Petroica

Belongs within: Petroicidae.

Petroica, the Australasian robins, is a genus of small, stout birds whose males often have contrasting colour patterns with dark upperparts and whitish underparts; a number of species are also bear red markings. The New Zealand robins P. australis and P. longipes are duller in coloration and longer-legged than other Petroica species.

The Australasian not-robins

Published 19 December 2018

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

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

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

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

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

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

Systematics of Petroica

<==Petroica Swainson 1830CC10 (see below for synonymy)
    |  i. s.: P. archboldiJT12
    |         P. bivittataJT12
    |         P. longipes (Garnot in Duperrey 1827) (see below for synonymy)CC10
    |         P. pusillaAP21
    |--P. goodenovii (Vigors & Horsfield 1827)BKB15, WS48 (see below for synonymy)
    `--+--+--P. macrocephala (Gmelin 1789)BKB15, CC10 (see below for synonymy)
       |  |    |--P. m. macrocephala (see below for synonymy)CC10
       |  |    |--P. m. chathamensis Fleming 1950CC10
       |  |    |--P. m. dannefaerdi (Rothschild 1894) [=Miro dannefaerdi, M. dannefordi, Nesomiro traversi dannefaerdi]CC10
       |  |    |--P. m. marrineri (Mathews & Iredale 1913) (see below for synonymy)CC10
       |  |    `--P. m. toitoi (Lesson 1828) (see below for synonymy)CC10
       |  `--P. traversi (Buller 1872)BKB15, CC10 (see below for synonymy)
       `--+--P. australis (Sparrman 1788)BKB15, CC10 [=Turdus australisCC10, Aplonis australisCC10, Miro australisCC10]
          |    |--P. a. australis (see below for synonymy)CC10
          |    `--P. a. rakiura Fleming 1950 [=P. (Miro) australis rakiura]CC10
          `--+--+--P. phoeniceaBKB15
             |  `--+--*P. multicolor (Gmelin 1789)CC10, BKB15, CC10 (see below for synonymy)
             |     |    |--P. m. multicolor (see below for synonymy)CC10
             |     |    `--P. m. campbelli Sharpe 1898WS48
             |     `--P. boodangBKB15 [=P. multicolor boodangM03; incl. P. multicolor leggiM03]
             `--+--P. rodinogasterBKB15 [=*Erythrodryas rhodinogasterG42]
                `--+--P. rosea (Gould 1839)BKB15, G42 [=Erythrodryas roseaG42]
                   `--Eugerygone rubraBKB15

Petroica Swainson 1830^CC10 [incl. Erythrodryas Gould 1842^G42, Miro Lesson 1831^CC10, Myiomoira Reichenbach 1850^CC10, Myioscopus Reichenbach 1850^CC10, Nesomiro Mathews & Iredale 1913^CC10]

Petroica australis australis (Sparrman 1788) [incl. Turdus albifrons Gmelin 1789, Miro albifrons, Muscicapa albifrons, Myioscopus albifrons, Petroica albifrons, Miro bulleri Sharpe in Buller 1905, M. australis bulleri, Turdus ochrotarsus Forster in Lichtenstein 1844, Miro ochrotarsus, Muscicapa saxicolina Bonaparte 1851]^CC10

Petroica goodenovii (Vigors & Horsfield 1827)^{BKB15, WS48} [=Muscicapa goodenovii^WS48; incl. P. ramsayi Sharpe 1879^WS48, P. goodenovii ruficapilla Mathews 1912^WS48]

Petroica longipes (Garnot in Duperrey 1827) [=Muscicapa longipes, *Myioscopus longipes, P. (*Miro) australis longipes, Myiothera novaezelandiae Lesson 1828]^CC10

Petroica macrocephala (Gmelin 1789)^{BKB15, CC10} [=Parus macrocephalus^CC10, Miro macrocephala^CC10, Muscicapa macrocephala^CC10, Myiomoira macrocephala^CC10, Petroeca (l. c.) macrocephala^CC10, Rhipidura macrocephala^CC10, Pachycephalus australis Stephens in Shaw 1826^CC10]

Petroica macrocephala macrocephala (Gmelin 1789) [incl. Miro dieffenbachii Gray in Dieffenbach 1843, Myiomoira macrocephala dieffenbachii, Petroica dieffenbachii, Miro forsterorum Gray in Dieffenbach 1843, Turdus minutus Forster in Lichtenstein 1844, Muscicapa minutus]^CC10

Petroica macrocephala marrineri (Mathews & Iredale 1913) [=Myiomoira macrocephala marrineri; incl. M. macrocephala enderbyi Mathews 1930]^CC10

Petroica macrocephala toitoi (Lesson 1828) [=Muscicapa toitoi, Miro toitoi, *Myiomoira toitoi, Petroeca (l. c.) toitoi; incl. Muscicapa albopectus Ellman 1861]^CC10

*Petroica multicolor (Gmelin 1789)^{CC10, BKB15, CC10} [=Muscicapa multicolor^CC10, Petroeca (l. c.) multicolor^CC10, M. erythrogastra Latham 1790^CC10, Petroica erythrogastra^CC10]

Petroica multicolor multicolor (Gmelin 1789) [incl. Muscicapa dibapha Forster in Lichtenstein 1844, P. modesta Gould 1838, P. pulchella Gould 1840, Muscicapa rhodogastra Latham 1802]^CC10

Petroica traversi (Buller 1872)^{BKB15, CC10} [=Miro traversi^CC10, Myiomoira traversii^CC10, *Nesomiro traversi^CC10, Petroica traversii^CC10]

*Type species of generic name indicated

References

[AP21] Arlott, N., & B. van Perlo. 2021. Collins Birds of the World. William Collins.

[BKB15] Burleigh, J. G., R. T. Kimball & E. L. Braun. 2015. Building the avian tree of life using a large-scale, sparse supermatrix. Molecular Phylogenetics and Evolution 84: 53–63.

[CC10] Checklist Committee (OSNZ). 2010. Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica 4^th ed. Ornithological Society of New Zealand and Te Papa Press: Wellington.

[JT12] Jetz, W., G. H. Thomas, J. B. Joy, K. Hartmann & A. Ø. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444–448.

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

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

[M03] Morcombe, M. 2003. Field Guide to Australian Birds 2^nd ed. Steve Parish Publishing.

[WS48] Whittell, H. M., & D. L. Serventy. 1948. A systematic list of the birds of Western Australia. Public Library, Museum and Art Gallery of Western Australia, Special Publication 1: 1–126.