Anna M. Kearns

Australia's arid-adapted butcherbirds experienced range expansions during Pleistocene glacial maxima.

A model of range expansions during glacial maxima (GM) for cold-adapted species is generally accepted for the Northern Hemisphere. Given that GM in Australia largely resulted in the expansion of arid zones, rather than glaciation, it could be expected that arid-adapted species might have had expanded ranges at GM, as cold-adapted species did in the Northern Hemisphere. For Australian biota, however, it remains paradigmatic that arid-adapted species contracted to refugia at GM. Here we use multilocus data and ecological niche models (ENMs) to test alternative GM models for butcherbirds. ENMs, mtDNA and estimates of nuclear introgression and past population sizes support a model of GM expansion in the arid-tolerant Grey Butcherbird that resulted in secondary contact with its close relative--the savanna-inhabiting Silver-backed Butcherbird--whose contemporary distribution is widely separated. Together, these data reject the universal use of a GM contraction model for Australias dry woodland and arid biota.

Testing the effect of transient Plio-Pleistocene barriers in monsoonal Australo-Papua: Did mangrove habitats maintain genetic connectivity in the Black Butcherbird?

Changes in climate and sea level are hypothesized to have promoted the diversification of biota in monsoonal Australia and New Guinea by causing repeated range disjunctions and restricting gene flow between isolated populations. Using a multilocus (one mtDNA locus, five nuclear introns) phylogeographic approach, we test whether populations of the mangrove and rainforest restricted Black Butcherbird (Cracticus quoyi) have diverged across several geographic barriers defined a priori for this region. Phylogeographic structure and estimates of divergence times revealed Plio‐Pleistocene divergences and long‐term restricted gene flow of populations on either side of four major geographic barriers between and within Australia and New Guinea. Overall, our data are consistent with the hypothesis that mesic‐adapted species did not disperse across the open dry woodlands and grasslands that dominated the transient palaeo‐landbridges during the Plio‐Pleistocene despite the presence of mangrove forests that might have acted as dispersal corridors for mesic‐adapted species. Our study offers one of the first multilocus perspectives on the impact of changes in climate and sea level on the population history of widespread species with disjunct ranges in Australia and New Guinea.

The impact of Pleistocene changes of climate and landscape on Australian birds: a test using the Pied Butcherbird (Cracticus nigrogularis)

Abstract Widespread cyclic aridity during the Pleistocene is hypothesised to have had a significant impact on widespread Australian birds causing range-wide contractions to historical refugia and population differentiation while in isolation. In this study we tested a priori hypotheses for the impact of Pleistocene climatic and edaphic changes on the population history of the widespread Australian Pied Butcherbird (Cracticus nigrogularis). Analysis of mitochondrial DNA sequences from 55 individuals of C. nigrogularis revealed low genetic diversity, poor geographical structure and signatures of a recent demographic expansion. In contrast with long-standing biogeographical hypotheses, our data suggest that C. nigrogularis was likely to have been restricted to multiple refugia across its current range rather than undergoing range-wide contractions to one or few refugia. In addition, we found no evidence for the Carpentarian Barrier of northern Australia having limited dispersal in C. nigrogularis, which contrasts with predictions from intraspecific taxonomy and with population structures of several other bird species. Our data add to the increasing number of phylogeographical studies of widespread Australian birds that show evidence of maintaining large effective population sizes despite widespread aridity, as well as species-specific, rather than ecosystem-wide, responses to Pleistocene climatic changes and biogeographical barriers.

Norfolk Island Robins are a distinct endangered species: ancient DNA unlocks surprising relationships and phenotypic discordance within the Australo-Pacific Robins

Uncertain taxonomy hinders the effective prioritization of taxa for conservation. This problem is acute for understudied island populations in the southwest Pacific Ocean, which are increasingly threatened by habitat loss, predation and climate change. Here, we offer the first test of taxonomic limits and phylogenetic affinities of the iconic Pacific Robin radiation (Petroica multicolor) in order to prioritize the conservation of its nominotypical subspecies, the endangered Norfolk Island Robin (P. m. multicolor). We integrate phylogenetic analyses of ancient DNA and quantitative measures of plumage and morphometric variation to show that the Norfolk Island Robin should be recognized as a distinct species. Phenotypic and genetic datasets contradict the longstanding treatment of Pacific Robins (including Norfolk Island Robins) and Scarlet Robins (P. boodang) as a single species. Instead, we show that Norfolk Island Robins are deeply divergent from Scarlet Robins and have more genetic similarity to Red-capped Robins (P. goodenovii) than to other Pacific Robins. This finding is unrepresentative of the current taxonomic and conservation status of the Norfolk Island Robin, which we propose should be recognised as an endemic endangered species. Our study clearly shows that in the absence of contemporary tissues, ancient DNA approaches using historical museum specimens can address taxonomic questions that morphological traits are unable to resolve. Further, it highlights the need for similar studies of other threatened Norfolk fauna with uncertain taxonomic status in order to ensure appropriate conservation prioritization.

Distinctiveness of Pacific Robin subspecies in Vanuatu revealed from disparate patterns of sexual dichromatism, plumage colouration, morphometrics and ancient DNA

Abstract The Pacific Robin (Petroica multicolor) is a polytypic species, with 14 subspecies recognised in the tropical south-western Pacific Ocean. Like most of the avifauna of this region, the Pacific Robin has received little taxonomic attention since early works, such as those by Ernst Mayr in the 1930s–1950s. Here, we used mitochondrial DNA (mtDNA), spectrophotometry of plumage colouration and morphological data to examine patterns of sexual dichromatism, and phenotypic and genetic variation of Pacific Robins in the Vanuatu Archipelago. We have shown for the first time that subspecies in Vanuatu display three types of sexual dichromatism: typical marked sexual dichromatism, and reduced sexual dichromatism, in which both sexes have either elaborate masculinised plumage or drab feminised plumage. Different types of sexual dichromatism were not correlated with phylogenetic relationships. We also find that distinctive mtDNA, bill-length and colour of the throat plumage support the naming of a new subspecies for the population on Tanna Island, P. m. tannensis subsp. nov., which has long been treated as consubspecific with that on nearby Aneityum Island. Our study highlights the importance of revisiting the taxonomy and evolutionary history of other Pacific Ocean avifauna with molecular data and quantitative tests of phenotypic differentiation between island forms.

Sequencing of the complete mitochondrial genome of the common raven Corvus corax (Aves: Corvidae) confirms mitogenome-wide deep lineages and a paraphyletic relationship with the Chihuahuan raven C. cryptoleucus

Previous studies based on single mitochondrial markers have shown that the common raven (Corvus corax) consists of two highly diverged lineages that are hypothesised to have undergone speciation reversal upon secondary contact. Furthermore, common ravens are paraphyletic with respect to the Chihuahuan raven (C. cryptoleucus) based on mitochondrial DNA (mtDNA). Here we explore the causes of mtDNA paraphyly by sequencing whole mitochondrial genomes of 12 common ravens from across the Northern Hemisphere, in addition to three Chihuahuan ravens and one closely related brown-necked raven (C. ruficollis) using a long-range PCR protocol. Our raven mitogenomes ranged between 16925–16928 bp in length. GC content varied from 43.3% to 43.8% and the 13 protein coding genes, two rRNAs and 22 tRNAs followed a standard avian mitochondrial arrangement. The overall divergence between the two common raven clades was 3% (range 0.3–5.8% in 16 regions including the protein coding genes, rRNAs and the control region). Phylogenies constructed from whole mitogenomes recovered the previously found mitochondrial sister relationship between the common raven California clade and the Chihuahuan raven (overall divergence 1.1%), which strengthens the hypothesis that mtDNA paraphyly in the common raven results from speciation reversal of previously distinct Holarctic and California lineages.

Nuclear introns help unravel the diversification history of the Australo-Pacific Petroica robins

Australo-Pacific Petroica robins are known for their striking variability in sexual plumage coloration. Molecular studies in recent years have revised the taxonomy of species and subspecies boundaries across the southwest Pacific and New Guinea. However, these studies have not been able to resolve phylogenetic relationships within Petroica owing to limited sampling of the nuclear genome. Here, we sequence five nuclear introns across all species for which fresh tissue was available. Nuclear loci offer support for major geographic lineages that were first inferred from mtDNA. We find almost no shared nuclear alleles between currently recognized species within the New Zealand and Australian lineages, whereas the Pacific robin radiation has many shared alleles. Multilocus coalescent species trees based on nuclear loci support a sister relationship between the Australian lineage and the Pacific robin radiation-a node that is poorly supported by mtDNA. We also find discordance in support for a sister relationship between the similarly plumaged Rose Robin (P. rosea) and Pink Robin (P. rodinogaster). Our nuclear data complement previous mtDNA studies in suggesting that the phenotypically cryptic eastern and western populations of Australias Scarlet Robin (P. boodang) are genetically distinct lineages at the early stages of divergence and speciation.

The handbook of the birds of the world. Volume 14: Bush-shrikes to old world sparrows

Undertaking research on owls is filled with many challenges, the most obvious being working on cryptic species in the dark. Trying to identify species can be very difficult, especially if your observations are based on the silhouette of a non-vocal owl roosting high in the canopy where its size is difficult to estimate through the foliage. If you are lucky this silent flier will do afly-by over your head, or better still, call to amate, giving you the chance to identify it. Inmany situations, however; the owlwill not be so obliging and will remain silent in its roost, leaving you to wonder: was it a masked owl or maybe a sooty owl or possibly a barn owl? The Owls of Australia – a field guide to Australian night birds by Stephen Debus will certainly help with these owl identification problems. This field guide provides a concise summary of Australia’s different owl species, focussing primarily on the identification and basic biology of individual species. The guide begins with a generic chapter on owls and then provides separate chapters for the two owl families and within these chapters sections on the Australian owls that fall within each family. This field guide also contains a chapter on the identification of frogmouths, which is helpful as frogmouths are often misidentified as owls. The opening chapter of this guide provides a very useful overview of owls, including information about their taxonomy and the characteristics of the two owl families found in Australia, the Tytonidae (barn owls) and the Strigidae (hawk owls). This chapter also provides an overview of food and hunting, behaviour, reproduction, handling and studying owls, distribution, threats and conservation and finishes with nomenclature and species limits. Chapter two provides a brief overview of owls in the fossil record. Chapters three and four provide relevant information about each owl species found in Australia. Chapter three represents the hawk owls (genus Ninox). There are separate sections for each of the five Ninox owls found in Australia (Powerful Owl, Rufous Owl, Barking Owl, Southern Boobook and Christmas Island Hawk-Owl) under the headings: Description and voice,Distribution,Food and hunting,Behaviour,Breeding, and Threats and conservation. The same format is used for the barn owls (genus Tyto) in chapter four which includes all five species of Tyto found inAustralia (SootyOwl, Lesser SootyOwl, Masked Owl, Eastern Barn Owl and Eastern Grass Owl). The information provided for each species is concise and well written. The format makes this field guide easy to use and the explanations of the differences between similar species will definitely make correct owl identifications more likely. Coloured plates of each species are also included in the guide. These plates depict both adults and juveniles with a combination of roosting and flying birds, further highlighting differences between species. Information about frogmouths (genus Podargus) is found in chapter five. This chapter contains an overview of frogmouth characteristics and highlights the differences between owls and frogmouths. The Tawny Frogmouth, Papuan Frogmouth and Marbled Frogmouth are all described with information about the distribution and habitat of each species. The inclusion of this chapter will help dispel the misbelief that frogmouths are owls. This field guide concludes with a chapter about threats, conservation and the future. Debus highlights the pressures faced by Australian owls such as habitat destruction, pesticides and pollution and persecution. He also discusses research and management, reserves, habitat restoration and enhancement, pest management, education, rehabilitation and the future. This chapter is a neat summary of human interactions with these species. It reinforces the ecological and social importance of Australian owls and suggests areas where future research and conservation should be focussed. Overall, The Owls of Australia – a field guide to Australian night birds is a must-have field guide for any owl enthusiast. This guide is concise (106 pp.) and easy to use with all the Australian owls included and the differences between these species are highlighted. The guide is well referenced and also contains a short glossary of key terms. I have no hesitation is recommending this guide as essential for anyone venturing out at night to study owls.