Birds of Cherry Lake, Altona, Victoria - Annotated Comments on Species and Seasonal Movements
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VOL. 11 (5) MARCH 1986 153 AUSTRALIAN BIRD WATCHER 1986, II, 153-166 Birds of Cherry Lake, Altona, Victoria - Annotated Comments on Species and Seasonal Movements By J.S. HUMPHREYS, 9 Pakenham Street, Blackburn, Victoria 3130 Summary Over a period of three years (July 1982 to July 1985 inclusive), 56 approximately three weekly surveys were made of the avifauna of Cherry Lake in metropolitan Melbourne (coastal Victoria). A total of 112 species (11 introduced) was recorded, 28 (25%) of them breeding. There was little seasonal variation in the average number of species recorded, but the composition of the avifauna changed seasonally: palaearctic waders and other migrants predominated in spring-summer; waterbirds and seabirds predominated in summer (possibly partly drought-related during the study period); winter visitors included altitudinal migrants and nectar-feeding lorikeets and honeyeaters when eucalypts were flowering. It is concluded that Cherry Lake is an important metropolitan bird habitat, particularly for waterbirds and grassland birds. Introduction The objective of this article is twofold- fir:st, to provide an annotated list of species sighted at Cherry Lake, Altona, Victoria, and second, to outline their seasonal patterns for the period July 1982-July 1985. These data will hopefully add to the already extensive, yet incomplete, information relating to the region's avifauna. Location Cherry Lake (37° 52'S, 144° 50'E, 3.0 m elevation), is situated within metropolitan Melbourne, and located approximately 15 km by road from the Melbourne G. P.O. (see Figure 1). Cherry Lake is a freshwater lake located on the basalt plains to the west of Melbourne, and the local area is consequently very flat. Its situation, only I km from the coast of Port Phillip Bay, has a significant effect on the number and types of birds found there. Port Phillip Bay and its surrounds are both nationally and internationally significant for the rich variety of birdlife supported by their coastal and wetland habitats (see Lane et al. 1984). Although Cherry Lake is located within the boundaries of the Local Government Authority of Altona, the Melbourne and Metropolitan Board of Works (MMBW) has jurisdiction over it, while the Altona City Council assumes responsibility for the upkeep of the adjacent recreation and resetve areas. As shown in Figure 2, the study area comprises Cherry Lake, the Cherry Creek inlet and the adjacent recreation areas. Climate Figure 3 shows the monthly rainfall totals as recorded at the meteorological station at Altona Council Offices adjacent to Cherry Lake. The nearest climatic station for which temperature data are available is located some 7 km west of Altona at Laverton, and Table 1 provides the mean daily AUSTRALIAN 154 HUMPHREYS BIRD WATCHER N 0 2 3 4 5 Kilometres "0 0"' Westgate 0: '""·~ WILLIAMSTOWN SALTWORKS PORT PHILLIP BAY Figure 1. Location of Cherry Lake, Altona, Victoria. N J .: :::~:::~~::•11 StoMn t -- Fence Une ·oo 200 300 Met•es Figure 2. Cherry Lake study area. VOL. II (5) MARCH 1986 Birds of Cherry Lake, Altona, Victoria 155 maximum and minimum temperatures recorded there. Temperatures range from a mean daily maximum of25.8°C in January to a mean daily minimum of 4.8°C in July (see Table 1). Meteorological records for the period 1967-1983 indicate that Altona experiences a mean annual rainfall of 605 mm distributed evenly over most months. As shown in Figure 2, the period of this study included the drought years of 1982-83 and 1984-85. The below average rainfall experienced at Altona for both these summers is apparent. In contrast, 1983 was a year of above average rainfall, and the extremely wet conditions experienced at Cherry Lake in the second half of 1983 most likely account for the absence of several species normally seen in the area during these months. In short, observations suggest that both numbers and types of species occurring at Cherry Lake have exhibited a close relationship to the general pattern of rainfall over the study period. mm 120 100 80 60 40 Means 1967-1983 20 1982 1983 1984 1985 Figure 3. Monthly rainfall, Altona, January 1982-July 1985. Vegetation Unlike Melbourne's undulating eastern suburbs, the flat basalt plains of its western suburbs are sparsely vegetated and consist essentially of grasslands. In this context, the immediate surrounds of Cherry Lake provide an excellent wetland area, combining grassy paddocks, native trees and shrubs, lakeside reed beds and areas of wetland weeds and grasses. The predominant dryland shrub vegetation of the lake surrounds comprises large areas of Tangled Lignum Muehlenbeckia cunninghamii and Thorny Plagianth Selanothamnus squamatus, and these species form favoured habitats for grassbirds, fairy wrens, chats and finches. The wetland areas of rushes and sedgeland (Carex spp., Gahnia spp., Juncus spp., Phragmites spp. and Typha spp.) are homes for V> Table 1 -0\ Maximum (upper) and minimum (lower) temperatures for Laverton (37° 52'S, 144° 45'E, elevation 6 m) July 1982-June 1985 Year Mean daily temperature ('C) J F M A M J J A s 0 N D Year 1982 13.1 17.8 16.7 19.8 25.2 23.6 20.7 1.9 4.9 4.5 7.1 9.9 12.0 8.9 1983 24.4 28.7 24.0 18.2 16.7 13.3 12.8 15.2 16.3 17.4 20.4 24.0 19.3 11.2 14.9 14.4 9.1 8.3 4.6 4.7 6.9 7.0 8.8 10.0 12.4 9.4 1984 23.9 26.0 22.5 19.5 18.0 15.1 12.9 15.5 15.3 19.6 22.4 22.6 19.4 :r: 12.6 13.0 10.7 8.5 5.4 4.7 3.6 6.1 5.9 7.6 10.2 10.7 8.3 c:::: ~ 1985 24.3 24.7 25.6 21.8 17.9 :r:'"0 12.4 12.6 14.5 11.0 6.5 :::0 1943-1984 av. 25.8 25.8 23.6 20.0 16.6 14.0 13.5 14.8 16.9 19.0 21.2 23.7 ~ 13.6 14.2 12.5 9.9 7.7 5.6 4.8 5.4 6.5 8.2 9.8 11.9 C/l Table 2 Variation in number of species by season Season No. trips Average no. species Standard deviation Spring 16 39.1 6.63 Summer 15 46.0 6.61 Autumn 13 46.2 6.05 Winter 12 44.8 7.32 VOL. 11 (5) MARCH 1986 Birds of Cherry Lake, Altona, Victoria 157 significant numbers of ibis, herons, spoonbills, egrets, waders, and other waterbirds. Even the areas heavily infested by weeds (especially Dumex crispus) contain concentrations of sandpipers and snipe in summer months. The existing trees have mostly been planted in the area by the Altona City Council, and comprise Melaleuca (especially M ericifolia, M nesophila and M styphelioides) and Eucalyptus species (especially E. leucoxylon, E. globulus, E. kitsoniana and E. cladocalyx). These trees provide habitats for parrots, honeyeaters, cuckoo-shrikes, magpies and introduced species. Land use Cherry Lake is located in an area of heavy industry, being in the midst of several large petrochemical complexes. Cherry Lake is now predominantly a recreational area, combining sports facilities with walking and running circuits, and fishing in the lake. Picnic facilities are available, and the adjacent area is used for various fairs and events throughout the year. Residential land use on the west and south sides ensures that human usage of the area is heavy. During the period of this study, it has been apparent that this factor has contributed significantly to damage to the area, largely through illegal off-road vehicular intrusion, pollution through rubbish dumping and weed invasion, excessive trampling of lake edges, and deliberately lit fires. These problems exacerbate the loss of wetlands resulting from MMBW and Council drainage and reclamation activities, and the loss of native vegetation that has occurred due to horses and rabbits grazing in the area. Methods The selection of Cherry Lake for this study originated from an entry in a Bird Observers Club publication that listed the area as a bird-watching region near Melbourne. On arrival in Melbourne in 1982, a reconnaissance of the area was made. I decided to make regular trips to the area despite its location some 40 km from my eastern suburbs home. Visits were made every month at approximately three-week intervals, although these were more frequent in spring and autumn in order to ascertain the approximate times of arrival and departure of migrant waders. A total of 56 trips was made from July 1982 to July 1985, eleven of which were in the company of fellow bird-watchers. A standard circuit of2-3 hours was traversed on each occasion, with observations commencing at dawn. The circuit commenced at the swampy areas and small lagoons of the south western corner of the lake (where waterbirds and some waders are usually prevalent but disappear or become less conspicuous once disturbed), continued around Cherry Lake, and concluded with a survey of the surrounding dryland environs. The trips were normally made on a Sunday morning, except when the weather was too bad for bird-watching or during the weeks of arrival and departure of waders, or when out-of-state visitors were interested to see the area. Because of the size of the study area itself (particularly Cherry Lake), and the many instances of human disturbance putting birds to flight, it was not possible to conduct an exact count of the numbers of all species and so only estimates were possible in some instances.