A simple dynamic model explains the diversity of island birds worldwide.

Colonization, speciation and extinction are dynamic processes that influence global patterns of species richness1-6. 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.

Monitoring mosquito richness in an understudied area: can environmental DNA metabarcoding be a complementary approach to adult trapping?

Mosquito surveillance programmes are essential to assess the risks of local vector-borne disease outbreaks as well as for early detection of mosquito invasion events. Surveys are usually performed with traditional sampling tools (i.e., ovitraps and dipping method for immature stages or light or decoy traps for adults). Over the past decade, numerous studies have highlighted that environmental DNA (eDNA) sampling can enhance invertebrate species detection and provide community composition metrics. However, the usefulness of eDNA for detection of mosquito species has, to date, been largely neglected. Here, we sampled water from potential larval breeding sites along a gradient of anthropogenic perturbations, from the core of an oil palm plantation to the rainforest on São Tomé Island (Gulf of Guinea, Africa). We showed that (i) species of mosquitoes could be detected via metabarcoding mostly when larvae were visible, (ii) larvae species richness was greater using eDNA than visual identification and (iii) new mosquito species were also detected by the eDNA approach. We provide a critical discussion of the pros and cons of eDNA metabarcoding for monitoring mosquito species diversity and recommendations for future research directions that could facilitate the adoption of eDNA as a tool for assessing insect vector communities.

Patterns of bird song evolution on islands support the character release hypothesis in tropical but not in temperate latitudes.

The character release hypothesis-which predicts that a decline in interspecific competition leads to the expansion of trait expression-remains to be tested for communication signals. Taking advantage of the fact that oceanic islands host fewer species than the mainland, we tested whether island birds show an increase in frequency bandwidth of acoustic signals compared with mainland birds. Given the higher animal diversity and more saturated acoustic space in the tropics, we expected acoustic character release, if any, to be stronger in the tropics than in the temperate zone. We field recorded 22 bird species (11 pairs consisting of an endemic island species and its closest mainland relative) breeding at similar latitudes and in similar habitats: six tropical pairs (São Tomé Island/Mount Cameroon) and five temperate pairs (Madeira Island/southern France). For each species, we measured the degree of acoustic interference experienced when vocalizing and the spectral characteristics of its song (minimum and maximum frequencies, bandwidth). As expected, island species spent more time vocalizing alone, and any overlap in vocalizations involved fewer species. The vocalizations of island species spanned broader frequency bandwidths than their mainland counterparts in the tropics (true for all six pairs), but this pattern was less evident in the temperate region (2/5 pairs with no marked differences and 1/5 with opposite pattern). Overall, the character release of communication signals only occurred where the differential in number of species was large (tropics). We discuss latitude differences and the potential factors driving the observed differences.

The origin of the world's smallest flightless bird, the Inaccessible Island Rail Atlantisia rogersi (Aves: Rallidae).

Rails (Aves: Rallidae) are renowned for their extreme dispersal capability, which has given rise to numerous island lineages. Many insular species lost the ability to fly as a response to release from predator pressure-a feature causing rapid extinction when humans subsequently introduced mammals. The world's smallest extant flightless bird, the Inaccessible Island Rail Atlantisia rogersi, is endemic to Inaccessible Island, Tristan da Cunha archipelago, in the central South Atlantic Ocean. It is placed in a monotypic genus, but its taxonomic affinity, as well as geographic origin, are disputed. Contrary to its suggested Old World origin, we demonstrate that the Inaccessible Island Rail is nested within the mainly South American 'Laterallus clade' and that it colonized ≥3 million-year-old Inaccessible Island from South America c. 1.5 million years ago. The taxonomy of rails has traditionally been based on morphology, and convergent evolution has caused many cases of misclassification. We suggest a re-classification within the 'Laterallus clade' and call for extended coverage of taxon sampling for DNA sequencing.

Coevolutionary patterns and diversification of avian malaria parasites in African sunbirds (Family Nectariniidae).

The coevolutionary relationships between avian malaria parasites and their hosts influence the host specificity, geographical distribution and pathogenicity of these parasites. However, to understand fine scale coevolutionary host-parasite relationships, robust and widespread sampling from closely related hosts is needed. We thus sought to explore the coevolutionary history of avian Plasmodium and the widespread African sunbirds, family Nectariniidae. These birds are distributed throughout Africa and occupy a variety of habitats. Considering the role that habitat plays in influencing host-specificity and the role that host-specificity plays in coevolutionary relationships, African sunbirds provide an exceptional model system to study the processes that govern the distribution and diversity of avian malaria. Here we evaluated the coevolutionary histories using a multi-gene phylogeny for Nectariniidae and avian Plasmodium found in Nectariniidae. We then assessed the host-parasite biogeography and the structuring of parasite assemblages. We recovered Plasmodium lineages concurrently in East, West, South and Island regions of Africa. However, several Plasmodium lineages were recovered exclusively within one respective region, despite being found in widely distributed hosts. In addition, we inferred the biogeographic history of these parasites and provide evidence supporting a model of biotic diversification in avian Plasmodium of African sunbirds.

Advances in Ecological Speciation: an integrative approach.

The role of natural selection in promoting reproductive isolation has received substantial renewed interest within the last two decades. As a consequence, the study of ecological speciation has become an extremely productive research area in modern evolutionary biology. Recent innovations in sequencing technologies offer an unprecedented opportunity to study the mechanisms involved in ecological speciation. Genome scans provide significant insights but have some important limitations; efforts are needed to integrate them with other approaches to make full use of the sequencing data deluge. An international conference 'Advances in Ecological Speciation' organized by the University of Porto (Portugal) aimed to review current progress in ecological speciation. Using some of the examples presented at the conference, we highlight the benefits of integrating ecological and genomic data and discuss different mechanisms of parallel evolution. Finally, future avenues of research are suggested to advance our knowledge concerning the role of natural selection in the establishment of reproductive isolation during ecological speciation.

Avian Island Radiations Shed Light on the Dynamics of Adaptive and Nonadaptive Radiation.

Understanding the mechanisms underlying species formation and differentiation is a central goal of evolutionary biology and a formidable challenge. This understanding can provide valuable insights into the origins of the astonishing diversity of organisms living on our planet. Avian evolutionary radiations on islands have long fascinated biologists as they provide the ideal variation to study the ecological and evolutionary forces operating on the continuum between incipient lineages to complete speciation. In this review, we summarize the key insights gained from decades of research on adaptive and nonadaptive radiations of both extant and extinct insular bird species. We present a new comprehensive global list of potential avian radiations on oceanic islands, based on published island species checklists, taxonomic studies, and phylogenetic analyses. We demonstrate that our understanding of evolutionary processes is being greatly enhanced through the use of genomic tools. However, to advance the field, it is critical to complement this information with a solid understanding of the ecological and behavioral traits of both extinct and extant avian island species.

DNA Barcode library of the endemic-rich avifauna of the oceanic islands of the Gulf of Guinea.

Background: The BioSTP: DNA Barcoding of endemic birds from oceanic islands of the Gulf of Guinea dataset contains records of 155 bird specimens belonging to 56 species in 23 families, representing over 80% of the diversity of the breeding landbird community. All specimens were collected on Príncipe, São Tomé and Annobón Islands between 2002 and 2021 and morphologically identified to species or subspecies level by qualified ornithologists. The dataset includes all endemic species and 3/4 of the extant endemic subspecies of the islands. This dataset is the second release by BioSTP and it greatly increases the knowledge on the DNA barcodes of Gulf of Guinea birds. All DNA extractions are deposited at Associação BIOPOLIS - CIBIO, Research Center in Biodiversity and Genetic Resources. New information: The dataset includes DNA barcodes for all 29 endemic bird species and for 11 of the 15 extant endemic bird subspecies from the oceanic islands of the Gulf of Guinea. This is the first major DNA barcode set of African birds. The three endemic subspecies of Crithagrarufobrunnea, an island endemic with three allopatric populations within the Archipelago, are also represented. Additionally, we obtained DNA barcodes for 16 of the 21 non-endemic landbirds and for one vagrant (Sylviacommunis). In total, forty-one taxa were new additions to the Barcode of Life Data System (BOLD), with another 11 corresponding to under-represented taxa in BOLD. Furthermore, the submitted sequences were found to cluster in 55 Barcode Index Numbers (BINs), 37 of which were new to BOLD. All specimens have their DNA barcodes publicly accessible through BOLD online database and GenBank.

A new species of scops-owl (Aves, Strigiformes, Strigidae, Otus) from Príncipe Island (Gulf of Guinea, Africa) and novel insights into the systematic affinities within Otus.

A new species of scops-owl (Aves, Strigiformes, Strigidae, Otus) is described from Príncipe Island, São Tomé and Príncipe (Gulf of Guinea, Africa). This species was discovered for science in 2016, although suspicions of its occurrence gained traction from 1998, and testimonies from local people suggesting its existence could be traced back to 1928. Morphometrics, plumage colour and pattern, vocalisations, and molecular evidence all support the species status of the scops-owl from Príncipe, which is described here as Otusbikegila sp. nov. Phylogenetic analyses suggest that this species descended from the first colonisation of the Gulf of Guinea islands, being sister to the clade including the mainland African Scops-Owl O.senegalensis, and the island endemics Sao Tome Scops-Owl O.hartlaubi and Pemba Scops-Owl O.pembaensis. The most diagnostic trait in the field is its unique call which, curiously, is most similar to a distantly related Otus species, the Sokoke Scops-Owl O.ireneae. The new species occurs at low elevations of the old-growth native forest of Príncipe, currently restricted to the south of the island but fully included within Príncipe Obô Natural Park. Otusbikegila sp. nov. takes the number of single-island endemic bird species of Príncipe to eight, further highlighting the unusually high level of bird endemism for an island of only 139 km2.

ResumoDescrevemos uma nova espécie de mocho-de-orelhas ou kitóli (Strigiformes: Strigidae: Otus) da Ilha do Príncipe, São Tomé e Príncipe (Golfo da Guiné, África). Esta espécie foi descoberta para a ciência apenas em 2016, embora suspeitas da sua existência tenham ganho força a partir de 1998, e testemunhos de habitantes locais sobre a sua ocorrência já estarem documentados em 1928. A morfometria, a cor e padrão da plumagem, as vocalizações e dados moleculares demonstram que esta população de mocho no Príncipe é uma espécie nova, que foi batizada de mocho-do-príncipe (lista mundial) ou kitóli-do-príncipe (nome nacional), Otusbikegila sp. nov. As análises filogenéticas indicam que esta espécie descende da primeira colonização das ilhas do Golfo da Guiné, sendo irmã do clado que inclui o mocho-d'ore­lhas-africano O.senegalensis, do continente, o mocho-de-são-tomé (ou kitóli-de-são-tomé) O.hartlaubi e o mocho-de-pemba O.pembaensis, ambos endémicos das ilhas que lhes dão o nome. No campo, a característica mais diagnóstica é o seu canto único que, curiosamente, é mais parecido com o da espécie de Otus mais afastada, o mocho-de-sokoke O.ireneae. A nova espécie ocorre nas zonas baixas da floresta nativa do Príncipe, atualmente restrita ao sul da ilha, mas totalmente inserida no Parque Natural do Obô do Príncipe. Otusbikegila sp. nov. eleva o número de espécies de aves endémicas restritas ao Príncipe para oito, sublinhando ainda mais o nível extremamente elevado de aves endémicas para uma ilha de apenas 139 km2.

Rapid parallel evolution of aberrant traits in the diversification of the Gulf of Guinea white-eyes (Aves, Zosteropidae).

Archipelago-endemic bird radiations are familiar to evolutionary biologists as key illustrations of evolutionary patterns. However, such radiations are in fact rare events. White-eyes (Zosteropidae) are birds with an exceptionally high colonization and speciation potential; they have colonized more islands globally than any other passerine group and include the most species-rich bird genus. The multiplication of white-eye island endemics has been consistently attributed to independent colonizations from the mainland; the white-eyes of the Gulf of Guinea archipelago had been seen as a classic case, spanning as great a breadth of phenotypic diversity as the family worldwide. Contrary to this hypothesis, our molecular phylogenetic analysis places the Gulf of Guinea white-eyes in just two radiations, one grouping all five oceanic island taxa and the other grouping continental island and land-bridge taxa. Numerous 'aberrant' phenotypes (traditionally grouped in the genus Speirops) have evolved independently over a short space of time from nonaberrant (Zosterops) phenotypes; the most phenotypically divergent species have separated as recently as 0.22 Ma. These radiations rival those of Darwin's finches and the Hawaiian honeycreepers in terms of the extent of adaptive radiation per unit time, both in terms of species numbers and in terms of phenotypic diversity. Tempo and patterns of morphological divergence are strongly supportive of an adaptive radiation in the oceanic islands driven by ecological interactions between sympatric white-eyes. Here, very rapid phenotypic evolution mainly affected taxa derived from the youngest wave of colonization, in accordance with the model of asymmetric divergence owing to resource competition in sympatry.

Metabarcoding options to study eukaryotic endoparasites of birds.

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.

Tracing the colonization history of the Indian Ocean scops-owls (Strigiformes: Otus) with further insight into the spatio-temporal origin of the Malagasy 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.

First record of Aedes albopictus (Skuse 1894) on São tomé island.

Biological invasions have critical impacts on native biodiversity and human societies and especially on oceanic islands that are fragile and threatened ecosystems. The invasive tiger mosquito Aedes (Stegomyia) albopictus (Skuse, 1894) native to Southeast Asia has been introduced during the past 30 years almost everywhere in the world, including the Americas, the Pacific, Europe and Africa. It has been reported for the first time in the Gulf of Guinea in 2000, first in Cameroon, then in Bioko Island in 2003 and more recently in Gabon in 2007. Here we report the first record of Ae. albopictus on São Tomé Island. Although we cannot estimate precisely the year of introduction on São Tomé Island, it most likely arrived within the last 10 years. By sequencing the mitochondrial cytochrome c oxidase gene from individual adults, we detected three haplotypes already present in mainland Africa. More studies are needed to explore the dynamics of its expansion and competition with insular native mosquitoes.

Insularity effects on bird immune parameters: A comparison between island and mainland populations in West Africa.

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.

Insularity effects on the assemblage of the blood parasite community of the birds from the Gulf of Guinea.

AIM: Lower species diversity, increased population densities and ecological niche enlargement are common characteristics of island faunas. However it remains to be determined if they extend to the parasite community. We tested if Haemosporidia parasite pressure varies between islands and the mainland with two different levels of analysis: i) at the host community level, and ii) with paired-species comparisons between islands and the mainland. LOCATION: Gulf of Guinea, West Africa. METHODS: We used molecular-based methods to identify avian Haemosporidian parasites (Plasmodium, Haemoproteus and Leucocytozoon) to describe their diversity, prevalence, host specificity and their phylogenetic relationships in five islands of the Gulf of Guinea and in nearby mainland areas. RESULTS: We found reduced Haemosporidia diversity on islands for Haemoproteus and Leucocytozoon, but not for Plasmodium. In addition, lower parasite prevalence on islands was found using a paired-species approach. Although the mean host specificity of the parasite community on islands did not differ from the mainland, we found a very distinct parasite species assemblage on the islands, which was composed of both the most generalist and the most specialist lineages. MAIN CONCLUSIONS: This study supports the hypothesis that parasite pressure is reduced on islands. Colonization is made by generalists with high host switching capacities, with some subsequently evolving into highly specialised parasites. This suggests that 'taxon cycle' dynamics may explain the assemblage of insular parasite communities.

The collection of birds from Mozambique at the Instituto de Investigação Científica Tropical of the University of Lisbon (Portugal).

The Instituto de Investigação Científica Tropical of the University of Lisbon, which resulted from the recent merger (in 2015) of the former state laboratory Instituto de Investigação Científica Tropical in the University of Lisbon, holds an important collection of bird skins from the Portuguese-speaking African Countries (Angola, Mozambique, São Tomé and Príncipe, Guinea Bissau and Cape Verde), gathered as a result of several scientific expeditions made during the colonial period. In this paper, the subset from Mozambique is described, which was taxonomically revised and georeferenced. It contains 1585 specimens belonging to 412 taxa, collected between 1932 and 1971, but mainly in 1948 (43% of specimens) and 1955 (30% of specimens). The collection covers all eleven provinces of the country, although areas south of the Zambezi River are better represented than those north of the river. The provinces with the highest number of specimens were Maputo, Sofala, and Gaza. Although it is a relatively small collection with a patchy coverage, it adds significantly to Global Biodiversity Information Facility, with 15% of all records available before and during the collecting period (1830-1971) being the second largest dataset for that period for Mozambique.

Global phylogeographic limits of Hawaii's avian malaria.

The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite within a global ecological and evolutionary context. Using fragments of the parasite mitochondrial gene cytochrome b and the nuclear gene dihydrofolate reductase-thymidylate synthase obtained from a global survey of greater than 13000 avian samples, we show that Hawaii's avian malaria, which can cause high mortality and is a major limiting factor for many species of native passerines, represents just one of the numerous lineages composing the morphological parasite species. The single parasite lineage detected in Hawaii exhibits a broad host distribution worldwide and is dominant on several other remote oceanic islands, including Bermuda and Moorea, French Polynesia. The rarity of this lineage in the continental New World and the restriction of closely related lineages to the Old World suggest limitations to the transmission of reproductively isolated parasite groups within the morphological species.

The collection of birds from São Tomé and Príncipe at the Instituto de Investigação Científica Tropical of the University of Lisbon (Portugal).

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.

Host associations and evolutionary relationships of avian blood parasites from West Africa.

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.