Corella,2002' 26(3): 79-84 AVIANPOPULATION CHANGES IN A DEVELOPINGURBAN AREA IN WESTERNAUSTRALIA OVER AN EIGHTEENYEAR PERIOD VICTORW. SMITH I KarrakatlaRoad. Goode Beach,Albany. western Australia 6330 Received:27 Nownbet 2000 Annual capture and recapture rates of a number o1 bird species obtained over an eighteen year period in an area cleared lor urbanization,have shown changes in populationswhich are consideredrelated to developmentin the area. The increase in thg number ol honeyeatersin particular,implies they havo benelitted from the prolilerationot nectar-producingnative plants in some residentialgardens. Other discrete changes ln the avian oooLllationare also described INTRODUCTION meant that much of lhe original vegetation was destroyed As water conservation was a priority in lhe area, quick-growing native shrubs In 1982, a bird-banding project was commenced to alld trecs which do not require much water werc oflen selected gathermorphometric data from avian speciesin the south for residential gardens. The bare or sparse nature of newly gardens years early of WesternAustralia. The continuationof this project to developcd blocks, a feature of some for several on, gave way !o tallcr shrubs and trees (up to l0 m in heigh0, in 2000 has provided unforeseen, though not entirely a relatively short time. Within two !o four years afte. completion unexpected,information on local populationtrends over of each rcsidence, several gardens grew flourishing slands of planls time. and small trees native to Western Australia. This provided on_8oing nectar sources throughout the year with. for e\amplc, CalListennn, Large areas of coastal Australia have undergone Grcvillea, Kunzea and MelaLeuca species flowering during the transition from remnant bushland to suburban winter and early summer and El.cdllptrr species flowering during development.Urbanization brings mixed blessingsfor the summer and autumn Furthermore, water was made frcely avrrlable ro lhe bird, b) mdnJ rcsident' birds.Clearing remnant bushland removes food resources, shelterand breedingsites. The provision of water, food Stuclysites and some vegetativecover in some residentialgardens, GOODE BEACH. A major part of this study was particularly the establishment of nectar-producing conducted in the author's garden, hereafter refened to as plants to encouragehoneyeaters, is certainly beneficial. Goode Beach, in one of the subdivisions.In 1982,upon Contrarily, bird-killing domestic animals are often completion of the house building, revegetationof the introducedto the area and the use of chemicalsfor pest garden commenced,working outwards from the house. control can havedeleterious effects on presentand future Native species were planted, including CaLListemon, generationsof birds. Grevillea, Calothamnus, Kunzea and several EucaLyptus This studyreports on changesin avianpopulations which species,including E. lehmanii which were resistantto "Dieback" haveoccuned over l8 yearsin a small,developing, coastal (Phytopthora and Armillaria intections), residentialarea in the extreme south of WesternAustralia. whereas some other ornamental eucalypts succumbed. Some indigenousMani and Jafiah saplingsalso survived. STTJDY AREA The housewas not fully occupieduntil 1986,but from Goode Beach (l17"56'E, 35'05'S) is ao isolated residential 1982 was visited every four to six weeks for periodsof enclave of 160 subdivisions (each block approximatcly 0.1 h) on severaldays at a time while retaining earthworkswere the southern shore of King George Sound and conriguous with completed.At eachvisit one 13 metre four shelf rnist net the central northern boundary of the Tomdirrup National Park, (30 m.) was next one of the soulhernmost national parks on rbc south coast of sq. erected to the house. The net Westem Australia. remainedopen all day, but was constantlymonitored and closedat night or during inclementweather, In 1982, when this study commenced, only 26 blocks (169.) were dcveloped. bua by 2000, houses have becn built on more By 1992, the vigorous growth of vegetation necessitated than 70 per cenl of the subdivisions. a changeof net site: three new sites were selected,all Prior to development, thc vegelation of Goode Beach resembled within 30 metresof the house,using netsof lengtheither that found in the adjacent Tomdirrup National Park, including 9 metres(20 sq. m.) or 13 metres.Nets remainedopen thickets of Pcppermint Agrrir rel?rrt/.r. mallee-type Jarrah fiom dawn to dusk to achieve maximum trapping effort Eu(olyptus ntrrSitnta, Matti E. caloplrylla, Karri, E. diyersicolor and low- ro medium heighr hearh interspersed wirh nectar- within a defined area of approximately 0.2 hectares. producing plants such as Bdntria, Adenantho.t, Anigozanrlnt and Callistenon. In January 1997 a wildfire burnr mosr of Tomdirrup METHODS National Park adjacenl ro rhe study arca (Smirh 200t). Birds were caughl in mist nels ar coode Beach from 1982 !o Due to the small size of thc subdivisions. most were cleared 2000. Birds retrieved from mist nels were individually banded with enlirely of vegetation before building commenced. Furthermore metal bands, and standard measurements were taken for a the need 10 maintain slashed firebreaks on undeveloped blocks concomitanl study on the demographics of the local avian population. V W.Smilh: population Auian changesin an urbanarea in WA Corella26(3) TABLE I Annurl net nrea avaihblc in coode Beach wirh average ner arcas from l98l ro 1987 and 1992 ro 2000. Number of nets and Days open Total net arca Averagc ner arca 1983 lx30 ll 930 198,1 46 4,10 1985 5l s30 I 308 1986 50 500 l9E7 38 140 199) 2x30 30 800 l99l 2x20 12 680 1994 I x20ilx3t) l9 950 1995 2x30 29 140 1996 I x 20;I x30 4{l 2 000 l 935 1991 lx20tlxl0 40 2 000 1998 2x30 3l I 860 1999 3x20 l9 2 1,10 2000 I x20rlx30 2 050 As nettlng was sporadic from I988 to 1991, results of nist net days they werc open each year. From these two figures has been capturcs were presentedfor those caught from 1992 to l9g7 and calculatedthe annual total net arca availablc in square metres. No irom I992 to 2000. Annual captLfe rates were calculated from netling was carried ou1 during period ot absencesfrom April to July year of onc 1o June of rhe following ycar. June in 1987, 1992. 1995 and 1998. Nclting commenced in Dcccmber 1982, so rhe firsr year's From 1992 onwards rwo external sites, Hilkop and Roadside(see records, lo the end of June 1983, represcntcdonly six months. Appendix l) wirhin one kilometre of Goode Bcach, were operaled During thal period the ner was erectcd and opened on 3l days. sporadicallyto confirm which bird specieswere prescnt within lhc Torndirrup National Park in the vicinity of Good€ Beach, bul lhis To facilitare subscquenlcomparisons, Table I shows lhe numbcr was no( inlcnded to provide comparable figures. A major wildfire of nets and area of each in square metrcs; also the numbcr of burnt bolh siles iir 1997. NewHolland Red Honeyeater Wattlebird 5 0 30 Silvereye White-browed Scrubwren Western Spinebill Grey Y53338F333 Currawong Figure AnnuaL (solid .1 Mplurc! black) and rercptures (hat(hed) of .tix [pecies: New ('lland Hon.Jeater: Sitvercte; westem Spinebitt; Red wattlebid: white'btu\'red Scrubwren ye ancl Grey Currcwong. (Note: The i.al scale o.f tequency difers betwein the Jtst and last three spedes of birds). 81 September,2002 V W Smith: AvianPopulation changes in an urban area in WA RF.SULTS abundant species and the predatory Grey Currawong Strepera versicolor (4 nectivores, I insectivore and I from Overall, 1554 birds of 4l specieswere captured omnivore)are shown (Fig. l) to demonstratethe variable 2000. Those December1982 to 1987 and from 1992 to capture patterns encountered. Annual totals of the Appendix l, in caught in Goode Beach were listed in remaining species (more than ten individuals banded) and 498 (329o) were descendingorder of abundance.Of these, recaptures are listed in Table 2. No pardalotes were 1982to June 1992,516 birds recaptured.From December recaptured,but banding and recapture rates and maxlmum at the one site in GoodeBeach. of 26 specieswere caught longevity recorded for the 13 remaining species in Goode Capture data during 1982 to 1987 and 1992 to 2000 Beach are summarizedin Table S Recapturerates varied for the 15 species most frequently banded in Goode from 6 per cent to 34 per cent. Six individuals of Beach. where more than ten individuals were banded threespecies were recaplurednine or more times.whereas (Appendix l), are shown in descending order of 2l individuals of five species were recapturedfive or abundancein Figure I and Table 2. The tlve most more times. TABLE 2 The number of birds captured (B = Banded) and recaptured (R) al Goode Beach from 1983 lo 1987 asd from 1992 to 2000, in each case for year ending 30 June. nata are for specics where more than l0 individuals were banded. For the top five most frequently banded species and the Grey Currawong,scc also Figure l First period Second period Totals 1983lo 1987 1992 to 2000 l st/2nd r983 19841985 t986 198? >><< i992 1993 1994 1995 19961997 1998 1999 2000 Periods Colden Whistler B 2tl l0 6 5 35 4t4l R I I Spolted Pardalote B 9/t0 R '7/t1 Drown Honeyeater B 4 R I Grey Fantail B 2 3/t3 R I Red'winged Fairy-wren B t'7 I 2/14 R 6l Strialed Prrdalote B 4/t0 R Inland Thornbill B 2 3^2 R 1 22 Laughing Kookaburra B 3 3/l0 R Red-eared Firetail B 3/9 R I Tolal (all spccies) 38/130 TABLE 3 Bandirg rates. in descendingorder of frequency,capture rates and lonSevityof 15 speciescaught in Goode Beach, for which more than l0 ildividuals were