VOL. 17 (8) DECEMBER 1998 365

AUSTRALIAN WATCHER 1998, 17, 365-369

Arctic Warbler: First Confirmed Record for Mainland Australia by C.J. HASSELL, Broome Bird Observatory, P.O. Box 1313, Broome, W.A. 6725

Summary On 23 January 1998, an Phylloscopus borealis was seen and subsequently caught in a mist-net in the grounds of the Broome Bird Observatory, Western Australia. The bird was subsequently seen feeding on caterpillars in the same area until 25 January 1998. A description of the bird is given from observations in the field and from in the hand. Identification of Arctic Warblers and similar is discussed. Although this is the first record for mainland Australia, there are previous records and specimens from islands off north-western Australia.

Introduction The Arctic Warbler is a small insectivorous bird with olive-green upperparts, whitish underparts and with a conspicuous pale supercilium. All populations of Arctic W arb1ers are highly migratory: they breed in northern parts of Eurasia, northern , Japan and western Alaska, and regularly migrate to spend the northern winter in South­ East , from Burma and Thailand, east to the Philippines and south to the Indonesian Archipelago (Cramp 1992). At 0740 h on 23 January 1998, at the Broome Bird Observatory, Western Australia (17°59'S, 120°22'E), I saw with the naked eye a bird that I did not immediately recognise. On fetching binoculars and viewing the bird again, I noted it was obviously a Phylloscopus warbler. I watched the bird with Janet Sparrow, a fellow warden at the Observatory, through a window for approximately 2 minutes before it moved out of view. We quickly moved outside where we found the bird again, and were able to obtain good views, as well as hear it call. We contacted two other keen bird­ watchers, Mavis Russell and George Swann, and set up three four-shelf monofilament mist-nets in the area that the bird was using. We obtained good views of the bird. Although photographic equipment was set up, we were unable to photograph the bird due to poor light and weather conditions. Eventually the bird flew into the second shelf of one of the mist-nets. I extracted the bird at 1105 h, and it was fully processed and photographed within 2 hours, during which time the bird was given a 20-minute break, when it was held in a bird bag in a cool and shady position. On release, the bird flew into a nearby Acacia, shook itself and began to glean insects.

Habitat and conditions The Broome Bird Observatory is a collection of nine buildings and a small camping ground, situated in coastal Pindan woodland dominated by Pindan Wattle Acacia eriopoda; other plants in this include Kimberley Bauhinia Lysiphillum cunninghamii, Medicine Bark Ventilago viminalis, Hakea macrocarpa, Wild Pear Persooniafalcata and Native Willow Ehretia saligna. The red Pindan soil supports grasses and a variety oflow native shrubs and flowering plants. A Kimberley Bauhinia was the tree favoured by the Warbler, where it kept to the lower branches and the trunk. At the time of the observation, there was complete cloud-cover and intermittent rain. A low-pressure system, which subsequently intensified to form Tropical Cyclone Tiffany, was centred approximately 140 km north-west of Broome. AUSTRALIAN 366 HASSELL BIRD WATCHER

Arctic Warbler at Broome, W.A., January 1998, showing conspicuous supercilium Plate 60 Photo: J. Sparrow

Dorsal view of the Arctic Warbler at Broome, W.A. Plate 61 Photo: G. Swann VOL. 17 (8) Arctic Warbler - DECEMBER 1998 First Confirmed Record, Mainland Australia 367

Description This description is a combination of our field-identification notes (after having viewed the bird through Carl Zeiss J ena 10 X 50 and 8 X 40 binoculars), completed plumage-description sheets and characteristics of the bird when observed in the hand.

First impressions My first impressions were of a long-bodied bird with a horizontal carriage (in contrast with Brown Honeyeaters Lichmera indistincta and Rufous-throated Honeyeaters Conopophila rufogularis, commonly seen around the area). With binoculars, the most striking feature was a long, narrow, pale-yellow supercilium, starting in front of the eye, near the bill, extending beyond the eye and curving down onto the side of the nape.

Bare parts The eye was large and dark with a deep-brown outer iris and black orbital-ring. The large, robust bill had a black upper mandible with a tiny pale tip (not discernible in the field); the base of the lower mandible was yellow-orange, with the distal half dark hom, with a tiny yellow tip. The base of the bill was 5.9 mm wide. Tarsi were pale hom with a very pale yellow stripe along the back of each leg. The width of the tarsus was 2 mm, and the bird took a size 02 band.

Head The bird had the distinctive supercilium and face pattern of a Phylloscopus warbler. The forehead and crown were dark olive, and the lores olive-grey. There was a very long, pale-yellow supercilium, which started from near the base of the bill, though, when viewed from above, the supercilia did not join above the upper mandible; it extended back above the eye and curved down onto the side of the nape. There was also an olive eye-stripe. The ear-coverts were pale yellow, mottled with olive (Plate 60).

Upperparts and upperwing The nape, mantle, back, rump and upper tail-coverts were all dark olive, slightly brighter towards the rump and upper tail-coverts. The scapulars were also dark olive; in the field, the upperwing was similarly dark olive when folded. In the hand, the primaries were grey-brown with narrow yellow-olive outer edges. The fifth primary (p5) was non-emarginated (note: p1 was taken as the innermost primary). The secondaries were also grey-brown, but with broader yellow-olive outer edges. The tertials were olive. The primary coverts were similar in colour to the primaries. In the field, a short, very pale wing-bar was noted; in the hand, this was seen to be formed by pale-yellow tips on the four inner primary coverts and the first secondary covert. The median and lesser coverts were grey-brown with an olive wash, but two of the median coverts also had pale tips. The longest primary on the folded wing extended 14.8 mm beyond the tip of the longest tertia!, exposed tertials (that is, from the tip of the scapulars to the tip of the longest tertia!) were 20.2 mm. The wing formula showed p9 = p5. The uppertail was grey-brown with olive outer webs; the three outer feathers had pale tips and pale-edged inner webs; the fourth outer feather lacked a pale tip, but had a pale-edged inner web (Plate 61).

Underparts and underwing The chin and throat were white with a yellow wash. The feathers on the upper breast were olive-grey with yellow tips and an overall yellow wash. This gave a AUSTRALIAN 368 HASSELL BIRD WATCHER

distinctive streaking as seen in the field. The remainder of the underparts were white with a yellow wash. The undertail was gunmetal-grey with pale tips and edging, similar to that on the uppertail. The undersides of the primaries and secondaries were also gunmetal-grey, with narrow white inner edges. The axillaries were lemon-yellow, and the underwing-coverts were white with lemon tips.

Call The bird called twice while we were watching it: it gave a harsh and relatively loud scolding double trrrrrick-trrrrrick or chrrrrrick-chrrrrrick, followed by a short pause and then repeated. The bird called both when in the tree and while in flight.

Separation from similar Phylloscopus warblers Other Phylloscopus warblers, similar to the Arctic Warbler, which need to be eliminated to confirm our identification are: the P. trochiloides, a migratory species which breeds from northern east to central Russia, and south to Kazakhstan, the and south-western China, and spends the non­ breeding season from , through Thailand to Indochina; the Large-billed Leaf­ Warbler P. magnirostris, a sedentary species, which ranges from India south to the Andaman Islands, and west to western and southern China; and the Eastern Crowned Leaf-Warbler P. coronatus, which breeds in eastern Siberia, northern and western China, Korea and Japan, and winters from eastern India east to Indochina and south to Java and Sumatra (King et al. 1989, Cramp 1992, Coates et al. 1997). I considered the Broome bird to be an Arctic Warbler because of the diagnostic combination of the following features: (1) Face pattern: This bird lacked the dark lateral crown-stripes and pale median crown-stripe diagnostic of the Eastern Crowned Leaf-Warbler (de Schauensee 1984, Flint et al. 1984, Lekagul & Round 1991). The long supercilium separated from the mandible, and strongly mottled ear-coverts indicated Arctic Warbler; the ear-coverts of the Greenish Warbler are usually less strongly marked (Dean 1985). (2) Underparts: The upper breast was streaked; Greenish Warblers usually have cleaner, virtually white underparts (Svensson 1984, Dean 1985, Cramp 1992). (3) Wing size, wing formula: Wing length was within the normal range for the Arctic Warbler, and too long for Greenish Warbler. The primary projection of the Broome bird showed the wing point = p8/p7; p7 is not the longest feather in the Greenish Warbler. In addition, the wing formula showed p9 = p5, whilst on the Greenish Warbler p9 = p1 (Williamson 1974, King et al. 1989, Cramp 1992). The fifth primary was not emarginated, in contrast with both the Greenish Warbler and the Large-billed Leaf-Warbler (Williamson 1974, King et al. 1989, Harris et al. 1990, Cramp 1992). (4) Tail: In the hand, the outer feathers of the tail had pale tips and pale edges on the inner web. Working towards the centre, the fourth feather had no pale tip, but had a pale-edged inner web and lacked pale outer webs, consistent with an Arctic Warbler; the Greenish Warbler has smoky white outer webs (Dean 1985).

Age The age of the bird was given as 1 + (that is, age unknown), due to our inexperience with this species in the hand. It was possibly 2 + (adult), judging by the deep-brown iris, which lacked a grey tinge. VOL. 17 (8) Arctic Warbler - DECEMBER 1998 First Confirmed Record, Mainland Australia 369

Other Australian records There are several other records of the Arctic Warbler on offshore islands and oil­ rigs, all in north-western Australian waters. In addition, the species has also been recorded as a vagrant in Papua New Guinea (Coates 1990). The first Australian record was a single specimen, which had recently died, collected on Scott Reef on 7 November 1979, and lodged at the Western Australian Museum (A16285) (McKean 1980). There have been several reports from Ashmore Reef since mid December 1990, including two in mid November 1997 (J. Darnell pers. comm.), and the species is probably a regular visitor there in small numbers (Pike 1993). A live bird was found on an oil-rig off Dampier on 24 December 1995, but subsequently died, and was lodged with the Western Australian Museum (WAM 19859); the record was accepted by the Royal Australasian Ornithologists Union Rarities Appraisal Committee (case 142, Patterson 1996). A single Arctic Warbler was seen on the Lacepede Islands on 17 December 1997 (Birds Australia Rarities Committee case 243, G. Swann pers. comm.). There was also a report of a Phylloscopus warbler, possibly this species, at Anna Plains Station, south-west of Broome, on 16 January 1996 (P. Collins & R. Jessop pers. comm.); unfortunately, due to the brief views obtained, its identity could not be confirmed (BARC case 220, T. Palliser pers. comm.). Thus, this is the first confirmed record of an Arctic Warbler on mainland Australia. These few records suggest one of two things: that birds have been pushed farther south than usual by cyclonic weather patterns; or it is possible that small numbers of Arctic Warblers regularly reach north-western Australia, but are not noticed due to the remoteness of the area and the resultant lack of observers.

Acknowledgements Thanks go to: David Eades, for his advice on appropriate measurements, wing-formula information, and publications regarding identification of warblers; Danny Rogers for his helpful comments on drafts of this paper; Janet Sparrow and George Swann for their assistance in identifying, processing and photographing the bird; Mavis Russell for assistance in processing the bird; and Phil Joy for his e-mail communications. References Coates, B.J. (1990), The Birds of Papua New Guinea, vol. 2, Dove, Alderley, Qld. --,Bishop, K.D. & Gardner, D. (1997), A Guide to the Birds ofWallacea, Dove, Alderley, Qld. Cramp, S. (Ed.) (1992), The Birds of the Western Palaearctic, vol. 6, Oxford University Press, Oxford, U.K. de Schauensee, R.M. (1984), The Birds of China, Oxford University Press, Oxford, U.K. Dean, A.R. (1985), 'Review of British status and identification of Greenish Warbler', British Birds 78, 437-451. Flint, V.E., Boehme, R.L., Kostin, Y.V. & Kuznetzov, A.A. (1984), A Field Guide to Birds of the USSR, Princeton University Press, Princeton, New Jersey, U.S.A. Harris, A., Tucker, L & Vinicombe, K. (1990), The McMillan Field Guide to Bird Identification , McMillan, New York. King, B. , Woodcock, M. & Dickinson, E.C. (1989), A Field Guide to the Birds of South-East Asia, Collins, London. Lekagul, B. & Round, P.D. (1991), A Guide to the Birds of Thailand, Saba Karn Bhaet, Bangkok. McKean, J.L. (1980), 'The first record of the Arctic Warbler Phylloscopus borealis from Australia' , Western Australian Naturalist 14, 200. Patterson, R.J. (1996), RAOU Records Appraisal Committee: Opinions and Case Summaries 1992-1995, RAOU Report 101, Royal Australasian Ornithologists Union, Melbourne. Pike, G. (1993), 'Birds of Ashmore Reef, Wingspan 11, 12-14. Svensson, L. (1984), Identification Guide to European , author, Stockholm. Williamson, K. (1974), Identification for Ringers, BTO Guide 2, British Trust for Ornithology , Tring, U.K. Received 21 March 1998 •