Journal & Proceedings of the Royal Society of New South Wales, vol. 150, part 2, 2017, pp. 220–231. ISSN 0035-9173/17/020220-12 A guide to the evolution and classification of Australian birds in 2017 Leo Joseph Australian National Wildlife Collection, National Research Collections Australia, CSIRO GPO Box 1700 Canberra ACT 2601 Email: [email protected] Abstract This article was first published in ‘The Australian Bird Guide’ (CSIRO Publishing, 2017). It is reproduced here with minor updates and modifications. Scientific names of individual species are listed in an Appendix except where pertinent to points in the main text. he recently published Australian Bird related to each other that really animates their TGuide (Menkhorst et al., 2017) comes conversation. Chats are honeyeaters. “Well, at a time of tremendous and ongoing change yes, I suppose that’s nearly been suggested,” in our understanding of bird evolution and the 1975 worker says. Owlet-nightjars next how the classifications we adopt can best to swifts. “Surely, you modern people have summarize that understanding. been misled!” Falcons next to parrots and Imagine two Australian ornithologists, not with other diurnal birds of prey. “Now one from 1935 and one from 1975, find- you’re delirious!” Budgerigars close relatives ing themselves perusing the new field guide of lorikeets, the Scrub-tits of whitefaces? in 2017 when this is being written. Both “Madness!” Shrewder, well-informed orni- recognize most but not all of the birds in it. thologists of any era would wryly note that Neither recognizes the Eungella Honeyeater hints of these relationships were often seen (but that 1962 photograph in Emu of a sup- in behaviour, eggs, nests, anatomy, moults posed Bridled Honeyeater now makes more and plumage. sense to our 1975 friend). The Grey Grass- The point here is that a revolution in wren, officially described in 1968 and thus ornithology, especially in systematics (the unknown to our 1935 colleague, was found scientific study of relationships and how to in 1975 in South Australia beyond where it classify according to those relationships), was first discovered around the western parts began in the late 1960s and today shows of the New South Wales-Queensland border. little sign of stopping because of the produc- Western Whipbirds, thought in 1935 to be tion of new field guides, such as the 2017 heading to extinction in Western Australia, Bird Guide. Arguably, American ornitholo- had been confirmed in eastern Australia just gist Charles Sibley started it by studying bird two years earlier in 1933. systematics through molecules, first proteins Both our ornithologists can see how bird then DNA, and especially at the higher names have changed and find much to talk taxonomic levels of order and family. Since about in this book, but it’s the ways in which the 1980s, techniques to read and analyse we now understand groups of birds to be DNA sequences have improved such that 220 Journal & Proceedings of the Royal Society of New South Wales Joseph — A guide to the evolution and classification of Australian birds in 2017 we can now sample DNA from most of the At the tree’s trunk, living birds divide genome – the full complement of DNA in into Palæognathæ (ratites, tinamous) and a cell. DNA provides new frameworks with Neognathæ (all others). The palæognaths which to understand how species are related continue to surprise. The flighted tinamous to each other in the avian evolutionary tree of the Americas are more closely related to of life, or phylogeny. A well-supported phyl- the extinct New Zealand moas among the ogeny helps us assess how any aspect of bird flightless ratites (emus, cassowaries and so biology has changed during the various proc- on) than some of the latter are to each other. esses of evolution. Kiwis appear closer to the extinct elephant Charles Sibley placed the birds of Aus- birds of Madagascar (Mitchell et al., 2014). tralia front and centre in this global, orni- A corollary is that flight must have been lost thological revolution, along with those of multiple times in the evolution of palæog- New Guinea and New Zealand (Sibley and nathous birds. Ahlquist, 1985). In looking at why this The Neognathæ, in turn, branches into happened, I hope the reader of today, if not the Galloanseres (waterfowls and chicken- our imaginary 1935 and 1975 friends as like birds) and the Neoaves (all other birds). well, will embrace three ideas. First, science Research in the study of whole genomes constantly refines our understanding of the in 2015 challenged the view suggested by avian phylogenetic tree and how we use clas- similar research from 2014. It is fair to say sification from the Class ‘Aves’, right down that much of this debate centres on how, to the level of the species, to summarize that in the absence of a complete fossil record, understanding. There are mis-steps along the our genomic technologies can recover from way, for sure, but that is how science, and DNA any kind of signal of evolutionary people, work. Second, the 2017 Guide and events that happened a very long time ago. its successors should look very different from It is also fair to remind ourselves that while each other and from their predecessors in it is always tempting to think of a new study the species and groups they recognize. Third, of avian relationships as being the best or research in systematics can enliven the way final word on a topic to date (and maybe it one observes any bird. When observing a is), the next study will likely differ (and it bird, we are looking at the latest steps in did — see Burleigh et al. 2015!), however ongoing and open-ended evolution. That slightly, but, again, that is how science works. makes things far more interesting than if our So, while it is reassuring that the composi- understanding of the birds and the names tion of most of the major groups of birds we use all just stood still. seems to be settled, there is still uncertainty as to where some of them fit on the avian The Big Picture evolutionary tree relative to each other. For Observing a community of birds is also akin example, it is now not debated that swifts, to looking at different branches of the phy- nightjars, owlet-nightjars, frogmouths and logenetic tree of birds. A brief summary of hummingbirds form a natural evolutionary our current understanding of the avian tree grouping. Research published at the end of of life from the roots to the tips will be help- 2014 suggested that that group is embedded ful (see details in Jarvis et al., 2014; Prum in the Neoaves whereas Prum et al., (2015) et al., 2015). 221 Journal & Proceedings of the Royal Society of New South Wales Joseph — A guide to the evolution and classification of Australian birds in 2017 placed it as the closest living relative of all South America’s three species of screamers other Neoaves. Other differences are appar- being on another and then all other living ent among the two recent genomic studies anseriforms essentially making up a third but I am struck by the commonalities more and final “very bushy” branch. Next, Aus- than the differences. For example, Jarvis et tralia’s four smallest rails, the White-browed, al. (2014) recognized that most Neoaves are Spotted, Spotless and Baillon’s Crakes, far in what they called the Passerea, which has from being a cohesive evolutionary group, several main lineages, the two main ones apparently represent three different lineages being so-called “core” landbirds (Telluraves) (Garcia-R. et al., 2014). The White-browed and waterbirds (Aequornithia). The Tellu- appears to be most closely related to a simi- raves branches into Australaves (passerines, larly odd African bird, the Striped Crake, parrots, falcons, South American seriemas) and the bush-hens. The Spotted is closest to a and Afroaves (kingfishers and relatives, owls, handful of similar Porzana species worldwide, eagles, woodpeckers, hornbills, trogons). whereas Spotless and Baillon’s are on a differ- Prum et al. (2015) retained the composi- ent branch as their own closest relatives. This tion and structure of the Telluraves, for is why they have recently been assigned to a example, especially its two enormous com- different genus,Zapornia , which is not very ponent groups together in the same pattern closely related to Porzana. It also reminds us of relationships but differs from the earlier that a “body plan” like that of small crakes work in how the ever-mysterious South may not always be a good indicator of who American Hoatzin is related to them. I can is most closely related to whom. live with that kind of debate! Resolution of Parrots and passerines (the latter loosely these debates will depend on how well we termed ‘perching birds’), which turn out can analyse any signal of the deep evolu- to be each other’s closest relatives in a phy- tionary past of birds that is present in their logenetically surprising result, yielded still genomes. further phylogenetic surprises. In passerine evolution, the first branching point led to A closer look New Zealand wrens in one lineage and all Considering some neognathous birds can other passerines in the other. Similarly in deepen one’s appreciation of Australia’s role parrots, the first branching point led to New in bird evolution. Megapodes (mound- Zealand’s kakapo, kea and kakas in one line- builders, such as the familiar Australian age and to all other parrots in the other. Our Brush-turkey), Plains-wanderer and Magpie understanding of passerine evolution has Goose each have their closest living phylo- advanced steadily to the point where remem- genetic connections in South America, the bering the detail of what we have learned is first being most closely related to curassows a formidable task.