On Rottnest Istcrnd Ottnestisland Lies 18 Kilometres Off the Western Australian Mainland, Almost Due West of Perth

on Rottnest Istcrnd ottnestIsland lies 18 kilometres off the Western Australian mainland, almost due west of Perth. lrregular in shapeand coveringan area of some 1,900 hectares, its varied I ,,*.*" natural features and diverse habitats give it a sp€cial charm. Not surprisingly, it has becomea favourite destination for WesternAustralian and other visitors. By its very nature, Rottnest Island catersfor a wide range of activities.For many, leisurely walks and bike rides around the island are the main assortment of butterflies, and a little regularly flies across Bass Strait from attraction. Others go there to fish and time is all you needto enjoy them. the mainland,appearing in Tasmania. swim, or scuba dive off nearby reefs. Butterfliesare insectsthat belongio Butterflies also make the crossing Somesimply enjoy the scenery,exploring the order Lepidoptera,a name of Greek to the Abrolhos islands, 60 to 80 ihe isolatedcoves and picturesquesalt origin that refersto the tiny scalesthat kilometresoff the WesternAustralian lakes.Still others find great enjoyment cover their wings. All butterflies stad coast near Geraldton. lt's not in the wildlife, watching quokkasand life as eggs,which hatch into small soft- surprising.therelore. that somespecies the abundant birdlife. There are, bodied caterpillars. These caterpillars also appear as vagrants on Rottnest, however,other attractionsfor the keen feed voraciously on their respectlve probably reaching the island with the obs€rver,particularly in spring and food plants, and grow through several aid of easterlywinds. early summer. These include an stagesuntil they are ready to pupate Seventeenspecies oI butterflies and form a chrysalis.In this immobile have so far been recordedon Rottnest. I Preuiouspage state they go through a miraculous Some of theseare residents,living and l,etam RottnestIsland. finally emerging as breeding on the island; others (like I Photo- MarcMuller transformation, transient visitors from lnset Lesserwanderer. perfectbutterflies. most of us) are Photo- Babs& Beftwells/CALM Butterflies are more robust than the mainland. might be expected, and some have Some of the speciesyou might well lnland lakesfrom LookoutHill, lBelow: remarkable powers of flight. The encounteron your next visit are shown I Rottnestlsland. I Photo- MarieLochman Australian painted lady, for example, on the follou'ing pages.

24 t o"cort: I Prlf Themonarch lawa feeds on a I loxicfoodplant. narrowleaf cottonbush. I Thismakes il unpalatableto predators. Photo- 'llevorl-undstrom lFar righl:Monarch bulleyfly pupa that I is closeto emergence. I Photo- PeterMarsack/l.ochm"n Ttansparencies

I Belou left: Silve"-chequeredochre I showingthe distinctive silvery white I markingson the undersideof the hindwing. Photo- DricMccrum a Belou centrc:Salt-bush blue on its I larvalloodplant grey sallbush Atlrplex I cinerea. Photo- AllanWills/CALM

I Belou right: Two-spottedIine-blue I showingthe characlerislic spots on the I trailingedge of the hindwing. Photo TrevorLundstrom uppersideof the buttedy's wing rs autumn. The larvae are green and brown with orange-yellowspots and extraordinarilywell camouflaged.They blotches.Underneath, the hindwing has generallypupate in shelteredplaces on distinctivesilvery white spots.These are the stem or leavesof the food plant, SILVER-CHEQUEREDOCHRE very noticeablewhen the bullerfly is the butterflieshalching within a few (Trapezites org enteoomot us) at rest, and distinguish it from other days. The speciesproduces several This small butterfly belongsto the specieson the island. generationsa year, and so can be seen skipper family; as name the suggests,rt in any of the warmer months. At times has a rapid skipping flight. lt is SALT-BUSHBLUE u,henthe butterfliesare very abundant, common on the island, adults first (Thec lines t hes serpentat a) welcome swallows can be seen appearing in early October, with The salt bush blue is a tiny swooping low over the salt bushes to numbers peaking grey-brown in November. butterfly, blue abovewith catch them. Occasionalspecimens may still be seen and white chequeredfringes to its around Christmas. Silver-chequered wings. Underneath.its colouringis TWO-SPOTTEDLINE-BLUE ochresare especiallyprevalent in areas more cryptic, blotched with greys and (Nacaduba biocellata) adjacent to the salt lakes, where the browns. It is so named becauselts This tiny butterfly inhabitsstands of food-plant prickle lily (Acanthocarpus caterpillarsfeed on varioustypes ofsalt- summer-scen ted watlle (Acacic preissii) is abundant.The butterfliesfly bush.On RottnestIsland it can often be rostelliferol, on which its caterpillars closeto the ground,often landing on low seen flying around seaberry saltbush feed. It may also be seen in spring shrubs or exposedrocks. A good place lRhagodia baccata) and grey saltbush aroundflowering shrubs in thebolanic to obsenrethem is at Vlamingh Lookout lAtriplex cinerea),\Nhich fringe manyof golf course.Males are lilac abovewith overlookingGarden Lake. Alongside the the island's salt lakes. A particularly blue basalareas, while femalesare blue roadbeh^reen Garden Lake and Herschel good place Lo find lhe butterfliesis with a broad border of brown. Lake, flowering shrubs of thick-leaved alongthe southernside of GardenLake, Underneath,both sexesare yellowish fan flower (Scaeuolacrossifolia\ attract not far from the main settlement.Salt- brown. Two small round spots on the many individuals,offering photographic bush blues are most common in spring trailing edgeof the hind wing givethe opportunities to the enthusiast. The and summer.but may also be seenin buttefly its name.

Lanosmm25 I r€f. Cabbagewhites are most I frequentlyseen around the settlement I aYeaon Rottnestlsland. Photo RobertPowell/CALM

I Fcr 1ef. The yellowadmiral has I strikingpale yelJow patches on the I forewing. Photo- DavidPik€

I Lowerfar left: Alslralianpainted lady I baskingin earlymorning sunshine. I Photo- RobertPowell/CALM

I Belorzr:The monarchis the largest I butterflyfound on Rottnestlsland. I Photo MattWillliams/CAlM

AUSTRALIANPAINTED LAD1 (Vanessakershoui) MONARCH (Danaus plexippus) This medium-sizedbuttedy is one species,with a of our most recognisedspecies, being This spectacular is by far commonly found throughout mainland wing spanof 9-10 centimetres, RottnestIsland. Australia.On RottnestIsland it is mostly the largestbutterfly on severalmay be seenin spring and earlysummer, either In spring and summer, gliding effortlessly flying, or basking on the ground u'ith seen at one time island. The monarch, also outstretched wings. It often feeds at over the in North the flowersof Roltnestlsland daisies calledthe wanderer,originated its range (Trachgmenecoerulea). There may well America,but hasnow extended Pacific to Australia, first YELLOWADMIRAL be a stablepopulation of paintedladies across the in Perth more than 100 (Vanessaitea) on Rottnest, as one of its preferred being recorded pale yellow patches yearsago. 0n RottnestIsland, it is most The on the food-plants, Cape weed \Arctotheca lakes,where the forewings give the yellow admiral its calendula), growson the island. However, often seennear the salt plant which it breeds, narrowleaf name,and immediatelydistinguish this like the yellow admiral, it is a strong on (Gompftocarpus fruticosus), medium-sizedbutterfly from all other flyer and known migrant, well able to cottonbush specieson the island.This species,also reachRottnest fuom the mainland. has becomeestablished. Unfortunately, calledthe Australianadmiral, is a narrowleafcottonbush is an introduced powerful insect that can travel long CABBAGEWHITE noxious weed, which needscontrol. If distances;it is thought to be a seasonal (Pieris ropae) the plant can be maintained at low visitor to the island, rather than a This medium-sized species is not densities rather than eradicated,then resident. It appearson the island in nativeto Australia,but wasaccidentally this spectacularaddition to Rottnest's winter and spring each year, having introduced to Victoria in 1937; it lepidopteranfauna will continue to be apparently migrated from the arrived in Perth more than fifty years enjoyedby its many visitors. mainland.It then breedson two annual aqo. [t is called the plant speciesthat grow prolifically cabbagewhite becauseits round the settlement at this time: larvae feed on cabbages native pellitory (Parietaria debilis) and and other plants in the the introduced stinging-nettle (Urlrta cabbagefamily; it will urens). Both these food-plants die off also breed on garden in summer. The caterpillars conceal nasturtiums.The cabbage themselves in dome-like shelters, white has only recently which will revealtheir presenceto the become establishedon keen observer.The butterflies often fly Rottnest, where it is fast round the treetops. They are, seen round the main however,more easilyseen when feeding settlement. Coming to at flowers or laying eggson their food- Australia from temperate plants. In the late afternoon, a good regions,it can fly in cool, placeto seethem is Vlamingh Lookout, cloudy weather, unlike where the males establish territories manynative species, which to meet virgin females, a behaviour are active only when it is knownas'hilltopping'. warm and sunny.

26 t*o"ro"u I Rrltr Lesserwanderers are infrequent I visitorsto the island. I Photo EricMccrum

I Louer right: The marbledxenica is I verycommon on Rottnest.Cryptic I colouyationon thehind wing provides camouflagewhen the butterflyis settled on the ground. Photo EricMccrum lFar ight: Small grass-yellowshave I onlyrecently been recorded on I Rottnest- Photo- RobertPowell/CALM lLouer far right: Commongrass-blue, I Photo - Ttevor l-undstrom

I Beloa: Salt bushat CardenLake. I RottnestIsland. I Photo- AndrewWilliams/CALM

LESSERWANDERER (Danaus chrgsippus) This native speciesis a smaller relative of the monarch. As its name implies, it is very mobile. lts main area of occurrenceis to north the of Perth, October,females two to three weeks but influxes of the butterfly commonly later.It canbe seenwherever the food- occur in the south-west when plant tall speargrass(Austrostipo favourableconditions prevail inland. At flauescenslgtows. small butterfly found on Rottnest times, it is common on Carden Island, Island. It is blue above,and pale grey and was first recorded on Rottnest rrr SMALLGRASS-YELLOW below with indistinct markings. April 1995. (Euremasmilax) Individuals may be seen flying around The yellowwings of this smallish grassedareas near the main settlement, MARBLEDXENICA species,brighter on the upper side, where one of its food-plants, an (Ceitoneuraklugii) make it conspicuousand easily introduced clovet has become The marbledxenica is abundanton identified.It occurswidely in mainland established.The butterflies are also RottnestIsland in spring and early Australia,but most abundantlyin the commonly seenin shelteredswales and summer.It is a medium-sizedbutterfly, north. Only occasionallydo influxes yellow-brown hollowsat the westernend ofthe island above,with an iregular occur in Perth. This specieswas Next time you plan a trip or holiday pattern of bold black markings. recordedfor the first time on Rottnest Underneath,it is colouredin varying lo Rottnest.consider travelling in in September1999. just shadesof dark grey and brown, spring or early summer and you which enablethe butterfly to blend COMMONGRASS-BLUE might experienceanother aspectof this playground. into its surroundingswhen settledon (Zizina labradus) island For a brief lew weeks, it the ground. Malesfirst appearin The common grass-blueis another comes alive with delicate splashesof colour as the butterflies emerge ftom their resting places to graceus with their transient beauty.

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Winnerofthe 1998 Alex Harris l\4edalfor excellence in science and environment reDortino. LANDSCOPE VOLUIVETIFTEEN NUMBER 4, WINTER2OOO

DISCOVERINGTHESWAN CAROLYNTHOIVSON DANS, PETER DANS & ANN STORRIE. ..1 6 BUTTERFLIESONROTTNEST ISLAND ANDREWWILLIAI\tS& R0BERT P0WELL ...... 23 The Swan Riuer is a recreation areo for humqnsand a homefor migratorg CRUISINGTHEWANDJINA COAST birds. Seepage 16. CHRISDONE MANAGINGA FIERY CHANGE Peak Charlesand PeakEleanora, RlcKsN EEUWAGT & NTGEL HtGG5...... 37 protecled uithin Peak CharlesNalional Pqrk, fom granite islands in a sea of FILLINGTHE GAPS bush.See poge 10. KEIRAN.I\4CNAMARA,TONY BRANDIS & ANGASHOPKINS. .. .43

I\4ARINEMIIVIICS _ FIENDISH FISH

A partnerchipbetueen State and Commonwealthgouerments, and a group ofpastoralists is helping to fill the gaps in the conseruationestqte. Seepage 43.

BUSHTELEGRAPH, ,,.,,.,,.,.,,.,,.4 ENDANGERED ELEGANTSPIDER ORCHID ,.,,.,.,,.. .36

URBANANTICS TREEToP M|CE...... 54

Butterllies haue a short life span, but Many marinecreaturcs haue euolued theg bring pleasure to mang people ingenio tts suruiual met hods. uho uisit Rottnest Island. Seepage 23. Seepage 49. txecutive Editor: RonKawalilak ManagingEditor: Ray Baiey Editor: DavidGough Story EditoE: CarlsEailey,Verna ConeLlo, Carolyi Thomson-Dans S(ientifidtechnical advice:AndrewBurbidge, lanAbbolt, Well-knownAustralian artist Ken Done NeilEurrows, PaulJones and stati of CALMScienceDivlsion captures the colour and tutbulence of the Designand production:TiffanyAbFrin. [,4arid DJrl'ie horizontal aaterfalh on the Kimberleg's lllustration: Gooitzenvan der ltleer Wandjina Coast. Marketing: Estellede San Miguel a {08)91140296 Faxi (08)9334 0498 Subscriptionenquiries: 6 (08)93340481 or (08)9134 0437 ColourSeparation by CoourboxDigilal PrintedinWestem Australia by LambPrint o ISSN0815 446t A naterial.opyrightNopa.tolthecontentsolihe publ(ation maybe reproduced withourthe (onsentolthe publirhert Pleasedo notsend unsoliciied materialto tAl/DJCOPf, butleeliree to telephoneihe Editor. Paintiw by Ken Done Visitl,Ai/DSCOPf online on ouraward-winning Internet site RacingTide, Kimberley Coast, May 1999 NalureBaseat httpr/wwwcalm,wa,gov,au (51 x 36 cm) oil uagon and gouache Publishedby on papef. Deparhentof Conservationand Land l\,,lanagenrent, DickPerry Avenue, Kensington, Western Australia

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