Paul J. Leader

81

Bull. B.O.C. 2011 131(2)Taxonomy of the Pacific Swift
Apus pacificus Latham, 1802, complex
by Paul J. Leader
Received 26 August 2010

Summary.— This paper considers the taxonomic implications of morphologicaldifferences within the Pacific Swift

Apus pacificus complex. Specimens of thefour currently recognised subspecies (nominate, kanoi, cooki and leuconyx) were

examined, plus kurodae (currently treated as a synonym of pacificus) and salimali(currently treated as asynonym of kanoi). Consistent plumage and structuraldifferences indicate that the current taxonomy of the complex is untenable. It is

proposed that salimali is a valid taxon but that kanoi is not (and should be treatedas a junior synonym of kurodae) and that pacificus, salimali, leuconyx and cooki merit

species stahis.

Swift Apus pacificus

widely distributed, breeding from Siberia east to
Kamchatka and Japan, south through China to Vietnam, Thailand and Myanmar, andPacific

isTibet, the outer Himalayas and Assam Hills (Chantler 1999). Four subspecies are generally

recognised (Chantler& Driessens 1995, Chantler 1999, Dickinson 2003): A. p. pacificus

Latham, 1802, A. p. kanoi Yamashina, 1942, A. p. cooki Harington, 1913, and A. p. leuconyx
Blyth, 1845. This paper reviews structural amd plumage differences between these taxa
(the 'pacificus complex') based on an examination of specimen material and considers thetaxonomic implications of these differences. Comparison is made with Dark-rumped Swift
A. acuticauda where relevant.

Material and Methods

A total of 146 Apus pacificus specimens was examined at the Natural History Museum,
Tring, UK (BMNH), Museum fur Naturkunde, Berlin, Germany (ZMB), the Yamashina
Tokyo, Japan (YIO), and the Institute for Zoology, Chinese
Academy of Science, Beijing, People's Republic of China (lOZ). These specimens included
44 nominate, 47 kanoi, 24 cooki and 13 leuconyx. Twelve A. p. kurodae Domaniewski, 1933,
Institute for Ornithology,

and six A. p. salimali Lack, 1958, specimens were also examined. The former is generally
treated as a synonym of pacificus and salimali as a synonym of kanoi (Vaurie 1965, Chantler& Driessens 1995, Chantler 1999, Dickinson 2003). The holotypes of kanoi, cooki and salimali
were included in my analyses. One specimen of A. acuticauda was examined and to
supplement this, data and photographs pertaining to 18 A. acuticauda specimens were also
provided (J. Hinshaw pers. comm.).
The following measurements were taken: wing length (maximum chord), length ofthe longest and shortest tail feathers measured from the tail base (from which depth of tailfork was calculated) and distance between the tips of the two longest primaries (measured
on the closed wing). All measurements were recorded to the nearest 0.5 mm. Plumage
differences were assessed in detail, with consideration given to those attributable to age
class (adult or juvenile), specimen condition and wear. Primaries are numbered from theoutermost (pi) inwards.

Bull. B.O.C. 2011 131(2)82Paul j. Leader

Results
Plumage differences.— The key plumage differences proved to be the size of the rump
patch, extent of pale fringes on the underparts, the depth and width of the throat patch, theground colour of the underparts and upperparts, and the colour of the underwing-coverts.
I found these to vary between taxa more than is generally indicated in most of the literature(though see Rasmussen & Anderton 2005), and I found consistent plumage differences
between most of the taxa examined. These differences are summarised in Table 1.
Structural differences.— found that size and structure varied between taxa andconsider that for most taxa there exist consistent differences from other taxa for one or moreof the parameters measured (see Table 2). There was little difference with regard to the
distance between the two longest primaries, except in the case of cooki, which is discussed
below. When combined, structural and plumage differences permitted most taxa examined
to be readily differentiated.

Diagnoses.— A. p. pacificus: in plumage and structure, pacificus is very similar to both
kurodae and kanoi (Figs. 1-4). There is extensive overlap in wing length between these threefortaxa, although in pacificus the tail is longer than in kurodae or kanoi (mean 75.1
for
vs.
71.1
mm
and
72.4
kurodaeandkanoi,
respectively),
althoughvaluesforpacificus
tail fork depth were similar (mean 32.8
for pacificus vs. 29.8
and 30.4
for kurodae
and kanoi, respectively), as was relative depth of the tail fork expressed as a percentage oftail length (mean 43.3% for pacificus vs. 42.0% and 41.8% for kurodae and kanoi, respectively).
Plumage differences from kurodae and kanoi are limited to a tendency for pacificus toexhibit a cleaner, whiter throat patch and a slightly broader rump patch than kurodae andkanoi, although many kurodae and kanoi possess a rump patch comparable to that of typical

mm

mm

mm

mm

mm

pacificus.

Kurodae: for separation from pacificus, see that taxon. I found this taxon inseparable interms of both plumage and structure from kanoi, even when comparing the holotype of kanoi
to a series from Japan (Figs. 3^) (see Discussion concerning the type locality of kurodae).

Kanoi: for separation from pacificus, see that taxon. As discussed above, 1 found kanoi

and kurodae inseparable.
Salimali: whilst wing length of salimali is similar to that of pacificus, kurodae and kanoimm vs. 179.9 mm, 182.3 mm and 181.4 for pacificus, kurodae and kanoi, respectively),
distinctly longer tailed (mean 79.0 mm vs. 75.1 mm, 71.1 mm and 72.4 mm for(179.8itispacificus, kurodae and kanoi, respectively). Tail fork depth is similar in all

four taxa, and asa consequence the relative depth of the tail fork expressed as a percentage of tail lengthisnotably different, averaging 37.4% for salimali vs. 43.3%, 42.0

% and 42.0 % for pacificus,

kurodae and kanoi, respectively. The similar wing length yet longer tail results in a lower
wing-tail ratio for salimali, 2.28 vs. 2.40, 2.57

and

2.51

for pacificus, kurodae

andkanoi,

respectively.
In plumage, salimali differs notably from all taxa examined in the pattern of the throat

patch, which forms a narrow pale strip on the centre of throat and is narrowest at the basewhere it tapers to a neat point (Fig. 5). (One leuconi/x specimen was examinedwhich had been over-stretched during preparation. As a result the throat patch was ratherof the bill,elongated and superficially similar to that of salimali but this specimen was otherwise
typical of leuconyx.) The throat patch is less than half the width of other taxa. The rump
patch is consistently narrow (c.10wide) and the crown and nape are mid brown,

mmcontrasting conspicuously with the mantle which is glossy black (Fig. h). The pale tips
to the underparts are much reduced comparedtt) pacificus, kurodae and ka)ioi, and morecomparable to leuconyx in this character.

^

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Paul J. Leader

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Bull. B.O.C 2011 131(2)84Paul J. Leader

TABLE 2
Summary of key structural differences between members of the Apiis pacificus complex andclosely related taxa.

padficus

kurodaekanoisalimalikuconxjx

cooki

acuticaudn*

Wing length(mm)

Tail length

Tail fork

Wing/tail

Tail fork as(mm)

depth (mm)ratio

% of fail length

Max.

190.0

83.

42.0

2.80

51.6

Min.

170.0

64.0

25.5

2.20

37.28

Mean

179.9

75.1

32.7

2.40

43.3

SD

4.63

4.47

3.6

0.13

3.89

n

43

42

42

42

42

Max.

188.0

77.0

34.0

2.79

49.2

Min.

174.0

66.0

24.5

2.40

34.0

Mean

182.3

71.1

29.8

2.57

42.0

SD

4.54

3.4

3.3

0.12

4.86

n

12

12

11

11

11

Max.

191.5

78.5

37.5

2.85

52.3

Min.

171.5

63.50

21.0

2.34

33.1

Mean

181.4

72.4

30.4

2.51

42.0

SD

4.07

3.25

3.25

0.11

3.50

n

46

47

47

46

46

Max.

183.0

85.0

35.0

2.46

41.2

Min.

177.0

72.0

24.0

2.14

31.2

Mean

179.8

79.0

29.6

2.28

37.4

SD

2.3

4.24

4.39

0.11

4.7

It

6

6

6

6

6

Max.

170.0

73.0

27.0

2.66

39.1

Min.

151.0

61.0

16.0

2.18

25.8

Mean

161.1

67.9

23.5

2.38

34.6

SD

5.43

3.97

3.44

0.14

4.40

n

13

13

13

13

13

Max.

181.5

82.0

28.0

2.67

38.4

Min.

162.0

65.0

15.0

2.17

21.7

Mean

172.4

73.0

21.5

2.37

29.3

SD

5.05

3.99

3.32

0.12

3.7

n

18

16

17

16

16

Max.

181.6

75.1

27.2

2.79

37.8

Min.

166.3

60.2

16.2

2.27

26.9

Mean

173.4

69.1

22.2

2.57

32.2

SD

4.55

4.98

3.72

0.17

3.53

16

15

16

16

15

data for all but one specimen provided by lanet llinshaw (Museum of Zoology, University of Michigan, Ann Arbor)

Paul J. Leader

85

Bull. B.O.C. 2011 131(2)Figure 1. Ventral view of specimens of Pacific Swift Apiis p. pacificiis (Paul J. Leader / Yamashina Institutefor Ornithology)miFigure 2. Dorsal view of specimens of Pacific Swift Apus p. pacificiis (Paul J. Leader / Yamashina Instihite for
Ornithology)

Paul J. Leader

86

Bull. B.O.C. 2011 131(2)Figure 3. Ventral view of five specimens of Pacific Swift Apiis pacificus kanoi on left and type specimen of'kurodae' on right (Paul J. Leader / Yamashina Institute for Ornithology)

Figure 4. Dorsal view of five specimetis ol Pacific Swill Apii^ pacifiai^^ kmioi on lefi and type specimen ol
kurodae on right (Paul |. Leailer / Yamashina Inslilute tor Ornitlu)logy)

Paul J. Leader

87

Cooki: at 172.4

Bull. B.O.C. 2011 131(2)mm, cooki has the second shortest mean wing length after leuconyx (161.1mm) and a tail length similar to that of kurodae and kanoi (73.0 mm vs. 71.1 mm and 72.4 mm).

mm vs. 23.5 mm for leuconyx and 29.6-32.7 mm forand the shortest relative depth of the tail fork expressed as a percentage oftail length (mean 29.3% vs. 34.6% for leuconyx and 37.4^3.3% for all other taxa).
Perhaps most importantly, whilst in all other taxa the longest primary was p2 in allIt

has the shallowest tail fork (mean 21.5

all ofher taxa),

mm longer than pi; n = 19), kurodae (2.1-6.1 mm longer;
mm longer; n = 32), salimali 6-4.9 mm longer; n = 6) and leuconyx

individuals: pacificus (p2 1. 1-8.5
n = 11), kanoi (1. 0-7.4(1 -3-4.8(0.

mm longer; n =9),of 18 cooki the longest primary is pi on 13 (72%) being l.O^.O

mm longer than p2, the other five have p2 longest by 0.7-2. 3 mm, which

is at the lower

endof fhe range for the other taxa.

found cooki to be distinctive in plumage and readily separable from all other taxa

Iusing a number of criteria. The rump patch is narrow (c.lOmmwide) with conspicuous
dark shaft-streaks which typically broaden near the feather tip to form broad, club-shaped

dark marks (Fig. 8), rather than the, at most, narrow, dark shaft-streaks (usually none)of all other taxa.

The upperparts and underparts are black and very different from allother taxa, which have dark brown upper- and underparts (or in the case of salimali andleuconyx black on the upperparts is restricted to the mantle). The underparts have broad,well-defined white fringes that approach those of A. acuticauda rather than any of the taxa
in the pacificus complex (Fig. 8). The throat patch is off-white with well-defined black shaft-streaks (more pronounced than in other taxa) and extends onto the upper breast (Fig. 9). The

upperparts possess an extensive green iridescence and often show narrow white fringes tothe scapulars in fresh plumage. Finally, the underwing-coverts are black and contrast withthe rest of the underwing, whereas in all other taxa the underwing-coverts are dark brownand hence similar to the rest of the underwing.
should be noted that the holotype is a very worn breeding adult (collected 2 June
1912) and that the rest of a series at BMNH from the type locality (Gokteik Caves, easternIt

Myanmar) are juveniles lacking fully grown wings. As such they appear, superficially atleast, smaller,

duller and browner (especially the juveniles) than specimens of cooki from

elsewhere. Flowever, they all share a comparable rump patch size and patterning with othercooki specimens, and the adult, once the effects of wear are considered, is comparable withother cooki specimens I have examined.

mmvs.
Leuconyx: much the smallest of fhe taxa examined; mean wing length is 161.1
to 182.3 for all other taxa. Mean wing length is closest to that of cooki, from which
172.4

mm

it

differs notably in other respects, especiallylength is also shortest; 67.9

plumage (see cooki for defails). Mean tailmm vs. 72.4-79.0 mm inall other taxa.

In plumage leuconyx is most similar to salimali in that the rump patch is consistently

narrow (c.lO mm wide) and the crown and nape are mid brown and contrast conspicuouslywith the mantle, which is glossy black (Fig. 10). However, the throat patch pattern isdistinctly different, being broad (covering the entire throat), off-white with fine dark shaft
streaks, while the lower border is ill-defined and typically extends onto the upper breast

with some mottling within the throat patch, especially at the sides and towards the lower
border (Fig. 9). The upper breast is mid brown, paler than in other taxa, becoming darker
over the lower breast and the rest of the underparts.

Distribution and breeding ecology
Pacificus breeds from Siberia east to Kamchatka and northern Japan, south to northernin Japan and nests on cliff faces and in caves,
China. It breeds from sea level to 3,000m

and on buildings. It is primarily a long to very long-distance migrant, with birds wintering

Bull. B.O.C. 2011 131(2)LeaderPaul

Right, top to bottom;

Figure 5. Ventral view of specimens of Salim All's
The Natural

Swift Apiis salimali (Paul J. Leader /©

History Museum, Tring)

Figure 6. Dorsal view of specimens of Salim All's
The Natural

Swift Apiis salimali (Paul J. Leader /©

History Museum, Tring)

FigureVentral view of specimens of Cook's
The Natural

7.

Swift Apus cooki (Paul J. Leader /©

History Museum, Tring)inIndonesia, Melanesia, Australia

andTasmania.
Kurodae and its junior synonym kanoi(see below) breed across much of eastern

China, southern Japan and Taiwan. In

China,

breedsitcommonlyineasternbut

its

statusGuangdongprovince,further west

isresearch

additional

demands

unclear and(particularlyinwestern Guangdong and eastern Guangxi
with regard to the distribution of cooki).

have examined one kauoi specimen at
ZMB collected on 15 May 1929 at Yao
Shan, Guangxi, which was perhaps a local
breeder. It nests on cliff faces, includingI

and in caves, andwinters in Malaysia, the Philippines andsea cliffs (Lack 1956a)

Indonesia.
Salimali breeds at very high altitudes(above 3,400 m) andiseast Tibetan Plateau

and adjacent high-altitude western

restricted to the

Sichuan.

Ithabituallynests on buildings, perhaps most famously
inthe Potala Palace,

distributionisLhasa.

Its

winterapparently unknown but,at the very least,itmust be an altitudinalmigrant.

Cooki

is

restrictedtolowlandMyanmar, northern Thailand, Vietnam
and Guangxi province, China. Based on
the available information,

the

taxon

is

restricted as a breeder to limestone caves(Smythies

1986,

Wells

1999,

Ngonjun& SitasLiwan 2001; P. D. Round2009) anditmember

of

/;;

lilt.

appears that this is the only
the pacificus

complexthat

habitually breeds in limestone habitat.s,

although this n*i|uires confirmation.

It

isPaul J. Leader

89

Right, top to bottom:

Figure 8. Dorsal view of specimens of Cook's
Swift Apus cooki (Paul J. Leader /The Natural©

History Museum, Tring)
Figure 9. Ventral view of specimens of Blyth's
Swift Apus leuconyx (Paul J. Leader /TheNatural History Museum, Tring)©

Figure 10. Dorsal view of specimens of Blyth's
Swift Apus leuconyx (Paul J. Leader /TheNatural History Museum, Tring)©

a short-distance migrant or near-resident

andhave examined winter-collected
specimens from Laos (November— YIO),
Vietnam (January— BMNH), Cambodia
I(January — BMNH),

thenorthern Shan

States, Myanmar (January— BMNH), andthere are two February Thai specimens (P.

D. Round in litt. 2009).

Leuconyx

is

a

mid

to

high-altitude

breeder, occurring at 1,300-3,800

m in

Bhutan and northeast India. Presumably facilitated by its
Pakistan,

Nepal,

smaller size, this is the only member ofthe pacificus

complex recorded

utilising

the nests of other birds, including thoseof hirundines (Lack 1956b). It is resident

or partially migratory, wintering at lower
altitudes

in

Nepal (Inskipp& Inskipp1985) and peninsular India (Vaurie 1965).

There is much variation in the timing
the breeding between

of

taxa,

which

is

the

variousunsurprising given thelarge range of the pacificus complex

themarkeddifferences

in

and

migratory

behaviour. The southernmost taxon cooki
isgenerally on eggs in Myanmar in May(Smythies 1986) or even early March innorthern Thailand (Ngonjun & Sitasuwan
2001) while leuconyx breeds March-May
in Nepal (Chantler 1999). However, most
pacificus are just returning to the breeding

grounds in May, with breeding in someareascommencing in June (Brazil 1991,

Chantler & Driessens 1995).

Bull. B.O.C. 2011 131(2)Bull. B.O.C. 2011 131(2)90Paul J. Leader

pad ficus
UkurodaeA kauoi

Figure 11. Scatter plot of wing and tail lengths (in mm) of pacificits, kurodae and kanoi.

Discussion
Based upon a combination of plumage and structure, I found each specimen of salimali,

and leuconyx to be readily separable, and that pacificus, kanoi ancd kurodae whilst
separable from the other taxa were very similar to each other. Both kurodae and kauoi areseparable from pacificus when compared as a series on the basis of the cleaner, white throat
patch and broader rump patch of pacificus, but there is substantial overlap in the size ofthe rump patch in these three taxa. I compared the holotype of kanoi to a series of kurodae
from Japan and found them to be inseparable, being unable to detect any of the differences(darker body, stronger greenish gloss, narrower throat patch and rump patch) identified by
Yamashina (1942). The type locality of kurodae is stated to be 'japan' although the holotype
was apparently lost during World War II (Mlikovsky 2007), making a comparison of theholotypes of kanoi and kurodae impossible. In size (wing and tail length) there is overlap
between all three, but with most overlap between kurodae and kanoi and a very clear

cooki

tendency for larger individuals to be pacificus (Fig. 11). Vaurie (1959, 1965) considered kajioi
separable from pmcificus based on differences in the upperparts and possibly the throat ('thewhite area of the throat is usually more restricted and less pure'), a feature which 1 foundHowever, given that Vaurie (1959,1965) treated salimali as a synonym of kanoi and examined specimens that included material

differentiated salimali from pacificus (and other taxa).

from within the range of salimali but not, apparently, the type of kanoi 1 find his diagnosisof kanoi and treatment of salimali unconvincing.

Based upon these findings, rather than treat kurodae as a synonym of pacificus
kurodae and kanoi to be synonyms, and as
precedence.

it

1

considerpredates kanoi by nine years, kurodae has

Despite frequently being treated as a junior synonym of kanoi (Vaurie 1959, 1965,
Chantler 1995, 1999, Dickinson 2003), found salimali to be a highly diagnosable taxon, with1

allindividuals examined separable from all other taxa, including pacificus, in both structure

and plumage. As noted above. Lack (1959, 1965) and Vaurie (1959) differed in their treatmentof salimali, despite considering the same five specimens atcollected in south-east

BMNH

Tibet.

1also examined these five specimens, plus a further specimen frtim Sichuan at RfZ.

Paul J. Leader

91

Bull. B.O.C. 2011 131(2)Lack (1958), in describing salimali, noted that the specimens were very similar to leuconyx
in plumage but differed in being larger, however he did not make mention of the distinctly
different throat pattern. Vaurie (1959, 1965) attached greater significance to the similar
size of salimali to kanoi, but as discussed above, based on an examination of the holotypesof both taxa, I find his conclusion that salimali and kanoi are similar in terms of plumage

unconvincing. It should also be noted that Vaurie (1959, 1965) used only wing length toassess size, and did not consider differences in tail length or tail structure. As demonstrated
above, these are also important in the diagnosis of salimali.

noteworthy that Deignan (1956) considered 17 specimens from western Sichuancollected during July, August and October inseparable from a series of nine kanoi collectedon the Batanes Islands, in the northern Philippines, and a further specimen from Fujian
province, China. These Sichuan specimens may be salimali, which was described in thesame year and of which Deignan was probably unaware at the time (his manuscript
It is

was submitted in April 1955), or they could indeed be kanoi, which may breed at lower
altitudes in the region, although this scenario seems unlikely given that western Sichuan isgenerally much higher than other parts of the province. It should be noted that his Augustand October specimens are almost certainly migrants. Unfortunately, Deignan (1956) does
not state in which collection(s) his Sichuan specimens are housed, as they clearly merit
re-examination. Ali & Ripley (1970) somewhat surprisingly and without explanation,
treated birds in south-east Tibet as kanoi, noting breeding in the Tsango Po Valley, which is
the type locality of salimali (Lack 1958).

Of the taxa examined, cooki is by far the most distinctive in plumage, and has a distinctly
different wing structure. The glossy black plumage and heavier rump patch streaking led
Lack (1956b) to remark that cooki resembles Dark-rumped Swift A. acuticauda more that it
resembles pacificus, and considered that 'cooki completely bridges the [morphological] gap'
between pacificus and acuticauda. This formed a large part of his argument that acuticauda
should be treated as a subspecies of pacificus. Lack (1956b) noted the distinct wing structureof cooki, and commented: 'In some other species of Apus, as mentioned later, the difference
between the first and second primary is a valuable aid in the determination of species, but
in A. pacificus it varies within the species'. Vaurie (1959), by contrast, was unequivocal in his
treatment of acuticauda as a valid species citing the all dark rump and distinct differences
in tail feather shape (with acuticauda having highly attenuated outer tail feathers), andthe close proximity (50 km) to breeding acuticauda and the nearest breeding leuconyx asevidence, but did not comment on differences in wing structure; his treatment of acuticauda
has been widely adopted since.
Like Lack (1956b), I consider cooki to resemble acuticauda more than other members of
the pacificus complex, being black above and below, and in the very broad white fringes tothe underparts. It is also very similar in overall structure (Table 2) to acuticauda, to which
it may prove to be more closely related. It should be noted that most data for acuticaudapresented in Table 2 were not collected by the author, and as such I am reluctant to discuss
the relationship between cooki and acuticauda in more detail. However, I consider it to beplausible that both taxa are not members of the pacificus complex (which may only comprisenominate pacificus, kurodae, salimali and leuconyx), and that the pacificus complex as currently

recognised may be polyphyletic.

Conclusions
Given that Apus swifts are profoundly adapted to an aerial existence, it has been argued
elsewhere (e.g. Brooke 1971) that consistent structural differences between apparently
closely related taxa are of taxonomic significance (e.g. Fry et al. 1988). Such an approachBull. B.O.C. 2011 131(2)92Paul J. Leader

has led to a substantial revision of the genus Apus (primarily within the dark-rumped
African taxa). Of the 17 species currently recognised by Gill & Donsker (2010), Lack (1956b)

recognised just seven (Lack recognised ten species in the genus, but three of these are nolonger placed in Apus by Gill & Donsker 2010).

There has been no systematic review of the pacificus complex since Lack (1956b) and
Vaurie (1965), and based on my findings above I consider it clear that structural differencesthat have subsequently led to extensive taxonomic revision of congenerics are also evident
in the pacificus

complex. The taxonomic importance of these structural differencesisfurther supported by consistent plumage differences, as well as by differences in migration
strategies and breeding ecology.

When both measurements and plumages are assessed, pacificus, salimali, cooki andleuconyx all satisfy the diagnosibility requirements of the Phylogenetic Species Concept.

Concept (BSC)
is problematic given that all four possess allopatric breeding ranges. However, it could
be argued that the marked differences in the timing and altitude of breeding, migration
strategy and, in the case of cooki, breeding habitat are effective isolating mechanisms andthat some members of the pacificus complex meet the requirements of the BSC (perhaps mostrobustly in respect of cooki). Molecular studies and research into potential vocal differences(a review of a small number of recordings suggests clear differences between taxa) could
further the taxonomic status of these taxa. I consider the present taxonomic arrangement of
the pacificus complex untenable and that the complex is best treated as four separate species.
Accordingly, propose the following taxonomic treatment:

Satisfying the non-interbreeding requirement of the Biological Species

1

Pacific Swift Apus pacificus Latham, 1801

subspecies kiirodae Domaniewski, 1933

Salim Ali's Swift Apus salimali Lack, 1958
Blyth's Swift Apus leuconyx Blyth, 1845

Cook's Swift Apus cooki Harington, 1913

The English names chosen recognise the predominately far easterly distribution of
pacificus (including kanoi) and avoid further use of the name 'Fork-tailed Swift' which 1
consider to be a distinctly inappropriate name given the structural characteristics of mostmembers of the genus. With the exception of pacificus, I have shied away from geographicalmonikers, to avoid introducing the potentially confusing name Himalayan Swift for
leuconyx (vs. Himalayan Swiftlet Collocalia brevirostris) and to commemorate some 'giants'of Asian ornithology.

Acknowledgements
Yoshimitsu Shigeta (YIO), Fu Min-Lei (lOZ), Robert Prys-Jones and Mark Adams (BMNH), and Sylke
Frahnert (ZMB) kindly permitted access to specimens in these collections. Yoshimitsu Shigeta and Peter
Kennerley assisted in tracing references, and Philip Round provided valuable information, including
photographs and measurements of Thai cooki specimens and on the status of the complex in Thailand. Janet

Hinshaw was especially helpful in providing measurements and photographs of A. naitiaiuda specimens at
the Museum of Zoology, University of Michigan, Ann Arbor, anci also provided useful references. Michael
Leven proffered helpful comments on the draft pre-submission. Finally,
David Wells whose comments greatly improved the quality of this paper.

1

thank Pamela Rasmussen andReferences:&Ali, S.
Ripley, S. D. 1970. Handbook of the birds of India and Pakistan, vol. 4. (Oxford
Brazil, M. A. 1991. The birdsof Japan. Christopher Helm, London.

Brooke, R. K. 1971. Geographical variation
Novit. 9(7): 93-103.

in the Little

Univ. Pres.s, New Delhi.

Swift Afws affinis (Aves: Apodidae). Durban Mus.

Paul J. Leader

93

Bull. B.O.C. 2011 131(2)Chantler, P. 1999. Family Apodidae (swifts). Pp. 388-157 in del Hoyo,
J., Elliott, A. & Sargatal, J. (eds.)
Handbook of the birds of the world, vol. 5. Lynx Edicions, Barcelona.
Chantler, P & Driessens, G. 1995. Swifts: a guide to the swifts and treeswifts of the world. Pica Press, Robertsbridge.
.

Dickinson, E. C. (ed.) 2003. The Howard and Moore complete checklist of the birds of the world. Third edn.
Christopher Helm, London.

Deignan, H. G. 1956. Eastern races of the White-rumped Swift, Apus pacificus (Latham). Bull. Raffles Mus. TJ-.
147-149.

& Urban, E. K. (eds.) 1988. The birds of Africa, vol. 3. Academic Press, London.
& Donsker, D. (eds.) 2010. IOC world bird names (version 2.5). http://www.worldbirdnames.org/

Fry, C. H., Keith, S.
Gill, F.

(accessed September 2010).
Inskipp, C. & Inskipp, T. 1991. A guide to the birds of Nepal. Christopher Helm, London.

Lack, D. 1956a. A review of the genera and the nesting habits of swifts. Auk 73: 1-32.
Lack, D. 1956b. The species of Apus. Ibis 98: 34-61.
Lack, D. 1958.

A new race of the White-rumped Swift.

/.

Bombay Nat. Hist. Soc. 55: 160-161.

Mlikovsky, J. 2007. Types of birds in the collections of the Museum and Institute of Zoology, Polish Academyof Sciences, Warszawa, Poland. Part 2: Asian birds. /. Natl. Mus. (Prague), Nat. Hist. Ser. 176(4): 33-79.
Ngonjun, P. & Sitasuwan, N. 2001. [Breeding behaviour and post-hatching development of Apus pacificus]. ].
Wildl. Hiailand 9(1): 18-22. [in Thai.]

Rasmussen, P. C. & Anderton, J. C. 2005. Birds of south Asia: the Ripley guide, vol. 2. Smithsonian Institution,
Washington DC & Lynx Edicions, Barcelona.
Smythies, B. E. 1986. The birds of Burma. Nimrod Press, Liss & Silvio Mattacchione, Pickering, ON.
Vaurie, C. 1959. Systematic notes on Palearctic birds. No. 38 Alcedinidae, Meropidae, Upupidae, andApodidae. Amer. Mus. Novit. 1971: 1-20.
Vaurie, C. 1965. The birds of the Palearctic fauna. Non-Passeriformes. H. F. & G. Witherby, London.
Wells, D. R. 1999. The birds of the Thai-Malay Peninsula, vol. 1. Academic Press, London.
Yamashina, Y. 1942. On a new subspecies of Micropus pacificus residing in Formosa and Botal Tobago. Bull.
Biogeogr. Soc. Japan 12: 79-80.

Address: c/o Asia Ecological Consultants Ltd., 127 Commercial Centre, Palm Springs, New Territories, Hong

Kong, People's Republic of China, e-mail: pjleader@asiaecol.com.hk© British Ornithologists' Club 2011