AUSTRALIAN 2 FIeLd ORNIThOLOgy OLSeN, TROST & MyeRS

AUSTRALIAN2 FIeLd ORNIThOLOgy AUSTRALIAN 2 OLSeN, TROST & MyeRS FIeLd ORNIThOLOgy

Ninox owls on the island of Sumba, Indonesia: Above — Sumba Boobook near Wanga,Below — Little Sumba Hawk-Owl near Lewa

Plate 2 Photos: J. Olsen & S. Trost

3

AUSTRALIAN FIeLd ORNIThOLOgy 2009, 26, 2–14

Owls on the Island of Sumba, Indonesia

JeRRy OLSeN1, SUSAN TROST2 and SUSAN d. MyeRS3

1Institute for Applied ecology, University of Canberra, Canberra, Australian Capital Territory 2601

244 Wybalena grove, Cook, Australian Capital Territory 2614317A Park Street, hawthorn, Victoria 3122

Summary

Four owl species are said occur on the island of Sumba, Indonesia: eastern Barn Owl Tyto javanica sumbaensis, eastern grass Owl T. longimembris, Sumba Boobook Ninox rudolfi, and the recently discovered Little Sumba hawk-Owl N. sumbaensis. We describe behaviour, including vocalisations, of all except the eastern grass Owl, provide measurements of eastern Barn Owl and Sumba Boobook specimens, including the first published weights, and the first egg measurements for eastern Barn Owls on Sumba. We discuss the taxonomy of the eastern Barn Owl and Sumba Boobook, and support a change of common name for Sumba Boobook to Sumba hawk-Owl. Studies are urgently needed to determine the status and conservation of all four owl species said to occur on Sumba.

Introduction

The island of Sumba lies at 10°S and 120°e in the Lesser Sunda chain in south-eastern Indonesia (see Olsen & Trost 2007 for a description). del hoyo et al. (1999) listed three owls for Sumba. We add the recently discovered Little Sumba hawk-Owl Ninox sumbaensis (Olsen, Wink et al. 2002) to Table 1.

Much of what has been written about the owls on Sumba has been material repeated from previous sources, with no new observations. here we add new observations and discuss these in relation to published sources. Wink et al. (2008) noted that morphology is often invariant in many owl species, but their distinctive calls, which are inherited and not learned, are of considerable taxonomic value, so we recorded calls of three Ninox species (two on Sumba and, for comparison, one in Australia) and discuss the relevance of these.

Methods

On three trips to the island (July 2001, december 2001–January 2002 and June–July 2002) JO and ST concentrated on finding and photographing the Sumba Boobook Ninox rudolfi and the newly described Little Sumba hawk-Owl (Olsen, Wink et al. 2002) at two

Table 1

Owls recorded on Sumba, Indonesia, after del Hoyo et al. (1999) and Olsen, Wink et al. (2002), using the most recent taxonomy of Christidis & Boles (2008). *Endemic species.

eastern Barn Owl Tyto javanica sumbaensis

eastern grass Owl Tyto longimembris

Sumba Boobook Ninox rudolfi*

Little Sumba hawk-Owl Ninox sumbaensis*


places: (1) in an inland forest ~600 m above sea level near Lewa, 49 km west of the main town of Waingapu (9°44′42″S, 119°59′6″e), and (2) in coastal lowland at Wanga near Melolo 42 km east of Waingapu (9°51′53.6″S, 120°37′57″e) in a deciduous and mangrove forest close to the ocean. No specific attempts were made to find other species, although we did look for eastern Barn Owls Tyto javanica sumbaensis in three church buildings in the town of Waingapu (9°39′27″S, 120°15′39″e) and in a limestone canyon south of Waingapu (9°47′24″S, 120°18′57″e). We also noted the date and location of any owls seen or heard along the road. Calls and behaviour of all owls were noted. Playback of taped territorial calls of the Sumba Boobook and Little Sumba hawk-Owl (provided by M. Linsley) and Southern Boobook Ninox novaeseelandiae (recorded by JO and ST in Canberra, ACT) were broadcast to elicit responses from owls. Moulted feathers found by JO at a church at Waingapu, and at an abandoned pump-house at Wanga, presumed to be from Barn Owls, were sent to Michael Wink, University of heidelberg, heidelberg, germany, for genetic analysis (dNA profiling).

Buildings and trees were searched for nests in Waingapu and Wanga, but only one, a deserted nest of a Barn Owl in an abandoned building at Wanga, was found; both intact eggs were measured with callipers. On Sumba, men and boys often kill birds and bats with air rifles and shanghais. We never encouraged this activity, but a specimen of a Barn Owl and of a Sumba Boobook previously killed were located and weighed with a Pesola spring balance and measured with callipers.

Following the Biological Species Concept, König et al. (1999) regarded as full species the members of a reproductive community that have evolved different patterns from members of another reproductive community. Often with owls these patterns are most easily perceptible in their vocalisations. Owls’ vocalisations are inherited and, unlike some passerines, have little geographic variation in dialect, so they are diagnostic of species and critical to the study of owl taxonomy (higgins 1999; König et al. 1999). For a mean 140 minutes per night JO and ST observed and video/audio-recorded episodes of calling with a Panasonic NV-MX300 digital video-camera (a) three different calling pairs of Little Sumba hawk-Owls over five nights near marker Km 49, and (b) four different calling pairs of Sumba Boobooks at four different locations over 13 nights: three pairs near Melolo, and one pair near Km 49 in the same forest as the hawk-Owls, calling at the same time as, and within 50 m of, a pair of them. The calls of each owl species were digitised from a Panasonic NV-MX300 digital videotape with an IBM microcomputer and were sampled at 44.1 khz. Cool edit Pro (version 1.2) was used to produce sonagrams.

SdM made recordings of a single Little Sumba hawk-Owl (one of a pair in a remnant patch of forest) and a single Sumba Boobook (at the edge of forest), with a Marantz PMd660 solid-state recorder with Sennheiser K6 microphone, at marker Km 51 ~3 km east of Lewa on the Lewa–Waingapu road, on 4 and 3 August 2007, respectively. Sonagrams were generated using Raven.

Results

Eastern Barn Owl Tyto javanica sumbaensis

Calls: adults gave a rasping call typical of Common Barn Owls T. alba (Bunn et al. 1982). A juvenile in a limestone canyon 15 km south of Waingapu gave a rasping food-begging whine typical of the eastern Barn Owl (as described by higgins 1999).

We saw eastern Barn Owls on the following occasions.11–12 July 2001, 1845 h, Waingapu Lutheran Church: two individuals perched in the church tower (Plate 3). Moulted feathers, collected from the beams and inside the church tower under these two individuals, were sent for dNA analysis (see p. 6).

14 July 2001, 1930 h, along road 57 km west of Waingapu and 1 km east of Lewa: two eastern Barn Owls were observed for 10 minutes in the middle of a rice field, perched in low trees.

VOL. 26 (1–2) MARCh–JUNe 2009 Owls of Sumba, Indonesia 5

Eastern Barn Owl, tower of Lutheran Church, Waingapu, Sumba, IndonesiaPlate 3 Photo: J. Olsen & S. Trost

Eastern Barn Owl eggs from nest in the attic of an abandoned pump-house near Wanga, Sumba, Indonesia

Plate 4 Photo: J. Olsen & S. Trost


15 July 2001, 1825 h, rice field 15 km west of Melolo: one eastern Barn Owl observed for 5 minutes, screeching, sitting in a tree on the edge of cleared field.

18 July 2001, 1829 h, 15 km south of Waingapu: an apparent fledgling, in a limestone canyon sunk into the plain with dry forest above it, heard food-begging (screeching), apparently from a pothole in the rocks.

28 december 2001, Wanga, 1906 h: an eastern Barn Owl landed in the top of dead tree in farmland (rice and cattle) 100 m away from a Sumba Boobook calling from a tree; no interaction was seen between the two owls.

24 June 2002, 1600 h, near Wanga: an old nest was found in the attic of an abandoned brick-walled building formerly housing a water-pump. Three white eggs, and primary feathers, assumed to be from the incubating female, were resting on debris, castings, rotting wood and other materials. One egg was broken; the two intact eggs measured 41.9 × 32.9 and 41.1 × 33.4 mm (Plate 4).

1 July 2002, 1600 h: a freshly dead eastern Barn Owl was found on the road between Waingapu and Lewa. Measurements (mm) were: wing 275, tail 107.4, mid-toe with talon 33.6, mid-toe talon 12.8, inner talon 16.1, hind talon 18.6, culmen without cere 23.0; wing-formula 9/8/10/7 from the outside; and weight 385 g.

eastern Barn Owls were the commonest owl seen along roads at night on Sumba. Some could have been misidentified eastern grass Owls Tyto longimembris, though most were close enough to identify unequivocally as Barn Owls. Twice we saw an eastern Barn Owl on farmland close to Sumba Boobooks, with no apparent conflict. examination of prey remains of eastern Barn Owls living in Waingapu suggested that the most common prey items were rats (Muridae), fruit-bats (Pteropodidae), and eurasian Tree Sparrows Passer montanus. Wink et al. (2004, 2008) concluded that moulted feathers from the Wanga and Waingapu individuals were genetically distant enough from the Common Barn Owl to constitute a possible separate species. Recordings of calls were not of high enough quality for analysis.

Eastern Grass Owl Tyto longimembris

No calls were recorded. The following observation was made.2 July 2002: one eastern grass Owl seen flying over the road between Waingapu and Melolo, identifiable by the long tarsi extending well beyond the tail-tip.

The status of the eastern grass Owl on Sumba is unclear. König et al. (1999) and higgins (1999) did not list the grass Owl for Sumba, contra del hoyo et al. (1999) and Coates & Bishop (1997), who said that it is a rare and local, probably resident species in the Lesser Sundas including Sumba. Jones et al. (1994) saw a single eastern grass Owl during the day in grassland near Melolo ~22 km from Waingapu; this bird, and the one in the present study, are the only published records of this species on Sumba.

Sumba Boobook Ninox rudolfi

Calls: the four different calls heard given by Sumba Boobooks are described in detail here.

1. Territorial Call: the main call given in response to playback of the Sumba Boobook territorial call was a cluck-cluck-cluck, or tok-tok-tok, like a laying hen, the notes repeated about 2.3 times per second (Figure 1a). It was never disyllabic, in contrast with the Southern Boobook of Australia which utters couplets about once every 3 seconds (higgins 1999) (Figure 1 b). On the sonagram of the territorial


Figure 1. Sonagrams from video taken with a Panasonic NV-MX300 digital video-camera of (a) Sumba Boobook Ninox rudolfi, near Melolo, Sumba, Indonesia, on 28 December 2001, (b) Southern Boobook N. novaeseelandiae (recorded by J. Olsen and S. Trost in Canberra, ACT, November 2003) and (c) Little Sumba Hawk-Owl N. sumbaensis (two, i.e. male and female of a pair, of six adults observed in forest south of marker Km 49 from Waingapu on the Lewa road, Sumba, on 2 January 2002, recorded by J. Olsen and S. Trost after owls responded to playback).


clucking call obtained by SdM (Figure 2a), each note lasted <0.1 second and was at ~0.8 khz, delivered at a rate of ~3 notes/second.

2. Bray Call: a food-begging call to the male. This was similar to the Bray Call of a female Southern Boobook food-begging from her mate (Olsen et al. 2002b).

3. Gobble Call: the male and female of a pair gave bursts of gobble-like calls reminiscent of a pair of domestic Turkeys Meleagris gallopavo, perhaps equivalent to the croak (por) calls of Southern Boobooks given during courtship or in duels with neighbours (see Olsen et al. 2002a).

4. Monkey Call: the male and female of a pair, or perhaps antagonists that were assumed to be on territorial boundaries, also made chuckling, squealing, monkey-like calls, perhaps a variation of the gobble Call. Locals believed that these calls were made by troops of monkeys, not owls, but we followed individual owls and determined that the calls were indeed given by Sumba Boobooks.

Sumba Boobooks were observed mainly at the edges of forest and mangroves at the two places that we repeatedly visited: (1) near Wanga 42 km east of Waingapu, at three sites (a) Small Farm, on the eastern edge of the forest, (b) Large Farm, ~2 km from Small Farm on the western edge of the forest, and (c) in mangroves along the ocean beach ~1 km north of Large Farm; and (2) near Lewa, 49 km west of Waingapu, in a degraded patch of forest that also contained hawk-Owls. Sumba Boobooks were seen and/or heard on 16 nights (15 and 17 July, 16, 21, 23–24, 27–31 december 2001; 1–2 January, 24, 28 June, and 1 July 2002). They were not confined to forest: they readily flew across open areas, and perched in single trees in open areas.

Figure 2. Sonagrams of recordings made with a Marantz PMD660 solid-state recorder and Sennheiser K6 microphone of (a) one Sumba Boobook Ninox rudolfi, and (b) one of two Little Sumba Hawk-Owls N. sumbaensis, both observed in forest at marker Km 51 from Waingapu on the Lewa road, Sumba, on 3–4 August 2007, recorded by S.D. Myers.


A Sumba Boobook shot by hunters on 2 July 2002 had the following measurements (mm): wing 231, tail 133, culmen without cere 16.0, culmen with cere 26.2, facial bristles 21.1, mid-toe 22.5, mid-toe with talon 30.9, tarsus without tarsal joint 39.2. Wing-formula was 7=8>9=6>10=5 from the outside, with no moult; body length was ~320 mm; and the owl weighed 222 g. Photographs and video of Sumba Boobooks showed dark-brown irides (Plates 2, 5), as stated by König et al. (1999), but contra Olsen (1999) who suggested that Sumba Boobooks have yellow irides.

We recorded no disyllabic call from Sumba Boobooks, unlike calls known from Australian Ninox owls, and they did not respond to playback of a Southern Boobook, which suggests some taxonomic distance from Australian Ninox owls.

Local people said the territorial tok-tok-tok calls of Sumba Boobooks increased in frequency in december before the Wet, before pigs moved into certain swampy areas near Wanga, so they called Sumba Boobooks Katuawe, which means ‘leader of the pigs’. We saw no dependent juvenile owls, but if the Bray Calls were from food-begging females, Sumba Boobooks may initiate some breeding in december–January with the beginning of the wet season. however, Jones et al. (1995) saw a possible nest in August 1992.

We observed Sumba Boobooks living in the same area with, and flying and perching in view of, eastern Barn Owls, and in the same area with Little Sumba hawk-Owls, with no apparent conflict. Sometimes Sumba Boobooks at Wanga or marker Km 49 stopped calling when the territorial tok-tok-tok call was played, and did not start calling again for the duration of our visit, or did not respond to any playback on certain nights.

Sumba Boobook near Wanga, Sumba, IndonesiaPlate 5 Photo: J. Olsen & S. Trost


Assuming that within an owl species individuals with deeper calls are males (Marks et al. 1999), the slightly larger Sumba Boobook, with calls deeper than its mate’s, which was videoed on 28 december 2001, was probably a male. If so, males may be about the same size as or slightly larger than females, as suggested by König et al. (1999), but contra Olsen (1999).

Little Sumba Hawk-Owl Ninox sumbaensis

Calls: the main call was a single note, a monosyllabic hoot repeated about every 2.5 seconds (Figure 1c). This appeared to be the species’ territorial call. A fledged juvenile made a churring insect-like call, similar to the call of a fledged Southern Boobook. No disyllabic calls were heard.

Little Sumba hawk-Owls were observed by JO and ST in only one location: the small, degraded forest patch near Lewa at marker Km 49 on the Waingapu–Waikabubak Road (9°44′42″S, 119°59′6″e) (Plates 2, 6). Although playback of Little Sumba hawk-Owl vocalisations was used on six occasions at other locations near Wanga, Melolo and Waingapu, no owls responded. The three pairs near marker Km 49 were always present, and always responded to playback. They were seen on six nights (20, 23–24, 27 december 2001; 2 January 2002; 1 July 2002).

On 24 december 2001 a fledged juvenile was observed with two adults. The juvenile was more rufous in colour than the adults, and used ‘head-winding’ when it watched insects gathered in the torch beam. Its only call was a ‘churr’ as if food-begging, like the food-begging call of juvenile Southern Boobooks but deeper. each member of the family moved around independently in the forest. Twice, one

Little Sumba Hawk-Owls near Lewa, Sumba, IndonesiaPlate 6 Photo: J. Olsen & S. Trost


adult flew and caught insects in the canopy, but did not feed the juvenile despite the food-begging calls. Villagers living near the forest said that they had seen two ‘red’ baby owls on the ground in the previous month, late November 2001.

The sonagram of the territorial hooting call obtained by SdM (Figure 2b) shows a monotonous, repeated single-note call of ~0.53–0.65 khz, each note slightly rising in frequency and lasting ~0.35 second, uttered at a rate of one call per 5 seconds. given the location, the owls observed may have been two of the six individuals observed previously by JO and ST, or hawk-Owls occupying one of those same territories.

Discussion

Eastern Barn Owl

Molecular analysis of taxa in the Barn Owl complex by Wink et al. (2004, 2008), including feathers from Sumba (sumbaensis), put the barn owls from Sumba into the same species as eastern Barn Owls from Australia, recognised as a full species separate from Tyto alba. however, Wink et al. remarked that subspecies sumbaensis is distant enough from the others to probably merit species status. In contrast, Christidis & Boles (2008), following Wink et al. (2004), considered all barn owls from southern Asia through Australia and the Pacific to be one species, T. javanica (gmelin 1788), with the common name eastern Barn Owl, although alternative common english names, they said, should be considered. Measurements of the eastern Barn Owl on Sumba fit within those measurements for T.a. delicatula (now T. javanica delicatula) given by König et al. 1999 (wing 247–294 mm, tail ~119 mm, and weight 230–470 g) and for T.a. delicatula by higgins (1999), but further analysis is needed before the taxon on Sumba is treated either as a separate species or a subspecies of T. javanica.

As with barn owls elsewhere in the world, the individuals observed on Sumba roosted and nested in buildings, but also utilised the shelter of limestone rock-faces, a common feature on the island.

Eastern Grass Owl

Little is known about this species and its status on Sumba. There is no specimen from Sumba to confirm its taxonomic identity, so it has not been confirmed that the owl reported by Jones et al. (1994), and the one seen by us, were not a new species of Tyto, rather than eastern grass Owls. however, the eastern grass Owl occurs elsewhere in Wallacea (Sulawesi and Flores: König et al. 1999), and it has been found recently in Borneo (Biun et al. 2006), so its presence in the Lesser Sundas may be expected. Further study is needed.

Sumba Boobook

The tok-tok-tok call appeared to be the main territorial call, whereas all Australian Ninox species have a disyllabic territorial call (higgins 1999). Southern Boobooks near Canberra (Olsen et al. 2002b) never used Monkey or gobble Calls like those uttered by the Sumba Boobook, although some made squeals that could serve the same function. Southern Boobooks use a boo-book call in place of the tok-tok-tok call used by Sumba Boobooks (Figure 1).


Southern Boobooks are said to occur on the nearby island of Savu (= Sawoe; higgins 1999), but they are probably not close relatives of the Sumba Boobook (Wink et al. 2008). Sumba Boobooks did not respond to playback of the territorial call of the Southern Boobook recorded in Canberra, but they did respond to playback of Little Sumba hawk-Owls, suggesting that an owl may be more likely to respond to playback of a species taxonomically or regionally close to it.

There is disagreement in the literature as to whether the male or female Sumba Boobook is the larger bird: Olsen (1999) claimed that females were larger, whereas König et al. (1999) claimed that males were larger. In the present study, where both male and female were sitting and calling together near Wanga, the slightly larger bird of a pair gave a deeper call. Although some have argued that in the Southern Boobook the female has the deeper call, this is unlikely because no researchers have confirmed this with marked birds (Olsen et al. 2002b; Olsen & Trost 2003), and in owl species around the world the individuals with the deeper calls are males (Marks et al. 1999). If this is so, the Sumba Boobooks that were larger and had deeper calls were males, as suggested by König et al. (1999).

Sumba Boobooks in the present study were similar in size to the Southern Boobook N. novaeseelandiae ocellata (Table 2), which is said to occur in northern Australia and nearby Savu (higgins 1999), but smaller than the subspecies N. n. boobook of eastern and southern Australia. They had noticeably shorter toes than either Southern Boobook subspecies (Table 2). Sumba Boobooks appeared to be much slower moving when rousing, scratching, or turning around on the perch than are Southern Boobooks (JO & ST pers. obs.). Though smaller, they moved like a much larger owl, i.e. a Powerful Owl Ninox strenua or a great horned Owl Bubo virginianus. Sumba Boobooks probably do not catch many flying birds or insects as do Southern Boobooks, a quick-moving, quick-flying species which hunts in the manner of accipiters. One Sumba Boobook attacked a rat held in a cage by villagers and knocked the cage over, so these owls probably take rodents, but also prey on reptiles, such as geckos which are common and continually call at night in the owl’s habitat (JO & ST pers. obs.). Raptors that capture reptiles or small rodents often have proportionally shorter toes than species that capture birds or aerial insects (Johnsgard 1990), and this difference is borne out in the comparative measurements in Table 2.

Table 2

Measurements of Sumba Boobook and Southern Boobook in mm; weight in g: (1) one unsexed Sumba Boobook Ninox rudolfi, and means from (2) Southern Boobook N. novaeseelandiae ocellata, northern Australia, (a) males (n = 20–22), (b) females (n = 24–26) (from Higgins 1999, p. 870) and (3) Southern Boobook N.n. boobook, Canberra,

ACT, (a) males (n = 9),(b) females (n = 5) (Olsen & Trost unpubl. data).

Taxon Wing Tail Weight Culmen Mid-toe Tarsus

(1) 231 133 222 16.0 22.5 39.2

(2a) 222 124 216 15.9 26.6 40.6

(2b) 227 125 234 16.8 26.7 40.8

(3a) 240 142 272 16.4 27.8 51.9

(3b) 246 143 327 16.9 29.4 51.6


The so-called Sumba Boobook differs from boobooks: it does not have a disyllabic territorial call, has much shorter toes, and males may be the same size or slightly larger than females. For this reason, therefore, we support adoption of the alternative common name, Sumba hawk-Owl (e.g. del hoyo et al. 1999). It was formerly considered a subspecies of the Southern Boobook, but such treatment is clearly incorrect on morphological and vocal grounds.

Little Sumba Hawk-Owl

As with the Sumba Boobook, the Little Sumba hawk-Owl gave no disyllabic call. however, unlike Sumba Boobooks, which often hunted and moved in open areas, Little Sumba hawk-Owls kept to cover. Furthermore, Sumba Boobooks lived in coastal mangrove swamps near Melolo, but Little Sumba hawk-Owls did not occur in this habitat. The Little Sumba hawk-Owl was recorded only from a small patch of degraded forest at ~600 m elevation south of the Km 49 marker near Lewa, on the Waingapu–Waikabubak road (JO & ST), and in a patch of forest at Km 51 on the Lewa–Waingapu road (SdM). It may be limited to remnant small forest patches at higher elevations on Sumba.

Conclusions

At least four owl species occur on Sumba—two Tyto and two Ninox—but too little is known about any of these species. Newton (1998) argued that island taxa are more at risk of extinction than are birds on continents, so both Ninox and, perhaps, both Tyto species on Sumba need urgent study and further protection.

Acknowledgements

Particular thanks to Stephen debus and Julia hurley for editing assistance, Mark Linsley and gerry Richards for providing tapes of Sumba owls, Colin Trainor, Les Christidis and Walter Boles for advice, and Michael Smith for assistance with sonagrams.

References

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Jones, M., Juhaeni, d., Banjaransari, h., Banham, W., Lace, L., Linsley, M.d. & Marsden, S.J. (1994), The Status, ecology, and Conservation of Forest Birds and Butterflies of Sumba, Indonesia, report to Indonesian directorate general of Forest Protection and Nature Conservation, Indonesian Institute of Sciences and BirdLife International, by dept Biological Sciences, Manchester Metropolitan University, Manchester, UK.

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duet?’, pp. 320–328 in Newton, I., Kavanagh, R., Olsen, J. & Taylor, I. (eds), Ecology and Conservation of Owls, CSIRO, Melbourne.

Olsen, J., Trost, S. & hayes, g. (2002b), ‘Vocalisations used by Southern Boobooks Ninox novaeseelandiae in and adjoining Aranda Bushland, Canberra, Australia’, pp. 305–319 in Newton, I., Kavanagh, R., Olsen, J. & Taylor, I. (eds), Ecology and Conservation of Owls, CSIRO, Melbourne.

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Received 20 May 2008

Editor’s note: The correct scientific name of the Sumba Boobook is Ninox rudolfi Meyer 1882, as also given by every authority since then, not ‘rudolphi’ as given by Christidis & Boles (2008). AFO follows Christidis & Boles (2008), who followed Wink et al. (2004), on the taxonomic treatment of the eastern Barn Owl. Wink et al. (2008) and König & Weick (2008) inexplicably reverted to treating javanica as a subspecies of Tyto alba, and separated the eastern Barn Owl as Tyto delicatula (including subspecies sumbaensis; correct spelling is delicatula, not ‘deliculata’ as given by Christidis & Boles in a few places).

AUSTRALIAN 2 FIeLd ORNIThOLOgy OLSeN, TROST & MyeRS

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