The Migration of the New Zealand Bronze Cuckoo, Chalcites lucidus lucidus (Gmelin).*
[Read before Wellington Branch, September 25, 1946; received by the Editor, September 26, 1946; issued separately, September, 1947.]
The distribution of Chalcites lucidus lucidus has been studied and maps presented showing the New Zealand areas occupied from August to November, 1945. Evidence is given of independent landfalls at scattered points, earliest in the north and north-east, latest in the extreme south.
Factors bearing on the migration of the species are discussed, and its probable range in time and space indicated. Possible interrelationship between migration routes and the south-east trade winds are discussed.
The subspecies of Bronze Cuckoo breeding in New Zealand is Chalcites lucidus lucidus (Gmelin 1788), commonly called in this country the Shining Cuckoo or Pipiwharauroa. It is migratory as also is the Tasmanian subspecies C. l. plagosus (not found in New Zealand), while two other subspecies are non-migratory tropical cuckoos. Comparatively little co-ordinated work has been done on the problems of the migration of either of the former subspecies. The purpose of this paper is to present the results of a recent investigation of the movements of the New Zealand subspecies while at the southern end of its range, together with a survey of what is known of its annual movements as a whole.
Although certain of the early Maoris are said to have believed that the Shining Cuckoo is a migrant, returning every winter to Hawaiki, the first scientific records of its migratory habit are due to Yate (1835) and Gray (1843). Colenso (1844) also supported this view.
Wallace (1876) considered the theory untenable, as it would involve an ocean flight of at least 900 miles to the nearest land beyond New Zealand, and at that period such flights were unknown. Wallace suggested that a partial migration might occur within New Zealand itself, which would be sufficient to account for the observed facts. Buller (1872), however, adduced evidence to show that after the birds first appeared in New Zealand in the spring they would subsequently be reported at Chatham and Macquarie Islands farther to the east, and he inferred, together with other New Zealand ornithologists, that migration overseas occurred.
[Footnote] * Work carried out with the aid of a Hutton Grant from the Royal Society of New Zealand. Assistance in the cost of printing this paper was given from the Publications Fund of Victoria University College.
Hutton and Drummond (1904) stated that the bird appears in the north of New Zealand regularly in the latter half of September and that early in October it is found in Wellington and in the South Island. After breeding, the birds depart from the southern portions of the country in the first and second weeks of January and do not leave the north until the end of January or perhaps later. They also give some data on the occurrence of the bird other Pacific Islands. It should be noted here that Hutton and Drummond did not give sources for these clear-cut statements, and, in fact, their discrepancy in regard to other data led to the investigation to be described.
Fulton (1910), in the course of his extensive paper on the subspecies, made a valuable contribution to our knowledge of the bird, but did not discuss its migratory behaviour in any detail beyond indicating his general acceptance of Hutton and Drummond's views.
Mathews (1918) disputed the point once more, considering as had Wallace, that only partial migration within New Zealand occurred. He pointed out that cuckoos have been reported in New Zealand when the birds were supposed to be absent from the country. In more recent years, circumstantial reports have appeared in the press and elsewhere of the arrival of cuckoos on the coast singly or in groups, while other data summarised by Mayr (1932) left little room for doubt that the species occurs overseas during the months it is not seen in New Zealand. It came to the writer's knowledge that birds were commonly to be found in New Zealand at times outside the limits specified by Hutton and Drummond, so that it seemed desirable to subject the New Zealand records to a more careful scrutiny. At the same time opportunity has been taken of checking at their sources reports of the arrival on the coast of birds flying inland from the sea.
Collection of Data.
When all available data hitherto recorded on the dates of initial appearance of the Shining Cuckoo in different parts of New Zealand were collated it was not found possible to derive sufficiently clear conclusions. Reports were scattered over a period of some fifty years and could not be compared one with another; for it is futile to attempt to correlate observations made in one district in one year with those made elsewhere in a different year. A complete series of records for the whole country in any one year was lacking. Consequently a mesh of observers throughout New Zealand was organised to study the arrival of the birds during the spring and summer of 1945–46. With the co-operation of the Forest and Bird Protection Society 5,000 questionnaire forms were distributed prior to the expected appearance of the birds. Altogether 223 observers forwarded useful reports. Each report was scrutinised, and any doubtful or improbable returns were referred to the observer concerned for further explanation, and if not capable of substantiation were discarded. It is felt that although more data would have been desirable, nevertheless sufficient co-ordinated records were obtained to justify the conclusions drawn.
The maps (Figs. 1 to 6) indicate distribution plots at half-monthly intervals from August to November, 1945. As the subspecies is a bird of strong flight and roaming nature, when recorded from any point it was regarded as occurring over an area of 15 miles radius about the point for the purpose of plotting. This would be a con-
servative estimate. Certain areas away from townships, such as the southern fiords, necessarily remained blank as no observers were there. The maps can be treated therefore only as a general guide and certainly cannot be complete. On the basis of these maps, and the accompanying appendix giving precise localities, dates, and nature
of observation, the following conclusions may be drawn as to the movements of the cuckoo while at its southern range in 1945.
Spring Arrival in New Zealand.
The first observations of the arrival of the cuckoo were made at Opua, Bay of Islands, and at Parau, Auckland, both on August 14. Within twenty-four hours it had been recorded at Nuhaka, Poverty Bay. The fact that these points are each separated by considerable distances (120 and 220 miles respectively), and that a fortnight elapsed before birds were reported at intervening points, would suggest that separate landfalls had been made by birds approaching from the north-west, some landing in the north and others continuing south-castward across the Bay of Plenty to Poverty Bay. During the ensuing fortnight two fresh incursions were made, bridgeheads appearing at Ohura (August 20) and in Wellington (Paraparaumu, August 20; Khandallah, August 28; Heretaunga, August 28). Meantime the previously established bridgeheads had been expanding, the central one extending south to Pukekohe (August 26) and to Piha (August 31), and the eastern bridgehead extending inland to Matawai (c. August 30), though the latter may have been fresh migrants from the Bay of Plenty. It is noteworthy that till the end of August no birds were reported from districts further than twenty miles from the sea, and that the known incursions were limited to the five areas specified in the North Island.
The first half of September was marked by the arrival of birds in the South Island, landfall being made at Blenheim (September 14) and at Scargill (September 15), probably both by birds radiating from the Wellington group. During the same period the range extended farther inland in the North Island, the deepest penetration being at Taihape, some fifty miles from the sea, which was reached by September 15. Other areas entered included Carterton (September 5), Feilding (September 5), and Wanganui (September 11) In the far north Kaitaia reported the birds on September 13, though it seems likely that they may have been present there earlier.
During the second half of September more areas of the North Island were occupied, including the volcanic plateau, birds being reported at Tokaanu on September 26. Meanwhile fresh landings were being made in the South Island, Greymouth reporting them first on September 17, only three days after Blenheim had been reached, though they were not reported from Nelson till September 21. nor from Farewell Spit lighthouse till the evening of September 27. As the two latter places lie between Blenheim and Greymouth, it is again probable that separate groups of birds made independent landfalls from the sea at these several points. In the case of Farewell Spit such is known to have been the case (see section of this paper on “Landfall Observations”). Other points occupied were Ngahere (September 29), Ravensbourne (September 18), and Hawarden (September 22). By September 28 Little Barrier Island had been reached.
During October the greater part of the North Island was occupied and further fresh incursions were reported in the South Island at widely scattered points, the dates being progressively later toward
the south. Stewart Island was not reached till November 8. Sufficient indication of the spreading of the birds through October and early November is given in the maps and appendix, and further localities and dates need not be listed here.
It is significant that in both the North and South Islands it was the coastal areas which were first occupied. A Maori belief that cuckoos follow the waterways did not receive confirmation, save in a few very local cases, too few to have general significance.
It is evident that the first birds arrive in the north and northeast of the North Island in early August, and thereafter the cuckoos gradually spread south-westward, corresponding to the general south-westward orientation of New Zealand. About three months elapse between the first arrival in the north and the first arrival in the extreme south. Independent landfalls appear to be made by separate groups of birds. Coastal areas on both the eastern and western coast of both islands are the first to be occupied, inland penetration following. A popular belief that the Shining Cuckoos reach Farewell Spit first and thence spread north and south is clearly disproved.
Actual landfall of birds arriving from the sea is an event seldom seen. The following reports have been investigated and can be taken as authentic.
Farewell Spit: P. E. White, Principal Keeper at the Lighthouse, supplies details of observations made in 1944 and 1945 (personal communications).
In 1944 a few birds arrived on September 29, but on the following day they were numerous and feeding on the larvae of Nyctemera annulata on Senecio and Lupin about the lighthouse. After about a week's stay the birds disappeared inland.
In 1945 the first birds were seen on September 27 at 5.30 p.m. They were then coming in singly from the sea from different directions at irregular intervals. They appeared very tired, and at first were so tame as to permit close approach, the lighthouse cats destroying a number. Later they became more wary. On succeeding days more birds arrived, and as the weather became rough they remained grounded, feeding on Nyctemera larvae and other insects, and “whistling all day long.” By the middle of October they all had disappeared inland.
Waikawa (Southland): H. Ross (1941, and in personal communications) has given details of observations he made in 1933 (November). The birds came in singly from the sea at night from 10 p.m. onwards. He records the earlier arrivals as calling intermittently from the trees where they were resting, and receiving feeble answers from the incoming birds—so that it appeared as if pathfinders were calling in their kin to safety. Ross states that the birds on land periodically set up such a calling, and every time it was followed after an interval by a barely perceptible answer from the sea, which grew stronger till the solitary migrant arrived. After a joyous welcome all would grow silent till the sequence was again repeated. This unique account has not been paralleled in other
districts yet. The migration would presumably be a subsidiary flight of birds from an area farther north on the mainland.
East Cape: Mayr (1932) records a dead bird taken at the lighthouse on November 5. This is presumably the same case as that given by Fulton (1910).
Kahurangi Point: Fulton (1910) records the arrival at the lighthouse of a bird on October 6 and three on October 13. In each case the advent coincided with north-west winds.
The two latter reports are taken from the literature, and the circumstances cannot now be checked; there is no reason to doubt the accuracy of any of the above cases. The fact that the birds have been seen on specific occasions arriving from the sea at two lighthouses on the west coast strongly supports the belief that they have in fact come from the direction of the Solomon Islands, their other known habitat.
Duration of the New Zealand Sojourn.
Numerous reports indicate that the birds are present in New Zealand at least until March, and sometimes April, after completion of the protracted breeding season. It appears that by the end of March the main body of the birds has already left, but more extensive observations on the matter are required. The following have been collected:—
Dunedin: An excellent series of records by Tily (personal communications) show that cuckoos were last reported in the Dunedin area on the dates following, for various years: 1938, March 23; 1940, February 29; 1941, February 24; 1942, January 13; 1943, March 23; 1944, February 17; 1945, January 12; 1946, April 9.
Mount Aspiring: 1944, February 21 (J. Aspinall).
Cheviot: Usually March or April (Wilkinson).
Departure from New Zealand.
White (personal communication) gives evidence of outward migration as observed by him at Farewell Spit Lighthouse. Usually about April the birds return to this locality, remain there for a week or so, and then disappear. He believes that they depart at night or in the early morning, as he has seen them in the evening, while on the following day not one has remained.
A night departure might be correlated perhaps with an evening breeze blowing from land to sea, such as commonly occurs after a warm day. The fact that birds occur at Farewell Spit for only about a week suggests that only one migratory group uses this locality as its point of departure. Banding will be necessary to ascertain if the departing birds are the same as those that arrive there in late September, and it is hoped that this work can be done in the future.
Fulton (1910) has reported that the birds generally leave Kahu-rangi Lighthouse in March, but two birds were seen there in April, 1908.
Some evidence has been obtained confirming the earlier belief that a number of cuckoos do not migrate. Such occurrences are known in overseas species. The following reports were received last season;
Manurewa: A young bird accompanied by three wax-eyes, seen in April or March, 1945 (E. Turtan).
Russell, Bay of Islands: May 10, 1945 (A. Closey).
Martinborough: May, 1944 (M. G. Hitchman).
Mauku, Pukekohe: May 1, 1945 (A. Oates), and June 22, 1945 (L. Gurney).
It is well known overseas that young cuckoos leave later than their parents, so it is reasonable to suppose that most cases of non-migrant or late-migrant birds observed in New Zealand are also young ones which failed to depart at the normal time. The case at Manurewa is clear.
Occurrence Beyond New Zealand.
The following confirmed records are available for C. l. lucidus (as distinct from the other subspecies with which in the past confusion has occurred):
Chatham Islands: Potts records its arrival and sojourn as corresponding to that observed on the New Zealand mainland.
Norfolk Island: March 28 [1913—Mayr (1932) fide Bell].
Lord Howe Island: February 12 [1915—Mayr (1932) fide Bell].
Solomon Islands: Mayr (1932) records that specimens have been taken from March 16 to September 25, and none from October to February, although the Whitney Expedition was present over that period. The numbers of specimens taken are given as follows: March (1). April (3), May (6), June (2), July (4), August (nil), September (2), October-February (nil).
At Sea: Hutton and Drummond (1904) report a specimen taken at sea between New Zealand and Lord Howe Island, but give no date.
Apparently no specimens have been taken in Australia, New Caledonia, or New Hebrides. Specimens previously reported from these areas prove to be other subspecies of C. lucidus (Mayr 1932).
Tabulating all accessible data we obtain the following seasonal distribution chart:
|Lord Howe I.||X|
Overlap periods occur when the subspecies is found at both ends of its annual range. It is clear then that migratory movement occurs over the periods March-April and August-September. Relatively small flocks are probably moving independently during those months. This would explain the New Zealand data, which indicate, e.g., that birds are certainly still arriving from the sea as late as September and early October, when the birds had already been established in the North Island for two months. It is even possible that some of the November arrivals in Southland and Stewart Island may be birds fresh from overseas.
[Footnote] * Ignoring non-migrants.
[Footnote] † Known to occur at Nissan and Feni, but dates not available.
[Footnote] ‡ Probably present, but not recorded.
Sparseness of data makes any present deductions largely hypothetical. Confirmation or refutation of reports that the subspecies has been taken in Queensland or the Capricorn Islands is still awaited. Present data would indicate that birds leaving New Zealand in
February, March, and April fly north-westward from various headlands across the Tasman Sea via Norfolk or Lord Howe Islands, and then northward to the Solomons. The complete lack of specimens from New Caledonia and New Hebrides, although other subspecies are well known there, seems to show that the New Zealand subspecies cannot normally use that route, if ever. Fig. 7 shows the suggested route, as also that probable for the Tasmanian subspecies C. l. plagosus, which winters in islands from Lombok to New Guinea. The routes of the two subspecies are roughly parallel, C. l. lucidus being displaced about 25† east of the other. The routes seem to correspond roughly with the direction of the South-east Trade Winds. It seems then that the cuckoos are wind-borne from their respective southern breeding lands to their tropical wintering places—and on the return flight are headed into the wind. On neither flight do they fly across the wind. Supposing the southern (and breeding) ranges to be the older home of the subspecies concerned, the adoption of the respective routes might have been a consequence of the direction of the trade winds. It is feasible to consider the ancestors of the New Zealand Shining Cuckoo as being sedentary New Zealand birds—as two other of the subspecies are to-day sedentary in the Pacific—and that the migratory habit arose as a consequence of recent glacial conditions rendering New Zealand inhospitable in winter. A similar history might have occurred in Tasmania.
Note on Breeding Habits.
Graham (1940) recorded C. l. lucidus adults feeding young cuckoos. H. Ross (personal communication) confirms the feeding of fledged cuckoos by adult cuckoos. It is not yet proven that cuckoos can hatch their young. The observations, however, would render some caution necessary before deciding that certain islands can or cannot be breeding places for the various subspecies of C. lucidus owing to the presence or absence of suitable foster-parent species.
The co-operation of the very many observers who furnished the data is gratefully acknowledged. In particular I have to thank the following: The Forest and Bird Protection Society, for distributing and collecting questionnaires, and whose late President, Captain E. V. Sanderson, gave much support to the inquiry; Mr. P. E. White, Chief Keeper, Farewell Spit Lighthouse; Mrs. I. Tily, who placed her extensive records at my disposal; Mr. Hugh Ross; Lieutenant D. H. Graham; Dr. Ernst Mayr, who kindly furnished data of the Whitney Expedition collections; and my wife for assistance in the preparation of maps.
Summary of Field Records of Arrival Dates, Spring, 1945.
Abbreviations: H, heard; S, seen; HS, heard and seen; NS, not stated whether seen or heard.
In cases where several records were received from one locality, only the earlier dates and observers are given, but the total number of records contributing to a plot is shown on the maps.
North Auckland:—Opua: H Aug. 14, M. Goodhue; H. Aug. 20, R. Shortridge et al. Rangiputa: HS Sept. 13, R. Thirkettle. Leigh: HS Sept. 20, T. D. Bathgate. Kawakawa: H Sept. 25, A. E. Tate et al. Mahurangi Heads: H Sept. 26, S. Sept. 28, T. T. Bond. Te Paki: H Oct. 1, L. D. Keene. Maunu: H Oct. 2, E. M. Dorchill. Warkworth: HS Oct. 2, M. E. Finlayson. Whangarei: H Oct. 3, L. Billings. Maraetai: HS Oct. 4, R. Baucke. Dargaville: H Oct. 9, R. A. Farrand. Kohukohu: HS Oct. 11, O. Wooster. Hokianga: H Oct. 21, V. Corfield.
Auckland:—Parau: H. Aug. 14, E. D. Hatch. Ohura: H Aug. 20, P. O'Connor. Pukekohe: H Aug. 26, R. J. Fenton. Piha: H Aug. 31, R. C. Abel. Cleveden: H Sept. 27, H. R. McKenzie. Auckland: HS, Sept. 28, many observers. Little Barrier Island: HS Sept. 28, C. M. Parkin. Otorohanga: H Sept. 30, G. M. Cruickshank. Huia: H Sept. 30, K. Thompson. Waitomo: H Oct. 2, D. H. Downard. Cambridge: H Oct 2, R. Newling. Katikati: H Oct., S Oct. 6, R. Goodyear; H Oct. 5, M. L. Perham. Hikuai: HS Oct. 6, G. V. McCall. Raglan: HS Oct. 6, K. S. Bird; et al. Hamilton: H Oct. 8, M. E. Pepperell. Pirongia: H Oct. 9, L. Valder. Thames: H Oct. 14, C. Donkin. Ngaruawahia: HS Oct. 14, J. A. Lamont. Whangamata: HS (two seen courting), W. Sanderson. Rotoiti: H Oct. 17, C. Branch; HS Oct. 21, H. F. Hamlett. Kawhia: HS Oct. 17, J. M. Fitzsimmons. Onehunga: Oct. 31, D. S. Barfoot. Te Aroha: S Oct. 27, G. Barnes.
Poverty Bay:—Matawai: H “end of August,” F. B. Gibson. Te Puia Springs: H Oct. 2, A. B. Williams. Te Araroa: H Oct. 3, G. W. Cormack. Otoko: HS Oct. 4, M. McLean; Sept. 26, Anon. Tolaga Bay: H Oct. 9, R. A. Berry. Opotiki: H Oct. 13, N. Potts.
Hawkes Bay:—Nuhaka: HS Aug. 15, N. McKay. Tikokino: HS Sept. 16, O. Hudson. Rissington: H Sept. 25, G. Absolum. Waimarama: H Oct. 1, F. R. Field. Waipukurau: H Oct. 2, G. L. Jamieson. Eskdale: H Oct. 4, A. H. Beattie. Pukehou: H Oct. 5, H. F. Hurfoot. Ongaonga: H Oct. 6, G. F. Gunson. Dannevirke: H Oct. 9, M. Mabbett. Hastings: HS Oct. 14 (3 observers). Kumeroa: H Oct. 15, M. N. Ellis. Waipawa: H Oct. 19, D. Nairn. Te Awanga: H Oct. 27, M. Mackie.
Taranaki:—Hawera: HS Sept. 28, L. A. Jennings. New Plymouth: H Sept. 30, B. B. Haywood; HS Oct. 1, B. Blundell. Tarata: H Oct. 3, J. Hallett. Eltham: HS Oct. 8, H. G. Belcher et al.
Wellington:—Paraparaumu Beach: H Aug. 20, T. Hunt. Heretaunga: H Aug. 28, I. D. Fell. Khandallah: NS Aug. 28, A. S. Seed. Taihape: H Sept. 5, B. A. Law. Ponatahi: NS Sept. 5, G. S. Roydhouse. Rangiwahia: NS Sept. 7, I. Foley. Mangamuhu: H Sept. 11, C. Potter. Wanganui: H Sept. 16, W. Monkhouse; S Sept. 16, Anon. Turangi: H Sept. 26, H. G. Matthews. Okoia: H Sept. 26, F. J. Pratt. Hunterville: H Sept. 16, A. Kilmister; HS Sept. 27, J. Anson et al. Lower Hutt: HS Sept. 27, A. Porter. Bulls: HS Sept. 28, N. Wilson; Sept. 30, many observers. Turakina: HS Sept. 24, L. McLeay at al. Foxton: H Oct. 2, G. W. Hughes. Marton: H Sept. 23, L. and F. Laird. Kiwitea: H Oct. 6, C. A. Barrett (“in bush at 1,200 ft. elevation”). Rewa: H Oct. 6, N. McDonald. Cross Creek: H Oct. 6, B. Stevenson. Aramoho: H Oct. 7, L. H. Humphrey. Makotuku Stream: H Oct. 7, T. Shout et al. Palmerston North: H Oct. 8, G. M. Harrison. Greytown: H Oct. 9, C. Morgan. Hautu: H Oct. 10, J. W. Rogers (“reported on Sept. 12, but this not certain”), Feilding: H Oct. 10, M. Barrie et al. Eketahuna: NS Oct. 10, M. Groves. Masterton: H Oct. 4, D. J. Cooper et al. Pongaroa: H Oct. 11, D. W. Gray. Levin: HS Oct. 12, M. J. Rolston. Pahiatua: NS Oct. 13, B. A. Handcock. Bush Grove: H Oct. 2. W. G. Groves.
Marlborough:—Molesworth: H Sept. 14, M. M. Chisholm. Tua Marina: H Oct. 16, F. W. Smith.
Nelson:—Nelson: NS Sept. 21, L. M. H. Brown; H Sept. 23, P. L. Fell; S Sept. 28, B. Cannington. Farewell Spit: HS Sept. 27 (“coming in from the sea”), P. E. White. Takaka: H Sept. 28, G. B. Petterson. Maitai Valley: H Sept. 21, T. Elliott; Sept. 30, P. Moncrieff. Motupipi: S Sept. 29, C. D. Russ. Murchison: H Oct. 5, M. Mooney; Oct. 8, D. Conway et al. Mapua: H Oct. 9, M. T. Woollaston. Motueka: H Oct. 25, R. Miller.
Westland:—Grcymouth: H Sept. 17, W. McKay. Ngahere: H Sept. 29, L. Mulcare. Jackson's Bay: H Oct. 14, D. D. Greaney. Te Kinga: HS Oct. 14, R. Dickson. Wataroa River (Mouth): H Oct. 20, S Oct. 28, W. Dehn.
Canterbury:—Scargill: HS Sept. 15, F. Loe. Christchurch: NS Oct. 3, M. Washbourne. Cashmere Hills: H Oct. 14, R. R. Maddren. Cheviot: HS Oct. 9, L. Wilkinson et al. Hawarden: H Sept. 22, M. A., Philpott. Ethelton: HS Oct. 14, N. Hyde. Southbrook: H Oct. 15, L. E. Wain; S Oct. 20, E. McClung et al. Ohoka: S Oct. 15, A. D. Saunders. Hanmer Springs: H Oct. 9, S Oct. 11, E. Westlake. Mount Fyffe, Kaikoura: H Oct. 17, E. C. Brown. Temuka: NS Oct. 19, G. Brown. Rangiora: H Oct. 17, O. C. Philpott. Pigeon Bay: HS Oct. 14, N. Duxbury.
Otago-Southland:—Ravensbourne: H Sept. 18, I. Tily. Leith Valley: H Sept. 26, A. McCraw. Waikaia: H Oct. 10, G. Dillon. Opoho: H Oct 29, I. McArthur. Otautau: S Oct. 17, D. Matheson. Balclutha: S Nov. 2, A. Anderson. Puerua: H Oct. 16, A. Dent. Half Moon Bay, Stewart Island: HS Nov. 8, C. E. Carrington.
Buller W., 1872. Birds of New Zealand, 77.
Colenso, W., 1844. Tas. J. Sci., 2, p. 227.
Fulton, R., 1910. Trans. N.Z. Inst., 42, p. 392.
Graham, D. H., 1940. Forest and Bird, 55, p. 4.
Gray, G. R., 1843. Appendix to Dieffenbach's Travels in New Zealand.
Hutton, F. W., and Drummond, J., 1904. Animals of New Zealand.
Mathews, G. M., 1918. Birds of Australia.
Mayr, E., 1932. Amer. Mus. Novit., 520.
Potts, T. H., N.D. (quoted in Animals of N.Z., Hutton and Drummond).
Ross, H., 1941. Forest and Bird, 60, p. 6.
Wallace, A. R., 1876. Geographical Distribution of Animals.
Yate. W., 1835. Account of New Zealand, p. 64.