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Polylepis forests are threatened high Andean ecosystems that harbour unique species of flora and fauna. However, there is little information on the avifauna associated with these forests in the Central Andes of Peru. We evaluated 12 bird communities in the Junin, Lima and Huancavelica departments of Peru and recorded richness-abundance data that were used to perform an analysis of α- and γ-diversity using Hill numbers. In addition, we built two species matrices (presence-absence data) for three previously identified key bird conservation areas and our study area, first with the species that regularly inhabit the Polylepis forests and second with the species of conservation interest. We found that the Polylepis forests of the Central Andes of Peru have a high diversity of birds. Some of these birds have a strong affinity for Polylepis forests, and another group is typical of the tree line of the Yungas. Moreover, we identified a unique set of 27 species of conservation interest in this region. Since the Central Andes of Peru also harbour three endemic species of Polylepis, it should be considered an important area for the conservation of high Andean biodiversity.

Whole-genome sequencing projects are increasingly populating the tree of life and characterizing biodiversity1-4. Sparse taxon sampling has previously been proposed to confound phylogenetic inference5, and captures only a fraction of the genomic diversity. Here we report a substantial step towards the dense representation of avian phylogenetic and molecular diversity, by analysing 363genomes from 92.4% of bird families-including 267newly sequenced genomes produced for phaseII of the Bird 10,000Genomes (B10K) Project. We use this comparative genome dataset in combination with a pipeline that leverages a reference-free whole-genome alignment to identify orthologous regions in greater numbers than has previously been possible and to recognize genomic novelties in particular bird lineages. The densely sampled alignment provides a single-base-pair map of selection, has more than doubled the fraction of bases that are confidently predicted to be under conservation and reveals extensive patterns of weak selection in predominantly non-coding DNA. Our results demonstrate that increasing the diversity of genomes used in comparative studies can reveal more shared and lineage-specific variation, and improve the investigation of genomic characteristics. We anticipate that this genomic resource will offer new perspectives on evolutionary processes in cross-species comparative analyses and assist in efforts to conserve species.

Why diversification rates vary so extensively across the tree of life remains an important yet unresolved issue in biology. Two prominent and potentially independent factors proposed to explain these trends reflect the capacity of lineages to expand into new areas of (i) geographical or (ii) ecological space. Here, we present the first global assessment of how diversification rates vary as a consequence of geographical and ecological expansion, studying these trends among 15 speciose passerine families (together approximately 750 species) using phylogenetic path analysis. We find that relative slowdowns in diversification rates characterize families that have accumulated large numbers of co-occurring species (at the 1° scale) within restricted geographical areas. Conversely, more constant diversification through time is prevalent among families in which species show limited range overlap. Relative co-occurrence is itself also a strong predictor of ecological divergence (here approximated by morphological divergence among species); however, once the relationship between co-occurrence and diversification rates have been accounted for, increased ecological divergence is an additional explanatory factor accounting for why some lineages continue to diversify towards the present. We conclude that opportunities for prolonged diversification are predominantly determined by continued geographical range expansion and to a lesser degree by ecological divergence among lineages.

Why diversification rates vary so extensively across the tree of life remains an important yet unresolved issue in biology. Two prominent and potentially independent factors proposed to explain these trends reflect the capacity of lineages to expand into new areas of (i) geographical or (ii) ecological space. Here, we present the first global assessment of how diversification rates vary as a consequence of geographical and ecological expansion, studying these trends among 15 speciose passerine families (together approximately 750 species) using phylogenetic path analysis. We find that relative slowdowns in diversification rates characterize families that have accumulated large numbers of co-occurring species (at the 1° scale) within restricted geographical areas. Conversely, more constant diversification through time is prevalent among families in which species show limited range overlap. Relative co-occurrence is itself also a strong predictor of ecological divergence (here approximated by morphological divergence among species); however, once the relationship between co-occurrence and diversification rates have been accounted for, increased ecological divergence is an additional explanatory factor accounting for why some lineages continue to diversify towards the present. We conclude that opportunities for prolonged diversification are predominantly determined by continued geographical range expansion and to a lesser degree by ecological divergence among lineages.

Why diversification rates vary so extensively across the tree of life remains an important yet unresolved issue in biology. Two prominent and potentially independent factors proposed to explain these trends reflect the capacity of lineages to expand into new areas of (i) geographical or (ii) ecological space. Here, we present the first global assessment of how diversification rates vary as a consequence of geographical and ecological expansion, studying these trends among 15 speciose passerine families (together approximately 750 species) using phylogenetic path analysis. We find that relative slowdowns in diversification rates characterize families that have accumulated large numbers of co-occurring species (at the 1° scale) within restricted geographical areas. Conversely, more constant diversification through time is prevalent among families in which species show limited range overlap. Relative co-occurrence is itself also a strong predictor of ecological divergence (here approximated by morphological divergence among species); however, once the relationship between co-occurrence and diversification rates have been accounted for, increased ecological divergence is an additional explanatory factor accounting for why some lineages continue to diversify towards the present. We conclude that opportunities for prolonged diversification are predominantly determined by continued geographical range expansion and to a lesser degree by ecological divergence among lineages.

Why diversification rates vary so extensively across the tree of life remains an important yet unresolved issue in biology. Two prominent and potentially independent factors proposed to explain these trends reflect the capacity of lineages to expand into new areas of (i) geographical or (ii) ecological space. Here, we present the first global assessment of how diversification rates vary as a consequence of geographical and ecological expansion, studying these trends among 15 speciose passerine families (together approximately 750 species) using phylogenetic path analysis. We find that relative slowdowns in diversification rates characterize families that have accumulated large numbers of co-occurring species (at the 1° scale) within restricted geographical areas. Conversely, more constant diversification through time is prevalent among families in which species show limited range overlap. Relative co-occurrence is itself also a strong predictor of ecological divergence (here approximated by morphological divergence among species); however, once the relationship between co-occurrence and diversification rates have been accounted for, increased ecological divergence is an additional explanatory factor accounting for why some lineages continue to diversify towards the present. We conclude that opportunities for prolonged diversification are predominantly determined by continued geographical range expansion and to a lesser degree by ecological divergence among lineages.

Why diversification rates vary so extensively across the tree of life remains an important yet unresolved issue in biology. Two prominent and potentially independent factors proposed to explain these trends reflect the capacity of lineages to expand into new areas of (i) geographical or (ii) ecological space. Here, we present the first global assessment of how diversification rates vary as a consequence of geographical and ecological expansion, studying these trends among 15 speciose passerine families (together approximately 750 species) using phylogenetic path analysis. We find that relative slowdowns in diversification rates characterize families that have accumulated large numbers of co-occurring species (at the 1° scale) within restricted geographical areas. Conversely, more constant diversification through time is prevalent among families in which species show limited range overlap. Relative co-occurrence is itself also a strong predictor of ecological divergence (here approximated by morphological divergence among species); however, once the relationship between co-occurrence and diversification rates have been accounted for, increased ecological divergence is an additional explanatory factor accounting for why some lineages continue to diversify towards the present. We conclude that opportunities for prolonged diversification are predominantly determined by continued geographical range expansion and to a lesser degree by ecological divergence among lineages.

Details of morphological measurements

Why diversification rates vary so extensively across the tree of life remains an important yet unresolved issue in biology. Two prominent and potentially independent factors proposed to explain these trends reflect the capacity of lineages to expand into new areas of (i) geographical or (ii) ecological space. Here, we present the first global assessment of how diversification rates vary as a consequence of geographical and ecological expansion, studying these trends among 15 speciose passerine families (together approximately 750 species) using phylogenetic path analysis. We find that relative slowdowns in diversification rates characterize families that have accumulated large numbers of co-occurring species (at the 1° scale) within restricted geographical areas. Conversely, more constant diversification through time is prevalent among families in which species show limited range overlap. Relative co-occurrence is itself also a strong predictor of ecological divergence (here approximated by morphological divergence among species); however, once the relationship between co-occurrence and diversification rates have been accounted for, increased ecological divergence is an additional explanatory factor accounting for why some lineages continue to diversify towards the present. We conclude that opportunities for prolonged diversification are predominantly determined by continued geographical range expansion and to a lesser degree by ecological divergence among lineages.

Cinnyris whytei skye, subspecies nov. Holotype: ZMUC 103.506, Ad. male, 30 Nov. 2002, Mafwemiro Forest, Rubeho Highlands, Mpwapwa District, Tanzania; collected by J. Bolding Kristensen. Description of holotype: Entire head and upper parts of body, including lesser and median wing coverts, iridescent Peacock Green (varying from Dark Viridian Green to Yellow Green depending on angle of view) with Dark Mouse Grey basal parts of feathers, upper tail coverts Marine to Azurite Blue; greater wing coverts and remiges Dark Neutral Grey, worn edges appearing lighter; rectrices Bluish Slate Black, outer rectrix with pale grey outer edge and medium grey distal quarter, next rectrix medium grey distal quarter. Upper breast same colour as head, with narrow violet transition to Paris Blue pectoral band (combined 4.4 mm wide), lower breast Scarlet with narrow blue terminus on most feathers (see Figs. 3 & 4) (15 mm wide), lateral feathers Lemon Chrome; underparts of body behind the red band between Mouse Grey and Light Mouse Grey, washed Citron Yellow on central belly; underwing-coverts Neutral Grey. Eyes dark brown, bill black, legs and feet black. Bill (tip to nostril) 18.0, wing 60.5, tarsus 15.5, tail 51.3 mm, 9.5 g, testes small, ossification complete. Paratype: ZMUC 103.507, Ad. female; 29 Nov. 2002, Mafwemiro Forest, Rubeho Highlands, Mpwapwa District, Tanzania; collected by J. Bolding Kristensen. Description of paratype: Upper parts from forehead to base of tail Mouse Grey, wing coverts Deep Mouse Grey, remiges Dark Mouse Grey, worn edges paler; rectrices Dull Violet Black, outer Deep Mouse Grey with narrow pallid grey outer and terminal edges. Side of head like upperparts, with Pale Mouse Grey anterior supercilium and blackish lore; lower head-sides, chin, throat and breast Light Mouse Grey with deep grey centers of feathers, sides Light Mouse Grey and belly to vent similar but appearing more olive-buff due to Citron Yellow wash towards the tips of the feathers. Axillaries Barium yellow, under wing-coverts to carpal edge Sea-foam Yellow; breast with darker feather centers. Eyes dark brown, bill black, legs and feet black. Bill 16.3, wing 57.5, tarsus 16.4, tail 44.4 mm, 9.5 g, ovary with no large follicles, skull 90% ossified. Diagnosis. Resembles other members of the C. afer species complex (Table 1) by its large size and relatively long tail, but differs from C. afer and C. stuhlmanni by having a relatively short and broad bill, and hence is most similar to C. whytei. Males differ from those of C. whytei from Nyika Plateau by having longer tarsi, a broader blue pectoral band (Table 4), and narrow blue feather-tips producing a scaly effect on much of the scarlet pectoral band (Figs. 3 & 4). Within its range, it is readily distinguishable from sympatric C. fuelleborni and C. moreaui, even in the field, by its larger size, more elongated body and tail, lack of olive wing-panel, very broad and dark red breastband (males) and deep grey underparts of the body. Similarly, it differs from C. manoensis of adjacent woodland habitats by size, shape, dark grey belly and, in males, broader breast-band. Other specimens examined and individual variation. Rubeho Highlands at Chugu Hill: ZMUC 93.056 ad. ³; southwestern edge of Mafwemiro Forest: ZMUC 93.057 ad. ³, ZMUC 94.021 ad. ♀ (skin and partial skeleton), ZMUC 101.719 ad. ³, ZMUC 101.720 ad. ³, ZMUC 101.721 ad. ♀, ZMUC 101.722 ad. ♀, ZMUC 101.723 ad. ♀, ZMUC 101.724 juv. ♀; Ukwiva Forest: ZMUC 93.129 ad. ³. Individual variation in measurements are reported in Table 4. The colours vary very little: underparts of males may vary from Mouse Grey over Quaker Drab to Drab, or Benzo Brown; thus, generally very dull greyish. Juvenile resembles adult females, but has a softer plumage and more uniform Mouse Grey to Quaker Drab underparts with little yellow wash on the belly. Etymology. The scientific name is used as a noun in apposition and acknowledges the contributions of the Skye Foundation to the education of African students. The Skye Foundation was established in 1997 in South Africa by the Zylstra Family Trust to fund postgraduate scholarships, tenable worldwide, and awarded on the basis of academic achievement in any subject. Distribution. This new sunbird inhabits a narrow ecological zone along the border between humid montane forests and drier woodlands in the rain shadow to the north and west, around 2000 m elevation in the Rubeho and Udzungwa Highlands of western Tanzania (Fig. 1). Localities are: (1) western edge of Kisinga-Rugaro Forest (Fig. 1), which covers a large granitic dome in the highland 20 km east of the town of Iringa (observations 16 February 2008 in forest/grassland mosaics along the western edge of the highland, at 7 ° 48'S, 35 ° 54'E, 2200 m, near the village Kidodi; JF and Michael K. Poulsen; photo documentation). (2) Image Forest Reserve (Fig. 1), south of Ibumu Village at 7 ° 22'–33'S, 36 ° 08'–12'E and around 2000 m (observations by JF, January 2000). (3) Mangalisa Forest (Fig. 1), at 7 ° 07'S – 36 ° 25'E, at c. 2200 m (forest edge and small groups of evergreen trees in adjacent farmland; observations by JF in Dec. 2001; this is a mesa-like highland in the northeastern part of the Great Ruaha Basin, close to the Rubeho Highlands but separated from them by arid lowland habitat. (4) Western edge of Ukwiva Forest (Fig. 1), approximately 7 ° 06'S – 36 ° 40'E at 2100 m, May 2000, and seen August–September 2002 (JK). (5) Mafwemiro Forest (Fig. 1), Mpwapwa District, the top ridge of the northern Rubeho Highlands (collecting on Chugu Hill 6°50'S 36°34'E, 2050 m by JK May 2000; observations and collecting by JF, JBK and JK at the southwestern forest edge at 7 ° 55–58'S, 36 ° 33–34'E, 1700–1900 m, Nov–Dec 2002). Additional populations could be expected to inhabit wooded mountain ridges west of Mafwemiro Forest and isolated mountain tops north of the Ruaha Basin, such as the Wota Mountains; however, skye was not detected during recent collecting trips to the Ukaguru and Kiboriani Mountains near Mpwapwa. Since most ornithological research in the Nyumbanitu and Ndundulu Mountains of the Udzungwa Highland (Fig. 1) has been conducted inside the forest, we do not exclude the possibility that the new sunbird could occur at the western edge of these forests. However, since it has never been seen near Iringa or anywhere further west in Tanzania, such as in well-collected sites in the southern highlands (Kipengere, Poroto and Livingstone Mountains), it seems reasonable to believe that Kisingo-Rugaro represents the range limit towards the southwest. Ecology. Cinnyris whytei skye of the Iringa Region of Tanzania has been recorded at 1700–2250 m along the eastern and northern parts of large undulating highlands, right on the transition between humid montane forest and the adjacent farm and fallow land extending towards the western sides of forest penetrating the rainshadow. These areas are rather nutrient-poor, with light brown sandy soils. Rainfall is mostly orographic on the eastern scarps, and considerable mist precipitation probably occurs, as the forests in question are often enshrouded at night by carpets of mist. Further, the trees are often covered with "old man’s beard" (Usnea), suggesting a strong mist effect. The sunbird is locally common and easily found, but restricted to the narrow ecological zone on the rainshadow (western) side of the highland forests (Fig. 7; with Bersema abyssinica, Maesa lanceolata, Myrica salicifolia, Nuxia congensta, Parinari excelsa, Podocarpus spp. and Syzygium spp.), in places where groups of small trees (Myrica salicifolia and Erica [ex- Philippia]) form a mosaic with montane grassland or in shrubby areas with bracken (Pteridium) and brambles (Rubus). The vine Tecomaria capensis is generally abundant, and its orange-red flowers seem to be an important food plant. Much of the forest edge habitat is strongly disturbed by human activity (cutting of poles, fires); there are clearings (after past cultivation) inside the forest, and much of the area outside the forest is cultivated. Some observations of the sunbird were thus in small clumps of evergreen trees in farmland within a few hundred meters of the forest edge. In (generally rocky) areas without strong human influence, the typical vegetation is open woodland (Brachystegia boehmii, B. microphylla, B. spiciformis and Uapaca kirkiana, some Acacia abyssinica) with tall grasses (Themeda triandra). The ecological zone in which this sunbird has been seen is only a few hundred meters wide, and most observations are right at the forest edge. Because intensive fieldwork has been conducted inside the forest, and considerable time spent in the more open habitats, we believe that the species does not normally occur in dense forest or open habitats, but primarily in the narrow transition between these habitats. Several other sunbird species occur locally; this large-bodied member of the C. afer complex (Table 1) seems to be narrowly squeezed between C. moreaui / C. fuelleborni in montane forest and C. kilimensis (Shelley), C. manoensis and C. venusta (Shaw & Nodder) in the more open grass-shrubland mosaic. Conservation. Cinnyris whytei whytei and C. whytei skye of Malawi and Tanzania, respectively, appear to be fairly common where they occur. However, their restricted and disjunct range seems to suggest a relict distribution. The generally high human density in rainshadow areas immediately adjacent to humid montane forests (Fjeldså & Burgess 2008) has resulted in a significant loss of habitat in this zone. Therefore, the mosaic vegetation that characterizes this transition zone under natural conditions has, in most places, been cleared for agriculture or now appears largely as bracken-covered fallow areas, with a sharp boundary towards the remaining (disturbed) forest in Tanzania. Some birds can be found in tiny thickets in the cleared land, but in general there are only a few places left with sufficient areas of habitat to accommodate a significant population. The situation is better for the nominate subspecies in Malawi, where most of the species’ range is restricted to the Nyika Plateau, a large protected area.

A) Time tree obtained using the Reltime method. Each node received a number. B) Dated nodes, including 95 % CI. Brown circles denotes BEAST results, yellow squares MCMCTREE results, and blue circles Reltime results. Node ID relates to node numbers in panel A, and can be seen in table format in Additional file 1: Table S1. (PDF 250 kb)

Diversification rate analyses using DR and BAMM

A) Time tree obtained using the Reltime method. Each node received a number. B) Dated nodes, including 95 % CI. Brown circles denotes BEAST results, yellow squares MCMCTREE results, and blue circles Reltime results. Node ID relates to node numbers in panel A, and can be seen in table format in Additional file 1: Table S1. (PDF 250 kb)

Nephelomyias, gen. nov. Ohlson, Fjeldså & Ericson Type species: Mitrephorus ochraceiventris Cabanis, 1873. Included species: Nephelomyias pulcher (P. L. Sclater, 1861) comb. nov., Handsome Flycatcher; Nephelomyias ochraceiventris (Cabanis, 1873) comb. nov., Ochraceous-breasted Flycatcher; Nephelomyias lintoni (Meyer de Schauensee, 1951) comb. nov. Orange-banded Flycatcher. Diagnosis: External morphology —Small passerine birds similar in proportions to several “contopine” flycatcher genera (clade F 4 in Ohlson et al. 2008; Contopini in Tello et al. 2009), e.g. Lathrotriccus and Empidonax, but bill flatter and relatively shorter, barely longer then the surrounding rictal bristles, and with a much smaller distal hook. Distinguished from other species traditionally included in Myiophobus by the combination of contrasting wing bars and pale panel on the distal two thirds of the secondaries, rich yellow to ochraceous underparts, and lack of streaking or flammulated pattern on chest and flanks. They are markedly distinct from other members of Hirundineinae, being less derived in both proportions and plumage pattern. They lack the unique colour pattern of Myiotriccus and the long wings, weak tarsi and predominantly rufous plumage of Pyrrhomyias and Hirundinea. The total length is 12.5- 14 cm (lintoni and ochraceiventris) or 9.5– 11 cm (pulcher). Plumage predominantly olive above and yellow below, with orange ochre breast in ochraceiventris and pulcher; head with prominent yellow to orange-red coronal patch (most prominent in males) and pale arched supraloral line and inconspicuous eye ring; wings and tail dusky to blackish with broad pale ochre to bright cinnamon tips of greater and median secondary coverts, forming two conspicuous wing bars; tertials and remiges edged whitish to pale ochre, except on the inner third of the secondaries, which forms a distinct blackish patch in the closed wing. Nephelomyias pulcher differs from the other two by being smaller with a proportionally shorter tail. Interspecific variation in plumage coloration involves tone and richness in colour of underparts and wing markings, colour of the supraloral stripe and eye ring and degree of grey tinge on the head. Apart from this variation, N. ochraceiventris has the ochre colour of the underparts extending over the sides of the head, and an all black bill (yellowish lower mandible in the other two); N. lintoni has pale iris (dark in the other two species). Anatomical characters — Cranial and syringeal material is only known for one species (N. ochraceiventris), so a full evaluation of anatomical characters cannot be made for the genus. Furthermore, cranial and syringeal morphology in Tyrannidae has been shown to be highly homoplastic (Birdsley 2002; Ericson et al. 2006; Ohlson et al. 2008) and any of the individual character states below are found in some other tyrant flycatcher clade. However, at least N. ochraceiventris shares with Myiotriccus, Hirundinea and Pyrrhomyias the following unique combination of characters (Lanyon, 1986, 1988a, 1988 b): 1) Superior interorbital fenestrae obliterated by ossification (found in many members of Elaeniinae and Rhynchocyclidae, but not in Tyranninae or Fluvicolinae other than Myiophobus flavicans, M. inornatus and M. fasciatus); 2) Lack of a fork at the posterior end of the trabecular plate in the nasal septum (characteristic for non- fluvicoline tyrant flycatchers, in Fluvicolinae only found in Myiophobus phoenicomitra and some specimens of M. roraimae); 3) 1–2 A elements form completely ossified rings around each bronchus in the syrinx (found in most tyrannids, absent in Ochthoeca, Tumbezia, Colorhamphus, Fluvicola, Arundinicola and Alectrurus in Fluvicolinae, in the tody-tyrants and Cnipodectes in Rhynchocyclidae, and in all members of Elaeniinae except Inezia and Zimmerius); 4) Bronchi separated by a calcified pessulus (found in many members of Rhynchocyclidae, but absent in all other tyrant flycatchers, except Sublegatus, Colonia, Machetornis, Zimmerius, Inezia, Pseudelaenia, Myiophobus flavicans, M. inornatus and M. fasciatus. Nephelomyias ochraceiventris further shares with Myiotriccus a slightly elevated trabecular plate, resulting in a sagittal ridge at the ventral end of the nasal septum (typical of elaeniines) and the lack of a notch at the anterior end of the nasal septum. Neither of these character states is found in Hirundinea, Pyrrhomyias or any member of Fluvicolinae, except Myiophobus phoenicomitra and M. roraimae. Habitat and behaviour: Distinguished behaviorally both from the other members of Hirundineinae and from their former congeners in Myiophobus by being more arboreal, inhabiting the canopy and subcanopy of humid montane forest. They forage for small arthropods (and possibly some fruit) by short sallies to air or foliage and by perch gleaning. Unlike other members of Hirundineinae, they usually travel in small groups which often accompany mixed foraging parties (Poulsen 1996), a behaviour that sets them apart from most tyrant flycatchers outside Elaeniinae (Ohlson et al. 2008). Distribution: All three species are restricted to humid forest in the Andes. Nephelomyias pulcher has a disjunct range, with populations in the Andean cloud forests (1500-2600 m) of Colombia and northern Ecuador and in the yungas of Bolivia and southern Peru. Nephelomyias lintoni and N. ochraceiventris are sandwiched between the two populations of N. pulcher, replacing each other in the upper montane and elfin forest (2200-3500 m) north and south of the North Peru Low. Molecular data: Phylogenetic analyses based on DNA sequence data from three nuclear introns of 126 species of Tyrannidae and allies show that Nephelomyias species do not belong to Fluvicolinae, where species of Myiophobus are placed (Fig. 1; Ohlson et al. 2008). Instead, they group with Myiotriccus, Pyrrhomyias and Hirundinea, forming the small clade Hirundineinae that constitutes an independent deep lineage in Tyrannidae. The relationship of this clade to Elaeniinae, Tyranninae and Fluvicolinae is currently unresolved. Etymology: The genus name Nephelomyias (from Gr. Nephéle =cloud, mod. L. myias = a flycatcher) highlights the restricted Andean cloud forest canopy habitat of all three species. The name is masculine in gender.

Ohlson, Jan I., Fjeldså, Jon, Ericson, Per G. P. (2009): A new genus for three species of tyrant flycatchers (Passeriformes: Tyrannidae), formerly placed in Myiophobus. Zootaxa 2290: 36-40, DOI: 10.5281/zenodo.191390

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.