of habitat. Effective conservation of the Principe Scops-owl requires regular monitoring and further studies focusing on reproduction and potential nest predation by introduced mammals. Widespread support for the conservation of the Natural Park is vital to ensure the protection of this species and the endemic-rich native forests of Príncipe on which it depends., [POR] O sucesso de medidas de conservação está dependente da qualidade da informação de base disponível para as espécies alvo. Neste estudo, recolhemos dados sólidos sobre a ecologia de Otus bikegila Melo, Freitas, Verbelen, Costa, Pereira, Fuchs, Sangster, Correia, de Lima & Crottini 2022, descoberto em 2016. Mapeamos a distribuição observada e potencial, inferimos associações de habitat, estimamos o tamanho da população e propomos a categoria da Lista Vermelha da União Internacional para a Conservação da Natureza (IUCN) para esta espécie. Foi feito um levantamento na Ilha do Príncipe durante as estações secas, longa e curta, registando a presença do mocho em pontos de amostragem ao longo de transetos. Estes dados foram usados para modelar a sua distribuição, revelando que Otus bikegila está restrito a 34,4 km2 no sul da ilha, dentro do Parque Natural do Obô do Príncipe. A maioria dos registos foram feitos em floresta nativa de baixa altitude. A acessibilidade foi a variável mais importante para explicar a presença do mocho ao nível da ilha, seguida pelo uso do solo, o que demonstrou que esta espécie está restrita a áreas de floresta, preferindo a floresta nativa. Através da análise de distâncias usando diferentes modelos, obtevese uma estimativa da densidade populacional variando entre 33,4 indivíduos/km2 (IC 95%: 23,6–47,2) e 46,4 indivíduos/km2 (IC 95%: 29,3–73,6), que resulta num tamanho populacional estimado variando de 1.149 (IC 95%: 813–1.623) a 1.597 indivíduos (IC 95%: 1.007–2.533). Propomos que a espécie seja classificada como Criticamente Ameaçada devido à pequena extensão de ocorrência, juntamente com a sua ocorrência num único local e um declínio contínuo inferido na extensão de ocorrência, área de ocupação, número de indivíduos maturos e área, extensão e qualidade do habitat. Para que a conservação de Otus bikegila seja eficaz, é necessário que a sua monitorização seja regular e que novos estudos se foquem na sua reprodução e potencial predação no ninho por mamíferos introduzidos. É essencial que haja um apoio generalizado para a conservação do Parque Natural, para garantir a proteção da floresta nativa de que dependem a maior parte das espécies endémicas da ilha, incluindo Otus bikegila., This project was supported by Forever Príncipe with additional funding from the National Geographic Society (Early career grant - EC-364C-18 to B.F.). Portuguese National Funds through the Foundation for Science and Technology (FCT) funded the B.F. PhD grant (2020.04569.BD), R.L. and M.M. post-doc grants (FCT/MCTES - SFRH/BPD/91494/2012; SFRH/BPD/100614/2014), A.C. Investigador FCT (IF/00209/2014) and 2020.00823.CEECIND/CP1601/CT0003 contracts, CIBIO (UIDB/50027/2021), and cE3c research units (UID/BIA/00329/2021). M.M. was further supported via the European Union Horizon’s 2020 research and innovation programme under grant agreement 854248.

There is growing interest in the study of avian endoparasite communities, and metabarcoding is a promising approach to complement more conventional or targeted methods. In the case of eukaryotic endoparasites, phylogenetic diversity is extreme, with parasites from 4 kingdoms and 11 phyla documented in birds. We addressed this challenge by comparing different primer sets across 16 samples from 5 bird species. Samples consisted of blood, feces, and controlled mixes with known proportions of bird and nematode DNA. Illumina sequencing revealed that a 28S primer set used in combination with a custom blocking primer allowed detection of various plasmodiid parasites and filarioid nematodes in the blood, coccidia in the feces, as well as two potentially pathogenic fungal groups. When tested on the controlled DNA mixes, these primers also increased the proportion of nematode DNA by over an order of magnitude. An 18S primer set, originally designed to exclude metazoan sequences, was the most effective at reducing the relative number of avian DNA sequences and was the only one to detect Trypanosoma in the blood. Expectedly, however, it did not allow nematode detection and also failed to detect avian malaria parasites. This study shows that a 28S set including a blocking primer allows detection of several major and very diverse bird parasite clades, while reliable amplification of all major parasite groups may require a combination of markers. It helps clarify options for bird parasite metabarcoding, according to priorities in terms of the endoparasite clades and the ecological questions researchers wish to focus on., Parasites of birds are extremely diverse, spanning no less than four different kingdoms (Chromista, Protozoa, Metazoa and Fungi). Our understanding of these communities and their fascinating interactions could benefit from metabarcoding approaches. This report provides a side‐by‐side comparison of different metabarcoding options for a broad description of avian eukaryotic endoparasite communities.

We present an updated bird checklist for the oceanic islands of the Gulf of Guinea. Their avifauna comprises 146 confirmed species, an increase of 19% in 15 years. Of these, 66 are resident landbird species (32 on Principe, 50 on Sao Tome and 11 on Annobon), including 29 endemic species, 17 endemic subspecies and 17 possibly non-native species. The remaining avifauna consists of six breeding seabird species, four non-breeding migrants, 62 vagrants and eight species of uncertain status. An additional 51 species have been reported but lack confirmation. Most recent changes reflect increases in observer activity and involve vagrant and unconfirmed species, but a few result from previously overlooked historical records and taxonomic changes. Of the three islands, most changes affected the avifauna of Principe, whereas little new information has come from Annobon. Future changes are predicted to arise from new reports and confirmation of vagrants, but also from further taxonomic revision of residents.

Few studies have quantified the extent of genetic differentiation within widely distributed polytypic African bird species with disjunct ranges. Current knowledge indicates that high levels of genetic differentiation are found for such lineages but generalization of the pattern requires further comparisons with other co-distributed taxa. We assessed the extent of phylogeographical structure across the range of the Olive Woodpecker Dendropicos griseocephalus using mitochondrial and nuclear intron data. The Olive Woodpecker occupies the forests of Central (Dendropicos griseocephalus ruwenzori) and Eastern (Dendropicos g. kilimensis) Africa, with a disjunct morphological lineage (Dendropicos g. griseocephalus) occurring in southern Africa. Each of the subspecies lineages can be diagnosed using morphology. Phylogenetic analyses of our sequence data recovered three monophyletic lineages with kilimensis sister to ruwenzori, and griseocephalus as sister to the clade uniting these two taxa. Molecular species delimitation methods and estimates of gene flow under the isolation-with-migration model suggest that the clade uniting the central and eastern subspecies may be recognized as distinct at the species level from the nominate subspecies, which is restricted to southern Africa. We conclude that D. griseocephalus (Boddaert, 1783) and D. ruwenzori (Sharpe, 1902) (including subspecies kilimensis) should be considered full species. The biogeographical pattern we uncover for the Olive Woodpecker differs from that of other co-distributed widespread species both in terms of the order of sequence divergence of lineages occupying different areas of endemism in Africa, and in the timing of divergence, being younger (0.5–0.7 mya BP) than that recovered for the co-distributed Square-tailed Drongo Dicrurus ludwigii (0.9–1.6 mya BP).

Colonization, speciation and extinction are dynamic processes that influence global patterns of species richness1,2,3,4,5,6. Island biogeography theory predicts that the contribution of these processes to the accumulation of species diversity depends on the area and isolation of the island7,8. Notably, there has been no robust global test of this prediction for islands where speciation cannot be ignored9, because neither the appropriate data nor the analytical tools have been available. Here we address both deficiencies to reveal, for island birds, the empirical shape of the general relationships that determine how colonization, extinction and speciation rates co-vary with the area and isolation of islands. We compiled a global molecular phylogenetic dataset of birds on islands, based on the terrestrial avifaunas of 41 oceanic archipelagos worldwide (including 596 avian taxa), and applied a new analysis method to estimate the sensitivity of island-specific rates of colonization, speciation and extinction to island features (area and isolation). Our model predicts—with high explanatory power—several global relationships. We found a decline in colonization with isolation, a decline in extinction with area and an increase in speciation with area and isolation. Combining the theoretical foundations of island biogeography7,8 with the temporal information contained in molecular phylogenies10 proves a powerful approach to reveal the fundamental relationships that govern variation in biodiversity across the planet.

AIM: On islands, species richness is reduced and interspecific competition relaxed in relation to the mainland, allowing species to use broader ecological niches. These factors are known to affect diet and morphology, but can also affect communication and acoustic signalling in particular. However, no study has ever compared insular and continental soundscapes to determine to which extent islands present reduced acoustic richness (number of co‐vocalizing species) and fewer constraints for vocalizing species. LOCATION: Sao Tome Island, Mount Cameroon, Madeira Island, Southern France. TAXON: Birds. METHODS: We compared two pairs of insular and continental soundscapes: one in a temperate zone, the other in the tropics. We recorded sounds produced in similar types of primary forests and measured acoustic richness and ambient noise profiles. We then assessed acoustic niche organization by computing, for each community, species turnover, temporal and frequency overlaps, and acoustic avoidance. RESULTS: We found fewer species co‐vocalizing on islands compared to mainland and in temperate compared to tropical region. Ambient noise was louder in the tropics and occupied a wider frequency range, especially on the mainland, thereby revealing a reduction in available acoustic space for tropical mainland birds. In this more crowded and noisy soundscape, species presented a higher acoustic turnover, overlapped less in time and in frequency with each other and acoustically avoided each other more when compared to the three other communities. MAIN CONCLUSIONS: Soundscapes differed and imposed fewer constraints on vocalizing species along the species diversity gradient from tropical mainland to temperate island. Acoustic niche partitioning increased with species richness and was associated with increased levels of acoustic interference. Results set a scene for an effect of relaxed competition on song evolution on islands, especially in the tropics.

Biodiversity information in Angola is limited or nonexistent, hindering the design and implementation of conservation strategies. The Escarpment forest is one of the most important areas for bird diversity in the country. However, there is almost no information about the territorial needs and habitat preferences of its threatened endemic birds. This study evaluated these needs and preferences in Gabela akalat Sheppardia gabela, a range-restricted endemic to the Central Escarpment. Eighteen individuals of Gabela akalat were captured and radio-tracked with the objectives of establishing their territory size (through home-range size estimates) and habitat preferences using compositional analysis. Home-range sizes were slightly larger than other Sheppardia species and Gabela akalat evidently avoided clearings and preferred forest habitat, although it was also able to use farmland areas and secondary growth to a lesser extent. Conservation measures should focus on the preservation of remaining old-growth forest through the establishment of a nature reserve in Kumbira. To assure the success of such an initiative, the local population should participate in planning, administration and enforcement. We outline some measures that could help address the economic needs of the local community while maintaining forest cover.

Data Paper The former Instituto de Investigação Científica Tropical-IICT (Lisbon, Portugal), recently integrated into the University of Lisbon, gathers important natural history collections from Portuguese-speaking African countries. In this study, we describe the bird collection from the Democratic Republic of São Tomé and Príncipe, which was fully taxonomically checked and georeferenced. The IICT bird collection contains 5598 specimens, of which 559 are from São Tomé and Príncipe, representing 85 taxa, including 19 endemic species and 13 endemic subspecies of birds. The specimens were collected between 1946 and 1973, although 43% of the records are from 1954 and 45% are from 1970. The geographic distribution of samples covers the whole territory, with a higher number of records from São Tomé than from Príncipe. The districts with highest number of records are Pagué (equivalent to Príncipe Island), and Água Grande and Mé-Zochi on São Tomé. Despite the relatively low number of specimens per taxon, the importance of the collection is considerable due to the high number of endemic and threatened species represented. Furthermore, it adds valuable information to the GBIF network, especially for a country whose two islands are each an Endemic Bird Area and for which substantial gaps in ornithological knowledge remain info:eu-repo/semantics/publishedVersion

Conservation management can no longer rely on protecting pristine habitats, but must consider the\ud wider landscape. This is especially true on oceanic islands where endemic species are believed to be\ud particularly susceptible to the extinction risks that accompany land conversion. Despite this, there is a\ud paucity of studies examining how endemic communities on oceanic islands may be distributed across\ud such human-modified habitats. Taking Príncipe Island in West Africa as a case study, we investigate how\ud avian communities vary across the habitats (primary forest, secondary forest, agricultural areas) of this\ud globally important centre of endemism. Here, recent policy reforms aimed at poverty alleviation and\ud increased food production are rapidly altering the current land-use mosaic. Across all habitats, 27 bird\ud species were encountered. Survey points in secondary forest and agricultural areas were, on average,\ud more diverse and held higher overall abundances of birds than those within primary forest. This was\ud true for both the entire avian assemblage and the endemic species alone. Nevertheless, two IUCN-listed\ud species were restricted to primary forest, and many other endemics occurred at higher densities within\ud this habitat. We demonstrate that agricultural areas and novel habitats, such as secondary forest, can\ud hold high abundances of endemic species and thus have the potential to act as a resource for biodiversity\ud conservation. A double-stranded approach to conservation is therefore required that both protects the\ud integrity of the primary forest and controls the rapid changes in agricultural land-use to ensure that it\ud continues to support a large component of the endemic avifauna.

Background The island of Madagascar and surrounding volcanic and coralline islands are considered to form a biodiversity hotspot with large numbers of unique taxa. The origin of this endemic fauna can be explained by two different factors: vicariance or over-water-dispersal. Deciphering which factor explains the current distributional pattern of a given taxonomic group requires robust phylogenies as well as estimates of divergence times. The lineage of Indian Ocean scops-owls (Otus: Strigidae) includes six or seven species that are endemic to Madagascar and portions of the Comoros and Seychelles archipelagos; little is known about the species limits, biogeographic affinities and relationships to each other. In the present study, using DNA sequence data gathered from six loci, we examine the biogeographic history of the Indian Ocean scops-owls. We also compare the pattern and timing of colonization of the Indian Ocean islands by scops-owls with divergence times already proposed for other bird taxa. Results Our analyses revealed that Indian Ocean islands scops-owls do not form a monophyletic assemblage: the Seychelles Otus insularis is genetically closer to the South-East Asian endemic O. sunia than to species from the Comoros and Madagascar. The Pemba Scops-owls O. pembaensis, often considered closely related to, if not conspecific with O. rutilus of Madagascar, is instead closely related to the African mainland O. senegalensis. Relationships among the Indian Ocean taxa from the Comoros and Madagascar are unresolved, despite the analysis of over 4000 bp, suggesting a diversification burst after the initial colonization event. We also highlight one case of putative back-colonization to the Asian mainland from an island ancestor (O. sunia). Our divergence date estimates, using a Bayesian relaxed clock method, suggest that all these events occurred during the last 3.6 myr; albeit colonization of the Indian Ocean islands were not synchronous, O. pembaensis diverged from O. senegalensis about 1.7 mya while species from Madagascar and the Comoro diverged from their continental sister-group about 3.6 mya. We highlight that our estimates coincide with estimates of diversification from other bird lineages. Conclusion Our analyses revealed the occurrence of multiple synchronous colonization events of the Indian Ocean islands by scops-owls, at a time when faunistic exchanges involving Madagascar was common as a result of lowered sea-level that would have allowed the formation of stepping-stone islands. Patterns of diversification that emerged from the scops-owls data are: 1) a star-like pattern concerning the order of colonization of the Indian Ocean islands and 2) the high genetic distinctiveness among all Indian Ocean taxa, reinforcing their recognition as distinct species.

The host specificity of blood parasites recovered from a survey of 527 birds in Cameroon and Gabon was examined at several levels within an evolutionary framework. Unique mitochondrial lineages of Haemoproteus were recovered from an average of 1.3 host species (maximum = 3) and 1.2 host families (maximum = 3) while lineages of Plasmodium were recovered from an average of 2.5 species (maximum = 27) and 1.6 families (maximum = 9). Averaged within genera, lineages of both Plasmodium and Haemoproteus were constrained in their host distribution relative to random expectations. However, while several individual lineages within both genera exhibited significant host constraint, host breadth varied widely among related lineages, particularly within the genus Plasmodium . Several lineages of Plasmodium exhibited extreme generalist host–parasitism strategies while other lineages appeared to have been constrained to certain host families over recent evolutionary history. Sequence data from two nuclear genes recovered from a limited sample of Plasmodium parasites indicated that, at the resolution of this study, inferences regarding host breadth were unlikely to be grossly affected by the use of parasite mitochondrial lineages as a proxy for biological species. The use of divergent host–parasitism strategies among closely related parasite lineages suggests that host range is a relatively labile character. Since host specificity may also influence parasite virulence, these results argue for considering the impact of haematozoa on avian hosts on a lineage-specific basis.

The study of island biodiversity has inspired many advances in evolutionary biology. However, whether patterns of microorganism diversity are influenced by insularity is poorly understood. In particular, microorganisms that live in symbiotic association, such as the microbiota that inhabit the gastrointestinal tract of bigger animals, are subjected to demographic and coevolutionary processes that may add complexity to the common expectation of impoverished diversity on oceanic islands. Here, we explore this topic by studying the cultivable gut bacteria of two sister species of birds, from Sao Tome island and nearby mainland Gabon, the endemic Sao Tome thrush Turdus olivaceofuscus and the African thrush Turdus pelios. We found no differences in the diversity of cultivable gut bacteria between these thrushes, suggesting that, unlike what is commonly found for macrofauna, insularity might not represent a strong constraint for gut bacterial diversity. Although further research on complete gut bacterial communities and a broader range of species and areas is needed, our initial results suggest that the cultivable gut microbial community may bypass the diversity loss associated with island colonization. This could arise from intrinsic factors such as their large population sizes within hosts and low rates of extinction. Furthermore, as gut communities are composed mainly by mutualistic bacteria, diversifying selection (against an impoverished bacterial community), may counteract the diversity loss brought about by the stochastic and demographic effects of the founder process.

Oceanic islands share several environmental characteristics that have been shown to drive convergent evolutionary changes in island organisms. One change that is often assumed but has seldom been examined is the evolution of weaker immune systems in island species. The reduction in species richness on islands is expected to lead to a reduced parasite pressure and, given that immune function is costly, island animals should show a reduced immune response. However, alternative hypotheses exist; for example, the slower pace of life on islands could favor the reorganization of the immune system components (innate vs. acquired immunity) on islands. Thus far, few island species have been studied and no general patterns have emerged. Here, we compared two immune parameters of birds from São Tomé and Príncipe islands to those of their close relatives at similar latitudes on the mainland (Gabon, West Africa). On islands, the acquired humoral component (total immunoglobulins) was lower for most species, whereas no clear pattern was detected for the innate component (haptoglobin levels). These different responses did not seem to arise from a reorganization of the two immune components, as both total immunoglobulins and haptoglobin levels were positively associated. This work adds to the few empirical studies conducted so far which suggest that changes in immune parameters in response to insularity are not as straightforward as initially thought.

The Gulf of Guinea oceanic islands (Príncipe, São Tomé, and Annobón) are among the most endemic-rich regions of the planet. Historical scientific studies of the islands’ unique biodiversity are scattered in a variety of publications, many of which are difficult to access. More recently, there has been a growing interest in the islands, which is reflected in a burst of new studies, reports, and ongoing projects. Here we aim to provide an updated and comprehensive synthesis, covering all the key information and references on the biodiversity of these islands. The goal of the book is to be a comprehensive reference for students, researchers, and conservationists dedicated to the study and preservation of this unique biodiversity. It also intends to serve as a basis for local stakeholders to make informed decisions, namely regarding conservation actions. The book is divided into three main sections: (1) a general overview of the islands and their biodiversity, including aspects of natural and human history (six chapters); (2) detailed accounts on different taxonomic groups (16 chapters); and (3) the conservation, environmental education, and research challenges that lie ahead (three chapters).