AUSTRALIAN FI ELD ORNITHOLOGY 2004. 21. 1-20 Beachcast Recovered at Zeally Bay, Torquay, , 1991-2003

JOHN PETER Birds Australia, 415 Riversdale R oad, East Hawthorn, Victoria 3123 (Email: j.peter@birdsaustrali a.com.au)

Summary The number of beachcast seabirds recovered along the shoreline refl ects several variables. including the abundance of seabirds present in nearby waters, their seasonal distribution at sea. rates and causes of mortality and the effects of the wind, currents, waves and tides that deposit their bodies onto the sand. These aspects are d iscussed in relation to the 18 species of seabirds, comprising 898 individuals, that were recovered during 140 regular beach patrols over a 2 km stretch of beach along Zeally Bay. Thr:.guay, Victoria. T he species that were recovered most often were Short-tailed Shearwater Pujfinus ienuirostris, Eudypwla minor, Fairy Prion Pachyptila /tirlllr and Fluttering Shearwater Puffinus /wuoni, and their occurrence is examined in detail.

Introduction For a brief period after 1911 , Zeally Bay at Torquay, Victoria, o n the no rthern shores of Bass Strait, was in the limelight of the seabirding world. In the winter of 1911, 20 specimens of prions (comprising three different species) were recovered after becoming beachcast during winter storms. Two of these specimens were subsequently described as a new species, Heteroprion (Pachyptila) belcheri (M athews 1912, Belcher 1914), even though the species had been well known by sailors, but undescribed by scientists, since the late 1700s (Murphy 1936). Zeally Bay is therefore the type-locality of the species, o ne of few such sites in Victoria. However, since that time the shores ofZeally Bay have not been regularly surveyed for beachcast birds, although records of seabirds washed ashore there have occasionally been published (e.g. Wheeler 1955, Pescott 1957, Wheeler 1957, G ibson 1964). More than 50 species of seabirds have been recor

Study site and method Zeally Bay (part of which is known as Fisherman's Beach), Torquay, about 15 km south of Gee long, is situated at the western end of the Bellari ne Peninsula, on the northern edge of Bass Strait. It is a shallow bay with a sandy beach running roughly north-east from Yellow Bluff, a low limestone headland, and is mostly backed by low vegetated sand- up to 20 m high. AUSTRALI AN 2 PETER FIE LD ORNITHO LOGY

During the highest tides, the water may reach the base of these dunes; at low tide the beach is up to 120 m wide.

Method Since la te 1991. when the Australasian Group of the Royal Australasian Ornithologists Union (now Birds Australia) established its Beach Patrol Scheme, I have conducted regular monthly surveys along a section of the beach at Zeally Bay, from Ye llow Bluff north-east to a large revegetatecl blow-out in the sand-dunes. a distance of 2 km. I also conducted several additional, often incomplete, incidental surveys. Regular surveys were conducted o n the fi rst weekend of each mo nth. except for the fi rst two, which were walked later in the month. Beach patrols were not co-ordinated with any particular phase of the tide, so that a full variety of tidal stages was experienced over the course of the p roject. During each patrol, the beach was thoroughly searched for beachcast corpses of birds. Although all beach cast b irds were recorded. the main focus of the survey was to record seabirds: for the purposes of this study, these are classed as those occurring in the orders Sphenisciformes (fam il y Spheniscidae (penguins)], Procell ariifonnes [families D iomcdeidae (albatrosses), Procellariidac (fulmars. petrels, prions and shearwaters). Hydrobatidac (sto rm-petrels), and Pelecanoididae (diving­ petrels)] and Pelecaniformes [families Pelecanidae (pelicans). Sulidae (gannets and boobies). Phalacrocoracidae (cormorants and shags) and Phaethontidae (tropicbirds)]. All surveys were made on foot: the high-water mark was examined first. and the lower littoral zone was searched on the return. The length of each survey was 2 km. the length of the beach: the return leg of the patrol was not treated as an extra distance. Where necessary, beachcast seabirds were identified with the aiel of Rowe & Plant ( 1989) and Marchant & Higgins ( 1990), and a few were identified afte r consultation with seabird experts Paul Scofield and David Eades at Birds Australia. However. most birds were identified on the beach and then disposed of, either by burying in the sand or depositing in the nearby sand-dunes beyond the high-water mark. so that they would not be recorded on a future survey: otherwise, beachcast birds can sometimes persist on the shore fo r some weeks as a decaying or dried corpse or a skeleton (Powlesland & Imber 1988) and potentially be recorded on a subsequent survey. Because they were disposed of at the beach, the corpses were not dissected or otherwise examined internally. All analyses dealt only wit h seabirds recorded on regular surveys. The results from each regular survey were submitted to the Birds Australia Beach Patrol Scheme. An interim report of this project was published in 1995, after three years of surveys (Peter 1995).

Terminology T he 'Reporting rate' is the total proportion of surveys on which a species was encountered. expressed as a percentage. In this survey, a 'wreck' is defined as the recovery of a species at the rate o f at least five birds per kilometre; this has been modified sl ightly from the definition given in Reid & Scofield (1996). A juvenile is considered to be a bird in its first year after hatching.

Results Overall, the re were 140 regul ar surveys conducted between November 1991 and July 2003, covering a total of 280 km of coast; 898 seabirds, comprising 18 species, were recovered at a mean rate of 1.47 species/survey, o r 0.74 species/km of coast covered; and the actual number of seabirds recovered was a mean of 6.41 seabirds/survey, or 3.21 seabirds/km of coast covered. In addition, a further two species of seabirds (Sooty Shearwater and White-tailed Tropicbird) were recovered only as incid ental records. The greatest diversity of species recovered was in late spring, summe r and early autumn, peaking in March, with a mean of 2.58 species r ecovered/survey (standard d eviation S.D. = 0. 67, ra nge = 0-4 species, number n = 12 surveys). The lowest diversity was in win ter and early spring, with the lowest recorded in August and September, when a mean of only 0.55 species/survey was recorded (Figure I). The mean number of seabirds recovered per survey was greatest in November [mean of 12.3 birds/km/survey (s.D. = 33.4, range = 0- l 18, n = 12 surveys)], with a steady d ecline thereafter for nearly a ll other months (Figure 2). The large numbers recovered in November and December directly re fl ect the number of wrecks that occurred in these months VOL. 21 (I ) Beachcast Seabirds, MARCH 2004 Zeally Bay, Vic. 1991-2003 3

3

2.5

2

1.5

0.5

0 ~ ~ . ~ . J F M A M J J A s 0 N D

Figure 1. Mean number· of species recovered per survey by month.

14 12 10 8 6 4 ·~ 2

~ ~ f/l l7l I 0 ~ ~ I ~ I I J F M A M J J A s 0 N D

Figm·e 2. Mean number of seabir·ds r·ecove 1·cd per· kilometr·e per survey by month.

(sec Wrecks, below). There were 33 surveys (23.6%) where no seabirds were recovered (this includ es two surveys where only birds other than seabi rds were found). The most commonly recorded species were Sho rt-tail ed Shearwater Puffinus tenuirostris, Little Penguin Eudyptu/a minor, Fairy Prion Pachyp1ila turtur and Fluttering Shearwater Puffinus hulloni, comprising 96% of the total number of birds recovered (Figu re 3). Of these species, only the Flu tteri ng Shearwater does not breed on islands in Bass Strait. Not coincidentally, these fo ur species were also generally (but not always) the most commonly recovered in the Birds Australia Beach Patrol Scheme between 1992 and J996. in which most surveys were conducted on beaches in southern Australia (Reid & Scofield 1996: Reid 1999a,b).

Wrecks Ten wrecks were recorded, at the rate of nearly one every year, with three species involved: Little Penguin, Fairy Prion and Short-tailed Shearwater. Only one wreck, o n 29 D ecembe r 1991, comprised two species, Short-tailed Shearwaler and Fairy Prion. Most wrecks were of Sho rt-tailed Shearwaters, and the magnitude of one was so great that it spanned two monthly surveys. Of the I0 AUSTRALIAN 4 PETER FIELD O RNITHO LOGY

0 Short-tailed Shearwater

0 Little Penguin

D Fairy Prion

• Fluttering Shearwater

• Other seabirds

Figure 3. P•·oporlions of difl'e•·ent seabird species recorded, based on the number of individual birds recovered.

Table I . Number of wrecks •·ecorded between November and April (no wrecks were recorded from May to October). November December Jwwwy Febru{//y March April 3 4 0 wrecks recorded in this survey, six occurred after strong wi nds: two were after onsho re easterl ies or south-easterlies, two foll owed strong westerlies or south­ westerlies, and two were preceded by gales of varying d irection. T he remaining four wrecks were not preceded by strong winds. All wrecks were recorded between November and April, with most in Novembe r and December (Table 1). For details o f individual wrecks, see individual species accounts.

Systematic list of ~pec i es recovered

Little Penguin Eudyptula minor Total number: 147 (maximum of 15 birds/survey) Reporting rate: 42.1 % Mean density: 0.53 bird/km

Wre cks l February 1992 7.5 birds/km not preceded by strong winds 1 April 2002 5.5 birds/km not preceded by strong winds

Banding recoveries Band number 190-78659 Banded at Ph illip Island, Victoria, on 22 December 1993 Recovered (beachcast) o n 3 February 1994, 74 km from banding locati on Band number 191-01669 Banded at Phill ip Island, Victoria, on 7 October 1999 Recovered (beachcast) on 18 December 1999, 73 km from banding locatio n VOL. 21 (1) Beachcast Seabirds, MARCH 2004 Zeally Bay, Yic. 199 1-2003 5

1.6 ,------., 1.4 1.2 1 0.8 0.6 0.4 0.2 O +JLL,.JU..,.JU.-"'..L.,-IU_,-JLJ'--""'--r.J£.L..,...OZ::'--'U-,-..JLL-,J£..u J FMAM J JASOND

Figure 4a. Mean number of Little Penguins •·ecove•·ed per kilometre per sm·vey by month.

J FMAMJJASOND

Figm·e 4b. Mean monthly reporting rates (%) of Little Penguins.

Although beachcast Little Penguins were record ed in al l months, with a reporting rate of a little more than 40%, they were encoun tered less often than the Short-tailed Shearwater, a seasonal visitor (see p. 9) . Nevertheless, despite being found beachcast throughout the year, a seasonal trend was apparent. The mean number of Penguins recovered per kilometre per survey was greatest between February and May. There was a distinct peak in the mean number of Penguins recovered in February [1.5 birds/km/survey (s.o. = 2.27, range 0- 15; n = 12 surveys)); thereafter, there was a steady and steep decli ne until July, with the lowest numbers recovered in spring, and a gradual increase in December and Janu ary (Figure 4a). This seasonal trend was also il lustrated by the monthly reporting rates. The highest reporting rates we re recorded between February and May, but with a peak in March (not February), and the lowest between September and November (Figure 4b). This coincides with th e timing of a wreck record ed (historically) along the same beach: during a beach patrol conducted in February J 957, 29 Li ttle Penguins were recovered at a rate of 9 birds/km (Wheeler 1957). greater than either of the wrecks recorded during the current survey. Studies of banded Little Penguins indicate that mortality at sea is markedly skewed towards juveniles (Dann 1992, Reilly 1994), and that most deaths occur in the first few months after fledging, mostly in late sum mer and au tumn, bet\¥een February and May (Reilly & Balmfo rd 1975, Dann eta/. 1992). It appears that AUSTRALIAN 6 PETER FIELD ORNITHOLOGY most morta lity of juveniles is caused by a combination of the e ffects of gastrointestinal parasites [especially liver flukes and tapeworms (platyhelminths) and ro undworms (nematodes)] and starvation. This is possibly a result of both poorly developed imm unity to internal parasitism and inexperi ence in fi nding food (Obendo rf I 978, Dann el a/. 1992, Harrigan 1992, Norman eL a/. 1992). Studies at , the nearest major colony to Torquay, have shown that juveniles rapidly disperse away from the colony in the months after leaving the burrow, and most juveniles from that colony tend to move west, towards Cape Otway (Reilly & Balmford 1975, Re il ly & Cullen 1982, Dann e1 al. 1992). Such a movement would bring them into waters off Torquay, and a few Little Penguins have been radio-tracked from Phillip Island to waters off Torquay (Weavers 1992, Coll ins e1 a/. 1999). In contrast. adults usually remain in waters nearer the colo ny, especially during the breeding season (Re illy & Balmford 1975, Reilly & C ull en 1982); most adults die at sea during winte r and early spring, mainly of starvation, though it is unclear whether the cause o f this is lack of available food or difficulties in obtaining food in the rough seas whipped up by strong winds (Dann 1992, Harrigan 1992, Norman era/. 1992).

White-headed Petrel Plerodroma lessonii Total number: One Reporting rate: 0.7% Mean density: < 0.01 bi rcl/km Single bird, 1 January 1999 Though said to be ma inly a winter visitor to the Geelong region (Pescott 1983), White-headed Petre ls have been recorded in Victorian waters in all months except Janu ary and July (Emison era/. 1987, Norman era/. 1996). This record, therefore, fil ls in a gap in that monthly d istribution.

Blue Petrel Halobaena caerulea Total number: Two (maximum of 2 birds/survey) Reporting rate: 0.7% Mean densi ty: < 0.01 bird/km Two birds, 25 November 199 1 Blue Petrels are recorded in Victori an waters mainly in winter and spring; records in Emison et a/. (1987) occurred only between May and Septembe r, although Norman eta/. (1996) indicated that the species occurs until November, which is when Blue Petrels were recorded in this survey.

Salvin's Prion Pachyplila salvini Total number: One Reporting rate: 0.7% Mean density: < 0.01 bird/km Single bird, 12 April 1992 Mainly recorded in Victorian waters in winter and spring, mainly between June and November (Emison eta!. 1987, Norman eta!. 1996). This record is, therefore, rather early (Scofield 1992). There is a historical record of several Salvin's Prio ns being recovered on this beach in July 1974 (Pescott 1983). VOL. 21 (I) Beachcast Seabirds, MARCH 2004 Zeally Bay, Yic.l991-2003 7

Antarctic Prion Pachyptila desolata Total numbe r: One Reporti ng rate: 0.7% Mean density: < 0.0 l bird/km Single bird, 4 May 2002 This species is said to be rare in the Gee lo ng region (Pescott 1983); that rarity is reflected by the single record in this survey. Nevertheless, a wreck has occurred along the shores of Zeally Bay: in the wreck of pri ons recorded by Belche r ( 1914) in 191 1, most were of this species.

Slender-billed Prion Pachypti!a belcheri Total number: One Reporti ng rate: 0.7% Mean density: <0.01 bird/km Single bird, 7 June 1998 (Single additional incidental record: single bird, 22 September L994) Given that Z eally Bay is the type-locality of this species, each specimen recovered p rovides an end uri ng link with the past. The recoveries of both birds were preceded by strong winds: the record in J une 1998 was after strong no rtherly winds, and the incidental record in 1994 fo ll owed at least a week of westerly and south-weste rly gales.

Fairy Prion Pachyptila turtur Total number: 62 (maximum of 22 birds/survey) Reporting rate: 19.3% Mean density: 0.22 bird/km Wreck 29 December 1991 l l birds/km preceded by strong easterly winds Beachcast Fairy Prions were recovered in all months except April. This corresponds with the year-round occurrence in Victo ri an waters indicated by Emiso n eta/. (1987), and probably reflects the relative abundance of the species in Bass Stra it, where there are breeding colo nies at 15 diffe rent locations (Marchant & H iggins 1990); it is the most commo n species of prion in the Geelong region (Pescott 1983). T he mean number of Fairy Prions recovered was greatest in December [1.0 bird/km/survey (s.o. = 3.16, range 0-11, n = 12 surveys)], which was largely because of a single substantial wreck that greatly influenced the result. If data fr om this wreck are excluded from the analysis, the g reatest monthly mean was in July [0.33 bird/km/survey (s.o. = 0.49, range 0- 1.5 , n = 12 surveys)]; see Figure Sa. Furthermore, most records in this survey also occurred in July, when the reporting rate was 42% (Figure 5b ). In the G eclong region wrecks have mostly been recorded in J uly and August (Pescott 1983) but, historically, local fishermen at Torquay considered that May was the month when the species was most abundant (Belcher 1914). T here was a substantial wreck recorded in this survey in late D ecember 199 1, when, after persistent easterly gales, Prions were recovered at a rate of 11 birds/km; the timing of this roughly coincides with a previous wreck reported at Torq uay in January 198 1 (Pescott 1983). In addition, it should be noted that the wings of unidentified prions (though AUSTRALIAN 8 PETER FIELD ORNITHOLOGY

1.2 ,------

0.8

0.6 0.4

0.2 1!7] fjJ ~ 0 ' J F M A M J J A S 0 N D

Figur·e Sa. Mean number· of Fairy Prions recovcr·ed per· kilometre per s ur·vey by month. Note that in December the grey area of the column indicates the mean if data from the wreck recorded in December 1991 are included; the striped ar·ea shows the mean if these data are excluded.

50 ,------~

40

30

20

FMAMJJASOND

Figure Sb. Mean monthly reporting rates{%) of Fairy Prions. probably from this species) were recovered in all mo nths between February and Octobe r, except May and September.

Sooty Shearwatcr Puffinus griseus (Single incidental record. 7 January 1995) This species was distinguished from the more usual Short-ta il ed Sheatwater by the length of its bill : the culmen length of this bird was c. 40 mm (the maximum length of that of a Sho rt-tailed Shearwater is c. 35 mm: Marchant & Higgins 1990). The timing o f this record (early January) may appear a little unseasonal, especially as Norman eta/. ( 1996) stated that th is species predominantly occurs in Victorian waters between March and August, and infrequently in October and November (and, by implication, no t in J anuary at all). However, Emison et al. ( 1987) indicated that it has been recorded in January, although most records were made between April and June. Examin ation of the Birds Australia Atlas database shows that in 1977- 81 there was a single Victorian record in January. VOL. 21 (1) Beachcast Seabirds, MARCH 2004 Zeally Bay, Vic. 1991- 2003 9

In addition, there is a historical record of skeletal remains of this species recovered beachcast along this beach on I 7 February 1957 (Wheeler L957): as these re mains were skeletal, the bird was q ui te possibly beachcast in January of that year. Furthermore, on the basis of three records [i ncluding Wheeler's ( 1957) recovery]. Pescott (1983) indicated that the species ·usua lly come[s] ashore [in the Geelo ng region] in the months from November thro ugh to April'.

Short-tailed Shearwate1· Puffinus tenuirostris Total number: 636 (maximum of 236 bi rds/survey) Reporting rate: 52.1% Mean density: 2.27 birds/km Wrecks 4 November 2000 11 8 birds/km preceded by strong north-easterly/ northerly/north-westerly winds 2 December 2000 44 birds/km preceded by strong north-easterly/ northerly/no rth-westerly winds 29 D ecember 1991 16 birds/km preceded by strong easterly winds 1 January 2000 15 birds/km preceded by strong so uth-easterly winds 5 D ecember 1993 10.5 birds/km preceded by strong westerly/south- weste rly winds 1 November 1997 9.5 birds/km no t preceded by strong winds 6 November 1994 9 birds/km preceded by stro ng westerly/south- westerly winds 6 December 1997 7 birds/km no t preceded by stro ng winds The patterns of movement of the Short-tailed Shearwater are among the best known for any Australi an bi rd (Rowley 1982). Adults vacate the ir breeding colonies on islands in Bass Strait and elsewhere in southern Australia in mid April, and juveniles follow in late April o r early May. They migrate to the northern Pacific Ocean, where they spend the austral win ter, and re turn to southern Australian waters in late September (Marchant & H iggins 1990). In this survey, Short-tailed Shearwaters we re recovered in all mon ths between October and June. A mo nthly analysis of th e mean number o f Sheanvate rs beachcast per kilometre per survey shows that the values for November and December were much greater than those for all other months. However, this refl ects the dramatic wreck of Shearwate rs recorded in late 2000 (see p. 10), the effects o f which influenced the regular SUiveys in November and December of that year. If the results from those two surveys ( 4 November and2 December 2000) are excluded, the monthly means for November and D ecember were 2.3 and 4.3 Sheanva te r I km/survey, respectively. Overall , from October o r November, the number o f beachcast Shearwaters increased to a peak in December, and declined thereafter until April, with anothe r slight peak in May (Figure 6a). There was little vari ation between the reporting rates for the mo nths spanning December to March. with a peak recorded in December. The mo nthly reporting rates after March were much lower, although a small peak was detected in May (Figure 6b ). In contrast, the annual pattern of recoveries of beachcast Shea1waters at Ba1won Heads. about 16 km east-north-east ofTorquay, showed th ree distinct peaks: (1) in December. when the number of Shea1w aters present at breed ing colo nies is at a maximum: AUSTRALIAN 10 PETER FIELD ORNITHOLOGY

14 12 I 10 8 . 6 - 4 - 2 ~ 0 ~ ~ ~ ~ ~ J F M A M J J A s 0 N D

Figu•·e 6a. Mean number of Sh01·t-tailed Sheanvaters •·ecovered per kilometre pe1· survey by month. Note that in November and Decem be•- the grey area of the column indicates the mean if data from the extraordinary wreck recorded in these months are included; the striped area shows the mean ifthese data are excluded.

100

80 = F 60 r" ~ I 40 - 20

0 ~. J F M A M J J A s 0 N D

Figure 6b. Mean monthly reporting rates (%) of Short-tailed Shcarwaters.

(2) in March, when the non-breeding adults are preparing to undertake migration; and (3) in May, when the newly fl edged young leave for their first migration (Pescott 1965). T he peaks detected in the present study (two, rather than three) were not nearly as clear-cut. There were eight wrecks recorded during this survey, a ll between November and January: three in November, four in December and one in January. T he largest was recorded in late 2000. It was first noticed on 21 O ctober, when Shearwaters began washing up o nto the beach, and were recorded at a rate of J 0.5 birds/km on an incidental survey. An intense low-pressure system had been centred over Victoria for the preced ing few days, with gale-force winds (varying from no rth-easterly to north-weste rly) and much rain . By the begin ning of November, when this species was recovered at a rate o f 118 birds/krn, the full extent of the wreck was apparent, and a residue of this wreck was still present in the following month, when Shean-vaters were recorded at 44 birds/km. This wreck in late 2000 was part of a much greater event, with unusually large numbers of Shea1waters beaehcast along the coasts of much of eastern and south­ eastern Austra lia, fro m south-eastern Queensland to Tasmania, and also in New VOL. 21 (I} Beachcast Seabirds, MARCH 2004 Zeally Bay. Vic.l99J-2003 II

Zealand (Mitchell 2000; Morris 2000, 2002; Stuart 2000; Andrew 2002: Hewish 2002; Wakefield & Wakefi eld 2002; Skira 2003). Such wrecks have long been known to occur; the first on record was in 185 1, noted during the cruise of HMS Huxley (Crowley 1992), and Belcher (1914) wrote of a wreck ncar Torquay where ' hundreds of these birds [were found] dead, pi led up on the beach· in the late 19th century. SheaJwaters experience greatest levels o f mortality between October and January, especially o n the return leg of their migration, when flying over waters off eastern or south-eastern Australia, and when the winds are generally unfavourable; to complete this final stage of the ir journey, they are oft e n forced to expend most of their reserves of energy. At this time. many birds d ie from starvation and exhaustio n, and when this coincides wi th periods of scarcity of food sources, associated with unusual sea-surface temperatures, as often occurs in the south-western Pacific Ocean in late spring and early summer. the result is huge numbers of birds washed ashore in wrecks (Serventy et a!. 1971: Rowley 1982; Ski ra 1986, 2003). It is interesting to note that during the three surveys in the present study (two regul ar and one incidental) that encompassed the wreck of late 2000, a total of 345 Shea1waters washed up along Z eally Bay. but there was only one other species recorded beachcast, a single Little Penguin. This species­ specific phenomenon was also noted on beaches in New South Wales (Mo rris 2002). Thus it appears that the cause of the wreck d id not affect species other than the Short-tailed Shea1water (see Discussio n).

Flu ttering Shea rwater Pujji11m gal'ia Total number: 18 (maximum of 4 birds/survey) Repo rting rate: 9.3% Mean density: 0.06 bird/km (Three additional incidental records: three birds on 9 February 2002. and single birds o n 25 March 1996 and 9 March 2002) Flutte ring Shemwaters breed on numerous offsho re islands in New Zealand. Most of the popula ti on is present around these colo nies between August and January (Marchant & Higgins 1990), but at least a few occur (and are, therefore. potentially beachcast) in northern Bass Strait in most months ( Emi o n et a/. 1987, Marchant & Higgins 1990, Norman 1992). Most records in Bass Strait are in autumn and winter [usually between March and June (Pe cott 1983, Emison eta/. 1987, Marchant & Higgins 1990)], less often, but nevertheless occasio na lly. as early as January and February, and as late as July and August (Emison eta/. 1987, Norman eta/. 1996), o r even September (Pescott 1983), and o nly ve ry occasio nally in other mo nths. At Zeally Bay, Fluttering Shearwaters were recovered in the present study in all months between December and July, with a single record outside this period, in September. The mean number of Shea1waters recovered was greatest between February and May, with a marked peak in Febru ary [0.25 bird/km/survey (s.o. = 0.62, range 0-2, n = l2 surveys)], wi th a steady decline recorded the reafter until June (Figure 7a). The monthly analysis of the reporting rates also shows that they were greatest between Februmy and May, when the reporting rate was 17% in each of those months (Figure 7b). This peri od coincides with the westerly movement across the Tasman Sea from New Zealand to eastern Austra lia by first-year birds and non-breed ing birds ( Imber & C rockett 1970, Marchant & Higgins 1990). A similar trend was recorded both at nearby Barwon H eads, where most Fluttering Shcarwaters were recovered in February and March, with other records in May and December (Pescott 1965), and a little farther along the coast at Ocean Grove (Gray 2002). Some authors AUSTRALIAN 12 PETER FIELD ORNITHOLOGY

0.3

0.25

0.2

0.15 . 0.1

0.05

0 J F M A M J J A S 0 N 0

Figure 7a. Mean number of Fluttering Shearwaters recovered per kilometre per survey by month.

18 16 14 12 10 8

6 ~ 4 2 0 J FMAMJ JASOND

Figure 7b. Mean monthly reporting rates (%) of Fluttering Shearwaters.

who indicate that the species is absent from Bass Strait in summer (e.g. Norman el a/. 1996) presumably refer only to adults (which re turn to their breeding grounds across the Tasman Sea) and have presumably not taken non-breeding birds (including juveniles) into account.

Shy Albatross Diomedea cauta Total number: Six (maximum of 1 bird/survey) Reporting rate: 4.2% Mean density: 0.02 bird/km Single birds on 1 February 1992, 5 July 1992, 4 November 1995, 5 July 1997, 8 April 2001 and 5 April 2003 The Shy Albatross was the only species of albatross to be recovered during the survey. This is supported by observations of albatrosses in inshore waters around Torquay where it is by far the most commo n species, and at Barwon H eads (Pescott 1965). In addition, it was the most commonly beachcast species of albatross recorded along this stretch of coast by Belcher (1914). It is the only VOL. 21 (I) Beachcast Seabirds, MARCH 2004 Zeally Bay, Vic. 1991 - 2003 13

al batross that breeds in Australian waters, and is recorded in the waters of Bass Strait throughout the year (Emison et at. 1987, Marchant & Higgins 1990), though least often in summer (when the Albatrosses are at the ir breed ing colo nies), with the lowest reporting rate in February (Emison eta!. 1987). Therefore, th e record in February I 992 is of interest, th ough certa inly no t unprecedented. Observations of Shy Albatrosses elsewhere in northern Bass Strait have shown no apparent seasonality (Norman 1992).

White-faced Storm-Petrel Pefagodroma marina Total number: Two Reporting rate: 1.4% M ean density: <0.01 bird/km Single birds on 2 December 1995 and 3 Novembe r 1998 (Two additional incidental records: single birds on 11 November 1995 and 17 February 1996) The nearest breeding colonies of the White-faced Storm­ Petrel are on Mud Islands and South Channel (Fo rt) Island, both in southern Po rt Phillip Bay, about 40 km away (Pescott 1983, Menkhorst et al. 1984, Emison eta/. 1987, Marchant & Higgin s 1990). A ll records in the present study (including incidental records) were made between November and February, when Storm-Petrels would be expected to be either at the breeding colonies or in waters nearby (Menkhorst eta!. 1984).

White-tailed Tropicbird Phaethon fepturus (Single incidental record: 21 April 2000) This is the most contentious bird included on this list. A single tail-feather (Plate 2), unequivocally belonging to this species (D.W Eades pers. comm.), was found beachcast among seaweed and other debris at the hi gh-tide mark after several days of strong westerly winds. It was white with a rachis, or central shaft, that was black on the dorsal surface but whi te on the ventral side; the total length was about 48 em, and it was 15 mm at its widest, gradually tapering to a po int. The contention arises, not from the obvio us identity of the owner of the feather, but from how much of a bird needs to be beachcast before it can be counted as a vali d record. Although th e record was submitted to the Victorian Rare Birds Committee, no decisio n of its validity was made. If accepted, this would constitute the fifth record of this species in Victori a, and by far the most westerly record for the State, the nearest having been at Lakes Entrance (Emison et a/. 1987, Eades & Palliser 2000).

Tail-feather of White-tailed Tropicbird, 21 April 2000. Platt: 2 Photocopy: John Pett: r AUSTRALIAN 14 PETER FIELD ORNITHOLOGY

Australasian Gannet Monts :serrator Total number: Four (maximum of I bird/survey) Reporting rate: 2.8% M ean density: 0.01 bird/km Single bi rd s on 5 M arch 1994. I D ecember 1996, 6 April 1997 and 3 November 1998. (Two additional incidental records: single birds on 9 March 1992 and 9 November 1996 ) Of the six Australasian Gannets recovered (including incidental reco rds), five were adults: the only juvenile (brown plumage with white spots), recovered on 9 March 1992. appeared to have died on the beach, rather than having been bcachcast, as a line of webbed footprints in the sand led to its corpse. Although Gannets occur in Victorian waters throughout the year (Emison eta!. 1987), in this survey all records (including incidentals) were made between November and April, coinciding with the breeding season, which might be seen to imply some link with breeding activities. H oweve r, the proximity of breeding colonies ca n be misleading. The nea rest breeding colonies are on Wedge Ligh t and Pope's Eye, both in southern Bay, abou t 34 km away. Elsewhere in southern Victori a, there arc four oth er colonies in Port Phillip Bay (all small and recently established) and two other, much larger, co lonies nea r Portland, on and at Point Danger (Marchant & Higgi ns 1990, Norman et a!. 1998, Norman 200 I ). It is tempting, then, to assume tha t Gannets beachcast around Torquay would have originated at one of th ese colonies. This assumption, however, may be inco rrect. Though no banded Gannets were recovered during th is survey, others have been: two recovered 'near Torquay' and near Point Addis (about 9 km so uth-wes t of Torquay) were both banded as juveniles on White I sland in the Bay of Plenty, on the North Island of New Zea land (ABBBS 1992, 1995).

Little Pied Corm01·ant Phalacrocorax me!anoleucos To tal num ber: One Reporting rate: 0. 7% Mean density : <0.01 bird/km Single bird , 3 November 1996 Though reasonably common at terrestrial wetlands around Torquay, Little Pied Cormorants are rarely, if ever, record ed in the marine environment of Zeally Bay.

Great Cormorant Phalacrocorax carbo Total number: One Reporting rate: 0.7% Mean density: < 0.01 bird/km Si ngle bird, 5 September 1993 The Grea t Cormorant is the most common species of cormorant of the beaches around Torqu ay. Small flocks are often seen roosting on sandy beaches or on cliff-ledges, or flying low over inshore waters. The recovery of this species is not unexnectcd. VOL. 21 (1) Beachcast Seabirds, MARCH 2004 Zeally Bay, Vic. 199 1- 2003 15

Australian Pelican Pelecanus conspicillatus Total number: One Reporting rate: 0.7% Mean density: <0.01 bird/km Single bird, 29 December 199 1 The nearest Pelican colony is on Mud Islands, Port Phillip Bay (Menkhorst et a/. J 988), but Pelicans arc only infrequently recorded around Torquay. usually seen gliding on thermals overhead, or occasionally at near-coastal terrestrial wetlands, but only very rarely seen on the marine wa ters of Zeally Bay.

Silver Gull Larus novaehollandiae Total number: 12 (maximum of 2 birds/survey) Reporting rate: 7.8% Mean density: 0.04 bird/km Two birds recovered on 13 December 1992, and single birds on 29 December 1991, 7 March 1993, 3 October 1993. 5 March 1994, 1 Janua ry 1995, l January 1996, 2 March 1996, 7 September 1996, I March 1997 and 1 January 2000. Most records of beachcast Silver Gulls were made between D ecember and March, peaking in March, with respect to both number of G ulls recovered per ki lometre per survey [0.17 (s.o. = 0.25, range 0-0.5, n = 12 surveys)] and reporting rate (33.3% ), with one other Gull recovered in September and another in October; this more-or-less coincides with the breeding season. Although there arc no Gull breeding colonies around Torquay, there are several on the Bellarine Peninsula and elsewhere in the Geelong region, especially on Mud Islands, where a huge colo ny exists (Pescott 1983, Menkhorst et a/. 1988, Peter & Starks 1997). Unfortunately, the ages of beachcast Gulls were not recorded; if these data were ava il able, they might have revealed a pattern to the mortality relating to breeding activities, such as an age bias towards juveni les that disperse soon after fl edging in the earl y part of th e year. Live Silver G ulls are commo n around To rquay. especially at the local rubbish tip ( < l km away from the north-eastern end of the study area) where thousands of Gulls gathered to scavenge amo ng the refuse, at least until the tip closed in September 1995. Given this large local population of Gulls and the relatively small number recovered during this su1vey, this species may appear to be unde r-represented in the overall tally. H owever, it probably reflects a shift to the increasing importance of terrestrial-based scavenging and a reduced dependence on the marine environment.

Caspian Tern Sterna caspia Total number: One Reporting rate: 0.7% Mean density: <0.0 I bird/km Single bi rd, 2 February 1997 Caspian Terns breed in small numbers on Mud Islands in Port Phillip Bay (Menkhorst et al. 1988, H ewish 2002), and, around Torquay, are uncommo n visitors to she ltered estuaries, but do not usually occur in the more exposed marine waters or adjacent sho res of Zeally Bay. The bird was beachcast at a time when the species would be expected to be dispersing from the breeding colony. AUSTRALIAN 16 PETER FIELD ORNITHOLOGY

Crested Tern S1e1na bergii Total number: One Reporting rate: 0.7% Mean density: <0.01 bird/km Single bird, I January 2001 (Single additional incidental record: single bird, 30 December 1993) Banding recm·e1y Band numbe r 072-379 16 Banded at Tro ubridge Island, S.A., on 13 December 1992 Recovered (beachcast) on 30 December 1993, 679 km from banding location T he largest breeding colony of Crested Te rns in Victori a is at Mud Islands in southern Port Phillip Bay. and several colour-banded Terns seen in the Torquay district (pers. obs.) were all banded at that colo ny (Victorian Studies G roup unpubl. data). The discovery of a beachcast Tern banded on Troubridge Island, hundreds of kil ometres away in South Australia (ABBBS unpubl. data), was thus a little unexpected. Analysis of banding recoveries of this species shows that there is an unusually high mortali ty rate in juvenile Terns, which comprise 86% of band recove ries (Minton 1992). This band was recovered from a first­ year bird.

M iscellaneous species A total o f 14 bcachcast corpses of birds other than seabirds, comprising 10 species, was also recovered: Domestic Chicken Gallus gallus: single, 7 J une 1992 Threskiornis molucca: two birds on 12 December 1992 and single bird on 2 February 1997 Rock Dove Columba Iivia: single, 24 August 1996 Galah Cacatua roseicapilla: single, 4 November 1995 Budgerigar /ll!elopsittacus undulatus: single, 1 January 1996 White-throated Needletail Hirundapus caudacutus: single, 8 March 1992 Austral ian Magpie Gymnorhina tibicen: sing le birds o n 1 November 1992, 4 November 1995 and 8 July 2001 Forest Raven Coli'lts tasmanicus: single bird, 8 July 2002 Little Raven C01vus m ellori: single bird, 2 February 2003 Skylark Alauda mvensis: single bird, 3 August 1996.

Discussion Overseas it is considered that a prime purpose of conducting regular surveys ofbeachcast seabirds is to assist in the monitoring of the effects of human activities at sea (e.g. Page eta/. 1982, Stowe 1982, Stenzel et al. 1988). Two of the most impo rLant issues here are the effects of oil po llution and litter. During this su rvey, I am aware of one minor event when a small quantity of o il was washed asho re (soiling the towels of unsuspecting beach-goers) on several beaches around Torquay. Fortunately, though de li berate searches for oiled birds VOL 21 ( I) Beachcast Seabirds. MARCH 2004 Zeally Bay. Vic. 1991 -2003 17 were co nducted, none was recovered (in fact, no beachcast birds were recovered on this occasion). Before the commencement of the cu rrent su rvey, however. seve ral oiled Little Penguins we re recovered near Torquay after an oil-spill off the coast ncar Cape O tway in May 1990 (Jessop & Du Guesclin 2000). I n addition. it has been suggested that ingestion of oil by Short-tailed Shearwaters in waters off south-eastern Queensland was a cause of the grea t wreck of October :zooo. though none of the beachcast birds found there, or anywhere else, showed external signs of oiling (Morris 2000); ce r tainly, none of the hundreds of beachcast Shearwaters recovered at Zeally Bay appeared to have any traces of oil on the plumage. Although no oiled birds have been recovered during this study. evidence of other pollution along the beach is more common and indicates the se rious haza rd to much marine life. A quick sca n of the tide-line along Zeally Bay reveals that although most litter washed up does not origin ate from fishing and boating activities, much docs: every yea r many metres of nylon fishing-line, as we ll as much nylon rope and netting of varying thickness, arc collected. It has long been recognised that entanglement in fishing equipment results in the death of so me seabirds. In the 19th century. for example, in one morning Hall (1894) recovered six Little Penguins, all tangled in fishing-nets. along one beach in Port Phillip Bay. During the present study, a beachcast Shy A lbatross (recovered on 4 November 1995) had a length of nylon fishing-line tangled around its legs. In addition, two of four Little Penguins recovered along a short stretch of beach near Bream lea (c. 5 km north-east of Zeally Bay) were entangled in green nylon cord (pcrs. obs. 28 February 1999), and Australian Fur Seals Arctoceplwlus pusillus entangled in fi shing-nets are also occasionally found on beaches in the area (pers. obs.). Further evidence of the entanglement of birds in fishing-line comes from an analysis of recoveries of Crested Terns banded in Victoria: of 92 recoveries, 13 ( 14.2%) were found entangled in fishing-line (Minton 1992); and. on one occasion on Mud Islands, a single length of fishing-line had hooked one Silver Gull and entangled 13 Crested Terns, all of which subseq uently died (Minton 1998). Many of the plastic yokes that are used to connect beer cans in a six-pack have been retrieved at Zeally Bay, but in this survey none has been found tangled around the body of a bird. Elsewhere some seabirds, especially Little Penguins, howeve r. occasionally become entangled in these yokes, someti mes ca usi ng the bird to die or lose co ndition as its mobility is impaired and it becomes ex hausted. or the wounds from such entanglement become infected, although Dann ( 1990) did not consider this entanglement to have a significant effect on the overall population. Full po t-mortem examination of corpses of bcachcast seabirds was beyond the scope of this survey at Zeally Bay. As a resu lt, therefore, the cause of death of birds without obvious external signs of trauma was unknown. In particular. no assessment could be made of any mortalities resulting from ingestion of (rather than entanglement in) plastic, evidence of which has come from va rious species found beachcast along the Victorian coastl ine (e.g. Brown et a/. 1986. Skira 1986, Ryan & Fraser 1988, D ann J 990, H edel & Gales 200 I ). Pieces of plastic are presumably swa llowed while seabirds are foraging, either deliberately, being mista ken for food or floa ting pumice, or incidenta lly, and the incidence of this is sa id to be increasing (Hindwood 1946, Chisholm 1967, Dann 1990). Although not usually fatal, plastics ca n cause physica l damage, such as perforation of the alimentary tract, or the process of digestion ca n induce toxic substances to be AUSTRALIAN 18 PETER FIELD ORNITHOLOGY released from plastic (Ryan 1988, Baker el a/. 2002). T he major threat of seabird mortality as a result or bycatch in fisheries operations (s ummarised by Baker el a/. 2002) is unlikely to be reflected in a survey such as this one.

A lthough the ca uses of death coul d not be determined for most of the seabirds was hed up along Z ea lly Bay, th e co nditions most likely to produce many bcaehcast birds arc known. M o~t seabird corpses arc beachcast on exposed beaches during periods of strong onshore winds (Powlcsland & Imber 1988) which. at Zcally Bay, arc either easterly or south-easterly, and occur only irregu larly. mainly in late spring and early summer. and again in au tumn. This coincides with th e period when so me seabirds that breed in Bass Strait and elsewhere in so uthern A ustralia are visiting local waters. From the orienta tion and shape of the coast. Z eally Bay is generally in the lee of orf hore westerly and north-westerly gales (and to an extent. from the position of Yellow Bluff, so utherly ga les) and parallel to the south-wes terly gales that regularly and often whip through Bass Strait. Surveys conducted after such winds have consistently produced low numbers of beachcast seabirds; winds blowing pa rallel to th e coas t have the ef fec t of distributing bcachcast birds at low densities over a wide area (Bibby & Lloyd 1977). The preva iling winds in Victoria arc north-westerlies and south-westerlies, with easterly winds much less common (except in Gippsland) ( Lee 1982). The proportion of clays where Torquay experiences onshore easterly or south-easterly winds is far outweighed by the proportion of wrecks preceded by strong onshore winds, and al though the numbers are too low to calcu late a sta tistica l significance of th ese easterly winds, the trend is evident. Su ch co nditions have long been known to cause large numbers of birds to be deposited on th e beach at Torquay: Belcher ( 1914) mentioned large numbers of L ittle Penguins beachcast ·particularly after easterly ga les·. and the wreck of prions he discovered in 19 11 was preceded by a strong south-easterly wine!; Pescott ( 1965) considered that easterly or south­ easterly gales produced the most fruitful conditions for beach patrols at nea rby Ba1won Heads; and similar trends have also bee n noted at Ocean Grove (Gray 1994. 1996 ).

Clearly, life at sea is perilous. and dea th by one or a combination of factors, including natu ral causes or th e result of human activi ties, is the fate that awaits many or th e seabirds tha t inhabit the waters of Bass Strait. M any carcasses will never he washed ashore but, given the right conditions, up to about 60% will (Bibby & Lloyd 1977). It is the recovery or these beachcas t birds under 'normal" conditions during regular surveys th at provides base line data on the mortality, distribution, movements ancl ecology of seabirds. so that in the event of potentially catastrophic circumstances, such as an oil-spill. typical patterns of mortality are already documented and available to researchers. Eve n without oil-spills, data coll ected in these surveys augment our knowledge of both well-studiecl and poorly known species of seabirds that occur in Bass Strait.

Acknowledgements

The-,e surveys would not have b e~: n con duct..:d without the constant co mpanionship of Tiger. who accompanit:d me on nearly every beach-walk. I am indebtt:d to Krist ine Kerr who. along with Toby and Monty. helped in so many ways. from walking beach patrols with 111 1:! tu giving computer acl vicc and commenting on dralh of the text. M any thanks to Paul Sco field who ro,tcrcd my int..: rcst in seabirds and encouraged my invulvcmen t with th e Beach Patrol Schcm..:: both ht: and David Eades kindly helped to ident ify some of the more mys terious specimens. Thanks also to the two anonymous referees for thc.: ir commen ts on a draft. YOL. 21 ( I) Bcachcast Seabirds. MARCH 2004 Zcally Bay. Vic. IY9 1-2UU3 IY

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Norman. F. I. ( IY92), ·Dist ribitio n and --1-1. Weavers. B.W. ( 1992). ·Seasonal foraging ranges and travels at sea of Little Penguins Eud)ptula mi11or. determin<.:d by radiotracking·. Emu 91. 302-317. Wheeler. J.R. ( 1957). ·Beach-washed birds at 'lb rquay'. Bird Obsen·er 305, 3. Wheeler, W. R. ( 1955). 'l o rq uay notes·. Bird Ob.1·en •er Feb. 1955. 2-3. J?eceh -eel .f A ugmt 2003 •