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Pacific Baza Aviceda subcristata Scientific name definitions

Guy M. Kirwan, Stephen Debus, and Peter Pyle
Version: 1.1 — Published March 21, 2025
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Introduction

The Pacific Baza is a medium-sized, broad-winged hawk with a short pointed crest, bold barring on the belly, and arresting yellowish eyes. It is found from the Lesser Sundas and Sulawesi through the Maluku Islands, Papua New Guinea and its satellite islands, the Solomon Islands, and northern and eastern Australia. It is found in a variety of predominantly coastal habitats, including rainforests, wet sclerophyll and swamp forests, woodlands, and edge habitats. While generally sedentary across its range, Australian populations are partly migratory, undertaking some local altitudinal and north-south movements and wintering along subtropical coasts.

The Pacific Baza is omnivorous, feeding primarily upon insects but also small vertebrates and fruits. Its flight is buoyant, and it typically soars and glides on flat to slightly bowed wings. It is notable for its distinctive display flights, in which up to three birds perform an undulating and acrobatic sky-dance.

The species remains relatively common across its core range, though it is less common on Sumbawa, Flores, and at the periphery of its Australian range. Listed as Least Concern under IUCN Red List criteria, it appears to benefit somewhat from forest fragmentation due to its preference for edge habitats, though it avoids extensively cleared areas.

Subspecies


SUBSPECIES

Aviceda subcristata timorlaoensis Scientific name definitions

Systematics History

Baza timorlaoensis A. B. Meyer, 1894, Abhandlungen und Berichte des Königl. Zoologischen und Anthropologisch-Etnographischen Museums zu Dresden 4(3):5—Timorlaut [= Tanimbar].

This name is based on two syntypes (SMTD C7259 and C7260), both originally held in the Museum für Tierkunde, Staatliche Naturhistorische Sammlungen Dresden, but the first-listed was destroyed during Allied bombing towards the end of World War II; the surviving example, a male, is variously reported to have been collected on 11 September 1882 or in May 1883, by Riedel (18). What is certain is that Meyer (19: 10) already reported the existence of these specimens.

Distribution

Islands in Flores Sea off southern Sulawesi, and Lesser Sundas (east to Damar, Babar, and Tanimbar Islands).

Field Identification

Subspecies <em>timorlaoensis</em> is small to medium-sized, with greater reversed sexual dimorphism than other members of the pale group; pale or very pale above, and variably washed rufous below (2).


SUBSPECIES

Aviceda subcristata pallida Scientific name definitions

Systematics History

Baza subcristata pallida Stresemann, 1913, Novitates Zoologicae 20:306.—Tual, Kai Islands.

The holotype, an adult male collected on 10 July 1900 by Heinrich Kühn, is held at the American Museum of Natural History, New York (AMNH 531635); the same collection holds the following paratypes: AMNH 531636, male, 4 March 1898, AMNH 531637, male, 15 June 1898, both collected on Tual Island; AMNH 531639, female, 14 November 1899, AMNH 531640, female, 26 February 1900, AMNH 531641, female, 27 February 1900, and AMNH 531642, sexed as a male but entered as a female by Stresemann, 27 February 1900, all collected on Goram Island (20, 21).

Distribution

Seram Laut Islands, Kai Islands (southern Maluku Islands).

Field Identification

Subspecies pallida is also very pale (like the previous); Stresemann (22) considered it to be smaller than A. s. timorlaoensis (three males of pallida had wing 286‒295 mm, four females had wing 300‒314 mm; eight males of timorlaoensis 295‒314 mm, seven females 310‒327 mm). Eaton et al. (23), who also remarked on the similarities between pallida and timorlaoensis, considered that the belly barring is less conspicuous in the present taxon.


SUBSPECIES

Aviceda subcristata reinwardtii Scientific name definitions

Systematics History

Falco (Lophotes) Reinwardtii Schlegel and S. Müller, 1841, in Temminck, Verhandelingen over de natuurlijke geschiedenis der Nederlandsche overzeesche bezittingen, Zoologie, Aves, p. 37, Plate 5 (1845).—Manado, Celebes [Sulawesi]; Seram was erroneously substituted by Berlepsch (24), but Stresemann (22), followed by Rothschild & Hartert (25), gave Ambon, and Mees (26) further clarified that the collector, Reinwardt, was present on Ambon during 27 June‒12 August 1821 (and that he never visited Sulawesi!). The lectotype and one of the paralectotypes was collected on Ambon.

In the original description, Schlegel and Müller listed five specimens: three males collected by Reinwardt in 1821 “[in the vicinity of Manado on Sulawesi]”, a female collected by Diard (1794–1863) on Borneo and another female collected by Forsten (1811‒1843) at different locality on Sulawesi, two of which were illustrated on their Plate 5; these birds are now known to be representatives of four different taxa, belonging to two different species, necessitating a lectotype designation to prevent nomenclatural confusion and to fix the identity of the present taxon (27). Consequently, Quaisser and Dekker (27) designated as the lectotype an adult male collected on Ambon in 1821 by Caspar Georg Carl Reinwardt (1773–1854), held in the Naturalis Biodiversity Center, Leiden (RMNH.AVES.87171), whilst the following paralectotypes are held in the same museum: RMNH.AVES.88925 (an adult male, also taken in 1821 on Ambon by Reinwardt), RMNH.AVES.87168–87169 (two adult females, the first collected at Pontianak, Borneo, by Pierre-Médard Diard, and the second at Tondano, Sulawesi, by Eltio Alegondas Forsten = Aviceda jerdoni celebensis), and RMNH.AVES.87172 (an adult male collected on Ternate in 1821 by Reinwardt = Aviceda subcristata rufa) (28). Multiple different taxa are represented in the type series. RMNH.AVES.87168 is also the holotype of Baza borneensis Brüggemann, 1876; RMNH.AVES.87169 and 87172 are syntypes of Baza celebensis Schlegel, 1873, and Baza rufa Schlegel, 1866 respectively. Schifter et al. (29) correctly noted that a specimen from Ambon held in the Naturhistorischen Museums in Wien could not possess type status as it was not collected until 1863.

Distribution

Seram and its western satellites (Boana, Ambon, Haruku), in central Maluku Islands.

Field Identification

Subspecies reinwardtii is much darker than other Indonesian taxa, being in this respect close to northwest Australian birds (sometimes recognized separately under the name njikena) and also to subspecies obscura of Biak Island (2). In slight contrast, Eaton et al. (23) considered reinwardtii to be only slightly darker than stresemanni, but also marginally smaller than the latter.


SUBSPECIES

Aviceda subcristata stresemanni Scientific name definitions

Systematics History

Baza stresemanni Siebers, 1930, Treubia 7, Supplement, p. 243.—Nal Besi, Buru. (30)

The holotype, an adult male collected on 17 June 1921 by Lambertus Johannes Toxopeus (1894‒1951), is held at the Naturalis Biodiversity Center, Leiden (RMNH.AVES.14019) (31, 28). Siebers (30) referred to a total of 15 specimens collected by Toxopeus (11 specimens) and the local collector Denin (four specimens), and the remainder of this material can therefore be considered paratypes.

Distribution

Endemic to Buru (central Maluku Islands).

Field Identification

Subspecies stresemanni is much like nominate subcristata, but smaller (wing 302–362 mm versus 305–349 mm) with blacker barring below, and a bright rufous ventral region (2).


SUBSPECIES

Aviceda subcristata rufa Scientific name definitions

Systematics History

Baza rufa Schlegel, 1866, De vogels van Nederlandsche Indië, De Valkvogels, pp. 41, 78, Plate 27, fig. 4, Plate 28, figs. 1‒3.—“Halmahera, Morotai, Batjan, Ternate en Tidore.”

Described on the basis of 11 syntypes, all held at the Naturalis Biodiversity Center, Leiden, as follows: RMNH.AVES.87172 is an adult male collected on Ternate in 1821 by Caspar Georg Carl Reinwardt (1773–1854); RMNH.AVES.87173 (an adult female collected in February 1862), RMNH.AVES.87174 (adult male, 18 September 1862), and RMNH.AVES.87175 (immature female, same date as previous) were all collected on Batjan by Heinrich Agathon Bernstein (1828–1865); RMNH.AVES.87176 is adult male taken at Galela, on Halmahera, on 14 August 1861, also by Bernstein; RMNH.AVES.87177 (adult female, 16 May 1861), RMNH.AVES.87178 (adult female, 4 August 1863), and RMNH.AVES.87179 (immature male, 7 August 1863) were all taken on Ternate by Bernstein; RMNH.AVES.87180 is an adult female collected on Tidore on 22 November 1863 by Bernstein; and RMNH.AVES.87181 (adult female, 19 September 1861) and RMNH.AVES.87182 (adult female, 29 August 1861) were both collected on Morotai, again by Bernstein (31, 28). According to the original labels, RMNH.AVES.87173, RMNH.AVES.87174, RMNH.AVES.87179, and RMNH.AVES.87175 served as models for the various illustrations that formed part of the original description.

Distribution

Halmahera and associated islands south to Bacan and Obi (northern Maluku Islands).

Field Identification

Subspecies rufa is a medium-sized taxon, washed rufous over the head, and has particularly bold and onto the breast, with rufous-colored underparts barring (2, 23).


SUBSPECIES

Aviceda subcristata waigeuensis Scientific name definitions

Systematics History

Aviceda subcristata waigeuensis Mayr, 1940, American Museum Novitates 1056:8.—Waigeo. (32)

The holotype, an adult female collected on on 26 December 1902 by Johannes Waterstradt (1869‒1944), is held at the American Museum of Natural History, New York (AMNH 531672) (20, 21).

Distribution

Endemic to Waigeo (West Papuan Islands).

Field Identification

Male has blackish ventral barring; female brownish barring (17). Considered similar to nominate subcristata but smaller on average (when comparing same sex) and varies in brown coloration above, and in strength of barring and rufous coloration on the underparts (2). Also similar to stenozona but larger (wing of female 314‒319 mm) (33, 17).


SUBSPECIES

Aviceda subcristata obscura Scientific name definitions

Systematics History

Aviceda subcristata obscura Junge, 1956, Zoologische Mededelingen Leiden 34:231.—Biak. (34)

The holotype, an adult male collected on 22 August 1953 by C. Hoogerheide, is held at the Naturalis Biodiversity Center, Leiden (RMNH.AVES.20985); five paratypes (two males, two females, and an immature) are also held at the same institution, of which four were also taken by Hoogerheide between September 1953 and March 1954, and the fifth was collected by Carl Benjamin Hermann Baron von Rosenberg (1817‒1888) on 25 March 1869 (RMNH.AVES.20986, RMNH.AVES.21433 and RMNH.AVES.21434, RMNH.AVES.22118, and RMNH.AVES.87170 (34, 31, 28).

Distribution

Biak and Supiori islands (in Cenderawasih Bay) (35).

Field Identification

Considered to be very close in appearance to subspecies reinwardtii of the southern Moluccas (2). Junge (34), however, distinguished it as follows: “These birds are near, but not identical with stenozona from West New Guinea. They are averaging smaller than both stenozona and reinwardtii (from Ceram, Ambon, and Haruku) ... In coloration the Biak specimens are nearest to stenozona, but they are darker on the crown, hind neck, upper back and upper tail coverts. Bars on the under side of the primaries generally darker, more blackish and more pronounced than in stenozona and reinwardtii. In the latter forms these bars are mostly more reduced, not extending over the whole breadth of the inner webs of the primaries. Colour of the under tail coverts as in stenozona.” Size (measurements from 34): wing length of males 278‒294 mm; wing length of females 287‒300 mm.


SUBSPECIES

Aviceda subcristata stenozona Scientific name definitions

Systematics History

Baza stenozona G. R. Gray, 1858, Proceedings of the Zoological Society of London 1858:169.—Aru Islands.

The holotype, a juvenile female collected by Alfred Russel Wallace (1823–1913) on an unknown date, is held at the Natural History Museum, Tring (NHMUK 1873.5.12.1693) (36).

Distribution

Western and southern New Guinea lowlands; the Aru Islands; and West Papuan Islands (Misool).

Field Identification

Subspecies stenozona is marginally smaller than waiguensis, with blackish-brown barring below (33, 37, 17). Size: wing length of male 290‒303 mm, wing length of female 296‒314 mm (17).


SUBSPECIES

Aviceda subcristata megala Scientific name definitions

Systematics History

Baza subcristata megala Stresemann, 1913, Novitates Zoologicae 20:305 (in key), 307.—Fergusson Island (D’Entrecasteaux Islands).

The holotype, an adult female collected on 16 June 1897 by Albert Stewart Meek (1871–1943), is held at the American Museum of Natural History, New York (AMNH 531689) (20, 21).

Distribution

Lowlands of northern and eastern New Guinea, including Yapen Island (Cenderawasih Bay) and the D’Entrecasteaux Archipelago.

Field Identification

Ventral barring is dark, broad, and complete (17). Subspecies megala is much like stenozona in coloration, albeit perhaps with a brighter rufous ventral region, but is rather larger (wing 310–348 mm) (37). Other size data, however, are slightly less impressive: wing length of male 298‒316 mm, wing length of female 314‒334 mm (33).


SUBSPECIES

Aviceda subcristata coultasi Scientific name definitions

Systematics History

Aviceda subcristata coultasi Mayr, 1945, American Museum Novitates 1294:11.—Manus Island. (38)

The holotype, an adult male, collected at Lombrum on Manus Island, on 25 July 1934 by William F. Coultas (1900‒1987) during the Whitney South Sea Expedition, is held at the American Museum of Natural History, New York (AMNH 335323); two paratypes—AMNH 334655, male, Petaiya, Manus, 29 January 1934; and AMNH 334656, female, Drabui, Manus, 13 January 1934—are held in the same institution (20, 21)

Distribution

Endemic to Manus (Drabui, Lombrum, and Petaiya) and San Miguel (Admiralty Islands, in the northwest Bismarck Archipelago) (38, 39).

Field Identification

Subspecies bismarckii and coultasi are similar, being medium-sized and much darker than other Papuan/Solomons taxa, with slate-colored upperparts, and more or less heavily blackish-barred underparts (37, 2). Mayr (38), however, compared coultasi principally to megala, saying that it differed in the adult male through being “paler gray on the throat and upper back; bars of breast and abdomen broader, deep brownish black, greater under wing-coverts with faint gray bars; black tail tip longer and tail relatively much shorter. Females also paler gray on throat and upper back, bars on under parts coarser and more blackish.”


SUBSPECIES

Aviceda subcristata bismarckii Scientific name definitions

Systematics History

Baza bismarckii Sharpe, 1888, in Gould, The Birds of New Guinea, part 25, text to Plate 4 labeled Baza gurneyi.—New Britain and New Ireland.

What has been reported to be the holotype, an adult male collected on “23 November 1881” by Theodor Kleinschmidt (1834‒1881), is held at the Natural History Museum, Tring (NHMUK 1886.12.20.51) (36). Sharpe clearly indicated that he was describing and had had illustrated a male collected on New Britain by “the late Dr. Kleinschmidt”, but he also mentioned that he had access to two specimens collected by the Revd. George Brown (1835–1917), one on New Ireland and the other at an unknown locality, both of which he considered to be the same taxon as the New Britain bird. In these circumstances, and without the benefit of a type designation in a contemporaneous volume of the Catalogue of the Birds in the British Museum (the relevant volume having been published prior to Sharpe’s description), it seems somewhat debatable whether Brown’s specimens should be regarded as paratypes or if all three skins (including that collected by Kleinschmidt) should be considered syntypes. Warren (36) stated that what she treated as the holotype of bismarckii was collected in late November 1881, but this seems doubtful given that the date of Kleinschmidt’s death is generally given as 10 April of that year.

Distribution

Endemic to New Ireland and New Britain, including Lavongai, Djaul, Lolobau, and Tabar (eastern Bismarck Archipelago) (39).

Field Identification

Barring on underparts broad, dark gray in males and brown-black in females (39). Now generally considered to be very similar to subspecies coultasi (e.g., 37, 2). Mayr (38), however, characterized the male as “Strikingly different from gurneyi-proxima. Bars of under parts pigeon gray, hardly darker than throat; white bars much narrower than gray bars, nape and upper back very pale gray; under tail-coverts deep ochraceous.” Females, on the other hand, he described as having “Breast and abdomen very heavily and coarsely barred with brownish black; under tail-coverts rufous ochre; throat dark gray; upper tail-coverts and tail-bars rather blackish gray; black tail tip very long; greater under wing-coverts barred with gray, lesser under wing-coverts ochraceous.” He went to remark that “The characteristics of this striking race, particularly the strong sexual dimorphism of coloration and the grayness of the bars in the male, are already indicated in the races of the Solomon Islands. On the other hand, bismarckii seems to have nothing to do with megala...”; the latter, in contrast, Mayr thought to be most closely related to coultasi (38).


SUBSPECIES

Aviceda subcristata gurneyi Scientific name definitions

Systematics History

Baza Gurneyi E. P. Ramsay, 1882, Journal of the Linnean Society of London 16:130.—Ugi. (40)

The type material of gurneyi, its provenance, and collectors have been subject to a fair degree of discussion in the literature. This taxon was described by Ramsay (40) from specimens collected on Ugi by the Reverend George Brown, and (one) from Cape Pitt by James F. Cockerell, but the latter is in the New Georgia group, which Ramsay (41) had earlier thought should be considered synonymous with New Guinea birds from around Port Moresby. According to Longmore (42), Ramsay (43) later corrected the provenance of his “Cape Pitt” specimen to “New Guinea”. Subsequently, Mayr (38) claimed that birds from New Georgia are similar to an undescribed taxon from the Bougainville and Shortland groups, which he named proxima (see below), and he thus restricted the type locality of gurneyi to Ugi, off Guadalcanal. Later still, however, Schodde (44) argued, evidently persuasively (given that few authorities since have maintained more than one taxon in the Solomons), that just one taxon, gurneyi, should be applied for birds in this region.

As related in most detail by McAllan (45), it is clear that Ramsay’s attribution of the Ugi specimens to Brown must have been a lapsus on his part, because his diary records a small collection received from Brown in mid-1881, which includes specimens from Ugi, but containing no birds of prey. As a result, to fix the type locality as Ugi, Longmore (42) proposed to treat a specimen now in the Australian Museum, Sydney, as the lectotype of gurneyi—an adult collected by “J. Stephens” in 1881 (AM A.10962). In addition, Longmore (42) also listed six paralectotypes in Sydney: AM A.11486, AM A.11487, A.11489, A.11490, and AM A.11491, all of them unsexed adults collected on Ugi, by Alexander Morton (1854‒1907) in 1881, as well as AM O.22343, an adult male, collected on an unknown date on New Britain by J. Cockerell. Furthermore, he referred to a seventh paralectotype as being held in the Queensland Museum, Brisbane (QM O.17872, per 45). However, while McAllan (45) accepted Longmore’s lectotype designation, he disputed the hypothesis that the Morton specimens could have been seen by Ramsay prior to his finalizing his description of gurneyi, because the former was still collecting on Ugi at the time, which would also invalidate the QM specimen. McAllan (45) argued also for exclusion of the Cockerell specimen because it is from New Britain, but suggested that a specimen in the Macleay Museum, Sydney (MM B.2937) should be considered a paralectotype, being “of a typical Cockerell make” and is labeled as being from the Solomons; given that Ramsay claimed that Cockerell had just one specimen from this region, it has clear claims to be considered it.

Synonyms:
Aviceda subcristata robusta Mayr, 1945, American Museum Novitates 1294:9.—Choiseul (38). The holotype, an adult male collected on Mount Maitombi, Choiseul Island, on 26 October 1929 by Ernst Mayr (1904‒2005) and Hannibal Hamlin (1904‒1982) during the Whitney South Sea Expedition, is held at the American Museum of Natural History, New York (AMNH 228276) (38, 20, 21). In the original description, Mayr (38) characterized this taxon as being “Similar to gurneyi, but larger; under parts, particularly of females, more heavily barred; axillaries of males always barred; under tail-coverts averaging deeper-ochraceous.” Schodde (44) synonymized robusta with gurneyi (see also ).
Aviceda subcristata proxima Mayr, 1945, American Museum Novitates 1294:10.—Bougainville (38). The holotype, an adult male collected near Kieta, on Bougainville, on 11 January 1928 by Hannibal Hamlin (1904‒1982) during the Whitney South Sea Expedition, is held at the American Museum of Natural History, New York (AMNH 220633) (38, 20, 21). Mayr (38) considered this subspecies to be “Very similar to robusta, but smaller and less heavily barred underneath, tail slightly longer.” For synonymization, see Thiollay (37).

Distribution

Endemic to the Solomon Islands, where absent only from smaller islands and Rennell (39).

Field Identification

Male has fairly narrow blackish bars below; barring even narrower in female, which also has browner upperparts (39). Subspecies gurneyi is small to medium-sized, with very little sexual dimorphism (except in tail length) and is much paler than the geographically adjacent subspecies bismarckii and coultasi, including the brown upperparts and reduced barring below (sometimes even absent) (37, 2).


SUBSPECIES

Aviceda subcristata subcristata Scientific name definitions

Systematics History

Lepidogenys subcristatus Gould, 1838, A Synopsis of the Birds of Australia, pt. 3, Plate 46 and text.—New South Wales, Australia.

Gould described and figured a female head in the description, and a similar-looking bird in the Birds of Australia account (Volume 1, Plate 25), where he noted, “All the specimens I have seen were collected either at Moreton Bay or on the banks of the Clarence." Of two Gould specimens of this species in what is now the Academy of Natural Sciences at Drexel University, Philadelphia, Stone (46) selected an adult female labeled as being from New South Wales (ANSP 2012) as the “type” [= lectotype], with ANSP 2011, also from New South Wales, thus a paralectotype. Two additional Gould specimens might also merit such a status, one in the World Museum, Liverpool (WML-VZ D332e) and the other in the Natural History Museum, Tring (NHMUK 1955.6N.20.1141; this collected by F. Strange).

Synonyms:
Baza subcristata queenslandica Mathews, 1912, Novitates Zoologicae 18:251.—Mackay, Queensland. The holotype, a female collected on an unknown date by an unknown collector (purchased by Gregory Mathews from the dealer Gerrard), is held at the American Museum of Natural History, New York (AMNH 531727) (20, 21). This subspecies was admitted by Peters (47), but synonymized by Hartert (48).
Lophastur subcristatus kempi Mathews, 1916, The Birds of Australia, Volume 5, p. 220.—Skull Creek, Cape York. The holotype, a female, collected on 22 December 1912 by Robin Kemp (1871‒1949), is held at the American Museum of Natural History, New York (AMNH 531725) (20, 21). Synonymized by Hartert (49) and then Peters (47).
Aviceda subcristata njikena Condon and Amadon, 1954, Records of the South Australian Museum 11:198.—Fitzroy River, Western Australia (50). The holotype is an adult male collected by Frederick Bulstrode Lawson Whitlock (1860‒1953) on 8 August 1924 and held at Museums Victoria, Melbourne (MV HLW 8329) (50). For synonymization, see Marchant and Higgins (51).

Distribution

Northern and eastern Australia.

Field Identification

Nominate subcristata is largest subspecies of all; it has brown to red-brown barring below and brownish upperparts (2). Size: wing length of male 305‒349 mm, wing length of female 320‒362 mm; tail length (sexes combined) 180‒230 mm (2).

Distribution of the Pacific Baza - Range Map
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Distribution of the Pacific Baza

Map last updated 13 January 2024.

Recommended Citation

Kirwan, G. M., S. Debus, and P. Pyle (2025). Pacific Baza (Aviceda subcristata), version 1.1. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, E. de Juana, and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.pacbaz1.01.1
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