THE WINSTON CHURCHILL MEMORIAL TRUST OF AUSTRALIA. Report by Dr Anna Kearns 2011 Churchill Fellow

Transcription

1 THE WINSTON CHURCHILL MEMORIAL TRUST OF AUSTRALIA Report by Dr Anna Kearns 2011 Churchill Fellow The Australian Biological Resources Study Churchill Fellowship to examine the taxonomy of the Pacific Robin species complex I understand that the Churchill Trust may publish this Report, either in hard copy or on the internet or both, and consent to such publication. I indemnify the Churchill Trust against any loss, costs or damages it may suffer arising out of any claim or proceedings made against the Trust in respect of or arising out of the publication of any Report submitted to the Trust and which the Trust places on a website for access over the internet. I also warrant that my Final Report is original and does not infringe the copyright of any person, or contain anything which is, or the incorporation of which into the Final Report is, actionable for defamation, a breach of any privacy law or obligation, breach of confidence, contempt of court, passing-off contravention of any other private right or of any law. Dr Anna Kearns 30 October

2 CONTENTS Introduction 3 Executive Summary 4 Programme 5 Main Body of Report 6 Conclusions & Recommendations 22 References 24 2

3 INTRODUCTION The overall goal of my ABRS Churchill Fellowship was to re-examine the taxonomy of Pacific Robins (Petroica multicolor) using the extensive collections at the American Museum of Natural History in New York, the Delaware Museum of Natural History in Wilmington, and the Academy of Natural Sciences in Philadelphia. My main objective was to assess the distinctiveness of the endangered Norfolk Island subspecies P. m. multicolor using genetic data and quantitative morphological data in order to better inform the management and conservation of these birds. I am extremely grateful to the Winston Churchill Trust and the Australian Biological Resources Study for giving me this fantastic opportunity to travel to various museums and institutions in the United States of America and learn about Pacific Robins and taxonomy in general. I would also like to extend my thanks to the many people who made this Fellowship possible by providing their time, expertise and access to specimens. Most important is Professor Kevin Omland at the University of Maryland Baltimore County (UMBC) whose interest in Petroica robins was the catalyst for me applying for this Fellowship. Nick Friedman provided me with an overview of the analysis of plumage colour and emergency technical support on the spectrophotometer machine. Paul Sweet, Peter Capainolo, Thomas Trombone and Merle Okada all made sure that my work at the American Museum of Natural History went off without a hitch. Jean Woods and Nate Rice graciously allowed me access to Pacific Robin specimens and workspace at the Delaware Museum of Natural History and the Academy of Natural Sciences, respectively. Thanks also to the numerous curators and collection managers who granted tissue loans from Pacific Robin specimens held in their collections Town Peterson and Mark Robbins at the Kansas University Biodiversity Collection, Robb Brumfield and Donna Dittmann at the Louisiana State University Museum of Natural Science, Thomas Webber and Andy Kratter at the Florida Museum of Natural History, and Sharon Birks at the University of Washington Burke Museum. Finally, thanks to Leo Joseph, Robert Palmer and Gaynor Dolman at the Australian National Wildlife Collection, Canberra for providing tissue samples and mitochondrial sequences of Scarlet Robins, and Jeremy Austin at the Australian Centre for Ancient DNA for agreeing to perform the DNA extractions and sequencing of toe-pad samples. 3

4 EXECUTIVE SUMMARY Dr Anna Kearns Postdoctoral Research Associate, Department of Biological Sciences, The University of Maryland Baltimore County 1000 Hilltop Circle, Baltimore, Maryland, USA (443) Project Description The overall goal of my ABRS Churchill Fellowship was to re-examine the taxonomy of Pacific Robins (Petroica multicolor) using the extensive collections at the American Museum of Natural History, the Delaware Museum of Natural History and the Academy of Natural Sciences. My main objective was to assess the distinctiveness of the vulnerable Norfolk Island subspecies P. m. multicolor. Highlights Working with Petroica multicolor specimens that were collected as part of famous expeditions (e.g. Whitney South Sea expedition) to the remote islands of the southwest Pacific in the early-mid 1900s. Exploring life 'behind the scenes' at the American Museum of Natural History, the Delaware Museum of Natural History and the Academy of Natural Sciences. Learning new techniques for the measurement of molecular and morphological variation for taxonomic purposes. Particularly how to use a spectrophotometer to measure colour variation in plumage, and how to collect tissue material from old preserved study skin specimens for molecular analysis. Discussions with colleagues at all the host institutions, and the opportunity to develop some exciting future collaborations. Conclusions and lessons learned Endangered Norfolk Island robins, P. m. multicolor, are morphologically distinct from the rest of the populations of P. multicolor in the southwest Pacific. However, because morphological traits graded subtly and smoothly among populations of P. multicolor, and between Pacific Robins P. multicolor and Scarlet Robins P. boodang, range-wide genetic data are essential for a thorough taxonomic revision to take place. Specifically, genetic data is needed to determine whether Norfolk Island robins warrant species-level recognition or if they form a species with the Australian mainland Scarlet Robins P. boodang or with the other populations of P. multicolor in the southwest Pacific. Changes to the taxonomic status of Norfolk Island robins has significant management implications, thus final taxonomic recommendations based on genetic data and quantitative morphological data will be made available to the relevant agencies for conservation planning. 4

5 PROGRAMME The University of Maryland, Baltimore County Baltimore, Maryland, USA Host: Professor Kevin Omland June, 2012 American Museum of Natural History New York, New York, USA Hosts: Dr Paul Sweet, Dr Merle Okada June, 2012 Delaware Museum of Natural History Wilmington, Delaware, USA Host: Dr Jean Woods June, 2012 Academy of Natural Sciences Philadelphia, Pennsylvania, USA Host: Dr Nate Rice June, 2012 The University of Maryland, Baltimore County Baltimore, Maryland, USA Host: Professor Kevin Omland 28 June - 05 July, 2012 *The 1st Joint Congress on Evolutionary Biology - 'Evolution 2012' Ottawa, Ontario, Canada July, 2012 The University of Maryland, Baltimore County Baltimore, Maryland, USA Host: Professor Kevin Omland July, 2012 *NB: my official program did not include time spent at the Evolution conference 5

6 MAIN BODY A. BACKGROUND The Pacific Robin (Petroica multicolor, J. F. Gmelin 1789) is a small elaborately coloured, insectivorous songbird that is distributed across four main island groups in the southwest Pacific (Solomon Islands, Vanuatu, Fiji and Samoa) and Norfolk Island, which is located approximately 1500 km from mainland Australia (see Figure 1). The species is divided into fourteen subspecies that exhibit differences in body size and plumage patterns (Mayr 1934; del Hoyo et al. 2007). There is also a morphologically similar species found on mainland Australia (Scarlet Robin P. boodang) (Schodde & Mason 1999; del Hoyo et al. 2007), which is sometimes considered to form a single species with the Pacific Robin (Garnett et al. 2011; BirdLife International 2012). FIGURE 1: Geographic range of Petroica multicolor, and variation in the degree of sexual dichromatism and other minor plumage differences between the fourteen described subspecies, and two morphologically differentiated island forms of P. m. similis. 6

7 Pacific Robins are unique among the Australasian 'red' robins (Family: Petroicidae, Genus: Petroica) for displaying variation in the degree of sexual dichromatism (males and females have different plumage colours or patterns) across its range. Variation in sexual dichromatism in Pacific Robins can be divided into three main types of malefemale plumage pairs see Figure 2: (1) 'typical' sexually dichromatic plumaged pair: elaborate black and red males and drab brown females. (2) 'drab' monochromatic plumaged pair: both sexes have female-like drab brown plumage. (3) 'elaborate' monochromatic plumaged pair: both sexes have male-like elaborate black and red plumage. FIGURE 2: Three types of male-female plumage in Pacific Robins as exhibited by two males and two females of (A) P. m. multicolor from Norfolk Island, (B) P. m. cognata from Vanuatu, (C) P. m. pusilla from Samoa. Specimens held at the American Museum of Natural History. 7

8 B. WHY DO WE NEED TO RE-EXAMINE THE TAXONOMY OF THE PACIFIC ROBIN SPECIES GROUP? The discovery, description and conservation of Australia's biodiversity is a major biological research priority for the Australian Government, and for the Australian Biological Resources Study (ABRS). Of particular importance is the conservation of species and populations that are currently being threatened by human-induced change such as climate change, habitat loss and feral pests and diseases. The Norfolk Island subspecies of the Pacific Robin P. multicolor is listed as 'Vulnerable' under the Australian Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) (Commonwealth of Australia 2005; Director of National Parks 2010), and listed as 'Endangered' using IUCN assessment criteria in the recently published 'Action Plan for Australian Birds 2010' (Garnett et al. 2011). Critically, however, the taxonomic status of the Norfolk Island subspecies is contentious, which has potentially significant implications for management and conservation of this population. Indeed, the IUCN and BirdLife International currently treat Scarlet and Pacific Robins as a single species, P. multicolor, as they believe there is inconclusive evidence for the separation of Australian mainland and southwest Pacific populations (BirdLife International 2012). The primary objective of my ABRS Churchill Fellowship was to perform the first quantitative assessment of morphological and genetic differentiation across the range of P. multicolor in the southwest Pacific, and to test the recent decision to split Pacific island populations (Pacific Robins P. multicolor) and mainland Australian populations (Scarlet Robins P. boodang) into two species (Schodde & Mason 1999). The taxonomy of the group to date has been based purely on interpretations of levels of morphological distinctiveness (Mayr 1934; Schodde & Mason 1999; Christidis & Boles 2008). The sole use of (arguably subjective) measures of morphological differentiation is particularly problematic in the case of the taxonomy of the Scarlet/Pacific Robin species group because morphological variation in this group appears to grade subtly among populations (with the exception of differences in the degree of sexual dichromatism). The decision to split Pacific island populations and mainland Australian populations into two species was based on what Schodde and Mason (1999) perceived to be a discrete disjunction in morphological traits between 8

9 these two groups. However, they themselves noted that the nominate subspecies of the Pacific Robin on Norfolk Island P. m. multicolor was the exception to two of the major morphological traits distinguishing the two species i.e., (1) body size: southwest Pacific P. multicolor are small, Norfolk Island P. m. multicolor are large, P. boodang are large, and (2) tail length: southwest Pacific P. multicolor have short tails, Norfolk Island P. m. multicolor have long tails, P. boodang have long tails. Similarly, the size of the white forehead spot (frons spot) of Norfolk Island males is more similar to the enlarged frons spot of P. boodang males than it is to the variably sized, but consistently smaller frons spots of males throughout the rest of the southwest Pacific. Unfortunately, no prior molecular study has had the necessary samples to address questions about the distinctiveness of Norfolk Island P. m. multicolor from either the rest of the Pacific island populations of P. multicolor or from the Australian mainland populations of P. boodang (Miller & Lambert 2006; Christidis et al. 2011). C. QUANTIFYING MORPHOLOGICAL AND GENETIC VARIATION IN PACIFIC ROBINS Over 200 specimens of the Pacific Robin are held in museums, and the vast majority of these are at the American Museum of Natural History in New York. Unfortunately, almost none of the specimens were collected within the past couple of decades when it has become standard practice to freeze a small amount of fresh tissue for molecular analysis before taxidermy of the skin takes place. Fresh or frozen tissue is the best source for DNA, however, it is possible to extract DNA from very old pieces of bone and skin with modified laboratory protocols and with close attention to limiting contamination of these 'ancient' DNA sources with fresh or 'modern' DNA sources. Prior to the commencement of my Churchill Fellowship I organised the loan of tissues from 49 Pacific Robin specimens from all fourteen described subspecies from several different institutions in the USA. Fourteen of these are recently collected frozen tissue samples (representing 5 subspecies) and 36 were toe-pad samples (scrapings of skin from the feet of the preserved museum skin from the American Museum of Natural History) (representing 13 subspecies). The toe-pad samples were then sent to Dr 9

10 Jeremy Austin at the Australian Ancient DNA Centre in Adelaide for DNA extraction and sequencing of two genes from the mitochondrial genome. This is a laboratory facility that specialises in obtaining DNA from old and degraded specimens. LEFT: Collecting toe-pad samples from 36 Pacific Robins at the American Museum of Natural History. RIGHT: Myself (back row, second from right) with Kevin Omland (back row, first on right) and his research group at the University of Maryland Baltimore County. The first week of my Churchill Fellowship was spent at the University of Maryland Baltimore County brainstorming with my host Professor Kevin Omland and other members of his research lab about the best methods to quantify variation in plumage and body size in Pacific Robins. As our objective was to test whether there were meaningful differences in body size and plumage between P. m. multicolor subspecies it was important that we sampled a diverse suite of morphological traits that would adequately summarise the breadth of variation exhibited across the range of the species. Our final approach was to assemble a (1) morphometric dataset: wing, tail and bill length measurements, and a (2) plumage reflectance dataset: reflectance measurements from plumage on the head ("crown"), back, throat and chest, taken from adult specimens of each subspecies at the American Museum of Natural History, Delaware Museum of Natural History and the Academy of Natural Sciences. A machine called a spectrophotometer (see photo below) was used to measure plumage reflectance within the bird visual range (300 to 700 nanometres (nm) wavelength). Different colours have differently shaped reflectance spectra, which reflect the different amount of light each colour reflects or absorbs at certain 10

11 wavelengths (see Figure 3). These raw spectral reflectance curves can either be analysed directly or they can be converted into tricolor variables, i.e., hue (colour), saturation and brightness. Spectrophotometry has many advantages over other popular methods used for the analysis of variation in colour. It is particularly desirable for Pacific Robins given the subtle grades in colour differences of the throat, crown, back and chest from island to island. Such subtle, graded differences are near impossible to categorise by eye into discrete characters (e.g. dark red, light red, orange, etc.). Equipment setup for spectrometry (top photos) and morphometrics (bottom photo). In the top, left photo the spectrophotometer is the silver and black box on the right, the light source is the cream box on the left with the blue optical fiber and reflectance probe connected to it. 11

12 FIGURE 3: Mean spectral reflectance curves measured for the crown, back, throat and chest plumage patches of Norfolk Island P. m. multicolor from 24 male (TOP) and 14 female (BOTTOM) specimens. 12

13 In my second week I traveled to the American Museum of Natural History (AMNH) where I spent 11 days in the 'bird vault' with their sizeable collection of Pacific Robins. Many of these specimens were collected during various expeditions to the southwest Pacific during the 1920s, and were among the specimens studied by the eminent ornithologist Ernst Mayr in the last thorough examination of morphological variation and taxonomy of the Pacific Robin, which were central to his ideas on geographic speciation (Mayr 1934). On my first day I was struck by the enormity of the task. Variation in both body size and plumage was even more subtle than the written descriptions in Mayr's work alluded to. I was also faced with the logistical problem of how to measure morphometric and plumage reflectance data for over 200 specimens in just 11 days! Thankfully my travel companion for this leg of the Churchill Fellowship (my father, Allen Kearns) also volunteered to be my research assistant! While at the American Museum of Natural History I also collected toe-pad samples from the 36 Pacific Robin specimens, which will be used to assess range-wide genetic variation in this species. Left: Series of Petroica multicolor feminina specimens. Right: Myself with a series of specimens representing all fourteen described Petroica multicolor subspecies. Both photos taken at the American Museum of Natural History. Following my time at the American Museum of Natural History, I travelled to the Delaware Museum of Natural History (Wilmington, Delaware) and then to the 13

14 Academy of Natural Sciences (Philadelphia, Pennsylvania). The visit to the Delaware Museum was particularly fruitful as this museum had eight specimens (4 females, 4 males) of the subspecies P. m. dennisi, which only had two specimens (1 female, 1 male) at the American Museum. I then returned to the University of Maryland Baltimore County to begin analysis of the plumage reflectance (126 males, 75 females) and morphometric (140 males, 86 females) datasets. My basic approach was to (1) use principle components analyses to summarise morphometric and plumage reflectance variation into a couple of variables (called 'principal components'), (2) calculate hue (formula H4a), brightness (formula B1) and saturation (formula S5a) for each plumage patch using the CLR colour analysis program (Montgomerie 2008), and (3) to use statistics (Analysis of Variation, ANOVA) to test whether subspecies showed significant differences in these variables among subspecies. The first principal component (PC1) from the principal components analysis of plumage reflectance, which was calculated independently for each individual and plumage patch, represented the majority of variation observed in plumage reflectance (percent of total variation explained by PC1: Crown = 93.7%; Back = 94%; Chest = 60.7%; Throat = 60.7%). PC1 could therefore be used as a surrogate for total overall variation in each plumage patch. D. IS THE NORFOLK ISLAND ROBIN MORPHOLOGICALLY DISTINCT? Observation 1: Norfolk Island Petroica multicolor multicolor is significantly larger than the rest of the Pacific island subspecies (ANOVA: p < in each comparison) see Figure 4 & 6, and Table 1. Observation 2: Female Norfolk Island Petroica multicolor multicolor have significantly brighter back plumage compared to females from the rest of the Pacific Island subspecies (ANOVA: p < in each comparison) see Figure 4 & 5. In contrast, hue, saturation and brightness of the back plumage patch did not significantly differentiate Norfolk Island males from other black-backed subspecies (p > 0.05), and Norfolk Island males overlapped entirely with the other subspecies with black-backed males in the principal components analysis (Figure 4). 14

15 FIGURE 4: Principle components analysis of (A) morphometric traits (wing, tail and bill length) and (B) plumage reflectance of back, crown, chest and throat plumage (wavelength nm) for males and females. Norfolk Island birds are shown in black. 15

16 FIGURE 5: Mean spectral reflectance curves for the back plumage patch in (A) females and (B) males showing distinct spectral curve shapes for brown and black plumaged morphs in both sexes. Photos show a male and female specimen from an exemplar subspecies from each main cluster of reflectance curves. 16

17 Observation 3: Norfolk Island Petroica multicolor multicolor wing and tail lengths overlap with the range of tail and wing lengths measured for the Australian mainland Scarlet Robin in a previous study (Schodde & Mason 1999) see Table 1. Wing-tail length ratios were similar between the sexes in P. boodang (male = 0.70, female = 0.71), but differed in P. m. multicolor (male = 0.75, female = 0.78). Observation 4: Norfolk Island Petroica multicolor multicolor and Australian mainland Scarlet Robins P. boodang have significantly different hue (ANOVA: F = 13.8, p < ) and brightness (ANOVA: F = 4.8, p = ) of the red chest plumage patch (based on 10 male P. boodang and 24 male P. m. multicolor). Chest plumage and body size variation in three Petroica species left to right: P. m. multicolor (Pacific Robin), P. boodang (Scarlet Robin), P. goodenovii (Red-capped Robin), P. m. polymorpha (Pacific Robin). TABLE 1: Minimum and maximum values recorded for wing and tail lengths of P. boodang and P. multicolor (P. boodang measurements from Schodde & Mason 1999) Scarlet Robin Wing length Tail length MALE FEMALE MALE FEMALE P. b. boodang P. b. leggii P. b. campbelli All P. boodang Pacific Robin P. m. multicolor P. m. becki P. m. feminina P. m. polymorpha All P. multicolor

18 E. MORPHOLOGICAL VARIATION ACROSS THE SOUTHWEST PACIFIC In section D, I showed evidence that the Norfolk Island robin is morphologically distinct from the rest of the Pacific Island subspecies on the basis of body size (represented by principal component 1 calculated from the bill, wing and tail length variables) and female back plumage (brighter back plumage). Here, I will provide a brief summary of the major patterns of morphological variation across the rest of the species' range in the southwest Pacific. Body size Male and female Pacific Robins from Vanuatu were significantly differentiated from those from Norfolk Island, Solomon Islands, Fiji and Samoa at principal component 1 (representative of body size) (p ). Body size in Pacific Robins from Fiji, Samoa and the Solomon Islands were not significantly differentiated from each other in either sex (p ) see Figure 4 & 6. Plumage Figure 7 provides a visual summary of the complex patterns of variation in plumage colour and the degree of sexual dichromatism among the Pacific Robin subspecies. Overlap of PC1 values for males and females of the same subspecies indicates that this subspecies is monochromatic, whereas non-overlap or partial overlap of PC1 values indicates a sexually dichromatic subspecies. This is best exemplified with the back plumage patch, where male and female PC1 values of the monochromatic 'elaborate' plumaged subspecies overlap with each other on the left hand side of the axis (e.g., Samoa P. m. pusilla and Solomon Island P. m. polymorpha), whereas those of the monochromatic dull plumaged subspecies overlap with each other on the right hand side of the axis (e.g., Vanuatu P. m. feminina), and those of dichromatic subspecies do not overlap with each other (e.g., Vanuatu P. m. ambrynensis). Subspecies with black plumaged females (P. m. pusilla, P. m. dennisi, P. m. polymorpha, P. m. similis) showed little overlap with each other and with the subspecies with brown plumaged females on the PC1 axis (ANOVA p < 0.05 for many, but not all, comparisons) (Figure 4). Similarly, subspecies with brown plumaged males (P. m. cognata, P. m. feminina, P. m. soror) are highly differentiated from the subspecies with black plumaged males on the PC1 axis (ANOVA p < for all comparisons) (Figure 4). 18

19 FIGURE 6: Body size variation between (A) females and (B) males from the major island groups within the range of the Pacific Robin. Principal component 1 was calculated from wing, tail and bill length measurements (ANOVA, males: F = 271.7, d.f. = 4,127, p < ; ANOVA, females: F = 131.8, d.f. = 4,72, p < ). 19

20 FIGURE 7: Variation in sexual dichromatism and plumage colour between major island groups, subspecies and sexes of the Pacific Robin. Here, plumage variation is summarised by principal component 1 calculated from the raw reflectance spectra curves from nm wavelengths. 20

21 F. ONGOING WORK The preliminary analyses of broad patterns of variation in plumage and body size across the range of the Pacific Robin, which I have presented in sections D and E of this report, are currently being prepared for publication in a peer-reviewed journal. This paper will also include a more fine-scale analysis of morphometric and plumage reflectance variation among subspecies within Vanuatu, Fiji and the Solomon Islands in order to determine whether recognition of multiple subspecies within each major island group is warranted. For example, do plumage reflectance or morphometric measurements significantly differentiate either the (1) three 'drab' monochromatic subspecies in Vanuatu, or the (2) three sexually dichromatic subspecies in Fiji, or the (3) Aneityum and Tanna island forms of Vanuatu P. m. similis (see photo below and Figure 1) from each other? Two island forms of Petroica multicolor similis showing differences in throat colouration left to right: two males and two females from Tanna island, and two males and two females from Aneityum island. Once genetic analysis is completed by my collaborator, Jeremy Austin, at the Australian Centre for Ancient DNA, a second peer-reviewed publication will be prepared exploring patterns of genetic differentiation of Pacific Robin populations across the southwest Pacific, and between Pacific island populations (Pacific Robins P. multicolor) and mainland Australian populations (Scarlet Robins P. boodang). Genetic and quantitative morphological data will be used to revise the taxonomy and evaluate the appropriateness of alternative hypotheses for the evolutionary history of the Pacific and Scarlet Robin species group. 21

22 CONCLUSIONS & RECOMMENDATIONS Morphological traits graded subtly and smoothly among populations of P. multicolor, and between Pacific Robins P. multicolor and Scarlet Robins P. boodang. Body size differences discretely separated two morphologically variable groups within the Scarlet/Pacific Robin species group (1) larger-bodied Australian mainland P. boodang and Norfolk Island P. m. multicolor, and (2) smaller-bodied southwest Pacific P. multicolor (Vanuatu, Solomon Islands, Fiji and Samoa). In contrast, discrete groups were difficult to delineate using plumage reflectance. Norfolk Island robins share many plumage pattern traits in common with Australian mainland Scarlet Robins P. boodang to the exclusion of the other Pacific island P. multicolor forms. Female Norfolk Island robins had significantly brighter back plumage than the other Pacific island P. multicolor forms. However, overall, plumage reflectance measurements of Norfolk Island robins fell within the spectrum of variation observed among Pacific island P. multicolor forms. Analysis of range-wide plumage reflectance and morphometric variation offered valuable new insight into the taxonomy of the Pacific Robin, however, rangewide genetic data are needed for a thorough taxonomic revision to take place. Most importantly, genetic data will allow a closer investigation of the distinctiveness of the endangered Norfolk Island robin, P. m. multicolor, which appears to be morphologically distinct from the rest of the populations of P. multicolor in the southwest Pacific, and perhaps also from mainland Australian Scarlet Robins P. boodang. Genetic analysis is currently underway at the Australian Centre for Ancient DNA. Genetic data will be used to evaluate the appropriateness of three alternative taxonomic hypotheses, which analysis of morphological variation alone cannot discriminate among: (1) All populations (mainland Australian P. boodang and Pacific Island P. multicolor) form a single morphologically variable species. (2) Norfolk Island populations and mainland Australian populations form a single species to the exclusion of the rest of the Pacific island forms in the Solomons, Vanuatu, Fiji and Samoa. (3) Norfolk Island populations warrant species-level recognition from 22

23 both mainland Australian P. boodang and from the rest of the Pacific island forms in the Solomons, Vanuatu, Fiji and Samoa. My final recommendations for the taxonomic revision of the Scarlet/Pacific Robin species group will be published in a peer-reviewed journal once final genetic and morphological analyses are completed. The primary motivation for reexamining species and subspecies boundaries in the Scarlet/Pacific Robin species group was to inform conservation planning for the better conservation and management of populations, subspecies and species in this group. Thus, the final taxonomic recommendations will also be made available to the relevant agencies for conservation planning. A taxonomic re-examination of the Scarlet/Pacific Robin species group will also provide valuable insights into fundamental evolutionary questions that remain unanswered about the cause and sequence of evolution of the perplexing variation in the degree of sexual dichromatism in Pacific Robins. A peerreviewed article on this subject is also in preparation. 23

24 REFERENCES BirdLife-International, Petroica multicolor. In: IUCN IUCN Red List of Threatened Species. Version < Downloaded on 10 October Christidis, L., Boles, W Systematics and taxonomy of Australian birds Collingwood, Victoria, Australia, CSIRO Publishing. Christidis, L., Irestedt, M., Rowe, D., Boles, W.E., Norman, J.A., Mitochondrial and nuclear DNA phylogenies reveal a complex evolutionary history in the Australasian robins (Passeriformes: Petroicidae). Molecular Phylogenetics and Evolution 61: Commonwealth-of-Australia, National Recovery Plan for the Norfolk Island Scarlet Robin Petroica multicolor multicolor and the Norfolk Island Golden Whistler Pachycephala pectoralis xanthoprocta. Department of the Environment and Heritage, Canberra. del Hoyo, J., Elliot, A., Christie, D., Caley, K., Handbook of the Birds of the World. Volume 12: Picathartes to Tits and Chickadees. Lynx Edicions. Director-of-National-Parks, Norfolk Island Region Threatened Species Recovery Plan. Department of the Environment, Water, Heritage and the Arts, Canberra. Garnett, S.T., Szabo, J.K., Dutson, G., The Action Plan for Australian Birds CSIRO Publishing, Collingwood. Mayr, E., Birds collected during the Whitney south sea expedition. American Museum Novitates 714: Miller, H.C., Lambert, D.M., A molecular phylogeny of New Zealand s Petroica (Aves: Petroicidae) species based on mitochondrial DNA sequences. Molecular Phylogenetics and Evolution 40: Montgomerie, R., CLR, version Queen s University, Kingston, Canada. (available at Schodde, R., Mason, I.J The Directory of Australian Birds: Passerines. Melbourne, CSIRO Publishing. 24