The Wingless Penguin

A couple of weeks ago, I put up a page on the 'terrestrial penguin' Cladornis pachypus, described from the Oligocene of Patagonia by the Argentine palaeontologist Florentino Ameghino. As it happens, Cladornis wasn't the only unusual penguin recognised from the Patagonian fossil record by Ameghino nor was it even necessarily the most unusual. That title should probably go to another species, the wingless Palaeoapterodytes ictus.

Anterior (left) and posterior view of humerus of Palaeoapterodytes ictus, from Acosta Hospitaleche (2010). Scale bar = 10 mm.

Like Cladornis, Palaeoapterodytes was based on only a single bone, in this case a humerus (upper wing bone) from the Early Miocene. And also like Cladornis, Ameghino's description of this bone indicated a truly remarkable bird. The distal part of the humerus lacked any sign of the facets that would normally articulate with the succeeding wing bones and, as a result, Ameghino concluded that the wing skeleton had been reduced to the humerus only. The crest and pits on the humerus marking the attachment of the wing muscles were also reduced. Ameghino's Palaeoapterodytes presumably had wings reduced to the merest nubs, effectively functionless and probably of little mobility. Nevertheless, the humerus of Palaeoapterodytes remained relatively robust, its breadth little less than that of other penguins.

I am not aware of any other bird with a wing structure anything like this. In other birds without functional wings, the entire wing skeleton becomes reduced, not simply truncated. Perhaps the closest approximation I have found is the wing of Hesperornis, which also lacks known wing bones beyond the humerus. However, the Hesperornis humerus is slender and gracile, and even without direct indication of the presence of more distal bones, it still looks to retain some remnant of the ancestral articulation. Also, the whole concept of a wingless penguin is decidedly problematic. Hesperornis derived its main propulsion in swimming from its feet and so its wings became reduced because they served little function. Penguins, on the other hand, get most of their propulsion from their wings, swimming in a manner that has been compared to flying underwater. Despite being flightless, penguins retain a wing skeleton that is, if anything, even more well developed than that of their flying relatives. For Palaeoapterodytes to have lost functional wings, it would have somehow had to change its mode of propulsion.

Reconstruction of the Palaeoapterodytes humerus with missing sections restored, from Acosta Hospitaleche (2010).

As a result, even while authors were cautiously considering Ameghino's interpretation of Cladornis, they treated Palaeoapterodytes with more scepticism. This scepticism was eventually concerned when the humerus was re-examined by Acosta Hospitaleche (2010). The reason for the lack of structure at its distal end was very simple: the original distal end had been broken off. The apparent lack of development of the muscle attachment structures was the result of erosion, not any indication of the bone's original appearance. When alive, Palaeoapterodytes had probably been very similar to, if not identical with, one of the several other penguin species known from around the same time and place. Unfortunately, the state of preservation of the type humerus is so poor that its exact identity cannot be determined, and Palaeoapterodytes ictus has been cast into the taxonomic limbo of nomen dubium. Ameghino's Cladornis may remain an intriguing mystery, but his Palaeoapterodytes is just a red herring.

REFERENCES

Acosta Hospitaleche, C. 2010. Taxonomic status of Apterodytes ictus Ameghino, 1901 (Aves; Sphenisciformes) from the Early Miocene of Patagonia, Argentina. Neues Jahrbuch für Geologie und Paläontologie—Abhandlungen 255 (3): 371–375.

The Patagonian Land Penguin

Take a good look at the figure above, which comes from Mayr (2009). It shows the fossilised tarsometatarsus (the fused long bone of the foot) of a bird from the late Oligocene of Patagonia. This may be one of the single most mysterious specimens in the fossil record. It represents all we know to date of Cladornis pachypus, described by Argentinean palaeontologist Florentino Ameghino in 1895. The appearance of the bone, being very broad and flat relative to its length, is quite bizarre and does not much resemble the tarsometatarsus of any other known bird.

The first thing that should be pointed out is that, whatever it was, Cladornis was a large bird. The specimen is not completely preserved (part of the proximal end of the bone has been lost) but its overall shape suggests that its original length was probably not too much longer than what we have. As such, the tarsometatarsus was probably comparable in length to that of a large pelican. However, it was much wider relative to length than that of a pelican, suggesting the possibility of a more robust bird. The shape of the bone's end indicates that the toes would have been widely spaced, and it may have even approached a zygodactyl arrangement (with two toes pointed rearwards and two forwards, like a modern parrot*) (Mayr 2009).

*When explaining this to my partner, I suggested that he imagine a parrot the size of a pelican. He shuddered and declared that he would rather not.

When Ameghino (1895) first described Cladornis, he interpreted it as an aquatic bird and suggested a relationship to the penguins, albeit in an extinct family Cladornidae (later authors would correct this to Cladornithidae). Later, noticing that it was preserved in association with terrestrial mammals, he declared that it was not marine and was possibly even terrestrial (he also included another species from the same formation, Cruschedula revola, in the Cladornithidae; this species is based on part of a scapula and there is no telling if it was related to Cladornis or not). He still maintained its relationship to the penguins (Ameghino 1906). Ameghino had a bit of a thing for trying to find the origins of all major modern vertebrate groups in his native South America (one of his other works was a book arguing for an Argentinean origin of humans) and it is possible that this was in play here. Nevertheless, the idea of a 'Patagonian land penguin' held sway until Simpson's (1946) review of the fossil penguins, in which he declared that Cladornis was "so very unlike any other penguin, recent or fossil, that I can only consider its reference to that group as erroneous".

This left Cladornis' taxonomic position completely up in the air (the question of whether Cladornis itself could get up in the air is, of course, currently completely unswerable). Wetmore (1951) included Cladornis in the Pelecaniformes, because...reasons. The closest he gave to an explanation was, "The only suggestion that has come to me is that possibly they may belong in the order Pelecaniformes, in which I have placed the family tentatively in the suborder Odontopteryges, where it is located with two others of almost equally uncertain status. This allocation is wholly tentative and is no indication of belief in close relationship in the three diverse groups there assembled". He would later move Cladornis into its own suborder, Cladornithes, and no close relationship to the 'Odontopteryges' (now the Pelagornithidae) has been suggested since. Our current understanding of bird phylogeny finds Wetmore's remaining 'Pelecaniformes' to correspond to three or four independent clades (the Pelecanidae, Suliformes, Phaethontidae and probably Pelagornithidae) so his assignment of Cladornis to this group becomes almost completely uninformative.

Which is pretty much where we're forced to leave things. Mayr (2009) included Cladornis in his chapter on 'land birds', with other taxa discussed in this chapter belonging to the clade Telluraves. However, this was motivated more by a lack of any idea what to do with it otherwise than anything else (it is possible that Cladornis' sub-zygodactyly played a role, but not all zygodactylous birds belong to the Telluraves). I did notice a similarity in proportions between the Cladornis tarsometatarsus and the corresponding bone in the large phorusrhacid Brontornis, making me wonder if anyone had ever compared the two, but this may well be only superficial. Most recent authors have assumed that the Cladornis tarsometatarsus is simply too weird, too unique, for any resolution of its affinities to be reached without first finding more complete remains of the animal.

REFERENCES

Ameghino, F. 1895. Sur les oiseaux fossiles de Patagonie et la aune mammalogique des couches a Pyrotherium. Boletín del Instituto Geográfico Argentino 15 (11–12): 501–602.

Ameghino, F. 1906. Enumeración de los Impennes fósiles de Patagonia y de la Isla Seymour. Anales del Museo Nacional de Buenos Aires, serie 3, 6: 97–167.

Mayr, G. 2009. Paleogene Fossil Birds. Springer.

Simpson, G. G. 1946. Fossil penguins. Bulletin of the American Museum of Natural History 87 (1): 1–99.

Wetmore, A. 1951. A revised classification for the birds of the world. Smithsonian Miscellaneous Collections 117 (4): 1–22.

Screech Owls

Eastern screech owl Megascops asio emerging from a nest-hole, copyright Zach.

For many people, owls are a group of birds known more by reputation than by encounter. Their nocturnal lifestyles and often cryptic habits make them rarely seen, and their diversity is often little appreciated. But despite being commonly referred to as a single homogeneity, owls actually come in a whole range of shapes and forms.

Megascops, the screech owls, is a genus of more than twenty species found over most of the Americas, though they are less diverse in North America than in the remainder of their range. They are also notably absent from the Caribbean; a single species from that region assigned to this genus, the Puerto Rican screech owl Megascops nudipes, was found in a recent phylogenetic study (Dantas et al. 2016) to be closer to the flammulated owl Psiloscops flammeolus of North America and may require reclassification. Despite what one might presume from the genus name alone, species of Megascops are small owls, around 20–25 cm in length. They have prominent grey facial discs and distinctly developed ear tufts. When disturbed, they will freeze upright in place with the ear tufts raised and the eyes almost closed; this, together with their broken brown or grey coloration, allows them to pass as an unremarkable piece of the tree they are sitting on. The most distinctive characteristic of the genus is their song, produced by members of both sexes, which comprises a rapid trill of several closely placed notes. The exact pattern of the song varies from species to species, and is commonly the most reliable method of telling each species apart (though, just for the sake of perversity, individuals that live in sympatry with members of another species may engage in mimicry). The species are otherwise often difficult to distinguish by external features alone. Just to confuse matters further, many (but not all) species of screech owl exhibit distinct colour morphs, with one morph being predominantly grey and the other rufous, that might be mistaken by the unwary for distinct species.

Pair of tropical screech owls Megascops choliba exhibiting distinct colour morphs, from Nucleo de Fauna.

As is not uncommon for owls, the majority of Megascops species are poorly known from a natural history perspective. Gehlbach & Stoleson (2010) provided a review of one of the North American species, the western screech-owl Megascops kenniscottii, that is probably typical of the genus. The diet of screech owls (like other small owls) is dominated by insects, with small vertebrates making up less than a fifth of their regular daily intake. Nesting takes place in holes in trees; nesting holes are claimed and defended by the male, who advertises its (and his) availability to females via the medium of song. Females respond to the males' advertisements by singing in reply, and pairs of owls will also respond defensively to songs from other owls nearby. The series of calls and responses in densely populated regions may develop into a full chorus of acknowledgements and challenges. Incubation of the clutch of about four eggs (which in the western screech owl is usually laid around late March–early April) is done solely by the female with the eggs taking about a month to hatch. The male collects food for her and the newly hatched chicks; after the chicks begin to fledge, both parents hunt for food for them.

The majority of screech owl species are not considered threatened conservation-wise though some of the more localised species may be vulnerable to habitat loss. Screech owls are reasonably tolerant of human activity and will even live and nest in suburban regions. They usually only disappear from a region once it becomes completely urbanised.

REFERENCES

Dantas, S. M., J. D. Weckstein, J. M. Bates, N. K. Krabbe, C. D. Cadena, M. B. Robbins, E. Valderrama & A. Aleixo. 2016. Molecular systematics of the new world screech-owls (Megascops: Aves, Strigidae): biogeographic and taxonomic implications. Molecular Phylogenetics and Evolution 94: 626–634.

Gehlbach, F. R., & S. H. Stoleson. 2010. Western screech-owl (Megascops kennicottii). In: Cartron, J.-L. (ed.) Raptors of New Mexico pp. 511–523. University of New Mexico Press: Albuquerque.

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.

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.

The Rosy Birds

Violet-necked lories Eos squamata, copyright Niels Poul Dreyer.

In taxonomic days of yore, it was a not uncommon practice for new genera to be baptised under the names of classical figures: gods, heroes, emperors, even the occasional prophet (the practice only died down once the barrel of available names became largely empty). In many cases, the connection drawn between the organism in question and its awarded namesake was tenuous at best. In others, it was simply non-existent. But in a favoured few cases, the association fit perfectly.

Eos is a small genus (recent authors have recognised six species) of lories found on islands in eastern Indonesia. They are named, of course, after the Ἠώς ῥοδοδάκτυλος, the 'rosy-fingered dawn', of the ancient Greeks. It takes no great insight to realise why they were so-called: all members of the genus are predominantly coloured in a vibrant red, together with varying extents of blue, purple and/or black. Green is usually absent from their plumage (with some noteworthy exceptions that I'll have cause to mention again), distinguishing them from most closely related parrots such as the rainbow lorikeets in the genus Trichoglossus. Charles Lucien Bonaparte (nephew to the other Bonaparte, and a prominent nineteenth-century ornithologist) stated in 1850 that Eos could be recognised by its "elegant form, small stature, compact, red plumage with more or less blue; compressed, moderate, red bill, with the cere apparent... and longish, not very broad, wedged tail".

Blue-streaked lories Eos reticulata, copyright Doug Janson.

For the most part, Eos species are found on islands between Sulawesi and New Guinea. The black-winged lory Eos cyanogenia is found on islands in Geelvink Bay, in the north-west part of West Papua, but not on the mainland of New Guinea itself. For the most part, no island is home to more than one species of Eos. The island of Seram is an exception, with the endemic blue-eared lory Eos semilarvata found in the central highlands, and the red lory Eos whatchumacallit (see below) closer to the coast (this species is also found on other islands in the South Moluccas). The blue-streaked lory Eos reticulata is found in the Tanimbar group east of Timor. The violet-necked lory Eos squamata lays claim to the North Moluccas, and the red-and-blue lory Eos histrio is found on Talaud and other islands to the north-west of Sulawesi (Juniper & Parr 1998).

Black-winged lory Eos cyanogenia, copyright Lip Kee Yap.

While the taxonomy of the group has been mostly stable in recent years, it was not always so. Bonaparte (1850) snidely commented that some species of Eos had been described "too many times". Hume & Walters (2012) referred to five described species of Eos, all based on isolated specimens since lost, whose identity has been contested. While it is possible that some may represent species now extinct, it is equally possible that they represented unusual individuals of living species. In the absence of examinable type specimens, the identity of most is of academic interest only. The exception is the 'red-and-green lory' Eos bornea, which was originally named Psittacus borneus by old Carolus Linnaeus himself on the basis of a description and plate of a lory supposedly from Borneo published in 1751 by George Edwards (Walters 1998). Edwards' bird, which he had bought as a stuffed specimen from a toyshop in London, was described as dark pink, with a yellow bill, and green patches on the wings and tail. However, no species quite matching Edwards' description is known from Borneo or anywhere else, and it was subsequently suggested that he may had an unusual or a faded specimen of the Moluccan red lory, with the Bornean locality being an error. As such, the name Eos bornea came into use for the red lory, replacing the later-published name 'Eos rubra'. However, Walters (1998) subsequently disputed this identification, recommending the continued use of E. rubra. At present, 'Eos bornea' still seems to be the more commonly used name, and my own sympathies would be more with maintaining the familiar usage than with insisting on strict adherence to the original concept.

Red lories, Eos... let's just say bornea, shall we? Copyright Arnaud Delberghe.

Because of their striking appearance, Eos species have been heavily collected for the pet trade. The have also been widely affected by habitat degradation with the clearing of primary forests. While populations of most species are still regarded as reasonably robust, the IUCN regards all except E. squamata as on the decline. Eos histrio is regarded as actively endangered, having all but disappeared from some of its home islands. In 1999, it was estimated that 1000 to 2000 red-and-blue lories were being captured and exported for the pet trade each year—despite the total population of this species probably being not much more than 20,000 individuals!

REFERENCES

Bonaparte, C. L. 1850. On the trichoglossine genus of parrots, Eos, with the description of two new species. Proceedings of the Zoological Society of London 18 (1): 26-29.

Hume, J. P., & M. Walters. 2012. Extinct Birds. T. & A. D. Poyser.

Juniper, T., & M. Parr. 1998. Parrots: A guide to the parrots of the world. Christopher Helm Publishers.

Walters, M. 1998. What is Psittacus borneus Linnaeus? Forktail 13: 124-125.

The Elaenia Elaenias

Yellow-bellied elaenia Elaenia flavogaster, photographed by Félix Uribe.

We are all aware that there are some truly stunning birds out there: majestic eagles and vultures, vibrant parrots and hummingbirds, eye-catching cranes and pelicans. But those of us who spend a lot of time contemplating the nature of bird diversity, whether as bird-watchers or ornithologists, will soon admit that the greater proportion of this diversity is composed of what are affectionately or not-so-affectionately referred to as Little Brown Jobs. In particular, the tyrant flycatchers or Tyrannidae of the Americas are one family of birds that is notorious for including some of the littlest, the brownest, and the jobbiest.

Elaenia is a genus of about twenty or so species of tyrannid found in Central and South America (Sibley & Monroe, 1990, listed eighteen, but phylogenetic studies suggest that some of these should be divided into more than one species—Rheindt et al. 2009). The name 'elaenia' does double service for these guys as both genus and vernacular name, though the members of some related genera are also labelled in the vernacular as 'elaenias'. As a result, Ridgely & Tudor (2009), without a trace of apparent irony, referred to the species of this genus as 'Elaenia elaenias'.

Mottled-backed elaenia Elaenia gigas, showing its distinctive divided crest, photographed by Nick Athanas.

The various species of Elaenia elaenias are notoriously difficult to distinguish, and none are particularly eye-catching. They are mostly greenish, though the slaty elaenia Elaenia strepera is dark grey, and the brownish elaenia E. pelzelni is (surprisingly) brown. Underparts may be white, or they may be yellow. One species in particular is labelled as the yellow-bellied elaenia E. flavogaster, but in this case it is not any more strikingly yellow than a number of other species, leading one to suspect whether its vernacular name is any sort of moral judgement. A number of species have some degree of white streak on the crown, and some have a small crest of feathers (the mottle-backed elaenia E. gigas has a well-developed, bifurcated crest). Elaenias are best distinguished by their calls, but that of course requires the bird in question to be calling.

Great elaenia Elaenia dayi, photographed by Thiago Orsi.

Though members of the tyrant flycatcher family in both affinities and appearance, elaenias consume a fair proportion of fruit as well as insects. In at least some species, fruit make up by far the greater part of the diet (Marini & Cavalcanti 1998). Different species often have different preferred habitats, and the relationship between habitat and phylogeny was examined by Rheindt et al. (2008). Two savannah-dwelling species, the plain-crested elaenia Elaenia cristata and the rufous-crowned elaenia E. ruficeps, appear to be the sister clade to the remaining species that mostly inhabit riparian habitats or montane and temperate forests (Elaenia species are largely absent from lowland tropical forest). The forest species fall into two clades nested among the riparian species. The great elaenia E. dayi, which happens to be the largest Elaenia species by a noticeable margin, inhabits the stunted montane forests of the south Venezuelan tepuis (if you've seen the film Up, this is the habitat in which that film is mostly set). Migratory habits, on the other hand, are less correlated with phylogeny than habitat preferences. A number of Elaenia species migrate between temperate breeding grounds and tropical wintering grounds, but migratory species may be closely related to sedentary species that inhabit the tropics all year round. Indeed, some species are mostly sedentary but have somewhat migratory populations in more temperate parts of their range.

REFERENCES

Marini, M. Â., & R. B. Cavalcanti. 1998. Frugivory by Elaenia flycatchers. Hornero 15: 47-50.

Rheindt, F. E., L. Christidis & J. A. Norman. 2008. Habitat shifts in the evolutionary history of a Neotropical flycatcher lineage from forest and open landscapes. BMC Evolutionary Biology 8: 1193.

Rheindt, F. E., L. Christidis & J. A. Norman. 2009. Genetic introgression, incomplete lineage sorting and faulty taxonomy create multiple cases of polyphyly in a montane clade of tyrant-flycatchers (Elaenia, Tyrannidae). Zoologica Scripta 38: 143-153.

Ridgely, R. S., & G. Tudor. 2009. Field Guide to the Songbirds of South America: The Passerines. University of Texas Press.

Sibley, C. G., & B. L. Monroe Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale University Press.

Barn Owls and Such

European barn owl Tyto alba, photographed by Nuno Barreto.

I have no idea where the 'wise old owl' stereotype originally came from. Perhaps it simply originated from their appearance: their broad faces, sedate manner, and slightly supercilious half-lidded gaze (those last two, of course, only applying under the circumstances most people would actually see an owl: as a half-asleep night-dweller rudely awakened during the day). Whatever the cause for their associations, owls are one group of birds that have commonly featured in popular culture. The Eurasian barn owl Tyto alba is one owl species that has long held a particular association with humans. Owls mostly do not build their own nests, but make use of suitable hollows and crannies that they find ready-made. The preferred food of barn owls is small mammals such as rats and mice (though they will not turn up their beaks at alternative fare such as reptiles or large insects when their favourite is not available). Put these two facts together, and human constructions (i.e. barns) can be paradise for a barn owl: ready-made secluded nesting spots in the roof-space, and a steady supply of rodents attracted to stored foodstuffs and/or refuse.

Greater sooty owl Tyto tenebricosa arfaki, photographed by Nik Borrow.

The European barn owl is just one species in the genus Tyto, within which König & Weick (2010) recognised 25 species from around the world. While some Tyto species, like T. alba, are found over a wide range, others are found in restricted localities (many on particular oceanic islands). Some are very poorly known: the Taliabu masked owl Tyto nigrobrunnea from Indonesia was described from a single specimen in 1939, with only a handful of sight records since to attest to its continued existence. The Itombwe owl Tyto prigoginei of central Africa was similarly unknown between its initial description in 1952 and the mistnet capture of a live female in 1996. Prior to its transfer to Tyto by König & Weick (2010), this last species was included in the genus Phodilus, the bay owls, which is the living sister group to Tyto. Together, these two genera form the family Tytonidae, separate from all other owls in the family Strigidae. Tytonid owls differ from strigid owls in a features such as having the inner and central toes of the foot similar in length (versus the inner toe being distinctly shorter than the central one in strigids), with the central toe being serrated on the underside. The species of Tyto have a distinctly heart-shaped facial disc (that of Phodilus species is almost reminiscent of Hello Kitty). Many Tyto species, such as T. alba, prefer open habitats, but some, such as the sooty owls Tyto multipunctata and T. tenebricosa of eastern Australia and New Guinea, inhabit rainforests. The smallest Tyto species are T. prigoginei at about 24 cm total length and the Galapagos barn owl T. punctatissima at about 26 cm, and the largest is the Tasmanian grass owl T. castanops, reaching up to 55 cm in length and about 1.25 kg in weight.

Tasmanian grass owl Tyto castanops, photographed by Murray Lord.

Other extinct species would have also probably broken the 1 kg mark. Tyto species have a long fossil record, going back to the Middle Miocene European species T. sanctialbani (Kurochkin & Dyke 2011). Tytonids of now-extinct genera had been abundant in Europe before that time, but Mlíkovský (1998) suggested that they had become temporarily extinct there in the Early Miocene, owing to a gap in the fossil record. Tyto sanctialbani was similar in size to the modern T. alba (Mlíkovský 1998), but a number of giant fossil barn owls are known from islands around the world. The largest include Tyto pollens and T. riveroi in the West Indies (the Bahamas and Cuba, respectively), and T. robusta and T. gigantea from Gargano. Gargano is a peninsula of southern Italy that was a separate island during the Late Miocene to Early Pliocene, at which time it was home to a distinctive endemic fauna including such animals as the absolutely insane small ruminant Hoplitomeryx, which possessed both a crown of five spike-shaped horns and long dagger-like canines. It has been suggested that this over-exuberant armature had evolved as a defence against Gargano's main predators, an assemblage of raptors including the aforementioned Tyto species. The larger of the two, T. gigantea, was about twice the size of a living European barn owl, and perhaps larger than any living owl (Ballmann 1976), though it was more gracile in build than the largest living Bubo species. Ballmann provides measurements for leg bones of T. gigantea and not wing bones, but if we assume similar proportions to a modern barn owl then we'd be looking at a wingspan for T. gigantea of about two metres. That, I submit, is enough to scare seven colours of crap out of any number of small mammals.

REFERENCES

Ballmann, P. 1976. Fossile Vögel aus dem Neogen der Halbinsel Gargano (Italien), zweiter Teil. Scripta Geol. 38: 1-59, 7 pls.

König, C., & F. Weick. 2010. Owls of the World, 2nd ed. Christopher Helm: London.

Kurochkin, E. N., & G. J. Dyke. 2011. The first fossil owls (Aves: Strigiformes) from the Paleogene of Asia and a review of the fossil record of Strigiformes. Paleontological Journal 45 (4): 445-458.

Mlíkovský, J. 1998. A new barn owl (Aves: Strigidae) from the early Miocene of Germany, with comments on the fossil history of the Tytoninae. J. Ornithol. 139: 247-261.

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.

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.

A King among Parrots

Moluccan King parrot Alisterus amboinensis, photographed by Helsinki***.

For today's post, I'm looking at the King parrots of the genus Alisterus. There are three recognised species in this genus: the Australian King parrot Alisterus scapularis of eastern Australia, the green-winged or Papuan King parrot A. chloropterus of central and eastern New Guinea, and the Amboina or Moluccan King parrot A. amboinensis of eastern Indonesia and western Papua. However, each species is divided into subspecies, and some subspecies are quite distinct from each other. For instance, Alisterus scapularis shows distinct sexual dimorphism: the male has a bright red head and breast while the female has a green head and breast. In A. amboinensis, both sexes have red heads. In A. chloropterus, the nominate subspecies has a green-headed female like that of A. scapularis, but the northwesternmost subspecies A. chloropterus moszkowskii has a red-headed female like that of A. amboinensis (Forshaw & Knight 2010). In relation to other parrots, Alisterus belongs to the tribe Psittaculini that extends into eastern and southern Asia and the Mascarenes, among which it forms a clade with the other Australian genera Aprosmictus and Polytelis (Mayr 2010) (and hybrids have even been recorded between A. scapularis and species of these two genera—Rutgers & Norris 1972).

Female (left) and male Australian King parrot Alisterus scapularis, photographed by Peter Firminger.

You might be wondering why, among an entire order of particularly regal birds, it is this particular genus that is honoured with the title of 'King' (I know I certainly did). As it turns out, the reason appears to be that Alisterus is not, properly speaking, the 'king of parrots', but 'King's parrot', named after Philip Gidley King, governor of New South Wales from 1800 to 1806 ('Stentoreus' 2004; I might as well also point out for the benefit of those not familiar with Australian history that the original 'New South Wales' was considerably larger than the current state by that name, taking in the entire eastern seaboard of Australia).

Papuan King parrot Alisterus chloropterus, photographed by Mehd Halaouate.

King parrots are generalist feeders on fruit and seeds, which has not always endeared them to horticulturalists. They nest in deep holes in hollow trees: while the entrance to an Alisterus scapularis nest may be more than nine metres high, the actual nest may be nearly at ground level (Rutgers & Norris 1972). They lay 3-6 eggs between October and December.

REFERENCES

Forshaw, J. M., & F. Knight. 2010. Parrots of the World. Princeton University Press.

Mayr, G. 2010. Parrot interrelationships—morphology and the new molecular phylogenies. Emu 110: 348-357.

Rutgers, A., & K. A. Norris. 1972. Encyclopaedia of Aviculture vol. 2. Blandford Press: London.

Name the Bug #8: Prosobonia cancellata

Prosobonia cancellata - photo by Ron Hoff.

Prosobonia cancellata, the Tuamotu sandpiper, is a small to medium-sized bird found on a small number of coral atolls in French Polynesia. It is currently endangered with probably about 1200-1300 surviving individuals in 2003, mostly on the two islands of Tenararo and Morane (Pierce & Blanvillain, 2004). Zusi & Jehl (1970) included Prosobonia in the subfamily Tringinae, which also includes the Tringa sandpipers, Numenius (curlews) and Limosa (godwits). Prosobonia differs from these genera in living higher up on the shoreline, including the atoll forest, feeding on small invertebrates gleaned among leaf litter and off trees. They also seem to eat a reasonable amount of plant material such as seeds.

Other Prosobonia species were once found on a number of tropical Polynesian islands, while P. cancellata itself was previously more widespread with a range extending to Kiritimati (Christmas Island) in Kiribati. Some authors have regarded the Tuamotu and Kiritimati populations as separate subspecies or species, but Zusi and Jehl (1970) pointed out that the only known specimen from Kiritimati (unfortunately no longer available) probably lay within the known range of variation for Tuamotu specimens. Prosobonia leucoptera was found on Tahiti and Moorea (again, some authors have regarded the two populations as separate species) while undescribed subfossils have been found on Henderson, Marquesas and Cook Islands. Prosobonia cancellata has also been placed in a separate genus, Aechmorhynchus, from P. leucoptera, but again Zusi & Jehl established that significant differences between the two species were few except for coloration pattern (P. cancellata has barred plumage, while P. leucoptera was plainer) so there can be little doubt of their close relationship relative to other taxa.

REFERENCES

Pierce, R. J., & C. Blanvillain. 2004. Current status of the endangered Tuamotu sandpiper or titi Prosobonia cancellata and recommended actions for its recovery. Wader Study Group Bulletin 105: 93-100.

Zusi, R. L., & J. R. Jehl Jr. 1970. The systematic relationships of Aechmorhynchus, Prosobonia, and Phegornis (Charadriiformes; Charadrii). Auk 87: 760-780.

Cranes Off the Rails (Taxon of the Week: Grues)

The 'Messel rail' Messelornis cristata - a specimen with preserved plumage. Photo from here.

Despite its presentation in years of fieldguides and other popular books, the bird order 'Gruiformes' has in recent times been scattered to the four winds, with analyses both morphological and molecular proclaiming its polyphyly. Nevertheless, molecular analyses such as Hackett et al. (2008) continue to support a clade roughly corresponding to the suborder Grues as recognised by Cracraft (1973)* containing the cranes and the rails. The morphological analysis of Livezey & Zusi (2007) on the other hand, does not support this clade, but it does support monophyly for each of the two primary divisions within Grues, the ralloid and gruoid lineages.

*Just to confuse matters, the name "Grues" has been used by different authors for clades of differing inclusivity. Mayr (2009), for instance, uses "Grues" for the Aramus + Gruidae clade, and refers to the larger clade as "core Gruiformes".

The ralloid line contains the living families Rallidae*, the rails, and Heliornithidae, the finfoots (or should that be finfeet?) Cracraft (1973) regarded the Cretaceous Laornis edvardsianus as a stem ralloid, but no-one else seems to have taken him up on this suggestion. More reliably on the ralloid stem are the Palaeocene to Oligocene Messelornithidae (Mayr, 2009). Messelornithids were medium-sized birds (about the size of a small chicken) best known from Messelornis cristata for which over 500 specimens are available, some even with preserved feathering. Messelornis was highly terrestrialised with limited flight capabilities and almost ludicrously long legs (loss or reduction of flight has been a common occurrence among the Grues). Its beak was relatively short and the overall appearance of Messelornis would probably have not been dissimilar to the modern cariamas.

*Hackett et al. (2008) resolved the Rallidae as paraphyletic to Heliornithidae, with Sarothrura (the flufftails) closer to Heliornis than to the other two included rails Himantornis and Rallus. A few places, at least online, have suggested recognising Sarothrura as a separate family from the Rallidae as a result, but I'd recommend waiting for a more detailed analysis with greater coverage of the Rallidae. Increased taxonomic coverage may return the flufftails to the other Rallidae, or it may make it more appropriate to treat the finfoots as derived rallids.


The sungrebe Heliornis fulica of tropical South America (I tried to find a picture of one carrying chicks, but no luck). Photo by Jerry Oldenettel.

The finfoots of the Heliornithidae are three species (one in Asia, one in Africa, one in South America) of tropical grebe-like birds, renowned for their reclusiveness. The South American sungrebe Heliornis fulica is the most distinctive in appearance of the three species (though mitochondrial analysis indicates that it and the Asian Heliopais personata form a clade to the exclusion of the African Podica senegalensis - Fain et al., 2007) and is also very distinct in its nesting behaviour. Heliopais and Podica, like most aquatic birds, have chicks that hatch out reasonably well-developed and immediately able to swim after their parents. Heliornis, in contrast, has altricial chicks that hatch out after only ten to eleven days of incubation. The really amazing bit, though, is what happens after the chicks hatch. The male sungrebe has a shallow pouch under each wing and he is able to transport the chicks inside this pouch, even flying with them. Whether the chicks remain in the pouches permanently or whether they are only placed in them while the male is travelling remains unknown. Funnily enough, while this chick-carrying behaviour was described by Alvarez del Toro in 1971, it had originally been recorded almost 140 years earlier by Prince Maximilian of Wied. It seems that everyone else had assumed the prince was smoking something.


Grey-winged trumpeters, Psophia crepitans. Photo by A. Vinot.

The gruoid lineage includes Psophia, the trumpeters, Aramus guarauna, the limpkin, and Gruidae, the cranes, as well as the fossil taxa Parvigrus pohli, Geranoididae and Eogruidae. Most recent authors agree that Aramus and Gruidae form a clade to the exclusion of Psophia. The chicken-sized Oligocene Parvigrus was originally described by Mayr (2005) as sister to Aramus + Gruidae, but he later (Mayr, 2009) revised its position to stem gruoid. Parvigrus lacked the long beak of limpkins and cranes, as do the Recent trumpeters, three species of similarly chicken-sized birds found in northern South America.

Whether Geranoididae and Eogruidae possessed crane-like long beaks is an unknown factor as skull material for both has not been found. Cracraft (1973) placed both outside the crown gruoids, but Clarke et al. (2005) placed Eogruidae inside the gruoid crown as sister to Aramus + Gruidae. The Eocene Geranoididae have been described only from leg bones (Wetmore, 1933, assigned some wing bones to Geranoides jepseni in his original description of this species but did not describe them) so little can be said about them except that they were large and long-legged. Wetmore (1933) commented on the unusually wide spacing of the trochleae (the 'knuckles') at the end of the tarsometatarsus suggesting that Geranoides had very widely splayed toes, but Cracraft (1969) later attributed to wide spacing to post-mortem distortion. Cracraft (1969, 1973) included a number of Eocene birds in the Geranoididae but admitted a lack of derived characters uniting them; Geranoididae may represent a paraphyletic assemblage of basal gruoids.


Distal ends of tarsometatarsi of the eogruids Proergilornis and Ergilornis, showing reduction of the inner trochlea in Proergilornis and its loss in Ergilornis. Figure from Cracraft (1973).

The Eocene to Pliocene Eogruidae were also decent-sized long-legged birds from central Asia and (in later times) Europe. Earlier authors recognised two families, Eogruidae and Ergilornithidae, but 'ergilornithids' are now recognised as derived eogruids. Eogruids were highly cursorial birds and a humerus attributed to Ergilornis suggests that it was flightless, though the earlier Eogrus aeola shows no sign of being so (Clarke et al., 2005). Originally three-toed, eogruids showed a reduction in the size of the inner toe, and Ergilornis and Amphipelargus (the latest of the eogruids) lost it entirely (it is easy to present a progression from flying and three-toed to flightless and two-toed, but be warned that three-toed species survived into the Miocene, well after the appearance of the two-toed forms). The only other birds to reduce the number of toes to two are the ostriches, and a relationship between ostriches and eogruids has been suggested in the past (generally in association with the idea that the ratites do not form a monophyletic group). However, Cracraft (1973) confirmed that eogruids were more similar in their fine morphology to gruoids than ostriches, and modern phylogenetic analyses do not support a close relationship of ostriches and gruoids.

Many people carry the impression that flightlessness in birds is associated with lack of predators. However, eogruids evolved flightlessness in an environment in which predators were no rarity (amongst others, they shared their world with such horrors as hyaenodonts and entelodonts*). Similarly, while the exact circumstances in which they became flightless is unknown, modern ostriches (Africa), emus (Australia) and rheas (South America) all live alongside significant predators or at least did so until recently. Obviously, something other than lack of predators is at play here.

*I always imagine Roald Dahl's hornswogglers to be something like an entelodont.

REFERENCES

Clarke, J. A., M. Norell & D. Dashzeveg. 2005. New avian remains from the Eocene of Mongolia and the phylogenetic position of the Eogruidae (Aves, Gruoidea). American Museum Novitates 3494: 1-17.

Cracraft, J. 1969. Systematics and evolution of the Gruiformes (class, Aves). 1, The Eocene family Geranoididae and the early history of the Gruiformes. American Museum Novitates 2388: 1-41.

Cracraft, J. 1973. Systematics and evolution of the Gruiformes (class Aves). 3, Phylogeny of the suborder Grues. Bulletin of the American Museum of Natural History 151: 1-127.

Fain, M. G., C. Krajewski & P. Houde. 2007. Phylogeny of "core Gruiformes" (Aves: Grues) and resolution of the limpkin–sungrebe problem. Molecular Phylogenetics and Evolution 43: 515-529.

Hackett, S. J., R. T. Kimball, S. Reddy, R. C. K. Bowie, E. L. Braun, M. J. Braun, J. L. Chojnowski, W. A. Cox, K.-L. Han, J. Harshman, C. J. Huddleston, B. D. Marks, K. J. Miglia, W. S. Moore, F. H. Sheldon, D. W. Steadman, C. C. Witt & T. Yuri. 2008. A phylogenomic study of birds reveals their evolutionary history. Science 320: 1763-1768.

Livezey, B. C., & R. L. Zusi. 2007. Higher-order phylogeny of modern birds (Theropoda, Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion. Zoological Journal of the Linnean Society 149 (1): 1-95.

Mayr, G. 2005. A chicken-sized crane precursor from the early Oligocene of France. Naturwissenschaften 92: 389-393.

Mayr, G. 2009. Palaeogene Fossil Birds. Springer.

Wetmore, A. 1933. Fossil bird remains from the Eocene of Wyoming. Condor 35: 115-118.

The Voice of the Turtle (Taxon of the Week: Streptopelia)

Eurasian collared dove Streptopelia decaocto, the most widespread Streptopelia species in Europe. Photo by Rovdyr.

The bird genus Streptopelia comprises the turtledoves or collared doves - thirteen to seventeen species (depending on preferred generic boundaries) of medium-sized, generally pinkish birds that have long garnered human admiration due to their attractive appearance and cooing vocalisations. The name "turtledove" is derived from the Latin turtur, which is itself an imitation of the sound made by the doves. The calls of different species of turtledoves are distinct, and often play a significant part in their identification (Slabbekoorn et al., 1999). Streptopelia doves are native to Africa and the warmer parts of Asia and Europe, but a number of species have been introduced to other parts of the world. Here in Perth, for instance, the laughing dove S. senegalensis and the spotted dove S. chinensis are both abundant (the former particularly so), while S. chinensis is also a successful exotic in Auckland back in New Zealand. Also widely introduced is the African collared dove or Barbary dove Streptopelia risoria*.

*The Barbary dove ("S. risoria") is the domesticated form of the African collared dove ("S. roseogrisea"), and most modern authors no longer regard the two as specifically distinct. S. risoria Linnaeus, 1758 has priority over S. roseogrisea Sundevall, 1857. However, it has become common practice for the name based on a "wild" taxon to be given preference over one based on a domestic taxon because of the often complicated nature of taxonomic concepts in relation to domesticated animals (Gentry et al., 2004), and so many authors have preferred to use S. roseogrisea for the combined taxon. A recent proposal to formalise this situation was turned down by the ICZN (ICZN, 2008), leaving S. risoria as the valid name for this species.


The Madagascar turtle dove Streptopelia picturata (aka Nesoenas picturata). Phylogenetic analysis indicates that this species is closely related to the pink pigeon Nesoenas mayeri (=Streptopelia mayeri) of Mauritius. Though distinct morphologically, the two species have very similar vocalisations. Photo from here.

In the past, Columbidae (pigeons and doves) have mostly been divided between two subfamilies, the Columbinae (standard columbids) and Treroninae (fruit-pigeons and fruit-doves), with separate monogeneric subfamilies for the morphologically distinctive genera Goura and Didunculus (and sometimes Otidiphaps) and a separate family Raphidae for the extinct dodo Raphus cucullatus and solitaire Pezophaps solitaria. This arrangement, never particularly sturdy at the best of times, has been blown out of the water by recent analyses (Pereira et al., 2007), which render the traditional Columbinae paraphyletic to the other subfamilies and Raphidae while the Treroninae becomes polyphyletic. To date, no-one has formally proposed a revised subfamilial classification of Columbidae, though Pereira et al. (2007) did recognise three well-supported clades in the family which they called simply A, B and C*.

*Because I have the comfort of knowing that no-one is going to take any notice of me in this matter, I can reveal that if we were to recognise these three clades as a subfamily each, they would become respectively Columbinae, Claravinae and Raphinae (going by the dates reported in Bock, 1994), and I find a certain pleasant irony in the idea that Raphinae would be the largest of the three.


The collared dove Streptopelia chinensis (=Stigmatopelia chinensis). Originally native to eastern Asia, the collared dove has been widely introduced elsewhere in the world. Photo by Charles Lam.

Whatever the eventual division of the family, Streptopelia will almost certainly remain a part of Columbinae, as it is the most closely related genus to Columba. Molecular analysis of fourteen of the sixteen species generally included in Streptopelia by Johnson et al. (2001) identified three main clades in the genus - a large clade containing the majority of species, a clade uniting S. chinensis and S. senegalensis, and a clade containing the Madagascan S. picturata and the pink dove Nesoenas mayeri of Mauritius. This three-part division is also reasonably consistent with morphological and vocal distinctions within the genus. The two smaller clades were in turn sister to each other, but the monophyly of Streptopelia as a whole was not proven; depending on the chosen method of analysis, either Streptopelia was monophyletic (the maximum likelihood results) or the main Streptopelia clade was sister to a clade containing Old World Columba and the two smaller clades (the maximum parsimony results). New World 'Columba' species were the sister clade to Streptopelia plus Old World Columba whatever the method; their recognition as a separate genus Patagioenas was proposed. Johnson et al. (2001) chose to retain Streptopelia in its previous circumscription, but with 'Nesoenas' mayeri also included. In contrast, Cheke (2005) suggested restricting Streptopelia to the main clade and recognising the smaller clades as separate genera Nesoenas (for mayeri and picturata) and Stigmatopelia (for chinensis and senegalensis). Johnson et al.'s (2001) system has the advantage of minimising the number of name changes involved; Cheke's (2005) system is potentially more robust to the uncertain monophyly of the broader Streptopelia; only time will tell which gains the greater popularity.

REFERENCES

Bock, W. J. 1994. History and nomenclature of avian family-group names. Bulletin of the American Museum of Natural History 222: 1-281.

Cheke, A. S. 2005. Naming segregates from the Columba–Streptopelia pigeons following DNA studies on phylogeny. Bulletin of the British Ornithologists' Club 125 (4): 293-295.

Gentry, A., J. Clutton-Brock & C. P. Groves. 2004. The naming of wild animal species and their domestic derivatives. Journal of Archaeological Science 31: 645-651.

ICZN. 2008. Opinion 2215: Streptopelia risoria (Linnaeus, 1758) (Aves, Columbidae): priority maintained. Bulletin of Zoological Nomenclature 65 (4).

Johnson, K. P., S. de Kort, K. Dinwoodey, A. C. Mateman, C. ten Cate, C. M. Lessells & D. H. Clayton. 2001. A molecular phylogeny of the dove genera Streptopelia and Columba. Auk 118 (4): 874-887.

Pereira, S. L., K. P. Johnson, D. H. Clayton & A. J. Baker. 2007. Mitochondrial and nuclear DNA sequences support a Cretaceous origin of Columbiformes and a dispersal-driven radiation in the Paleogene. Systematic Biology 56 (4): 656-672.

Slabbekoorn, H., S. de Kort & C. ten Cate. 1999. Comparative analysis of perch-coo vocalizations in Streptopelia doves. Auk 116 (3): 737-748.