VOL. 11 (2) JUNE 1985 35

AUSTRALlAN BIRD WATCHER 1985. II. 35-45

A Rockhopper x Royal Penguin Hybrid from Macquarie Island

By KN.G. SIMPSON, Science Department, Victoria College - Burwood Campus, Burwood, Victoria 3125*

Summary A specimen of Eudyptes penguin (Spheniscidae: Aves) originally collected in 1957 from North Head, Macquarie Island, after being identified as a Snares Penguin Eudyptes robustus Oliver 1953, has been re-identified as a hybrid between the Rockhopper Penguin E. chrysocome filholi Hutton 1878 and the Royal Penguin E. chrysolophus schlege/i Finsch 1876. Some facial identification features are discussed.

Introduction AEudyptes penguin skin in the collections of the Museum of Victoria (MV) has a somewhat chequered history of identification and is festooned with labels and amendment tags. B7313, an adult female, was originally M/57 /B/111 collected by M. P. Hines under the auspices of Australian National Antarctic Research Expeditions (ANARE) on 3 November 1957, in the North Head Rockhopper/Royal Penguin colony, Macquarie Island. It was identified in the field as a Snares Penguin Eudyptes robustus. Another penguin of generally similar appearance, MY B7312, was also collected during 1957. B7313 certainly (possibly B7312 as well), was submitted to the late Dr (Sir) R. A Falla in New Zealand for confirmation of identification, and published by Keith & Hines (1958). B7312, collected on 17 March 1957 after completing its moult, does meet all of the identifiable characters of E. robustus and I accept it as such. One earlier record of Snares Penguin at Macquarie Island was on 5 February 1950 [Gwynn (1953) - see his plate facing p. 150] and that bird too, I accept as being E. robustus, a Snares Penguin. Keith & Hines (1958) noted that B7313 'was found in a mixed colony of Royal Penguins and Rockhopper Penguins Eudyptes chrysocome (Forster) but was not mated'. They also noted 'ovary was in full breeding condition'. The skin, taken in November, is in excellent plumage and shows no sign of moult. Initial label data were as follows: Label I. 'Michael Hines' Antarctic Collection, 1956-57.' Label 2. ANARE label - 'Macquarie Island, North Head, 3/ 11 /'57, (Face) M. P. Hines, M/57 /B/1 11 '. Note in pencil added by A. R. McEvey: 'E. robustus by Falla'. (Reverse) 'Bill uniformly brown Feet pinkish, black soles Iris red, tending to brown T.L. to tail 670 (mm) to toes 685 (mm) Flipper span 483 mm Weight 7 lb 2 oz·.

*Formerly Antarctic Division, Department of Supply, Melbourne AUSTRALIAN 36 SIMPSON BIRD WATCHER

Discussion The North Head colony is one of several on Macquarie Island where some small number of Royal Penguin nests meet and are interspersed among nests of Rockhopper Penguins. Most of the Royal and Rockhopper Penguin colonies on the island are discrete from each other. The breeding season of the two species is largely concurrent; sympatry thus occurs in some limited areas (Figure 1).

1

2

3 1. North Head

2. Aurora Point

4 3. Double Point

4. Rockhopper Point 5 5. Cape Star 6

6. Caroline Point

Figure 1. Six localities on Macquarie Island where Royal Penguin and Rockhopper Penguin colonies are very close together or where they actually merge. Other such contacts may occur but were not recorded during my period on the island, December 1963- March 1964; December 1964- March 1966. These six sites are likely localities for hybrids to be found. Hybrid B7313 came from North Head. Drawing by Nicolas Day VOL. 11 (2) JUNE 1985 Rockhopper x Royal Penguin Hybrid, Macquarie Is. 37

Male Erect-crested Penguin 'paired' with female Royal Penguin, Flat Creek, Macquarie Island, 14-31 January 1964. Note wide space about the pair. Plate 6 ANARE photograph: KN.G. Simpson

The opportunity for potential hybridisation is fairly obvious when so many Royal and Rockhopper colonies are so closely positioned or overlapping. Occasionally, Macquarie Island is visited by other Eudyptes species, e.g. the Snares Penguin mentioned in the paper so far (Gwynn 1953), and also by a steady trickle of Erect-crested Penguins E. sclateri. The potential of these for 'pairing' at least temporarily, although it was the moulting seasonjollowing the local breeding season, was demonstrated by a male Erect-crested which 'paired' with a female Royal Penguin during the moult. This was at Flat Creek, to the north of Aurora Point, between 14 and 31 January 1964 (Plate 6). The two penguins aggressively defended an area two or three times larger than is normally utilised by moulting Royal Penguins. During 1970 B7313 was identified as a Rockhopper by Simpson and A R. McEvey, based initially on superciliary stripe-crest (SSC) texture and on the position of the anterior tip of the SSC. An amendment tag was added: 'On point of origin of crest, and crest texture, colour and composition, I consider it to be E. chrysocome - (signed) A R. McEvey, 22/9/70'. AUSTRALIAN 38 SIMPSON BIRD WATCHER

In 1972 I again examined the specimen and noted that across the black of the anterior crown and frons, but not visible at the feather surface, were many short parti-coloured black and yellow feathers. The laterally positioned and exposed SSe is chrome-yellow, much richer in colour than that of the normal adult E. c.filholi, and rather approaching the golden-yellow (sometimes almost reddish golden) frontal crest of the adult E. c. schlegeli. Snares Penguins have yellow SSes also, but perhaps not so richly coloured as in this particular specimen. The spread of yellow-black feathers across the frons and anterior crown is a diagnostic character of the Macaroni E. chrysolophus chrysolophus/ Royal E. c. schlegeli complex and (so far as is known) is not exhibited in other extant Eudyptes penguins. I have named it the 'frontal crest'. Available specimens of Eudyptes in the MV collections were examined for the presence of small yellowish/black frontal plumes. They were found only where they should be, on Macaroni and Royal Penguins. None were found on any Rockhopper from any source nor on the specimens of Snares Penguins, Fiordland Penguins E. pachyrhynchus, or Erect-crested Penguins E. atratus available to me. In B7313 the anterior tip of the SSe is perhaps 2-3 mm broader than is normal for Rockhopper Penguins. In this it again superficially resembles the Snares Penguin. The nature or texture of the SSe is definitely fibrous. I have identified this feature as an absolute character of the Macaroni/Royal complex, and of all Rockhoppers. In this character B7313 shows its correct affinity. The other Eudyptes species - Snares (including the specimen B7312), Fiordland and Erect-crested- all have their own absolute character, silky textured SSes. This character of the sse, fibrous versus silky, is fundamental in separating the two natural groups of Eudyptes penguins. In B7313 the anterior tip of the SSe is positioned precisely on (at) the middle (bisection) of the g/c baseline*, another absolute character of the Rockhopper Penguin complex. The anterior tip of the SSe in the Snares Penguin (as exemplified by B7312) is always positioned forward of the g/c baseline bisection.

In the skin of B7313, perhaps in life too, the SSe is depressed closely against the sides of the head, quite unlike the protruding, 'untidy' posterior portion of the SSe of the average Rockhopper Penguin. This may well have been a principal reason for it being picked out of the North Head colony for collection. But, in yet two more head characters, the 'illusion' of a Snares Penguin is created and maintained. The lores of this bird B73 13 are reflective (glossy). This is a Snares feature but is also frequently a Macaroni/Royal feature and is therefore not so surprising. In Macaroni/Royals, the lores are very variable (see Plate 12) and not all of the paler-lored birds have reflective lores.

*The g/c baseline is a line drawn precisely from the angle of the gape (g) to the proximal base of the exposed culmen (c). It is of great value in separating the species of Eudyptes with lateral sse and is my own 'invention.' VOL. II (2) JUNE 1985 Rockhopper x Royal Penguin Hybrid, Macquarie Is. 39

Comparison of four Eudyptes penguin skins from Macquarie Island: Top Royal Penguin 82478. A fairly typical specimen. Note massive bill, pale face (variable from black to white in the entire population), black upper !ores (may be entirely or partly black). A fibrous frontal crest arises on frons, spreads across head and back over the eyes. The colour is a rich gold, almost 'red-gold' in some birds. See also Plate 12 of live Royal Penguins. Second Top The hybrid Rockhopper x Royal Penguin 87313. Note smaller bill, dull black face but 'glossy' or 'reflective' black !ores. Particularly note the position of the fibrous SSC at its most anterior point, and compare it with the Rockhopper (below). Second Bottom Rockhopper Penguin 811865. Note bill only slightly less in size to hybrid penguin; dull (non-reflective) black face and I ores. Particularly note the position of the fibrous sse at its most anterior point- it terminates at precisely the same point as does that of the hybrid penguin. Now compare this with the Snares Penguin at bottom. Bottom Snares Penguin 87312. Note medium-sized bill, glossy black face and !ores. Particularly note position of the anterior point of the silky SSC - it arisesfor~va rd of the position where both hybrid and Rockhopper Penguin's SSC arises. This is the pa.rticular Snares Penguin taken in the same year as the hybrid bird. Plate 7 Photograph of Museum of Victoria ski ns: KN.G. Simpson AUSTRALIAN 40 SIMPSON BIRD WATCHER

Details of the hybrid Rockhopper X Royal Penguin B7313 (upper) and of the Rockhopper Penguin 811865 (lower). The fleshy white 'fillets' along the edge of the lower mandible and into the gape have shrunk beyond recognition on the skins displayed in this series of pictures- this pale skin is a prominent feature of all Eudyptes species and races except the Fiordland Penguin, but is not preserved in museum skins. Plate 8 Photograph of Museum of Victoria skins: KN.G. Simpson

Some age characteristics may be operating in the Macaroni/Royal complex with regard to lore colours and reflectiveness, but I do not have information on this at present. Rockhopper lores are normally non-reflective (dull black or deep grey). Incidentally, the frons, crown, nape and side of neck are also glossy, similar to Macaroni/Royal, Snares and Erect-crested Penguins, but just for the moment these are not being considered as definitive areas for identification purposes within Eudyptes penguins. The second of these head features is that, as the skin of B7313 is viewed, the feathers across the rear of the crown are smoothly lying over the nape. There is no obvious transverse line of feathers, the 'coronal line' as I term it, as is seen in a dorsal head view of any adult Rockhopper of any race. In Rockhopper adults, these feathers are in fact longer than those of the similarly coloured nape feathers and so protrude at all times. They are often displayed or emphasised by the wind in life and may possibly be erectile to some extent as well. Photographs of Snares Penguins normally show slicked­ down coronal line and nape feathers. So too do photographs and specimens of Macaroni/Royals- in life the side-swept plumes of the frontal crests blow VOL. 11 (2) JUNE 1985 Rockhopper x Royal Penguin Hybrid, Macquarie Is. 41

Details of the right face of the hybrid Rockhopper x Royal Penguin 87313. The anterior point of origin of the lateral sse is the primary recognition feature visible. Plate 9 Photograph of Museum of Victoria skin: KN.G. Simpson

about but the nape and crown feathers are rarely disturbed. Fiordland Penguins also have a slight extension of the posterior crown feathers to give a variable coronal line. Usually these appear in photographs as smoothed down into the nape feathers. Two further features of B7313 favour 'Rockhopper'. Firstly, the body is broadly of Rockhopper proportions, not of Royal or Snares which are decidedly larger on average. Secondly, the underflipper pattern is that of the local Rockhopper Penguin E. c. filholi in type. At Macquarie Island, the Macaroni/Royal complex has rather similar underflipper patterns to those of the Rockhopper Penguin, but larger. Snares Penguins normally have more black on the underflipper pattern; B7312 does not have as much black on the underflipper as some other specimens I have examined.

Conclusion B7313 has, in effect, both frontal crests and superciliary stripe-crests. In reality there are no truly 'Snares Penguin' features on the skin at all - all is illusion. When placed amid a row of E. c. filholi skins from Macquarie Island, the chrome-yellow and depressed sse is very obvious and the penguin looks decidedly odd. Superficial resemblance of the skin is certainly to E. robustus as which it was identified in the field and subsequently by Falla. One can readily imagine the collectors believing it to be a different species - its true affinities are well disguised indeed. On the evidence presented here I am convinced that the penguin B7313 is in fact a hybrid between the Rockhopper and Royal Penguins. AUSTRALIAN 42 SIMPSON BIRD WATCHER

Details of the fibrous-textured lateral sse of the hybrid Rockhopper X Royal Penguin B7313. The tip of one of the smaller, yellow frontal feathers is just visible in the top right third of the photo. In this particular specimen these tiny feathers are well hidden across the crown front. Plate 10 Photograph of Museum of Victoria skin: KN.G. Simpson

Details of the Snares Penguin B7312. Particularly note where the point of anterior origin of the silky SSe occurs- it reaches further forward than it does in the Rockhopper and hybrid penguins displayed above. Plate II Photograph of Museum of Victoria skin: KN.G. Simpson VOL. II (2) JUNE 1985 Rockhopper x Royal Penguin Hybrid, Macquarie Is. 43

Breeding Royal Penguins at Macquarie Island, November 1965 approx. Note jet-black, glossy Iores of nearest bird, and duller, parti-coloured !ores of bird at rear. Both penguins clearly demonstrate the nature, proportions, and disposition of the golden, fibrous- textured frontal crests. Plate 12 ANARE photograph: K.N.G. Simpson (/) -3::: '"0 (/) 0z

Jlote thBt fliprer has eliatJ,tly contracted oD drying - total lenrrth not quite accurate to life. 1 measured 56/J?/180 mm.

:7-+-­~t

Figure 2. A comparison of the underflipper patterns (right sides only) of the penguins discussed in the paper: from left- Royal Penguin 82478; hybrid Rockhopper/ Royal Penguin 87313; Rockhopper Penguin 811865; Snares Penguin 87312. Tracings directly from flippers, then photo-reduced. Drawing by KN.G. Simpson VOL. II (2) JUNE 1985 Rockhopper x Roya l Penguin Hybrid, M acqua rie Is. 45

Acknowledgements The opportunity to look closely at members of the genus Eudyptes came through the auspices of ANARE, and of the CSIRO Division of Wildlife and Rangelands Research. Some travel to southern museums was financed by a grant from the Science and Industries Endowment Fund, administered by CSIRO. I thank the (then) Director Dr John Ling, and present Curator of Birds, Mr Shane Parker, for access to specimens in the South Australian Museum. I also thank the (then) Director Mr John McNally and present Director Dr Barry Wilson, the (then) Curator of Birds Mr Allan McEvey and Assistant Ms Belinda Gillies, for access to the collections of the Museum of Victoria. The map was drawn by Nicolas Day. The manuscript was read and commented on by Shane Parker; Mr Mike Carter; Prof. Mike Cullen, Zoology Department, Monash University, Victoria; Mr Ron Brown, Fisheries and Wildlife Division, Victoria; and Dr Gavin Johnstone, Antarctic Division, Department of Science and Technology, Hobart.

Author's note This is the second of a short series of occasional papers I am presenting on the genusEudyptes. The prior paper in the series is Simpson & McEvey (1972). Additionally, the text provided on the genus, plus the line drawings executed on my behalf by Peter Trusler and colour plate (Plate 3) by Nicolas Day in the new bird book of which I am Editor (Simpson & Day 1984), are counted as part of this particular series. In recent years I have written the text entries for the genus Eudyptes in three books (Simpson 1972, 1975, 1976). Further, comments or modifications based on my earlier researches on the genus have been acknowledged by the following authors of books or papers: Brown & Corrick (1970); Condon (1975); Green & McGarvie (1971); Green (1980); Pizzey (1980); and Serventy & Whittell (1976).

References Brown, R.S .. & Corrick, A H. , (1979), 'A moulting Fiordland Penguin on Lady Julia Percy Island, Victoria', Aust. Bird Watcher 8, 61-64. Condon, H.T. (1975), Checklist of the Birds of Australia, Pa rt I Non-Passerines. R.AOU, Melbourne. Green, R.H. & McGa rvie, A.M., (1971), 'The birds of King Island',Rec. Queen Viet. Mus. 40, 1- 42. G reen, R.H. (1980), 'Snares Crested Penguin: a third Australi an record', Tas. Nat. 60, 11. Gwynn, AM. (1953), 'Some additions to the Macquarie Island list of birds', Emu 53, 150-152. Keith, K & Hines, M.P., (1958), 'New and rare birds at Macquarie Island, 1956-1 957', CSIRO Wildlife Res. 3, 50-53. Pizzey, G.M. (1980), A Field Guide to the Birds of Australia, Collins, Sydney. Serventy, D.L. & Whittell, H.M. (1976), Birds of Western Australia, 5th Ed ition, University of W.A Press, Nedlands, W.A. Simpson, KN.G. (1972), Birds in Bass Strait, A.H. & A.W. Reed, Sydney, for BHP. Simpson, KN.G. (1975), Text entry for rare seabirds, in Reid. A.J., Shaw, N.J. & Wheeler, W.R., Birds of Victoria, 6, Rare Species, pp. 20-28. Simpson, KN.G. (1 976), Text entries for Eudyptes species, in Frith, H.J. (Consultant Edito r). The Reader's Digest Complete Book of A ustralian Birds. Reader's Digest Services, Sydney. pp. 31-32. Simpson, KN.G. & Day, N. (1984), Th e Birds of Australia - A Book of Jdentijication, Currey O'Neil, Melbourne. Simpson, KN.G. & McEvey, A.R. . (1 972). 'Snares C rested Penguin: two Australian records·. Emu 72. 110-111. •