Sparrows of the West

Recent decades have seen significant shifts in the classification of birds, particularly among the Passeriformes, the perching birds. These shifts have lead to the recognition of a number of major groups that were previously obscured. Among these recent elevations are the New World sparrows of the Passerellidae.

Gambel's white-crowned sparrow Zonotrichia leucophrys gambeli, copyright Gregory Smith.

The New World sparrows are part of a broader radiation known as the nine-primaried songbirds, along with such luminaries as finches, tanagers, and their Old World namesakes. The name 'nine-primaried' refers to the number of well-developed primary feathers (the long outer ones) in the wings; most other perching birds have ten distinct primaries. Though the nine-primaried songbirds have long been recognised as a coherent group, there has been a lot of disagreement over their subdivision. Historically, these subdivisions were strongly influenced by different bill shapes representing different diet specialisations, but recent molecular phylogenies have demonstrated that bill shape is more labile than previously recognised. The New World sparrows were usually regarded previously as a subgroup of the generalist seed-eating family Emberizidae, along with the buntings of the Old World, but molecular phylogenies have asserted the division between the hemispheres. Not all New World representatives of the old Emberizidae have shifted to the Passerellidae: a significant component of the Neotropical fauna (including the finches of the Galapagos islands) have instead proven to be closer to the fruit-eating tanagers of the Thraupidae. As currently recognised, the passerellids are a fairly coherent group of about 140 species distributed around North and South America.

Goldwn-winged sparrow Arremon schlegeli schlegeli, copyright Nick Athanas.

In general, the passerellids are small birds with simple, conical bills. Most are dull brownish in coloration though many are strikingly patterned, particularly around the head. Some are more distinctive: the South American sparrows of the genus Arremon often stand out as particularly colourful. Most passerellids are fairly retiring in their usual habits, foraging at or close to ground level. As noted before, they are mostly generalist feeders. Their short bills are excellently suited for milling the small seeds which make up a large part of their diet. However, they will also take insects and other small invertebrates. One widespread North American species, Ammodramus savannarum, has earned the vernacular name of "grasshopper sparrow" as a result. Notable outliers dietwise are the Neotropical bush-tanagers of the genus Chlorospingus which are primarily berry feeders. These largely greenish birds were previously classified with the Thraupidae as a result before molecular data led to their reassignment.

Common bush-tanager Chlorospingus flavopectus, copyright Becky Matsubara.

Whereas Neotropical members of the Passerellidae are mostly sedentary, North American species are often migratory, moving north with the approach of summer. However, migration is commonly related to environmental conditions. A number of species are migratory in the northern parts of their range but may be found in their southern territories year-round. In some species, migrating populations will leap-frog over resident populations, moving further south than any resident individuals during the winter months. Many passerellid species are strong singers and courting males will often select an exposed branch to sing from in contrast to their usual skulking habits. Other species, particularly those inhabiting open habitats where trees and shrubs are in short supply, may have prominent aerial displays. Males of one of these latter species, the lark bunting Calamospiza melanocorys, moult during the breeding season into black plumage with contrasting white patches on the wings and tail. During the remainder of the year, they are dull in coloration like their females. Nesting is conducted close to ground level like feeding with the nest often being a small cup in the ground concealed under vegetation. Where breeding has been studied in detail, passerellids are commonly what has been called "socially monogamous". Males and females will form what appear to be monogamous pairs with one male remaining close to one female (though construction of the nest and incubation are done by the female alone). However, genetic studies on nestlings have found that chicks are not uncommonly not the child of their apparent 'father', indicating that females have not remained faithful to their mate.

Yellow-striped brush-finch Atlapetes citrinellus, copyright Ron Knight.

Prior to molecular studies, authors had suggested a possible division of North American passerellids between two evolutionary lineages based on ecology and behaviour, the grassland and brushland sparrows. A molecular study of passerellids by Klicka et al. (2014) identified eight well-supported clades within the family. Two further species, the large-footed finch Pezopetes capitalis of Central America and the Zapata sparrow Torreornis inexpectata of Cuba, were not robustly assigned to a clade. Identified relationships were comparable to but not entirely congruent with prior hypotheses. For instance, most 'brushland sparrows' (of the genera Passerella, Zonotrichia and Junco) belonged to a single clade but the remaining 'brushland' genus Melospiza was placed in a clade mostly made up of 'grassland' species. The diverse South American genus Arremon was supported as monophyletic but others were not. In particular, the North American Ammodramus was divided between two widely separated clades. This lead to the resurrection of the genus Ammospiza for a group of saltmarsh-breeding species. Deeper relationships within the family deserve further investigation.

REFERENCES

Hoyo, J. del, A. Elliott & D. A. Christie (eds) 2011. Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds. Lynx Edicions: Barcelona.

Klicka, J., F. K. Barker, K. J. Burns, S. M. Lanyon, I. J. Lovette, J. A. Chaves & R. W. Bryson, Jr. 2014. A comprehensive multilocus assessment of sparrow (Aves: Passerellidae) relationships. Molecular Phylogenetics and Evolution 77: 177–182.

The Origins of Song

The world is currently home to roughly ten thousand known species of bird. These come in a significant range of varieties and sizes: ostriches, hummingbirds, penguins, sandgrouse. But one particular clade of birds accounts for roughly half of all living species: the true songbirds of the Euoscines.

Brown treecreeper Climacteris picumnus, a representative of an early-diverging Australian clade of songbirds, copyright Patrick Kavanagh.

Though the name 'Euoscines' doesn't appear to have received a whole lot of usage in the literature, the clade it refers to actually has a long history of recognition. The Euoscines are one of the major subgroups of the well-recognised order Passeriformes, the perching birds. Members of the Euoscines include such familiar animals as finches, crows, wrens, swallows, skylarks, sparrows, and a whole host of others. On a morphological basis, Euoscines are mostly united by the distinctive structure of their syrinx, or voice-box, which is controlled by five pairs of intrinsic muscles (Ericson et al. 2002; by way of contrast, the lyrebirds and scrubbirds that form the clade most closely related to the Euoscines have only three pairs). This complex syringeal structure is doubtless a factor in the elaborate songs that characterise many representatives of the clade and from which the group gets its vernacular name. Molecular data has further strengthened the case for the Euoscines.

Whereas the phylogenetic integrity of the Euoscines is no considered by most researchers to be beyond reproach, its exact origins are a little more mysterious. Outside the Euoscines, the members of the Passeriformes fall into three well supported clades. As noted above, the immediate sister group of the Euoscines is a small Australian clade, the Menurae (the Menurae and Euoscines together form the singing birds, the Oscines). Another very small clade, the New Zealand wrens of the Acanthisittidae, is thought to represent the sister group of all other Passeriformes. The largest clade of Passeriformes outside the Euoscines is the Suboscines, whose members include such examplars as the broadbills and pittas of the Old World tropics, and the antbirds, tapaculos and tyrant flycatchers of the New World. The Suboscines form the sister clade to the Oscines.

Australian logrunner Orthonyx temminckii, another early-diverging exemplar, copyright JJ Harrison.

We also have a fairly clear idea of basal relationships within the Euoscines, primarily from molecular data. I won't dwell on details here (I am aware that while litanies of names can hold a lot of interest for myself, others may find them more tedious) but a detail that has garnered attention is that a preponderance of the basal euoscine lineages are enitrely or predominantly Australasian. This, together with the Australasian distribution of two of the other three major passerine clades, has lead to the proposal that Australasia represents the ancestral homeland for the Euoscines as a whole. But when did the Euoscines first make their appearance?

This is where things begin to get fuzzier. The fossil record of Passeriformes, as for many other birds, is very patchy and often difficult to interpret. Possible passerine bones have been identified from the early Eocene of Australia but they are fragmentary and their identity has been questioned. The earliest well-preserved passerines come from the early Oligocene of Europe (Bochenski et al. 2021). These fossils preserve features indicating that at least the oscine and suboscine lineages had diverged by this time. Attempts to apply molecular dating to the passerine phylogeny, however, have lead to proposals that the major lineages of passerines diverged much earlier, during the Cretaceous era in fact. The divergence of the passerines has then been linked to the break-up of Gondwana, beginning with the isolation of the New Zealand wrens as New Zealand separated from Antarctica about 80 million years ago.

Spotted pardalote Pardalotus punctatus, representing the meliphagoid lineage of Australasian songbirds, copyright Patrick Kavanagh.

Personally, I find this completely incredible. Firstly, it implies a gap of at least 25 million years or so at the beginning of the passerine fossil record (if we accept the Australian fossils as passerines). I've already noted that passerines do not have a great fossil record overall, particularly in the Southern Hemisphere where they are supposed to have originated, but other small birds do have a decent fossil record in the Northern Hemisphere during this time period. The absence of passerines from Europe and North America in the Palaeocene and Eocene does seem likely to be genuine. Secondly, it implies the survival through the devastation of the end-Cretaceous extinction event of not just at least three lineages of passerines but also those bird lineages that diverged before the passerines. At a bare minimum, that requires at least ten clades of birds surviving the Cretaceous and more than likely requires significantly more, most of those lineages also having no recognisable Cretaceous fossil record. Meanwhile, all other non-bird dinosaurs that we do know were around, many of them ecologically very similar, were completely wiped out. Thirdly (and this is perhaps the one that really gets me), it requires that these passerine lineages divided by continental drift then failed to disperse enough over the next eighty million years to obscure the imprint of said drift. Need I remind you that birds can fly? Hand-waving explanations such as the members of many of these early-diverging lineages being poor fliers, or the northern and southern continents being further apart at the time, just don't cut it in my opinion. Why should we assume that if modern Acanthisittidae or Menurae are poor fliers, their extinct relatives also had to be? Eighty million years seems like more than enough time for variation in flight strength to evolve. And a re Suboscines even any more prone to being poor fliers than Euoscines? As for the greater distance between continents, passerines have made their way to isolated oceanic islands (such as those in the mid-Atlantic) that were never close to any landmass. Phylogenetic evidence suggests that some modern passerine groups are indeed the descendants of long-distance dispersals, such as the South American vireos being apparently descended from Asian ancestors, or Hawaiian honeycreepers originating from near the Arctic. And of the previously mentioned European Oligocene passerines, some such as Wieslochia weissi were possibly not part of the Suboscines + Oscines clade (Manegold 2009), indicating that passerines of this grade could indeed make the ocean crossing. So no, the idea of Cretaceous songbirds is just not something I buy right now.

REFERENCES

Bochenski, Z. M., T. Tomek, M. Bujoczek & G. Salwa. In press 2021. A new passeriform (Aves: Passeriformes) from the early Oligocene of Poland sheds light on the beginnings of Suboscines. Journal of Ornithology.

Ericson, P. G. P., L. Christidis, M. Irestedt & J. A. Norman. 2002. Systematic affinities of the lyrebirds (Passeriformes: Menura), with a novel classification of the major groups of passerine birds. Molecular Phylogenetics and Evolution 25: 53–62.

Manegold, A. 2009. The early fossil record of perching birds (Passeriformes). Palaeontologia Africana 44: 103–107.

The Australasian Not-Robins

I've complained in the past about the decided lack of imagination displayed by many British naturalists when describing the fauna of Australasia. So many animals got lumbered with the names of European species to which they bore a superficial resemblance but of which they were not necessarily close relatives. So we got warblers that are not warblers, cod that are not cod, and the subject of today's post: robins that are not robins.

Male scarlet robin Petroica boodang, copyright Patrick Kavanagh.

Petroica is a genus of small perching birds found widely in Australasia, including species on various islands of the south Pacific. They are dumpy little birds whose males often have contrasting colour patterns with a dark dorsum and a light underside, though a couple of species are uniformly black. A number of species have red patches on the forehead and/or breast, and it is not too difficult to see why British naturalists chose to compare them to the European robin. They are insectivores, gleaning prey from vegetation or on the ground.

Over a dozen species are recognised in the genus Petroica, though the exact number varies depending on the author. Phylogenetic studies indicate four main lineages within the genus (Kearns et al. 2018) with some correlation between phylogeny and distribution. An Australian clade includes the scarlet robin P. boodang, the flame robin P. phoenicea, the pink robin P. rodinogaster and the rose robin P. rosea. As is indicated by their names, these are all red- or pink-chested forms, and they are found in woodlands in southeastern and southwestern Australia where they usually feed from leaves and branches. Females are duller in coloration, mottled grey or brown above and having the red on the underside lessened or lost; for the most part, the same pattern applies to females of the species described below.

Red-capped robin Petroica goodenovii, copyright Patrick Kavanagh.

More arid parts of Australia are inhabited by the red-capped robin Petroica goodenovii which is more terrestrial in habits than the preceding species. The red-capped robin forms a clade with two insular species, the Norfolk Island robin P. multicolor and the Pacific robin P. pusilla, the latter being found over a wide range from the Solomon Islands to Samoa (with a subfossil record from Tonga). The Norfolk Island robin is endangered with only an estimated 400 to 500 pairs surviving, a position whose severity was not fully appreciated until recently owing to the Norfolk Island and Pacific robins previously being regarded as conspecific with the Australian scarlet robin (Kearns et al. 2016). Kearns et al. (2016, 2018) also identified a strong genetic divergence between Pacific robins from the Solomon Islands and the eastern part of their range, suggesting the possibility of a further species division. However, they did not support such a divergence for the Samoan population which had previously been suggested as a candidate species by plumage and song characters.

Snow mountain robin Petroica archboldi, copyright Papua Expeditions.

The third clade includes two montane New Guinean species, the subalpine robin Petroica bivittata and the snow mountain robin P. archboldi. The male subalpine robin has a black back and white breast, without any red patches, and the species is found in high mountain forests and shrublands. The snow mountain robin, on the other hand, is a large Petroica species that is mostly slate-grey in coloration with a small red patch on the upper breast. It is found at the highest altitude of any bird in New Guinea and is the only bird found there in rocky scree habitats above the tree line. Both the New Guinean Petroica species, but particularly P. archboldi, have disjointed, localised ranges, and Kearns et al. (2018) expressed concern about the snow mountain robin's likelihood of future survival in the face of mining pressures and temperature rises.

North Island robin Petroica longipes, copyright Tony Wills.

The fourth and final clade, albeit a weakly supported one, unites the New Zealand Petroica species. Historically, most authors have recognised three Petroica species in New Zealand that, with the typical pithiness often associated with discussions of the somewhat depauperate New Zealand fauna, were generally known simply as the robin P. australis, the black robin P. traversi, and the tomtit P. macrocephala. However, multiple subspecies have been recognised within both the robin and the tomtit and recent years have seen calls for all to be recognised as distinct species (potentially raising the number of species in New Zealand to nine). Acceptance of these proposals has been varied: the North Island robin P. longipes now seems to be generally accepted as a separate species from the South Island P. australis but I have seen less recognition of more than one species of tomtit. The New Zealand robins are largely terrestrial feeders, and are noticeably longer-legged than other Petroica species. Male New Zealand robins are also duller in coloration with brownish backs. The more arboreal tomtits are the more similar in overall appearance to Petroica species from elsewhere. Most tomtit males are black above and white or yellow below. For the most part, female tomtits resemble other Petroica species in being duller than the males, brown above rather than black, but the female Auckland Island tomtit P. (macrocephala) marrineri is closer in appearance to the male. The Snares Island tomtit P. (macrocephala) dannefaerdi is uniformly black in both sexes. In this it resembles the larger black robin of the Chatham Islands, some distance east of New Zealand's South Island. Black robins are most reknowned for their conservation history with introduced predators reducing the entire species' population to only five individuals in 1980, including only a single breeding female. An intensive management program was instituted beginning with the capture and transfer of the entire population to a predator-free island. Higher breeding rates were encouraged through the removal of egg clutches from robin nests, with the bereaved birds laying a new batch to replace them and the original clutch placed in a nest of the local tomtit race to be raised cuckoo-style. As a result of this effort, population numbers increased until the current black robin population numbers about 250 individuals. Obviously, that's by no means enough to count their survival assured (and questions still linger about what, if anything, will be the long-term effects of inbreeding from such a minute founding populations) but it's still one heck of a lot better than what it was.

REFERENCES

Kearns, A. M., L. Joseph, L. C. White, J. J. Austin, C. Baker, A. C. Driskell, J. F. Malloy & K. E. Omland. 2016. Norfolk Island robins are a distinct endangered species: ancient DNA unlocks surprising relationships and phenotypic discordance within the Australo-Pacific robins. Conserv. Genet. 17: 321–335.

Kearns, A. M., L. Joseph, A. Thierry, J. F. Malloy, M. N. Cortes-Rodriguez & K. E. Omland (in press 2018) Diversification of Petroica robins across the Australo-Pacific region: first insights into the phylogenetic affinities of New Guinea's highland robin species. Emu.

Finches in Drag

Green-headed tanager Tangara seledon, copyright Dario Sanches.

In many parts of tropical South America, it is common to see small flocks of brightly coloured small birds foraging among vegetation, plucking off berries or hunting for insects. In many cases, these flocks may contain individuals of multiple or even several species. These are the tanagers, one of the Neotropical region's most characteristic bird families.

Tanagers are members of the bird clade known as the nine-primaried songbirds (so-called because their wings have nine functional primary feathers rather than the ten of other songbirds) that also includes the finches, buntings and cardinals. The largest genus of tanagers, and indeed one of the larger genera of birds in general, is Tangara. This genus includes about fifty species found in various parts of the neotropics. In their overall structure, they are fairly uniform: small, sturdy birds with a stout, moderate-length bill and an average-length tail (Hilty 2011). In other words, they have a fairly unremarkable, finchy-type appearance. In colour and patterning, however, they are considerably more varied, to the extent that I am at a loss to know where to begin. There are species of a rich, deep blue and of a bright, emerald green. There are species with bold, contrasting patterns of blues, blacks, greens or golds; there are species of a solid, uniform brilliance. There are species with caps or chests of orange or black. There are even a few, such as the plain-coloured tanager Tangara inornata, that eschew the gaudy pigments of their congeners entirely in favour of more restrained patterns of greys and beiges. In many species, males and females show little or no difference in appearance; however, in the black-capped group (including species such as the black-capped tanager T. heinei), the males have contrasting patterns of black and blue or yellow whereas the females are largely green and grey.

Golden tanager Tangara arthus, copyright Alejandro Bayer Tamayo.

As noted above, tanagers feed on a mixed diet of fruit and insects. The fruit part is dominated by small berries that they can either swallow whole or mash with their bills before swallowing them piecemeal. Studies on the mixed-species flocks formed by Tangara species have found that while different species show very little variation in how they obtain the fruit component of their diet, they usually show very distinct specialisations in how they forage for insects. Some hunt for insects along branches, others prefer to look on leaves. Branch-hunting species may differ in the thickness and density of branches preferred, or in the mode of searching employed. For instance, the golden tanager T. arthus and flame-faced tanager T. parzudakii can both be found foraging on moss-covered branches, but the flame-faced tanager usually catches insects by probing directly into the moss whereas the golden tanager usually either focuses on the moss-free sections or catches insects sitting on the moss surface without probing. A few species catch insects aerially, making short sallies from a perch.

Blue-grey tanager Thraupis episcopus, indicated by phylogenetic analysis as a species of Tangara, copyright Mdf.

Somewhat unexpectedly for a genus of this size and diversity in a group as taxonomically challenging as the tanagers, molecular phylogenetic studies have largely corroborated Tangara's monophyly. They have also supported the monophyly of most of the species groups recognised within the genus of the basis of similarities in plumage patterns (Sedano & Burns 2010). The only exception has been the discovery that many of the species previously included in the genus Thraupis form a clade nested within Tangara, leading to the suggestion that these two genera should be synonymised (apart from in informal discussions online, I'm not aware of anyone suggesting the alternative that Tangara be split). The 'Thraupis' species are larger and plainer in coloration than most other Tangara species. A few taxonomists have also suggested that the colourful green tanagers of the genus Chlorochrysa should be included in Tangara, but this relationship has not been supported by molecular data. Chlorochrysa species are glossier than the often more matt-coloured Tangara, and they have an acrobatic mode of foraging involving postures such as regularly hanging upside-down that differ from any Tangara species.

REFERENCES

Hilty, S. L. 2011. Family Thraupidae (tanagers). In: del Hoyo, J., A. Elliott & D. Christie. Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds pp. 46–329. Lynx Edicions: Barcelona.

Sedano, R. E., & K. J. Burns. 2010. Are the northern Andes a species pump for Neotropical birds? Phylogenetics and biogeography of a clade of Neotropical tanagers (Aves: Thraupini). Journal of Biogeography 37: 325–343.

The Brown Honeyeaters

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Brown honeyeater Lichmera indistincta, copyright JJ Harrison.

Honeyeaters are one of the first groups of birds likely to be noticed by newcomers to Australia (after the crows and magpies, of course). Though generally not large birds, they are active, noisy and often colourful. Individuals or small groups of them will almost invariably be seen around trees in flower, seeking out nectar and squabbling over access to the best blooms.

Here in Perth, one of the more common honeyeater species is the brown honeyeater Lichmera indistincta. This is one of the smaller honeyeaters and as such might be less commonly noted by the casual observer, but it is abundant nonetheless. The brown honeyeater is one of a genus of about ten species of small, slight honeyeaters with slender decurved bills found from the Lesser Sundas of Indonesia to New Caledonia and Vanuatu (Higgins et al. 2008). Lichmera indistincta is the only species found in continental Australia. Most of the species are locally more or less abundant though some have quite restricted ranges, being found only on specific islands. A few are considered near-threatened. Lichmera species are predominantly grey-brown or greenish in colour; perhaps the most strikingly coloured is the black-necklaced honeyeater L. notabilis of the island of Wetar in the Lesser Sundas, which is yellowish-olive above and yellow below, with a striking white throat patch outlined in black.

Indonesian honeyeater Lichmera limbata, copyright Lip Kee.

Lichmera honeyeaters occupy a wide range of habitats but often prefer to be in the vicinity of water, occupying river-side woodlands and stretches of mangroves. One subspecies of the silver-eared honeyeater L. alboauricularis olivacea has a distribution that closely follows river systems in northern New Guinea. Favoured food plants of the brown honeyeater in Australia include Myrtaceae such as Eucalyptus and Melaleuca, and Proteaceae such as Banksia and Grevillea. They will also take small insects and spiders; I suspect that the proportion of nectar to insects in the diet depends on the availability of the former. Nests are open cups constructed of plant matter such as grass and pieces of bark bound together with spider web and other fibres. Small clutches of one to three eggs are brooded by the female alone, taking about two weeks to hatch, though the chicks are fed by both parents. The call of the brown honeyeater, which can be heard year-round, has been rendered as 'sweet-sweet-quarty-quarty'.

Nectar, of course, is not a hugely nutritious food source per volume (being mostly water), and a small bird like a brown honeyeater has to feed fairly constantly to keep itself going. Even though its metabolism slows down when sleeping, a brown honeyeater will still lose about half a gram of body weight overnight (Collins 1981) which is pretty impressive when you consider that the entire bire only weighs about eight grams (imagine if the average lost five kilos every night...) To make up for this loss, the bird feeds most heavily in the early morning, as well as retaining water for the last half-hour or so before going to sleep. And so it is that the honeyeater gets through the night.

REFERENCES

Collins, B. G. 1981. Nectar intake and water balance for two species of Australian honeyeater, Lichmera indistincta and Acanthorhynchus superciliosis. Physiological Zoology 54 (1): 1–13.

Higgins, P. J., L. Christidis & H. A. Ford. 2008. Family Meliphagidae (honeyeaters). In: Hoyo, J. del, A. Elliott & D. Christie (eds) Handbook of Birds of the World vol. 13. Penduline-tits to shrikes pp. 498–691. Lynx Edicions: Barcelona.

The Hawaiian Honeycreepers: Diversity in Danger

'Apapane Himatione sanguinea, copyright Peter LaTourette.

In 1938, avian malaria was discovered to have affected pigeons in the city of Honolulu (Amadon 1950). This might have seemed like a minor detail—except among breeders, pigeons do not normally elicit much concern from the average person—but it was to prove a disaster. From the pigeons, the disease spread into native birdlife of the Hawaiian archipelago and wreaked havoc. Many species living at lower elevations were wiped out, unable to withstand the disease's effects. Others were forced into remnant populations above an elevation of 1500m, where the disease's mosquito vectors were unable to survive.

Among the malaria's victims were several species of the Hawaiian honeycreepers, a group of small birds unique to the archipelago. The honeycreepers have become recognised as one of the classic examples of an island adaptive radiation, like the Madagascan vangas or the Galapagos finches. From the original colonisation of the archipelago by what was probably a fairly generalised finch-like bird, perhaps some five or six million years ago (Lerner et al. 2011), the Drepanidini have diversified into a disparate array of seed-eaters, insectivores and nectar-feeders. Some have evolved massive reinforced bills to crush the seeds of local trees such as koa or naio. Other have long slender bills that they use to reach into the depths of flowers or prise insect larvae from holes in bark. Currently, about fifty species of honeycreeper are known to have been present in the Hawaiian archipelago prior to human settlement; new ones continue to be described from fossil or subfossil remains. Sadly, due to factors such as habitat loss, competition with and predation by introduced fauna, and diseases such as the aforementioned malaria, only about twenty species remain alive today and many of those are critically endangered.

Maui 'alauahio Paroreomyza montana, copyright Markus Lagerqvist.

Older references will refer to the Hawaiian honeycreepers as their own family, the Drepanididae, due as much to long-standing uncertainty about their relationships to other birds as to their own distinctiveness. Many authors, such as Amadon (1950), argued for a connection between the honeycreepers and the South American flowerpiercers of the tanager family, believing that the nectar-feeders among the Drepanididae were closer in appearance to the group's original ancestor. However, recent studies, both molecular and morphological, have been unified in supporting a connection between the honeycreepers and the finches of the Fringillidae, leading to the demotion of the 'family' Drepanididae to a 'tribe' Drepanidini of the fringillids. In his original studies on the honeycreepers, Perkins recognised two subgroups: the 'melanodrepanines' were mostly nectar-feeders and were largely black and/or red in coloration, whereas the 'chlorodrepanines' were mostly seed-eaters or insectivores and usually yellow or greenish. Recent studies have supported the 'melanodrepanines' as a clade but identified the 'chlorodrepanines' as paraphyletic.

Po'o-uli Melamprosops phaeosoma, copyright Paul Baker.

One unusual feature of many Drepanidini is that they carry a distinctive scent that has been referred to as the 'drepanidine odour' (this site describes it as a sweet, musty smell). Two primarily insectivorous genera, the po'o-uli Melamprosops phaeosoma and the ʻalauahios Paroreomyza, lack this 'drepanidine odour', and on the basis of this and a couple of other points it has been questioned whether they are properly assigned to the Drepanidini. However, the osteological analysis of Drepanidini by James (2004) confirmed their position as drepanidines, a result that has since been corroborated by molecular analyses. It seems likely that Melamprosops and Paroreomyza are basal drepanidines outside an 'odoriferous' clade (Pratt 2014). Together with the akikiki Oreomystis bairdi, these species form a basal grade of generalist feeders with fairly slender bills. It is possible that the akikiki and the Maui ʻalauahio Paroreomyza montana are the only members of this grade surviving.

Laysan finches Telespiza cantans, copyright S. Plentovich.

The next clade of drepanidines to diverge in molecular phylogenies includes the Hawaiian finches, an assemblage of often seed- or fruit-eating species with thick, strong bills (Pratt 2014). James' (2004) osteological analysis did not resolve the finches as a single clade, instead intermingling them with the aforementioned grade. Again, the finches have been hard hit by extinction, with the only survivors being the palila Loxioides bailleui, the Laysan finch Telespiza cantans and the Nihoa finch T. ultima. Amadon (1950) noted that the Kona grosbeak Chloridops kona was extremely rare even when first discovered in the late 1800s, being restricted to an area of only 'a few square miles' in the Kona district of Hawai'i. The grosbeaks of the genus Chloridops and the koa finches of the genus Rhodacanthis had particularly strongly developed bills for cracking seeds, looking almost parrot-like in the case of Chloridops (James 2004). Of uncertain relationships to the finches are two unusual extinct species, the 'o'u Psittirostra psittacea and the Lanai hookbill Dysmorodrepanis munroi. The 'o'u was a fruit-eating, large-billed bird that was once widespread on the main islands of the Hawaiian archipelago (in contrast to most other honeycreeper species, which were mostly restricted to a single island). It was last definitely recorded in 1989 and continued survival is considered unlikely. The Lanai hookbill was a particularly bizarre species in which the mandible and maxilla were curved toward each other, so that the base of the bill gaped open even when the beak was closed. The single known specimen is unusual enough that Amadon (1950) did not accept that it represented an actual species, expressing the opinion that it was probably a deformed 'o'u specimen; current authors accept it as a good species.

Crested honeycreeper Palmeria dolei, from the US Geological Survey.

As noted above, the nectar-feeding 'melanodrepanines' form a well-supported clade including three surviving species: the 'i'iwi Drepanis coccinea, the crested honeycreeper or akohekohe Palmeria dolei and the 'apapane Himatione sanguinea, the last of which is one of the more abundant living honeycreepers. The melanodrepanines have slender bills, which in the species of Drepanis (the 'i'iwi and two extinct species of mamo) are long and downcurved. Also probably belonging to the melanodrepanines is the extinct ʻula-ʻai-hawane Ciridops anna, which shared their black and red plumage despite being a fruit- rather than a nectar-feeder.

Kaua'i 'akialoa Akialoa procerus (front) and Kaua'i nukupuu Hemignathus hanapepe (rear), from Keulemans (1890).

The final group of drepanidines to be considered here is also the largest, and contains the most surviving species: the 'amakihis of the genus Chlorodrepanis, the 'akepas Loxops, and related taxa. These are slender-billed insectivorous forms with the more generalist species being similar in appearance to the basal genera Paroreomyza and Oreomystis. Indeed, the classification of drepanidines by Amadon (1950), which was decidedly more lumpy than the current norm, subsumed the latter two genera in an expanded Loxops. Possibly related to this group are the extinct 'akialoas of the genus (wait for it...) Akialoa, which had an extremely long down-curved bill. Two other genera of this group, Hemignathus (including the ʻakiapolaʻau Hemignathus wilsoni) and the Maui parrotbill Pseudonestor xanthophrys, are unique among passerines in having a maxilla that significantly overhangs the much shorter mandible. The Maui parrotbill, despite being primarily an insectivore, has a heavier bill somewhat reminiscent of the finch group, and James' (2004) morphological analysis (which was primarily based on skull features) associated it with Psittirostra and Dysmorodrepanis rather than with Hemignathus; the latter association, however, is supported by molecular analyses, indicating a single origin for the unequal bills.

The loss of this remarkable radiation can be regarded as nothing short of a tragedy. Only two species of Hawaiian honeycreeper are currently regarded as not threatened (as given in the IUCN listings at Wikipedia), the 'apapane and the common 'amakihi Chlorodrepanis virens. Even these species could become endangered as a warming climate allows malaria-carrying mosquitoes to encroach further on their highland refuges. And something truly wonderful could be lost from the world.

REFERENCES

Amadon, D. 1950. The Hawaiian honeycreepers (Aves, Drepaniidae). Bulletin of the American Museum of Natural History 92 (4): 151–262.

James, H. F. 2004. The osteology and phylogeny of the Hawaiian finch radiation (Fringillidae: Drepanidini), including extinct taxa. Zoological Journal of the Linnean Society 141: 207–255.

Lerner, H. R. L., M. Meyer, H. F. James, M. Hofreiter & R. C. Fleischer. 2011. Multilocus resolution of phylogeny and timescale in the extant adaptive radiation of Hawaiian honeycreepers. Current Biology 21: 1838–1844.

Pratt, H. D. 2014. A consensus taxonomy for the Hawaiian honeycreepers. Occasional Papers of the Museum of Natural Science, Louisiana State University 85: 1–20.

Orioles: The Genuine Article

Eurasian golden oriole Oriolus oriolus, copyright Crusier.

It is widely appreciated that the British during the age of exploration were probably not the most imaginative of baptisers. Thanks to their tendency to label the fauna of foreign lands with the names of familiar animals back home, we are regularly confronted with warblers that aren't warblers, cod that aren't cod, monkeys that aren't monkeys. And for years, many an American has laboured under the mistaken impression that they know what an oriole is. This post is about the real orioles.

The Oriolidae are a family of birds found mostly in the tropics of the Old World, from Africa to Australia. Only a few species in the family are known from temperate climes. One of these is the original oriole, the European Oriolus oriolus, which migrates between sub-Saharan Africa and its breeding range in Europe and central Asia. The name 'oriole' is derived from the Latin word for 'golden', and there is no question of this being an appropriate name for the European bird. The male's plumage is almost entirely golden yellow, with the wings being black. As is commonly the way with birds, the females are less dramatic, being predominantly green. Despite the males' bright coloration, though, orioles are by all accounts fairly retiring birds, usually remaining secluded in the tree canopy, where they seek out fruit and small insects.

Black-and-crimson oriole Oriolus cruentus malayanus, copyright Christopher Hill.

The majority of the about thirty remaining species of Oriolus are also some combination of gold, green and/or black, but there are notable exceptions. A clade of Australo-Papuan and Moluccan species, identified by Jønsson et al. (2010) as the sister group to the other Oriolus species, contains relatively dull brown or greenish species. The Moluccan species in this clade bear a strong resemblance to friarbirds, a group of honeyeaters found in the same region, to the extent that the black-eared oriole Oriolus bouroensis was first described as a friarbird. It has been suggested that this represents a case of mimicry with the retiring orioles gaining a degree of protection from their resemblance to the aggressive friarbirds (Dickinson 2004). Another Asian clade identified by Jønsson et al. (2010) includes mostly red and black species. It also includes the silver oriole Oriolus mellianus in which the red coloration has been mostly lost, so that it is mostly silver-white with a black head and wings.

Male and female Australasian figbirds Sphecotheres vieilloti, copyright Jim Bendon.

Also included in the Oriolidae are the three species of figbird in the genus Sphecotheres, found in the Australo-Papuan region. The figbirds, as their name suggests, have a higher proportion of fruit in their diet than orioles. They are also more sociable, living in small flocks. Figbirds are distinguished from orioles by the presence of patches of bright red bare skin around their eyes; they are otherwise a dull greenish colour. Recent studies have also indicated oriolid affinities for Pitohui, a genus of two red and black birds, the hooded pitohui P. dichrous and variable pitohui P. kirhocephalus, found in New Guinea. Previous authors have included six species in Pitohui, but phylogenetic studies have revealed that the genus in the broad sense is widely polyphyletic, with the remaining species belonging to different bird families. The red and black markings of the 'pitohuis' are a case of aposematic coloration, advertising that its bearer is toxic. The pitohuis contain batrachotoxins in their skin and feathers, a similar substance to that found in the poison-arrow frogs of South America. Contrary to what you may read elsewhere, the pitohuis were not the first known case of toxicity in birds, though it was one of the most definite ones. It has been known since ancient times that migratory quail Coturnix coturnix are toxic at certain points on their migratory route: the biblical book of Numbers describes a case of mass poisoning suffered by the Israelites during the exodus. Other examples of birds that are at least seasonally toxic include the spur-winged goose Plectropterus gambensis and the bronzewing pigeons of the genus Phaps (a brief review of bird toxicity is provided by Bartram & Boland, 2001). As far as is known, all cases of toxicity in birds result from feeding on something containing the relevant toxic substance (probably beetles, in the case of pitohuis) which is then sequestered by the bird.

Mounted North Island piopio Turnagra tanagra, copyright Te Papa.

The Australo-Papuan distribution of these two genera, together with the basal position of the Australo-Papuan species in the genus Oriolus, suggests that the family originated in this area before crossing the Wallace Line to diversify in Eurasia and Africa (Jønsson et al. 2010). An Australo-Papuan origin for the orioles also correlates with the presence of a fossil oriolid, Longmornis robustirostrata, in the early Miocene Riversleigh deposit of Australia (Boles 1999). It also correlates with the recent identification as oriolids of the now extinct New Zealand piopios of the genus Turnagra (Zuccon & Ericson 2012). The piopios were two species (the South Island piopio Turnagra capensis and the North Island T. tanagra) of mostly brown songbirds, also commonly known as the New Zealand thrushes. Their song was described as being amongst the most beautiful of any New Zealand bird, both complex and with a propensity towards mimicking other birds. Though seemingly common at the time of European settlement, they declined rapidly and probably became extinct around the start of the 20th Century. The affinities of the piopios were long contentious, with leading suggestions including a relationship with the whistlers of the Pachycephalidae, or with the bowerbirds of the Ptilonorhynchidae. Zuccon & Ericson (2012) marshalled an array of molecular, morphological and behavioural evidence in favour of a relationship with the orioles, though this stands in contrast with an earlier molecular study that supported the bowerbird hypothesis (Zuccon & Ericson noted that the cytochrome b sequence reported in the earlier study did not correspond with the one they found themselves, and suggested that it may have been the result of contamination). The dull coloration of the piopios compared to other orioles was explained by Zuccon & Ericson as a loss of sexual dimorphism, but this may have been unnecessary: they seem to have overlooked the similarly dull coloration of a number of other basal oriolids. The fact that the piopios were described as more terrestrial than the other oriolids is also not unusual in the New Zealand context. After all, the New Zealand bird fauna is famed for its tendency towards terrestrialisation (it even included a terrestrial owlet-nightjar!) In an environment where the main threat came from above in the form of birds of prey, the ground must have seemed like a welcoming place to be.

REFERENCES

Bartram, S., & W. Boland. 2001. Chemistry and ecology of toxic birds. ChemBioChem 2: 809–811.

Boles, W. E. 1999. A new songbird (Aves: Passeriformes: Oriolidae) from the Miocene of Riversleigh, northwestern Queensland, Australia. Alcheringa 23: 51-56.

Dickinson, E. C. 2004. Systematic notes on Asian birds. 42. A preliminary review of the Oriolidae. Zool. Verh. Leiden 350: 47-63.

Jønsson, K. A., R. C. K. Bowie, R. G. Moyle, M. Irestedt, L. Christidis, J. A. Norman & J. Fjeldsa. 2010. Phylogeny and biogeography of Oriolidae (Aves: Passeriformes). Ecography 33: 232–241.

Zuccon, D., & P. G. P. Ericson. 2012. Molecular and morphological evidences place the extinct New Zealand endemic Turnagra capensis in the Oriolidae. Molecular Phylogenetics and Evolution 62: 414–426.

Riroriro

The grey warbler or riroriro Gerygone igata, photographed by Peter Bray.

The eighteen recognised species of the genus Gerygone are an assemblage of small, drab-coloured birds found mostly in the Australo-Papuan region, with G. sulphurea found in the Malay Peninsula, Indonesia and the Philippines, and G. flavolateralis found in New Caledonia and Vanuatu. These are another group of birds that have tended to draw the short straw in the vernacular name stakes: G. igata, one of the most abundant of New Zealand's native birds, is usually identified by the uninspiring 'grey warbler'. Personally, I prefer the more onomatopoeiac Maori name for these lively little birds: 'riroriro' (it has been suggested in some circles that it could possibly be referred to as the 'grey gerygone'; this proposition shall be treated with the scorn that it deserves). The riroriro and its congeners feed on small insects that they mostly glean from leaves or small branches, generally in the middle to upper canopies (Ford 1985). A certain amount of their prey is caught in the air, while the riroriro and the brown warbler G. mouki of eastern Australia also forage in lower vegetation than other species. The riroriro is also the only Gerygone species known to forage on the ground (Keast & Recher 1997).

Gerygone species build hanging purse-shaped nests; this is a brown warbler Gerygone mouki photographed by Peter.

Somewhat unusually for a decently-speciose passerine genus, the circumscription of Gerygone has been fairly stable in recent years, and the genus has mostly been supported as monophyletic. The only exception of recent times has been the New Guinean G. cinerea, recently reclassified by Nyári & Joseph (2012) as a species of Acanthiza. In the early 1900s, some authors divided Gerygone species between smaller genera (for instance, the Australian ornithologist Gregory Mathews, who never met a genus he couldn't break down). One species so separated was the Chatham Island warbler G. albofrontata, which is something of an island giant compared to other Gerygone species, weighing about 12 g while other species are about 6 to 7 g (Keast & Recher 1997). Unfortunately, the Chatham Island warbler was not included in the phylogenetic analysis of Gerygone by Nyári & Joseph (2012), but it was not identified as significantly separate from other Gerygone species in the morphological analysis by Ford (1985).

The Chatham Island warbler Gerygone albofrontata, from here.

REFERENCES

Ford, J. 1985. Phylogeny of the acanthizid warbler genus Gerygone based on numerical analyses of morphological characters. Emu 86: 12-22.

Keast, A., & H. F. Recher. 1997. The adaptive zone of the genus Gerygone (Acanthizidae) as shown by morphology and feeding habits. Emu 97: 1-17.

Nyári, Á. S., & L. Joseph. 2012. Evolution in Australasian mangrove forests: multilocus phylogenetic analysis of the Gerygone warblers (Aves: Acanthizidae). PLoS One 7(2): e31840.

The Parulidae: Not-warblers, Not-ovenbirds and Not-redstarts

Black-crested warbler Myiothlypis nigrocristata, photographed by Mikko Pyhälä.

There is no denying the current status of English as the de facto lingua franca of the world*. And yet, I feel that a complaint must be laid at the feet of the Brits: they're a bit unimaginative when it comes to animal names. Many a British explorer, upon being presented with some hitherto unfamiliar product of the natural world, proceeded to label it with the name of whatever inhabitant of his native Europe he felt bore some vague resemblance. And hence, even today, there are significant groups of animals such as the Parulidae that are almost without a vernacular name to genuinely call their own.

*The potential irony of this sentence is not lost on me.

The Parulidae are a family of birds found throughout the Americas, though in the northern United States and Canada they are represented by migratory species that retreat further south in the cold months. Many of the migratory species have males with brightly coloured breeding plumage and are consequently idolised by North American bird watchers; non-migratory species, on the other hand, tend to have similarly subdued males and females (Update: see comments below). Members of the Parulidae are generally referred to as 'warblers' or 'wood warblers', despite not being at all closely related to the European warblers. Instead, parulids are members of the 'nine-primaried oscines', the passerine clade that also includes such birds as finches, buntings, sparrows, cardinals and tanagers. Within the nine-primaried oscines, parulids are closely related to the Icteridae, another American clade containing its fair share of representatives doomed to masquerade under stolen names (Barker et al. 2013).

Ovenbird Seiurus aurocapilla on its nest, photographed by M. C. Donald.

Though the nine-primaried oscines as a whole are fairly stable in their membership, recent years have seen a fair bit of shuffling back and forth between the clade's constituent families. As a result of this shuffling, the name 'Parulidae' has come to be associated with a core clade that excludes a number of more uncertainly placed taxa previously included in the family, such as the Central American wrenthrush Zeledonia coronata. A recent comprehensive study of the molecular phylogeny of the core parulids by Lovette et al. (2010) also resulted in a proposed shifting of many generic boundaries within the clade. According to Lovette et al., the basalmost member of the Parulidae is the ovenbird Seiurus aurocapilla, a migratory but monomorphic, relatively large parulid of North and Central America. Just to confuse matters, the name 'ovenbird' has also been used for an unrelated group of South American birds of the genus Furnarius. To be charitable, this is not a case of inappropriate name-saking, but refers to the construction by both groups of domed nests resembling an old earthernware oven. The next member of the parulids to split off was the worm-eating warbler Helmitheros vermivorus, a relatively long-billed species that migrates between the eastern United States and Central America.

Swainson's warbler Limnothlypis swainsonii, photographed by Greg Lavaty.

Next comes a clade of eight species classified in the genera Parkesia, Vermivora, Mniotilta, Limnothlypis and Protonotaria. The black-and-white warbler Mniotilta varia is noted for its distinctive feeding behaviour: it crawls along branches like a nuthatch or creeper, gleaning insects from the bark. The prothonotary warbler Protonotaria citrea is a bright yellow species that Kurt Vonnegut devoted some time to in Jailbird: "The song of a prothonotary warbler is notoriously monotonous, as I am the first to admit...Still—they are capable of expressing heartbreak—within strict limits, of course" (I personally feel the same about skylarks). The waterthrushes of the genus Parkesia are larger, terrestrially-feeding species.

Chestnut-sided warbler Setophaga pensylvanica, photographed by Cephas.
Other North American species are placed by Lovette et al. in the larger genera Geothlypis, Oreothlypis and Setophaga. The last genus contains the species previously included in Dendroica, but the recognition that the American redstart Setophaga ruticilla (again, no relation to the European redstart) is nested within Dendroica leads to the use of the older name. These genera include some of the most colorful parulids. The remaining genera Myiothlypis, Basileuterus, Cardellina and Myioborus form a mostly Neotropical clade. Myioborus species are also known as redstarts, presumably by comparison with the European birds as not one of them actually possesses a red tail. The name 'whitestart' has supposedly been proposed instead, but the only time that name appears to see use is when it is referred to by someone explaining why they are not using it...

REFERENCES

Barker, K. F., K. J. Burns, J. Klicka, S. M. Lanyon & I. J. Lovette. 2013. Going to extremes: contrasting rates of diversification in a recent radiation of New World passerine birds. Systematic Biology 62 (2): 298-320.

Lovette, I. J., J. L. Pérez-Emán, J. P. Sullivan, R. C. Banks, I. Fiorentino, S. Córdoba-Córdoba, M. Echeverry-Galvis, F. K. Barker, K. J. Burns, J. Klicka, S. M. Lanyon & E. Bermingham. 2010. A comprehensive multilocus phylogeny for the wood-warblers and a revised classification of the Parulidae (Aves). Molecular Phylogenetics and Evolution 57: 753-770.

Whistling for Whistlers

Male and juvenile golden whistler Pachycephala pectoralis, photographed by S. Lloyd. Female golden whistlers resemble the juveniles.

The name Pachycephalidae (or some orthographic variant thereof such as Pachycephalinae) has long been used to refer to a group of small insectivorous birds from the Australo-Papuan region (summarised by Boles 1979 as 'large-headed stout-bodied birds with poorly developed rictal bristles'). In the past, taxa included in the Pachycephalidae included the New Zealand genera Mohoua and Turnagra, the crested shriketit Falcunculus frontatus and the crested bellbird Oreoica gutturalis. However, as has often been the case with the more generalised groups of passerine birds, recent authors have tended to whittle the family's contents down as molecular studies have scattered the constituent taxa about the family tree. In its most recent iterations, Pachycephalidae generally corresponds to the taxa included in clade 'CC5CC6b' of Jetz et al. (2012), comprising primarily the genera Pachycephala and Colluricincla, plus a small number of satellite taxa.

Bare-throated whistler Pachycephala nudigula, photographed by Lars Peterssen.

The genus Pachycephala is currently used for the whistlers, a group of about forty species of mostly long-tailed, stout-billed birds, often (but not always) with sexually dimorphic coloration, with a contrasting pectoral band (most often black in the males) dividing the throat from the chest. The exact number of species in the genus is somewhat uncertain due to disagreements about the status of several constituent populations: the golden whistler P. pectoralis complex, for instance, includes over 65 named taxa variously recognised as species or subspecies (Jønsson et al. 2010). Species of Pachycephala are found from southeast Asia through to Fiji and Tonga. Some of you may recall whistlers featuring in Dougal Dixon's Life after Man as giving rise to an island radiation including nut-cracking, wood-pecking and predatory species (my only question being, who was the Hart that the plesiomorphic species in the radiation is supposed to be named after?)

Grey shrike-thrush Colluricincla harmonica, photographed by Sammy Sam.

Colluricincla, the shrike-thrushes, includes at least four species found in Australia and New Guinea (excluding a couple of species better included in Pachycephala). They are larger, slenderer and more narrow-headed than the whistlers, with less dimorphic coloration. The grey shrike-thrush C. harmonica of Australia has a high reputation as a singer. Some recent authors have also suggested inclusion of two further New Guinean species, the rusty pitohui Pitohui ferrugineus and white-bellied pitohui P. incertus, in Colluricincla. The genus Pitohui has been used to include a group of about half a dozen New Guinean species in the Pachycephalidae, which are relatively large and brash as pachycephalids go. They are variously reddish, black, or some combination of the two (the white-bellied pitohui has, as its name indicates, a yellowish-white underside). They have become most notorious in recent years for the discovery that, with the apparent exception of P. incertus, they are in fact toxic, with their skin and feathers containing batrachotoxins comparable to those found in the arrow-poison frogs of South America. Like the arrow-poison frogs, the birds probably do not generate the toxin themselves, but accumulate it from a diet of toxin-carrying melyrid beetles. However, molecular studies have indicated that the genus Pitohui as previously recognised is polyphyletic. The hooded pitohui P. dichrous and the variable pitohui P. kirhocephalus, the latter of which is the type species of the genus, are more closely related to the Oriolidae than the Pachycephalidae, while three species remain close to Pachycephala and Colluricincla. As well as the two species mentioned previously (which may be included in Colluricincla or maintained as a distinct genus for which the name Pseudorectes is available), the black pitohui 'Pitohui' nigrescens should be included in the Pachycephalidae as its own genus Melanorectes. As well as being closer to black than the reddish Pseudorectes species, Melanorectes nigrescens apparently possesses a 'peculiar musky smell' (Rothschild & Hartert 1913).

Rusty pitohui Pseudorectes ferrugineus, photographed by Dubi Shapiro.

The remaining two species of the Pachycephalidae are placed by Jønsson et al. (2010) in the genus Coracornis: the maroon-backed whistler C. raveni of Sulawesi and the Sangihe shrike-thrush C. sanghirensis of Sangihe, north of Sulawesi (as the vernacular name suggests, this species was previously included in Colluricincla). Neither of these species appears to be particularly well-known: in particular, C. sanghirensis was first described in 1881 but not observed again for over 100 years until 1985 (Rozendaal & Lambert 1999). So long was the gap between observations that several authors had, in this time, assumed that the original specimen must have been mislabelled and come from somewhere in New Guinea rather than Sangihe. This misinterpretation was encouraged by the belief that the species was directly related to the little shrike-thrush Colluricincla megarhyncha, found on the wrong side of the Wallace line to easily colonise Sangihe. As it is, C. sanghirensis is restricted to only a small area of forest on Sangihe at an altitude above 600 m, and was regarded by Rozendaal & Lambert (1999) as critically endangered. Its identification with Coracornis rather than Colluricincla was done by Jønsson et al. (2010) on the basis of molecular analysis; when comparing C. sanghirensis with Colluricincla, Rozendaal & Lambert (1999) do not appear to have also considered Coracornis raveni.

Sangihe shrike-thrush Coracornis sanghirensis, photographed by Marc Thibault.

REFERENCES

Boles, W, E. 1979. The relationships of the Australo-Papuan flycatchers. Emu 79: 107-110.

Jetz, W., G. H. Thomas, J. B. Joy, K. Hartmann & A. O. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444-448.

Jønsson, K. A., R. C. K. Bowie, R. G. Moyle, L. Christidis, J. A. Norman, B. W. Benz & J. Fjeldså. 2010. Historical biogeography of an Indo-Pacific passerine bird family (Pachycephalidae): different colonization patterns in the Indonesian and Melanesian archipelagos. Journal of Biogeography 37: 245-257.

Rothschild, W., & E. Hartert. 1913. List of the collections of birds made by Albert S. Meek in the lower ranges of the Snow Mountains, on the Eilanden River, and on Mount Goliath during the years 1910 and 1911. Novitates Zoologicae 20 (3): 473-527.

Rozendaal, F. G., & F. R. Lambert. 1999. The taxonomic and conservation status of Pinarolestes sanghirensis Oustalet 1881. Forktail 15: 1-13.

Birds of the Sun

Handsome sunbird Aethopyga bella, photographed by Tonee Despojo. This species was only recently separated at species level from the lovely sunbird Aethopyga shelleyi; one of the distinguishing features of the two is the purple ear-patch in A. bella.

The sunbirds are definitely forerunners in the tally of the world's most brilliantly coloured birds. This family of long-billed nectar-feeders, found in tropical regions of the Old World, is often compared to the New World hummingbirds. Like hummingbirds, the males of most sunbirds shimmer with brilliant iridescent colours (the exceptions are the spiderhunters of the genus Arachnothera); the females are much more restrained, generally shades of olive-green or brown. However, though hummingbirds are committed aerialists (as befits their relationship with the swifts and nightjars), sunbirds are, as Passeriformes, more likely to feed while perched on a stem alongside their chosen flower. Also, while sunbirds are primarily nectar feeders, they also feed to a fair extent on small insects (this is also true of hummingbirds).

Male (above) and female (below) of fork-tailed sunbird Aethopyga christinae. Male photographed by Frankie Chu, female by Neil Fifer.

Sunbirds are also a rather less diverse group than hummingbirds, both in number of species and in external appearance. Because of their structural similarity, authors have differed in the number of genera recognised in the family, but one group that has generally been differentiated is the Aethopyga sunbirds of southern Asia. Aethopyga species tend to be smaller than other sunbirds, with relatively short but strongly downcurved bills. The male has the central tail-feathers elongate (Ali & Ripley 1999). Aethopyga species are also distinguished from other sunbirds by the structure of the tongue. As with other sunbirds, the tongue is elongate, with the sides curved inwards to form a double tube. Differing from others, the end of the tongue is divided into two inwardly open tubes but with a basal bifurcated plate connecting the tubes:

Tongues of sunbirds of different genera showing differences in morphology, from Cheke & Mann (2001).

Cheke & Mann (2001) listed seventeen species of Aethopyga, with an eighteenth species being added by Mann (2002). Several of these species are also currently recognised as polytypic, with multiple subspecies. Though Mann's (2002) 'new' species was simply derived from the elevation of previously-recognised subspecies, one entirely new species of Aethopyga, A. linaraborae from Mindanao in the Phillippines, was only described as recently as 1997. No large scale analysis of the interrelationships between Aethopyga species appears to have been published as yet, but centres of diversity are the Philippines and the Himalayas.

Elegant sunbird Aethopyga duyvenbodei, photographed by Marc Thibault. Having been informed by their vernacular names that Aethopyga sunbirds are, in turn, handsome, lovely and elegant, it is all the sadder to say that this last species from Sangihe, near Sulawesi, is regarded as endangered.

REFERENCES

Ali, S., & S. D. Ripley. 1999. Handbook of the Birds of India and Pakistan, together with those of Bangladesh, Nepal, Sikkim, Bhutan and Sri Lanka, 2nd ed., vol. 10. Flowerpeckers to Buntings. Oxford University Press.

Cheke, R. A., & C. F. Mann. 2001. Sunbirds: A Guide to the Sunbirds, Flowerpeckers, Spiderhunters and Sugarbirds of the World. A & C Black Publishers.

Mann, C. F. 2002. Systematic notes on Asian birds. 28. Taxonomic comments on some south and south-east Asian members of the family Nectariniidae. Zool. Verh. Leiden 340: 179-189.