Vol. 25 No. 2-text

Vol. 25 No. 2
Journal of the
Volume 25, Number 2. December 1991
President P. Davie
Vice -President S. Fairbairn
Secretary R. Hill
Treasurer T. Florin
Minutes Secretary H. Biddle
Activities Officer A.O. Richards
Conservation Officer E. Karplus
Journal Editor A.K. Morris
Newsletter Editor T. Karplus
Records Officer R.M. Cooper
Other Committee Members D. Seims
H. Jones
The object of the club is to promote the study and conservation of Australian
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Volume 25, (2) December 1991
This paper discusses various aspects of waterbird relationships from Lake Illawarra, N.S.W.
and its surrounding freshwater wetlands. A total of 96 species were recorded from the study
area between January 1981 and December 1990. These consisted of 27 resident species,
34 nomadic species and 35 migratory species. Spatial interrelationships from ten sample
units on the Lake and seven sample units from the peripheral wetlands are compared
empirically and statistically illustrating population structure, species diversity, species
evenness, species equatability, species richness, biomass distribution and trophic position
relative to the Lakes food web. Breeding resource facilities and the relative importance of
sample units are discussed in relation to the overall ecology of Lake Illawarra and its
peripheral wetlands.
Page 29 Australian Birds Vol 25 No 2INTRODUCTION
Lake Illawarra is a large shallow, coastal saline lagoon situated approximately 80
kilometres south of Sydney, New South Wales. It is an early -intermediate barrier estuary,
its entrance to the Pacific Ocean being a weakly active fluvial delta system at Windang (Roy
1984). The entrance channel is constantly being changed by shifting aeolian sands and a
high energy beach front (Young 1976), with either the north or south arm intermittently
connected by a tombolo to the rocky Windang Island, situated approximately 120m off shore
(Figure 1). Tidal flow into the Lake is restricted by estuarine islands and the partial in -filling
of the entrance channel to support Windang Bridge. This causes salin ity to be highly variable
within the Lake, depending on western stream inflow and the limited tidal influence (Eliott
eta/. 1976, Harris 1977). Four major watercourses enter the western perimeters ofthe Lake,
with the two larger streams, Macquarie Rivulet and Mullet Creek, depositing large annual
quantities of fluvial sediment and embody their own in -filling delta systems. Further details
on the Lakes hydrology and physiography can be found elsewhere (Eliott et al. 1976, Young
Three brief analyses of Lake Illawarra’s aquatic avifauna have appeared previously
(Howarth and Grant 1982, Mills 1983, Wood 1985). All three of these studies are of short
duration or anecdotal, and make little or no allowance for seasonal fluctuations of migratory
species’ populations, nomadism of endemic waterfowl and shorebirds, or the response of
avian population trends to climatic conditions over eastern Australia. There has been no
previous analyis of the Lakes peripheral wetlands with the brief exception of Killalea Lagoon
and its environs (Smith & Chafer 1987) and Coomaditchy Lagoon (Howarth & Grant 1982).
Similarly, no attempt has been made to correlate the concentration of species present with
the availability of suitable food resources, i.e. the littoral and benthic flora and fauna, or to
assimilate the function of the Lakes peripheral wetlands as a breeding habitat resource or
as a habitat refuge for drought affected species from the interior of the continent.
This paper attempts to draw some correlation between these factors based on a nine
year observation period and to illustrate both empirically and statistically the importance of
key habitats within the study area and their relative importance to the Lakes ecology.
Lake Illawarra has a total area of 3227 ha.(West 1985). Of this approximately 1070
ha. contain seagrass meadows (King 1988) and the author estimates a further 120 ha. of
inter -tidal mud and sand flats and saltmarsh are available for waterbird usage (see also
Yassini 1985). The peripheral wetlands encompass a total area of approximately 600 ha.
of which approximately 120 ha.is perennial water and associated aquatic vegetation, the
remainder is seasonally inundated wet meadow and ephemeral pondages.
Lake Illawarra was broken up into ten sampling units which are similar to those used
by Wood (1985). Where they differ, the present author believes these units represent a more
discrete appreciation for the avian community relationships involved in each unit (Figure 1).
December 1991 Page 30Additionally they correspond closely to the three most important sectors of the Lake outlined
by Mills (1983). The freshwater wetlands surrounding the Lake were separated into seven
sample units using relatively natural boundaries (Figure 1).
The study period is inclusive of January 1981 to December 1990, a period of 119
1 1
months or almost 10 years. The results presented in this paper are the cumulative results
of several specific and casual studies undertaken by the author and several colleagues
during the study period and outlined as follows: casual familiarization censuses of the study
area 1981-82; a monthly census of most sample units from January 1982 -December 1984
(18 censuses) and random casual censuses of most sample units thereafter; a detailed
study of the Windang estuary from January 1983 -June 1989 (156 censuses, Chafer 1989b);
a complete census of waterfowl in the study area in June/July 1985 and 1986 (Chafer 1985,
1986 and unpublished data); a three year study of Killalea State Recreation Area and its
environs 1982-1985 (Smith and Chafer 1987) and casual censuses thereafter; a continuing
study of the entrance and Why Juck Bay 1987-1990 by Chris Brandis (results used by
permission); census work at Coomad itchy Lagoon and Korrungulla Swamp by Ron Imisides
1981-1989 (results used by permission); casual censuses from throughout the study area
by Lindsay E. Smith during the study period (results used by permission). All censusing was
conducted at random in relation to to time of day and weather conditions, except those
conducted in the entrance where censuses were conducted largely at high or low tides to
limit the effect of waterbird movement during intertidal periods.
The results are presented in the form of a systematic list. The vernacular and
scientific names of a species are followed by, its status, period of usual occurrence (in
months) for migratory and nomadic species, population extremes, breeding occurrences
and habitat preferences (refer Table 1) during the study period and a brief annotated
account of the species general ecology in the study area. The habitat key is also used to
illustrate the environment of each sample unit in Figure 1, more detailed descriptions of the
sample units can be found elsewhere (Harris 1977, Mills 1983, Yassini 1985, Smith & Chafer
1987, King 1988). Table 2 is a tabulated account of the maximum number of individuals of
each species in each sample unit during the study period. No number indicates that species
was not recorded from that unit during the study period. At the bottom of the table are the
total number of species per unit (S), a measurement index of species diversity in each unit
(H’), the number of equally common species per unit (eH’) and an index for species
evenness in each community (E). The derivation and interpretation of these computations
are explained below. Figures 2 and 3 are rarefraction curves for Lake Illawarra and its
peripheral wetlands respectively. These offer a better measure of species richness in each
sample unit (Siegfried 1981, James & Rathburn 1981, Ludwig & Reynolds 1988, Krebs
1989) and is used to determine the number of expected species from a sample unit given
a hypothetical or real total number of individuals present, and to provide a visual comparison
of the species richness of the compared sample units.
Page 31 Australian Birds Vol 25 No 2To Wollongong & Sydney
Mullet Creek
Coomaditehy Lagoon
Koonawarra Bay
yan, Bevans Island
Ash Ponds Bay (
F ` Wtndang Bridge

Wuldang Island
Wollingurry Creek
Liale Lake
North Shellharbour Swmap
South Shellharbour Swamp
I t
km P Killalea Lagoon
fresh meadows
Dunmore Swamps
C.’ rock platform
To Nom, Killalea State Recreauon Area
December 1991 Page 32Key Sample unit Habitats
letter name available
A Koong-burry Bay s,t,u, v, w,x
B Koonawarra Bay s,t,z
C Yallah Bay s,t
D Koona & Haywards Bays s,t,u, v, w,x
E Karroo Bay s,t,v,z
F Why Juck Bay s,t,u,v,w
G The entrance s,t, v, w,z
H Windang Peninsular s,t,v,w
Griffins Bay s,t,u,v
J Lake Heights foreshore s,t,z
K Coomaditchy Lagoon s,t,v,x,y
L Korrongulla Swamp s,t,v,x,y
M Kanahooka Dam s,t,v,x,y
N Yallah Swamps & Ash Ponds s,t,v,x,y
O Albion Park Swamps s,t,v,x,y
P Killalea S.R.A. & environs s,t,u,v,w,x,y,z
O Little Lake ,t,v,x,y,z
Geographical names and sample unit boundaries of Lake Illawarra (A -J), its peripheral
wetlands (K-40) and habitats available in each sample unit (summarised from Table 1).
Classification of habitats on Lake Illawarra and its peripheral wetlands (modified from
Goodrick 1970)
Page 33 Australian Birds Vol 25 No 2Table
Key Type and description
s Shallow waters: Open water generally <3 metres deep and either saline, brackish or fresh, generally contains significant necktonic fauna and submergent vegetation. Saturated water margins: Intertidal mud/sand flats between high qnd low water marks and inclusive of substratum covered by < 200mm water at low tide. Receding water margins and muddy edges of freshwater bodies. Generally contains a large invertebrate fauna. u Saltmarsh: Largely exposed marginal vegetation dominated by samphire (glasswort) Sarcocornia quinqueflora and bordered by rushes and sedges. v Reed swamp: Reed/sedge meadows in low saline and freshwater environments. Includes dense Phragmites sp. beds around Lake margins. w Casuarina swamp: Medium to dense forest dominated by Casuarina glauca, generally on waterlogged land behind saltmarsh or reed swamp. Western and southern Lake margins and Dunmore. x Fresh meadows: floodplain grasses and herbs subjected to seasonal inundation, seasonal swamps vegetated with luxuriant semi -aquatic flora. Generally along Macquarie Rivulet, Mullet Creek and Dunmore. y Freshwater swamp: Deeper more permanent freshwater bodies including man made structures, largely bordered by tall emergent vegetation such as Spike Rush Eleocharis sp., Cumbungi Typa sp. and rushes Juncus sp. Includes most peripheral wetlands. z Rocky shore: Inter- tidal rockshelf surrounding Windang Island and rocky shoals at a number of sites along the northern, western and southern margins of Lake Illawarra and Little Lake. December 1991 Page 3430 500 1000 1500 2000 2500 3000 Figure 2 Observed number of individuals Rarefraction curves for ten sample units on Lake Illawarra. These curves illustrate comparative species richness, and can be used to predict the number of species present in each sample unit based on; Abscissa: the total number of individuals observed during a census. Ordinate: the predicted number of species for that total. A – Koong-burry Bay, B – Koonawarra Bay, C -Yallah Bay, D – Koona & Haywards Bays, E – Karroo Bay, F – Why Juck Bay, G – The entrance, H – Windang Peninsular, I – Griffins Bay, J – Lake Heights foreshore. 500 1000 1500 2000 2500 3000 Figure 3 Observed number of individuals Rarefraction curves for seven sample units from the Peripheral wetlands of Lake Illawarra. These curves illustrate comparative species richness, and can be used to predict the number of species present in each sample unit based on; Abscissa: the total number of individuals observed during a census. Ordinate: the predicted number of speciesfor that total. K – Coomaditchy Lagoon, L – Korrungulla Swamp, M – Kanahooka Dam, N – Yallah Swamp and Ash Ponds, 0 – Albion Park Swamps, P – Killalea S.R.A. and environs, 0 – Little Lake and North Shellharbour Swamp. Page 35 Australian Birds Vol 25 No 2tah tre STATISTICAL ANALYSIS The data obtained during this study and presented in Table 2, was subjected to several statistical analyses to evaluate the species diversity, number of equally common species, evenness of species populations and species richness in each of the seventeen sample units previously defined in this paper. The purpose of these analyses was an attempt to determine (statistically) which, if any, sample unit(s) were of more, or less, significance to the avifaunal ecology of Lake Illawarra and its peripheral wetlands. In order to accomplish this the ten Lake sample units were compared to each other and the seven wetland areas were likewise compared. This splitting of the two basic ‘macro – habitats’ was affected because of the obvious differentiating utilization by the species present of each of the two basic habitats (see discussion). The formulae used to determine each of the indices used are delimited below, along with a brief discussion of their use and interpretation. The indices used were selected following discussions outlined in Peet (1974), Smith (1980), Krebs (1985,1989) and Ludwig & Reynolds (1988). The species diversity of each of the sample units is calculated using the Shannon -Weiner index formula (Ludwig & Reynolds 1988): H’= – F (pi loge)pi 1=1 where H’= diversity index number s = number of species pi = proportion of Ah species to the total species of that sample unit This is the most commonly used diversity index (Krebs 1989) and is recommended by most leading ecology texts for use in large communities where the total number of species is known (Krebs 1985, Ludwig & Reynolds 1988). The larger the index number, the greater the diversity of the sample unit. The number of species which can be regarded as common in respect to the total number of species recorded from a sample unit is determined using the formula: I eH’= e( (pi loge)Pi) i=1 where eH’ = number of relatively common species recorded from that sample unit e = the base log use and the other subscripts are as defined in the previous index above. Page 39 Australian Birds Vol 25 No 2This number can also be obtained by simply calculating the reciprocal (antilog) of the H’ index value for that particular sample unit (Peet 1974, Ludwig & Reynolds 1988). Theoretically this calculates the number of equally common species in the sample unit. The resulting index number can be compared directly with the numerical results in Table 2 to evaluate the particular species these are likely to be. Evenness, or equitability of a community, is ideally a situation in which all species are of equal number in the total population. In reality this situation rarely occurs and a number of formulae have been introduced to compare the evenness of species across a normal community population. have used Ludwig and Reynolds (1988) recommended I Hill’s E5 formula. (1/D)-1 E eH’- 1 where E = evenness of the community eH = defined above D = E pi2 (where pi is proportionallity as defined above) i=1 Thus the diversity (H’) index for a sample unit can be compared directly with the evenness (E) index of that sample unit. The closer E approaches H’ the poorer the diversity of the community and the closer E is to 1, the greater the evenness in population structure for that habitat. The final statistical analysis used in this paper is to generate a rarefraction curve for each sample unit. These are presented in Figures 2 & 3. According to Ludwig and Reynolds (1988) and Krebs (1989), these curves offer the best comparison for species richness in each sample unit. The higher the species expected (E(Sn)) per total individuals, the greater the species richness of that sample unit. Concurrently, the steeper the rarefraction curve, the greater the evenness of species populations present in that sample unit. Such curves have been utilized previously in Siegfried (1981) and James & Rathburn (1981). Using rarefraction curves it is possible to illustrate a comparison of species which should be present (E(Sn)) in a sample unit for a particular total population (sample size (n),e.g. 1000). Thus the expected number of speciesfor each sample unit is calculated using the formula: December 1991 Page 40- s – E(Sn) = E 1- 1=1 n n Where E(Sn)= Expected species Ni = Number of indivduals of the ith species s = species N = Total number of species in the community n = sample size (a nominal value, 0 to < Ni per sample unit) Curves generated in Figures 2 & 3 were calculated using the ‘RAREFRAC’ computer program in Ludwig and Reynolds (1988). The E(Sn) number were generated for incremented values of 100, between 0-2800 (or cumulative total population totals) and then divided by two, allowing for seasonal varia -tion (i.e. austral summer and austral winter) in species differentiation. Thus the modified formula used here is: Is – Ni – P(Sn) = 1 i=1 n n 2 Where P(Sn) = Predicted numberof species per s.u. and other parameters are as defined above The resulting curves not only illustrate a comparison of species richness in each sample unit, but can also be used directly to estimate the number of species present in a sample unit at any time of the year given a total, real, or hypothetical population. Such a total can be obtained by ‘on site’ counting of all observable individuals or from the results of aerial photography. These graphs give a clear indication of avifauna! species richness in each sample unit, however low sample unit curves should be treated with caution, as they may be of vital importance to a few key species. The best example of this is sample unit H, which is of comparatively low species richness, yet of vital importance to Anseriformes and Podicipediformes as a feeding area, as well as to much of the Lakes primary production and its resulting food chain (see discussion). Preliminary testing of rarefraction curve predictions were carried out in most sample units by the author and colleagues during December 1990, January, February, April and July 1991. These initial results agreed with the predictions to within 1.5 species of the expected number of species for the population recorded. Further testing is being undertaken and these results will be reported elsewhere. Page 41 Australian Birds Vol 25 No 2RESULTS These results show that during the study period 96 species of waterbird were recorded from the study area. Of these 85 species were found on the Lake, while 76 species were recorded from the peripheral wetlands. The number of species found in each sample unit (s.u.) are recorded in Table 2. During the study period 27 species were found to be generally resident, 35 species migratory and 34 species nomadic. On the Lake, the entrance (s.u. G) produced the highest total number of species (67) over the study period, while on the peripheral wetlands, Killalea S.R.A. and its environs (s.u. P) also produced 67 species. A total of 22 species were recorded breeding in the study area during the study period. Furthermore 28 species were found to be mainly vertebrate carnivores (consuming mainly fish species), 56 species invertebrate carnivores and 15 species generally herbivorous. This compares favorably with similar studies overseas (Knox 1986). Statistically, greatest diversity from the Lakes sample units occurs in s.u. D, the south-western corner (Table 2) and this s.u. also has the greatest species richness (Figure 2). This tends to indicate that this area has a wider range of micro -habitats available for species utilization than the other sample units on the Lake, although the entrance (s.u. G) is equally comparable when one takes into account the higher disturbance incidence of this area (cf. Chafer & Brandis 1991). These two areas and s.u.’s A (Koong-burry Bay),F (Why Juck Bay) and (Griffins Bay) represent the most ecologically important portions of the I Lakes shoreline, based on both statistical and empirical data (Table 2, Figure 2). However when the total biomass and productivity of each sample unit is taken into consideration, the seagrass meadows off Windang Peninsular (s.u. H), is of immense importance (cf. Harris 1977), a point elaborated on in the discussion. In the peripheral wetlands, s.u.’s N (Yallah swamps and the Ash Ponds), O ( North Shellharbour Swamp and Little Lake) and P (Killalea S.R.A. and environs) offer, statistically, the greatest diversity of species and richness (Table 2 and Figure 3). Nonetheless it should be noted that all peripheral wetlands mentioned herein are used by resident (and some nomadic) species as breeding stations (see Table 2), a point enlarged on below. During the study period at least 15 species were recorded with total populations exceeding 200 individuals at any one time (Table 3). December 1991 Page 42Table 3 Maximum counts of the 15 most abundant waterbirds recorded in the study area 1981-1990 (this study and Wood 1985). Silver Gull 5000+ Little Pied Cormorant 533 Grey Teal 2820 Bar -tailed Godwit 430 Straw- necked Ibis 1200 Eurasian Coot 420 Black Swan 1172 Little Tern 362 Chestnut Teal 970 Australian Pelican 335 Hoary -headed Grebe950 Little Black Cormorant 234 Crested Tern 900 Maned Duck 206 Great Cormorant 600 Avian biomass totals for Lake Illawarra (Figure 4) and the peripheral wetlands (Figure 5) were calculated by extrapolating a mean annual population for each species from available data, then combining all species biomass for each Order (except Silver Gull Laws novaehollandiae) and representing this as a percentage of the total biomass for the two ‘macro -habitats’. They are illustrated as pie charts, with Silver Gull being separated from other Charadriiformes because of its consistently large resident population and its subsequent bias on the representation of other Charadriiformes in the graph. Total avian biomass for the Lake was estimated at 7192.5 kg/yr and at 1894 kg/yr for the peripheral wetlands. PODICIPEDIFORMS 1% PELECANIFORMS 1 9 % CICONIFORNES 3% ANSERIFORMS 62 GRUIFORMS 1% CHARADRI ‘FORMES 4% Silver Gull I 0% Figure 4 Biomass distribution for the six taxonomic Orders of waterbirds and Silver Gull on Lake Illawarra, expressed as a percentage of the total biomass. To calculate biomass, a mean annual population was estimated for each species and the resulting biomass per year estimate for each species in an Order combined. Silver Gull is separated to distinguish bias of other Charadriiformes. Mass estimates based on biometric data from Serventy (1985), Pringle (1987), Marchant et al.(1990). Page 43 Australian Birds Vol 25 No 2PODICIPEDIFORMS 1 % PELECANIFORMS 9% 1 CICONIFORVIES 1 9% O ANSERIFORMS 31 GRUIFORMS 9 fi CHARADRIIFORMES 3% O Silver Gull 1 8% Figure 5 Biomass distribution for the six taxonomic Orders of waterbirds and Silver Gull on the peripheral wetlands of Lake Illawarra, expressed as a percentage of the total biomass. Biomass calculated as per Figure 4. DISCUSSION Recher (1966), showed that in inter -tidal mud/sand flats, the vertical differentiation of the littoral invertebrate fauna within the substrate, can be compared favorably with the available food resources in a stratified forest. If one also considers the availability of free swimming organisms (the nekton) in the near shore (neritic) environment and their interaction with the benthic (bottom dwelling) flora and fauna, it is easy to understand the complex nature of such a littoral environment and the huge food resource which is available to the waterbirds which frequent such habitats. This can be especially appreciated when two or more congeners are present at any particular location, as each species feeds in a unique manner, thus minimizing the effect of direct competition between species for the available food resources (Siegfried 1981, Knox 1986). On Lake Illawarra, Anseriformes are primarily concerned with grazing submerged and emergent aquatic vegetation, occasionally consuming invertebrates. Although they are few in species, comparably they occupy the largest percentage of total biomass for all species combined (approx. 4486 kg/yr, Figure 4) and should therefore be regarded as the main (avian) primary consumer group on the Lake. Charadriiformes can be divided into two broad groups, the waders (Charadriidae, Scolopacidae and allies) principally feeding on littoral and benthic invertebrates. The second group, gulls and terns (Laridae) customarily feed on nekton (both pisces and crustaceans, though gulls also take invertebrates opportunistically), this includes Silver Gull which has also become a general scavenger December 1991 Page 44within the Lake environment. Average summer populations of Charadriiformes (excluding the ubiquitous Silver Gull) total around 750 individuals (Chafer 1989) and they are generally restricted to foraging in four principal s.u.’s (A,D,F & G). Excluding Silver Gull as a separate entity (approx. 720 kg/yr.) it can be observed that other Charadriiformes compose a much smaller percentage of the total Lake biomass (278 kg/yr, Figure 4) and food consumption is likewise of a lesser magnitude. Nevertheless a considerable quantity of individual invertebrates are consumed by the species present due to their high metabolic rate (e.g. Schneider 1978, Dann 1987, Kiviat 1988) and their greatest concentration occurs concurrently in s.u.’s with the greatest quantity of benthic and littoral invertebrates (Harris 1977). Pelecaniformes (approx. 1350 kg/yr, Figure 4) prey largely on neritic nekton and should therefore be regarded as the main secondary (avian) consumer group. Ciconiformes (approx. 212 kg/yr) prey on epifaunal invertebrates, amphibians and neritic nekton, while Gruiformes (approx. 72 kg/yr) feed largely on emergent, submergent and littoral vegetation occasionally consuming littoral invertebrates. Species in these latter two Orders generally have a large individual biomass, though their total populations are quite variable and, along with some Charadriiformes, appear to respond to the seasonal abundance of prey, climatic conditions over eastern Australia and falling water levels in the Lake. This causes them to be much more obvious during extended dry periods on the coast and/or times of inland drought. The Australian Pelican Pelecanus conspicillatus has increased in numbers through the study period, probably the result of the increasing population created by the establishment and expansion of a breeding colony on the nearby Five Islands Nature Reserve in 1983 (Smith 1984, Battam et a/. 1986, Gibson 1989). Three species of Podicipediformes occur on the Lake, two species (Great -crested Grebe Podiceps cristatus and Australasian Grebe Tachybaptus novaehollandiae) are relatively negligible in their impact on the Lakes ecology, however the third species of Podicipediforme, Hoary -headed Grebe Poliocephalus poliocephalus, can appear in very large numbers from time to time (with a corresponding biomass ranging between approx. 124-350 kg/yr). Its preference for epifaunal invertebrates (Fjeldsa 1983) found in the rich seagrass beds of s.u.’s F,G & H (Harris 1977) must have a considerable impact on these organisms populations during the period of the Grebes visit. This diversity of foraging strategy allows waterbirds to exploit the variety of food resources available on the Lake and the species diversity, richness and population dynamics of each sample unit is a testament of the nutrient trap and subsequent primary production each unit provides (cf. Siegfried 1981). As most food resources of estuarine avifauna are benthic or neritic in nature (both flora and fauna), sufficient areas containing these resources must be continually available to support a diverse avifauna. Unfortunately, such resources on the Lake are being rapidly depleted, mainly due to land reclamation and subsequent modification of the benthos around Windang Bridge, in Koonawarra and Griffins Bays and proposed developments in Koona Bay. The long term effect of these changes are uncertain though the results reported here and in Wood (1985) will provide a data base for future researchers to work with. Page 45 Australian Birds Vol 25 No 2stream source LAKE !LIGHT’ fluvial ILLAWARRA detritus photosynthesis products from autochtholous detritus saltmarsh, bacteria 5 blue-green algae seagrasses and phytoplankton microfauna macro -algae herbivorous birds (swans, ducks etc.) zooplankton herbivorous detritus feeding fish invertebrates suspension & filter feeding invertebrates benthic feeding detritus feeding fish plankton feeding fish fist; vertebrate carnivores invertebrate carnivores (pelican, cormorants, egrets (waders, ducks, ibis gulls, terns, herons) spoonbills, grebe) Ocean Figure 6 A simplified food web for Lake Illawarra, N.S.W., showing relative tropic levels for the three principal feeding categories of avifauna mentioned in text. Modified from Barnes (1974) and Harris (1976). December 1991 Page 46Because of their relative inaccessibility, sample units A and D are of extreme importance as a waterbird refuge for roosting and also contain important feeding habitats for Anseriformes, Ciconiformes and several Charadriiforme species, particularly Pacific Golden Plover Pluvialis fulva. Populations of up to 82 Pacific Golden Plover have been recorded from these two sites and although this seems a small number, it represents approximately 2% of the over -summering population visiting Australia and 6% of the N.S.W. population (Chafer 1989, Morris 1990, Smith 1992 in press). Such sites are regarded as being of international importance under the terms of the RAMSAR convention (Navid 1984, McComb & Lake 1988) and the JAMBA schedule (Morris 1990). Concurrently, s.u.’s F,H & contain important seagrass and macro algae beds (Harris 1977, West et al. 1985, King I 1989), which are important as the basis for all forms of marine and littoral ecosystems (McRoy & Helfferich 1980, Hutchings 1983, Knox 1986, Day etaL 1989, Larkum etaL 1989). The importance of these aquatic meadows in the estuarine food web is best understood by considering the following brief explanation. The products of photosynthesis (primary production) can be used directly by herbivorous grazers (ducks, swans, fish and invertebrates) and indirectly by benthic and nektonic fauna for feeding, avoiding predators, hunting and in particular, the spawning of pisces. Phytoplankton (diatoms, dinoflagelates and other single celled algae) reproduce en mass in the seagrass meadows and are subsequently consumed by zooplankton (copepods, amphipods and invertebrate larvae). These organisms, as well as the copious organic detritus resulting from the decomposition of marine vegetation and fauna, as well as that derived from fluvial deposition, supply an abundant food supply for the vagile and sessile filter feeding nekton, benthic invertebrates and detritivores. These organisms are subsequently preyed upon by carnivorous invertebrates and neritic nekton, which are in turn preyed upon by the wading and aquatic avifauna, which act as the apex of the Lakes food web (Ferguson -Wood 1959, Barnes 1974, Harris 1977, McRoy & Helfferich 1980, Smith 1980, Day & Grindley 1981, Hutchings 1983, Knox 1986, Day etaL 1989, Larkum et aL 1989 and Figure 6). It is thus imperative that all sites containing substantial benthic flora are retained in situ, so as to ensure a continued biodiversity of all organisms in the Lakes ecosystem. All seven sample units containing peripheral wetlands mentioned herein provide suitable breeding sites for 20 of the 22 species recorded as breeding during the survey period (the other two breeding in littoral casuarina forest). They are essential environments for most Gruiform es as well as Black Swan Cygnus atratus, Black Duck Anas superciliosa, Australasian Grebe and several endemic Charadriiformes and the migratory Latham’s Snipe Gallinagohardwickii. South Shellharbour Swamp is the only current breeding location in the Illawarra for the Black -winged Stitt Himantopus himantopus (Chafer 1989) and appears to be the only coastal breeding location for this species south of Sydney in N.S.W. (Blakers et aL 1984). This site is also what appears to be the main foraging location for Latham’s Snipe in the Illawarra, though the secretive nature of this species make detection arduous. Page 47 Australian Birds Vol 25 No 2Anseriformes occupythe highest percentage of peripheral wetland biomass, 594 kg/ yr (Figure 5), Ciconiformes and Pelecaniformes are also reasonably numerous (363. and 350 kg/yr respectively) though members of the later Order primarily use these sample units as a roosting, bathing and rarely, breeding (Little Pied Cormorant Phalacrocorax melanoleucos) habitat. In the peripheral sample units where feeding does occur, it probably plays only a secondary role in the feeding ecology of Pelecaniformes. At times nomadic Ciconiformes such as Straw -necked Ibis Threskiornis spinicollis, can outnumber residents, but appear to concentrate in areas of short term abundant prey. Gruiformes are generally restricted to peripheral habitats owing to their preference of freshwater environments. Charadriiformes and Podicipediformes occupy only a minor percentage of total biomass though as in saline environments, their higher metabolic rate ensures a relatively high consumption rate of available food resources. These analyses show that the remaining peripheral wetlands are of significant value to the Lakes avifauna and as such need to be included in any overall view of the Lakes ecology with respect to its avifauna. With such views in mind it is essential that the peripheral wetlands mentioned herein are afforded suitable protection by the relevant authorities, to provide enough future suitable breeding and foraging sites to cater forthe species that utilise them. The effects of climatic conditions over eastern Australia on the Lakes avifauna have been briefly addressed previously (Mills 1883, Wood 1985). A comparison of general annual weather conditions in N.S.W. during the study period (Anon 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990), with the occurrence of nomadic species (e.g. Hoary -headed Grebe, crakes, Red -kneed Dotteral Erythrogonys cinctus, Sharp -tailed Sandpiper Calidris acuminata etc.), show a general trend of increased occurrence during periods of inland drought. This compliments previous analyses that the Lake and its peripheral wetlands constitute an integral part of the coastal retreats utilised by nomadic species during periods of poor precipitation in other parts of the state (Mills 1983, Wood 1985). In conclusion it can be stated that Lake Illawarra has a year round total waterbird population ranging from 5000-8000+ individuals, probably partially dependant on climatic conditions over eastern Australia, while its peripheral wetlands often hold combined populations in excess of 2000 individuals. Such sites are recommended by the conveners of the RAMSAR convention to be of international significance and warrant suitable protection (Navid 1984, McComb & Lake 1988, Morris 1990). Although such protection is available in the study area at present, it is largely by default and few of the important sample units mentioned herein have any official protection. I have attempted to illustrate which sample units are of significant importance to the Lakes ecosystem and it is hoped that the relevant authorities will take notice and prevent further urban or destructive beautification and reclamation developments in these areas and thus afford the necessary security needed for the future biodiversity of the entire Lake Illawarra basin. December 1991 Page 48Finally, it would be useful for a series of papers similar to this, or the excellent collective work of Siegfried (1981), to be published correlating the waterbird dynamics of a significant proportion of New South Wales estuaries. Although some work is currently in press concerning shorebirds (Smith 1992), seagrass beds have been reasonably well mapped (West et aL 1988) and several aerial surveys of waterbirds have been published by the N.S.W. National Parks and Wildlife Service (e.g. Kingsford 1989,1990), no complete picture is available as to which estuaries are important, what portions of these estuaries are employed by ayes from an ecological standpoint which species of waterbird (and their , population dynamics) utilise these facilities or how these populations interact with the benthic and littoral food resources contained within N.S.W. estuarine environments. ACKNOWLEDGEMENTS am particularly grateful for the personal records, assistance in the field and I companionship of Chris Brandis, Ron Imisides and Lindsay E. Smith, without whose encouragement and support, much of the field work carried out in this study would not have been feasible. G.Barwell, P.Bath, L.Hurt, M.Parkinson and F.Ramsey also contributed personal records and assisted in field work at various times. I thank D.G.Gosper, K.Chafer, C.Brandis and A.K.Morris for providing many useful criticisms of an earlier draft of this paper. SYSTEMATIC LIST Italic letters after each entry indicates preferred habitat (refer to Table 1). Months in parentheses refer to period of usual occurrance; numbers, population extremities through entire study area during study period. Great -crested Grebe Podiceps cristatus Nomadic/visitor (Jun -Nov, 1-40), largely restricted to western margins and occasionally northern margins of Lake, foraging around deeper seagrass beds. Habitat s Hoary -headed Grebe Poliocephalus poliocephalus Nomadic (all months, 40-900), erratic in its appearance, being relatively common in 1982, 83, 84, 86, 88 and generally absent in 1985, 87, 89, 90. Prefers the eastern margins of the Lake, particularly around dense Zostera and Ruppia beds of Why Juck Bay and Windang Peninsular, where it presumably feeds on the rich benthic fauna. Occasionally found breeding in small loose colonies of 6-12 pairs on Coomaditchy and Killalea Lagoons (Smith & Chafer 1987). 1400 recorded in August 1980, just outside study period (R.Imisides pers comm., Blakers et aL 1984). Habitat s,y Australasian Grebe Tachybaptus novaehollandiae Resident (<100), not usually present on Lake, however several records from Why Juck Bay and the entrance west of of Windang Bridge suggest some tolerance of saline conditions. Common, with breeding populations on all peripheral wetlands. Habitat s,y Australian Pelican Pelecanus conspicillatus Resident (125-335), breeds locally on Five Islands Nature Reserve (Battam et a/. 1986, Gibson 1989). Well distributed throughout study area with largest concentrations occurring in the entrance and Why Page 49 Australian Birds Vol 25 No 2Juck Bay. Small numbers on most peripheral wetlands, with North Shellharbour Swamp and Coomaditchy Lagoon being particularly favoured as bathing, drinking and preening sites where, presumably, it is removing excess salt from its feathers. Habitat t,u,y,z Darter Anhinga melanogaster Nomadic (1-5), mostly occurring along lower Macquarie Rivulet and adjacent bays, occasionally appearing in larger swamps and lagoons. Habitat s,w,y Great Cormorant Phalacrocorax carbo Nomadic (40-600), found throughout study area, largest concentrations in entrance during winter months (Apr -Sep). Habitat s,w,y,z Pied Cormorant Phalacrocorax varius Resident? (5-27), generally restricted to western margins of Lake, fishing in deeper waters. Infrequently recorded loafing on entrance sand bars and fishing in surf margins. Habitat s,y Little Black Cormorant Phalacrocorax sulcirostris Nomadic (33-342), largest concentrations appear in entrance, found throughout study area, up to 150 roost at Korrungulla Swamp. Habitat s,w,y,z Little Pied Cormorant Phalacrocorax melanoleucos Resident/nomadic (194-533), occasionally breeding on Dunmore Swamps (Chafer 1989a) and Korrungulla Swamp, well distributed throughout study area with up to 350 roosting at Korrungulla Swamp. Habitat s,w,x,y,z Pacific Heron Ardea pacifica Nomadic (1-4), appearance presumably drought induced, generally fresh meadows and freshwater margins. Habitat t,x,y White-faced Heron Ardeanovaehollandiae ResidenVnomadic (all months 15-90), ubiquitous, opportunistic, showing little habitat preference, occasionally flocks at sites of abundant invertebrate prey, e.g. 81 near Kanahooka Lagoon June 1981 (R.Imisides pers. comm.). Habitat s,t,u,w,x,y,z Cattle Egret Ardeola ibis Migratory/nomadic (Mar -Nov, 1-220), fresh meadows and flood plain sections along western streams. Habitat t,w,x,y Great Egret Egretta alba Nomadic (all months, 1-25), largest concentrations in entrance during autumn, otherwise ones and two’s on most water margins. Habitat t,u,w,x,y Little Egret Egretta gafzetta Nomadic (all months,1-17), largest congregations in entrance during autumn, otherwise ones and two’s from most water margins. Habitat t,u,w,x,y Intermediate Egret Egretta intermedia Nomadic (all months, 1-7), usually an autumn/spring visitor to southern and western Lake margins. Habitat t,u,y Eastern Reef Egret Egretta sacra Nomadic (all months, 1-3), confined to rock platforms around Windang Island and Little Lake. Habitat t u z Striated Heron Butroides striatus Resident (1-8), secretive, can occur anywhere around Lake Illawarra and Little Lake, though most observations from western stream entrance margins, particularly where casuarinas Casuarina glauca are present. Probably nesting Macquarie Rivulet delta, Wollingurry Creek and Mullet Creek (infered from presence of juveniles in spring and early summer at these locations). Appears to be increasing in numbers. Habitat t,u,v,w,z Rufous Night Heron Nycticorax caledonicus Nomadic/resident? (all months, 1-13), nocturnal habit creates uncertain status. Small resident population at Primbee reported by Wood (1985) disbanded after removal of roost trees (R.Imisides pers. comm.). Small population Macquarie Rivulet delta. Habitat t,w December 1991 Page 50Black Bittern Dupetor flavicollis Resident (1-5), presence of immatures at several locations on western Lake margins suggests local breeding. Only recorded from dense casuarina stands along western watercourses. Habitat t,w Australasian Bittern Botaurus polioptilus Nomadic, lone birds recorded irregularly from Albion Park, Dunmore and North Shellharbour Swamps and Killalea Lagoon (Smith & Chafer 1987). Its crepuscular habit suggest it may be more common than records imply. Habitat t,v,y Glossy Ibis Plegadis falcinellus Nomadic (2-20), appeared only during drought conditions inland, few records. Habitat w,x Sacred Ibis Threskiomis aethopica Nomadic (3-100), irregular visitor, largely around Lake margins and fresh meadows. Habitat t,u,v,w,x Straw -necked Ibis Threskiornis spinicollis Nomadic (7-2000), generally confined to wet meadows, infrequently on western Lake margins. Habitat t,u,x,y Royal Spoonbill Platalea regia Nomadic (1-47), largest numbers repeatedly from Koona Bay and North Shellharbour Swamp, though occurs in all sample units. Habitat t,u,w,x,y Yellow -billed Spoonbill Platalea flavipes Nomadic (1-5), usually in small numbers with P.regia groups. Most often recorded in entrance and Koona Bay. Habitat t,u,y Black Swan Cygnus astratus Resident/nomadic (200-1172), breeds in all peripheral wetlands. Largest concentrations (often >500), occur in association with macro
algae and seagrass meadows off Windang Peninsular, Griffins Bay, Why Juck Bay
and Koong-burry Bay. Small flock (6-52) regularly observed flying north to north-
west during late spring and summer nights over authors residence. A large influx of
this species occurred in January/February 1991 with a maximum of 2212 recorded
from Lake Illawarra on 7 February 1991, just outside study period. Habitat s,v,y
Freckled Duck Stictonetta naevosa Nomadic (1-16), only recorded from Albion Park
Swamps and Kanahooka Lagoon January 1981 through February 1983 during
periods of inland drought. Habitat y
Australian Shellduck Tadorna tadornoides Nomadic (1-18), only recorded from Nov 1982
to Feb 1983 from Albion Park Swamps and Kanahooka Lagoon. Occurred once on
Lake (Wood 1985). Habitat t,u,y
Pacific Black Duck Anas superciliosa Nomadic (40-350), generally restricted to peripheral
freshwater wetlands where it breeds intermittently. Maximum of 113 recorded from
Lake, mainly south-western corner, occasionally breeds on western lake margins.
Habitat s,t,v,w,x,y
Mallard Anas platyrhynchos Introduced (1-20), recorded from most locations infrequently.
Habitat s,t,x,y
Grey Teal Anas gibberifrons Nomadic (300-2820), often the most numerous waterbird in
the study area (regularly >500),with sample unit counts frequently >500 for Koona,
Why Juck and Griffins Bays. Most often encountered loafing on shoreline or drifting
in shallow water, only infrequently encountered feeding, a habit similarly observed
by Wood (1985). Habitat s,t,u,v,w,x,y,z
Chestnut Teal Anas castanea Resident/nomadic (250-970), particularly favours seagrass
meadows off Windang Peninsular, Koona and Koong-burry Bays, showing a strong
association with Gracilaria and Ruppia seagrasses and macro algae beds (Harris
Page 51 Australian Birds Vol 25 No 21976, King 1988). Breeds in some peripheral wetlands. Habitat s,t,u,v,w,y
Australasian Shoveller Anas rhynchotis Nomadic (2-144), presence probably controlled by
conditions inland. Prefers western and northern brackish margins of Lake, particularly
Griffins Bay. Habitat s,y
Pink -eared Duck Malacorhynchus membranaceus Nomadic (1-153), presence probably
controlled by inland drought, generally only recorded from peripheral wetlands,
though up to 142 recorded in Lake entrance near Picnic Island for nine days in July

  1. During this period no feeding or swimming apparently occurred, all birds were
    observed loafing on a mud bank by a number of observers during diurnal hours.
    Habitat s,t,u,y
    Hardhead Aythya australis Nomadic (1-52), usually only recorded from peripheral wetlands
    and occasionally Griffins Bay. One, possibly two pair bred at Korrungulla Swamp in
    September 1990, the only local breeding record known to the author. Habitat s,t,y
    Manned Duck Chenonetta jubata Resident (16-210), prefers western floodplain margins,
    rarely recorded from Lake. Habitat s,t,v,x,y
    Blue -billed Duck Oxyura australis Nomadic (1-8), only recorded from Killalea Lagoon
    (Smith & Chafer 1987). Habitat s,y
    Musk Duck Bizura lobata Nomadic/resident (1-40), largest numbers appear from Ash
    Ponds, Koona and Haywards Bays. Ones and two’s from most freshwater wetlands.
    The presence of juveniles on Killalea Lagoon and Korrungulla Swamp suggest local
    breeding. Habitat s,y
    Buff -banded Rail Rallus philippensis Resident (1-8), present along Lake margins
    containing reed beds. Breeding recorded from Why Juck Bay. Habitat t,u,v,w,y
    Lewin’s Rail Rallus pectoralis Resident? (1-2), only recorded from Dunmore, January 1987
    (C.Sonter pers. comm.) and Korrungulla Swamp, August to October 1987. Habitat
    Bail lon’s Crake Porzana pusilla Nomadic (1-4), only recorded from Killalea Lagoon (Smith
    & Chafer 1987). Habitat t,y
    Australian Crake Porzana fluminea Nomadic (1-5), muddy reed bed margins in entrance,
    Why Juck and Griffins Bays. Also from North and South Shellharbour Swamps and
    Killalea Lagoon (Smith & Chafer 1987). Habitat t,v,y
    Dusky Moorhen Gallinula tenebrosa Resident (12-68), breeding populations on most
    peripheral wetlands and in Griffins Bay. Habitat s,t,v,w,y
    Purple Swamphen Porphydo porphyrio Resident (86-120), breeding populations on all
    peripheral wetlands and Griffins Bay (contrary to Wood 1985). Present on Bevans
    Island in entrance and occasionally found in Why Juck, Koong-burry and Haywards
    Bays. Habitat t,u,v,w,x,y
    Eurasian Coot Fulica atra Nomadic (10-550), usually prefers freshwater bodies, with
    breeding recorded from Coomaditchy and Killalea Lagoons. Occasionally large rafts
    appear in northern Lake bays. Feeding behaviour on muddy flats as reported by
    Wood (1988) has been observed on several occasions from Griffins Bay and
    Coomaditchy Lagoon. Habitat s,t,y
    Comb -crested Jacana lrediparragallinacea Only record is of a lone bird on Killalea Lagoon
    and Dunmore Swamp, Jul -Aug 1984 (Smith & Chafer 1987). Habitat t,y
    December 1991 Page 52Painted Snipe Rostratula gallinacea Lone bird recorded from South Shellharbour Swamp
    in Nov 1986. Habitat t,v
    Pied Oystercatcher Haematopus longirostris Resident (1-5), regularly recorded from Lake
    margins, particularly south-western corner and entrance. Breeding attempted at
    Macquarie Rivulet delta and Wollingurry Creek entrance in Oct 1982 and Nov 1985.
    The presence of immatures with adults foraging and loafing on entrance shoals in
    mid summer suggest at least occasional success. Rarely recorded from Little Lake,
    South Shellharbour and Korrungulla Swamps. Habitat t,u,z
    Sooty Oystercatcher Haematopus fuliginosus Visitor (1-3), breeds on nearby Five Islands
    Nature Reserve (Gibson 1989) and infrequently found on Windang Island and
    estuarine sand flats east of Windang Bridge. Habitat t,z
    Masked Lapwing Vanellus miles Resident (24-150), ubiquitous around most water margins
    and wet meadows, forms flocks up to 106 in Albion Park and Dapto areas during
    winter. Habitat t,u,w,x,y,z
    Banded Lapwing Vanellus tricolor Lone bird at South Shellharbour Swamp in Nov 1988
    (Chafer 1989b). Habitat y
    Grey Plover Pluvialis squatarola Summer visitor (Sep -Jan, 1-7), all records from sand flats
    east of Windang Bridge or saltmarsh in Why Juck Bay, with individuals remaining
    only a few days before moving on during southern migration. Most birds recorded
    in September still retain near complete breeding plumage. Habitat t, u
    Pacific Golden Plover Pluvialis fulva Summer migrant (Aug -Apr, 1-92), associates strongly
    with saltmarsh communities. Three important sites on Lake are Koona Bay (1-82),
    Haywards Bay (1-36) and Koong-burry Bay (1-51). A fourth site adjacent to Picnic
    Island (1-26) has recently been destroyed during foreshore beautification works.
    The Lake Illawarra population represents 2% of the Australian summering population
    (Chafer 1989b, Smith 1992). A small population (12-20), irregularly recorded from
    South Shellharbour Swamp. Habitat t,u,x,y,z
    Red -kneed Dotterel Erythrogonys cinctus Nomadic (1-15), presence probably reflective of
    dry conditions inland. Fairly regular at several sites from Jan 1984 -Oct 1986, after
    which the species has been generally absent from the study area. Breeding
    recorded from Koona Bay and Killalea Lagoon. Habitat t,u,v,x,y
    Hooded Plover Charadrius rubricollis Lone bird at Windang in Apr 1988. Nearest regular
    population at Bhrewerre Beach, Jervis Bay (Chafer 1984b). Habitat t
    Mongolian Plover Charadrius mongolus Three records of lone birds from Windang in Sep
    1983, Dec 1984 and Dec 1987. Habitat t
    Large Sand Plover Charadrius leschenaultii Two records of lone birds from Windang in Nov
    1984 and Aug 1988, two birds in Sep 1987. Habitat t
    Double -banded Plover Charadrius bicinctus Winter migrant (Jan -Sep, 1-34), generally
    confined to sand flats east of Windang Bridge and Koong-burry Bay, though two’s
    and three’s from most sample units. Habitat t,u,x,y
    Red -capped Plover Charadrius ruficapillus Resident (21-55), generally confined to
    Windang sand flats and saltmarsh communities at Koona, Haywards and Koong-
    burry Bays. Breeding recorded from all three sample units as well as Griffins Bay.
    Habitat t,u,y
    Black -fronted Plover Charadrius melanops Resident (6-14), usually confined to freshwater
    Page 53 Australian Birds Vol 25 No 2margins, occasionally visiting saline environments at Why Juck and Griffins Bays.
    Breeding recorded from Albion Park Swamps, Coomaditchy and Killalea Lagoons.
    Habitat t,u,x,y
    Black -winged Stilt Himantopus himantopus Resident (6-32), can occur in any sample unit.
    Breeding attempted at Killalea Lagoon in Nov 1981 and Yallah Swamps in Mar 1984.
    Has breed successfully at South Shellharbour Swamp (September -December)
    since 1985. Habitat t,u, w,y
    Red -necked Avocet Recurvirostra novaehollandiae One record of 21 birds at Windang on
    7 Jul 1984. These birds were extremely nervous and even attempted to feed in surf
    swash at Windang beach. Habitat t “
    Ruddy Turnstone Arenaria interpres Summer migrant (Sep -Mar), generally found on rock
    shelf at Windang Island and Boonerah Point, occasionally on entrance shoals.
    Wood (1985) recorded them from several other sites. Habitat t,x,y
    Eastern Curlew Numenius madagascariensis Summer migrant (Aug -Apr, 2-32), largest
    numbers occur in entrance. Habitat tu,z
    Whimbrel Numenius phaeopus Summer visitor (Aug -Jan, 1-7), generally found on mud
    flats at Windang with individuals rarely staying more than a few days, presumably
    due to a lack of suitable habitat. Habitat t,u,y
    Little Curlew Numenius minuta Lone bird on playing field adjacent to Why Juck Bay in Sep
  2. Habitat x
    Wood Sandpiper Tringa glareola Lone bird at South Shellharbour Swamp in Sep 1987.
    Habitat t,y
    Grey -tailed Tattler Tringa brevipes Summer migrant (Sep -Apr, 2-25), only recorded from
    entrance shoals, Windang Island and Little Lake. Habitat t,z
    Wandering Tattler Tringa incana Summer migrant (Oct- Mar, 1-2), only recorded from rock
    shelf around Windang Island (see Chafer 1989b for details). Most southerly
    recorded location in N.S.W. (Chafer 1984a, Doyle et al. 1985). Habitat z
    Common Sandpiper Tringa hypoleucos Lone birds recorded from Koong-burry Bay, Mar
    1981 and Little Lake, Dec 1988,1989. Habitat t,u,z
    Greenshank Tringa nebularia Summer migrant (Aug -Apr, 1-70), largest numbers from
    entrance shoals (up to 60) where they favour a small area between Picnic and
    Bevans Islands. Habitat t,u,y
    Marsh Sandpiper Tringa stagnatilus Summer migrant (Aug -Mar, 1-4). Habitat t,u,y
    Terek Sandpiper Tringa terek Three records of lone birds from Windang sandflats, Oct
    1983, Nov -Dec 1984, Dec 1985. Habitat t
    Latham’s Snipe Galliango hardwickii Summer migrant (Aug- Mar, 1-20), largely crepuscular
    in habit and restricted to reed/sedge beds and adjacent muddy margins. Largest
    congregations from South Shellharbour Swamp (<18). Habitat t, v,y
    Black -tailed Godwit Limosa limosa Summer migrant (Aug- Mar, 1-4). Habitat t,y
    Bar -tailed Godwit Limosa lapponica Summer migrant (recorded all months, 11-430), found
    throughout Lake sample units with largest numbers in entrance and Why Juck Bay.
    Habitat t,u,x,y,z
    Red Knot Calidris canutus Summer migrant (Aug -Apr, 2-146), mostly appears as a
    passage migrant during southern migration. Largest concentrations in entrance and
    Why Juck Bay. Habitat t,u
    December 1991 Page 54Great Knot Calidris tenuirostris Summer migrant (Aug -Apr, 1-9), usually found in
    association with Bar -tailed Godwits. Habitat, t,u,x
    Sharp -tailed Sandpiper Calidris acuminta Summer migrant (Aug -May, 6-782), presence
    largely controlled by conditions elsewhere across eastern Australia (Lane 1987).
    Greatest numbers recorded in the 1982-83 summer during inland drought (Wood
    1985). Largest flocks (up to 381) appeared adjacent to Picnic Island an area now
    destroyed by foreshore beautification work. Habitat t,u,x,y,z
    Pectoral Sandpiper Calidris melanotos Lone birds from adjacent to Picnic Island in Feb
    1984 and Nov 1986. Habitat t,u
    White-rumped Sandpiper Calidris fuscicollis Lone bird at Windang, Oct -Nov 1984 (Smith
    & Chafer 1989). Habitat t
    Red -necked Stint Calidris ruficollis Summer migrant (recorded all months, 7-190), largest
    numbers occur on entrance sandflats with smaller numbers intermittently from
    several sample units around the western margins of the Lake. Habitat t,u,y
    Curlew Sandpiper Calidris ferrunginea Summer migrant (Aug- Apr, 10-200), most regularly
    appears in entrance and Koona Bay. Habitat t,u,y
    Sanderling Calidris alba Summer visitor (Aug -Apr, 1-38), only found on sandflats east of
    Windang Bridge, most regularly during the autumn northern migration (Feb -Apr).
    Habitat t
    Silver Gull Larus novaehollandiae Resident (1300-5385), breeds on nearby Five Islands
    Nature Reserve (Gibson 1989), ubiquitous and uberous in all sample units. Habitat
    s,t,u, w,x,y,z
    Pacific Gull Larus pacificus Winter visitor (May -Jan, 1-9), generally only found in Lake
    entrance, all birds recorded (total= 29, mean= 2.9 +or- 2.3 s.d.) were immatures
    except for one adult on 14 January 1989. Habitat s,t,z
    Kelp Gull Larus dominicus Resident (2-35), breeds on nearby Five Islands Nature Reserve
    (Gibson 1989), usually only observed from Lake entrance and Coomaditchy
    Lagoon, though occasionally wanders into Lake proper. Habitat s,t,u,z
    Whiskered Tern Chilidonias hybrida Summer visitor (Sep -Dec, 1-33), erratic in its
    appearance and duration of occurrence. Habitat s,t,x,y
    White -winged Tern Chilidonias leucoptera Summer migrant (Nov -May, 1-8), apparently
    restricted to the entrance and around Windang Island. Displays close affinity with
    Little Tern population. Habitat s,t
    Gull -billed Tern Gelochelidon nilotica Lone birds at Windang, Sept 1987 and Coomaditchy
    Lagoon, Dec 1988. Habitat s,t,y
    Caspian Tern Hydroprogne caspia Winter visitor (Feb- Nov, 1-75), largest numbers occur
    May -Jun, generally in entrance. Rarely recorded outside Lake environs. Habitat s,t,z
    Common Tern Sterna hirundo Summer visitor (Oct -Apr, 1-100), regular only as a passage
    migrant during southern spring migration. Most birds are S.h.longipennis, however
    several individuals, presumably belonging to S.h.hirundo with black -tipped red bills
    and red legs have also been observed (see Chafer 1989b), feeds entirely in marine
    environment. Habitat s,t,z
    Arctic Tern Sterna paradisea Lone bird observed loafing with other terns at Windang on
    sand flats 17 Oct 1988.
    White -fronted Tern Sterna striata Winter migrant (1-100), restricted to Windang Island and
    Page 55 Australian Birds Vol 25 No 2entrance sand flats, feeds entirely in marine environment. Habitat s,t,z
    Little Tern Sterna albifrons Summer migrant (Sep -May, 1-362), one of the larger
    populations in N.S.W. (Fox 1975, Morris 1979). Endemic breeding sub- species now
    poorly represented in this population (see Chafer 1989b, Chafer and Brandis 1991).
    Habitat s,t,u,y,z
    Crested Tern Sterna bergii Resident (26-900 (Wood 1985)), breeds regularly on nearby
    Five Islands Nature Reserve (Gibson 1989), most regularly found in entrance.
    Habitat s,t,y,z
    Anon. 1981. Brief notes on the year 1981. Monthly Weather Review, New South Wales,
    December 1981: 14-18. Bureau of Meteorology, Sydney.
    Anon. 1982. Brief notes on the year 1982. Monthly Weather Review, New South Wales,
    December 1982: 5-10. Bureau of Meteorology, Sydney.
    Anon. 1983. Brief notes on the year 1983. Monthly Weather Review, New South Wales,
    December 1983: 6-11. Bureau of Meteorology, Sydney.
    Anon 1984. Part B, Notes on the weather for 1984. Monthly Weather Review, December
    1984: 20-24. Bureau of Meteorology, Sydney.
    Anon. 1985. Part B, Notes on the weather for 1985. Monthly Weather Review, December
    1985: 20-24. Bureau of Meteorology, Sydney.
    Anon. 1986. Part B, Notes on the weather for 1986. Monthly Weather Review, December
    1986: 20-23. Bureau of Meteorology, Sydney.
    Anon 1987. Part B, Notes on the weather for 1987. Monthly Weather Review, December
    1987: 20-24. Bureau of Meteorology, Sydney.
    Anon. 1988. Part B, Notes on the weather for 1988. Monthly Weather Review, December
    1988: 20-35. Bureau of Meteorology, Sydney.
    Anon. 1989. Part B, Notes on the weather for 1989. MonthlyWeather Review, DeceMber
    1989: 20-36. Bureau of Meteorology, Sydney.
    Anon. 1990. Part B, Notes on the weather for 1990. Monthly Weather Review, December
    1990: 20-36. Bureau of Meteorology, Sydney.
    Barnes, R.S.K. 1974. Estuarine Biology. London: Edward Arnold Ltd.
    Battam H.,Leishman A.J.& Smith L.E. 1986. Nesting of the Australian Pelican on Martin
    Island, Five Islands, New South Wales. Aust. Birds 20, 61-62.
    Blakers M.,Davies S.J.J.F.& Reilly P.N. 1984. The Atlas of Australian Birds. Melbourne:
    RAOU & Melbourne University Press.
    Chafer C.J. 1984a. Two unusual waders sighted at Lake Illawarra. The Stilt 5, 25.
    Chafer C.J. 1984b. The northern distribution of the Hooded Plover in N.S.W. The Stilt 5, 27.
    Chafer C.J.1985. 1985 Winter wader survey. LB.O.C. Newst Sept 1985: 7-8.
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    19, 17-38
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    C.J. CHAFER 69 Lake Heights Road, Lake Heights. N.S.W. 2502.
    After a week on Norfolk Island during 4-9 September 1982, where the only wader we could
    find was a single tattler, my wife and I spent the week of 10-18 September on Lord Howe.
    Among the various waders that appeared during that week, notable was an influx of Oriental
    Plovers Charadrius veredus, which have not been recorded there before.
    Numbers were as follows:
    11 September: One at the airport swamp; none elsewhere on the island.
    13 September: Altogether 47, all but three scattered along the airport’s grass runway and
    on the grass verge of the road. Of the three, one was at the airport swamp and two on the
    sea front opposite the school.
    16 September: Altogether 53, well scattered along the grassed parts of the island (39 at the
    airport, three opposite the school, five near the shops and wharf, six on Old Settlement Flat).
    They kept to the grass flats and, unlike the Golden Plovers Pluvialis fulva, Bar -tailed Godwits
    Limosa lapponica and Turnstones Arenaria interpres, did not move off to the shore at low
    Page 59 Australian Birds Vol 25 No 2All 53 were still present on the 17 and 18 September. They seemed very tame, taking
    little notice of people riding by on bicycles (the standard transport on the island), of cars, or
    of planes landing and taking off; some were even of the grass by the airport building, ignoring
    waiting passengers walking about. One road -killed bird measured culm en 22.9, tarsus 44.7.
    All were very alike in appearance, none with real breeding plumage and most
    seeming to fit book descriptions of im matu res. Upperparts were plain pale buff -brown, the
    feathers with broad margins of the same colouring but even paler; this upperparts colour was
    quite different from that of any plover have seen in New Zealand, a sort of faded washed-
    out brown with a buff tone pervading the whole surface, especially obvious on the pale
    feather margins. The broad superciliary and the face, chin and throat were washed very pale
    buff, the same as on the upper -feather margins, the wash extending onto the chest and
    fading to the whiteish of abdomen and undertail. The wash varied in prominence; on some
    birds it was strong, terminating abruptly at mid -chest, one terminating in a double scallop
    rather like a Turnstone’s chest band; others had only a very faint wash. One bird had its
    whole foreneck and breast with an apricot tinge, ending abruptly across mid -chest.
    Distinctive also was that the birds stood tall, with long yellow -brown legs and an erect trim
    appearance. In flight, the upper parts were uniform apart from a narrow white tip to the tail,
    and the feet extended slightly beyond the tail.
    On the ground, they kept loosely together but well spaced out, often chasing one
    another accompanied by a rippling rrrrr call. In flight, they gave a normal plover pit call.
    On our return to New Zealand, alerted the Ornithological Society of New Zealand
    regions of the possibility of a spillover to New Zealand. One bird was found, seen at the
    Greymouth airfield, West Coast, South Island, from 24 September to 2 October 1982
    (Lauder in Classified Summarised Notes, 1982 Notornis 31, 62).
    B.D. Heather, 10 Jocelyn Cres, Silverstream, New Zealand.
    December 1991 Page 60NOTICE TO CONTRIBUTORS
    Contributors are requested to observe the following points when submitting articles and
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  14. References to other articles should be shown in the text – ‘…B.W. Finch and M.D. Bruce
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    Finch, B.W. and M.D. Bruce. 1974. The Status of the Blue Petrel in Australian Waters Aust.
    Birds 9, 32-35
  15. Acknowledgements to other individuals should include Christian names or initials.Volume 25, No.2 December 1991
    Chafer C.J.
    Waterbird Dynamics of Lake Illawarra and Its Peripheral
    Wetlands 29
    Heather B.D.
    Oriental Plovers on Lord Howe Island 59
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