Vol. 19 No. 2-text

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Journal of the
Vol 19, No 2 April, 1985
ISSN 0311-8150
Registered by Australia Post Publication No NBH0790THE N.S.W FIELD ORNITHOLOGISTS CLUB
PATRON A.R McGill. 0 A M
D Turner
The object of the Club is to promote the study and conservation of Australian birds and the
habitats they occupy
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Manuscripts should be sent to the Editor at Dept of Ornithology Australian Museum 6 8
College Street, Sydney 2000Vol. 19, No. 2 April, 1985
Lake Illawarra is a large coastal lagoon some ten kilometres south of Wollongong, NSW. From
general observations spanning many years it appears to be significant as a drought refuge for
waterfowl and as a wintering ground for migratory waders, and this study was undertaken as an
attempt to quantify the importance of the lake to these and other waterbirds. The lake was
sub -divided into 12 areas so that the relative ecological importance of each could be assessed,
and 12 censuses, at approximately monthly intervals, were undertaken over a 12 -month period.
surveyed only species in the orders: Podicipediformes (grebes), Pelecaniformes (cormorants
and allies), Ciconiiformes (herons and allies), Anseriformes (ducks), Gruiformes (crakes and
rails), and Charadriiformes (waders, gulls and allies). also reviewed past records, and mention
is made of all waterbird species for which can trace reports of occurrence on the lake. know of
no reports of any seabirds (Procellariiformes), and only a single report of a Little Penguin
Eudyptula minor (Sphenisciformes), on the lake18 AUSTRALIAN BIRDS 19121
The geography and hydrology of Lake Illawarra has been studied in detail (Anon 1976, 1982)
Briefly, it is a coastal saline lagoon 9.5 km long and 5.5 km wide, largely surrounded by urban
development (Fig. 1). It has an area of 32 km2, a perimeter of 40 km and a catchment of 200 km2
The maximum depth is about 3.5 m, with almost 25 per cent of its area less than 1.2 m deep (Fig.
2). Restricted by Windang Bridge, its entrance to the sea consists of small islands surrounded by
myriad channels, salt marshes and sand or mud flats. The main channel changes in location
and depth depending on rainfall in the catchment area and wind or wave action at the entrance
During recent years it has been about 3 km long, 100 m wide and 2 m deep. The entrance is
occasionally completely closed by a sand bar
Little fresh water enters the lake during dry weather and, because of the barrier formed by
the sand bar, the volume of sea water exchanged during each tide cycle is only about two per
cent. An appreciable tidal rise and fall occurs in the entrance channel but the main body of
water fluctuates only about five cm. Salinity usually approaches that of the sea, but rainfall in
the catchment has a marked effect on both lake level and salinity. After heavy rain the level may
rise 1.5 m and the salinity may fall to 25 per cent of that of sea water. but such a surge is usually
discharged within about four days.
The extensive marginal shallows, including the underwater delta barrier shelf, support a
dense growth of sea -grasses (Fig. 2). Zostera sp. (eel -grass) is predominant, but Ruppia spp. are
also common. Most exposed margins and tidal flats consist of sand or sand and mud mixtures
(50-95 per cent sand).
Twelve censuses were undertaken between May 1982 and May 1983 but began preliminary
work in June 1981 to gain familiarity with tidal influence, access and favoured habitats The
lake was divided into 12 areas (A -L, see Fig. 1) and the number of individuals of each bird
species was recorded in each The area surveyed is enclosed by the high water mark and the
sand bar at the entrance; surrounding waterways such as Mullet Creek, Macquarie Rivulet and Wollung urry
Creek were not included.
Censuses, all conducted on foot, were made at intervals of approximately one month. Boat
access to deeper water was not considered necessary because nearly all birds were seen at
depths of less than two metres used a 17 x 60 mm telescope and 8 x 40 mm binoculars, and
coverage was considered reasonably complete
The results of the survey are presented in Tables I and II The following discussion deals mainly
with this survey but also contains references to species recorded in the past but not during myAUSTRALIAN BIRDS 19 (2) 19
Figure Map of Lake Illawarra, showing census areas and major geographic features
survey. It focuses on population levels, seasonal fluctuation, habitat preference and
GREBES (Podicipedidae)
Although previously recorded as uncommon except for occasional large aggregations on the
backwaters of the lake (Gibson 1977), Hoary -Headed Grebes Podiceps poliocephalus were
common all year, favouring the western edge of the delta barrier shelf (Area H). Rafts often
contained 300+ birds feeding actively in association with Silver Gulls. Several Great Crested
Grebes P. cristatus were present in deeper waters of Koonawarra Bay during May 1982, when
lake salinity was average and stable. Subsequent to the survey, a flock of 39 was recorded in the
same area on 25 August 1984 (L.E. Smith, pers. comm.). did not record the Australian Little
Grebe P. novaehollandiae. It occurs only rarely; I know of no sightings between June 1979 and
May 1984, but its presence was noted by Howarth & Grant (1982) in 1979. This grebe tends to
avoid saltwater habitats and was not, for example, recorded by Gosper (1981) in similar
environments during an extensive survey of the Hunter and Richmond River estuaries
elsewhere in New South Wales.
PELICAN (Pelecanidae)
The population of Australian Pelicans Pe/ecanus conspicillatus was evenly distributed and
stable during the survey (average count 190). Birds usually rested on favoured banks remote
from disturbance.
DARTER (Anhingidae)
Two Darters Anhinga melanogaster were seen in Area C on 3 August 1982. The species is rare
on the lake, generally preferring fresh water
Cormorants (Phalacrocoracidae)
Four species occur regularly on the lake. Preferred roosts were sand flats in Areas G and H, and
trees on Picnic and Bevans Islands. Little Pied Cormorants Phalacrocorax me/ano/eucos were
easily the most numerous but Little Black Cormorants P. su/cirostris were also common. Counts
of Great Cormorants P. carbo generally ranged between about 20-60, but 268 were recorded in
early August 1982. Pied Cormorants P. varius were least numerous and preferred more remote
locations such as the sand bank north-west of Bevans Island, rocks off Hooka and Gooseberry
Islands, and tree -root debris in Macquarie Rivulet delta.
White-faced Herons Ardea novaehollandiae, Great Egrets Egretta a/ba and Little Egrets E
garzetta were the most common species Counts of White-faced Herons typically ranged from
about 20-30, but 75 were counted in early September 1982, when water level was very lowAUSTRALIAN BIRDS 19 (2) 21
Figure 2 Map of Lake Illawarra, showing depth contours and major ecological features22 AUSTRALIAN BIRDS 19 (2)
after protracted dry weather; most were foraging in shallow sea -grass beds around Cudgeree
and Bevans Islands. Little Egrets (average count 11) were almost as common as Great Egrets
(average count 14), and there was no marked fluctuation in numbers of either species. Cattle
Egrets Ardeola ibis were recorded irregularly in small numbers.
Plumed Egrets E. intermedia, Mangrove Herons Butorides striatus, Rufous Night Herons
Nycticorax caledonicus, and Black Bitterns Dupetor flavicollis were recorded only occasionally.
The two last-named were first noted in February 1983 at Macquarie Rivulet delta, which
supports a relatively large stand of swamp oak Casuarina glauca. I subsequently noted Rufous
Night Herons on 19 March 1983, and saw one Black Bittern on 10 March, one on 17 March,
and another on 28 May 1983. Shy and easily overlooked, both species may be resident.
Although did not record them on any census, about six Rufous Night Herons roost daily in
Pinus insignis trees at nearby Primbee and fly out at dusk each night to feed, usually northwards
towards Griffin Bay but sometimes southwards towards Korungulla Swamp (R.N. Imisides,
pers. comm.). Because single birds have sometimes been spotlighted while feeding on the lake
foreshores it is probable that this group uses the lake and Korungulla Swamp as feeding
grounds all year round. The Pacific Heron Ardea pacifica, Little Bittern Ixobrychus minutus and
Australasian Bittern Botaurus poiciloptilus have been occasionally recorded in the past.
STORKS (Ciconiidae)
The Black -necked Stork Xenorhynchus asiaticus was recorded only prior to the survey.
Royal Spoonbills Plata/ea regia (average count 20) and Sacred Ibises Threskiornis aethiopica
(average count 49) were evenly distributed and nearly constant in numbers. Yellow -billed
Spoonbills P. flavipes were seen on five censuses but in very small numbers, and saw
Straw -necked Ibises T. spinicollis only once, resting on the sand bar off Hooka Point.
Black Swans Cygnus atratus were consistently recorded in good numbers in all sea grass areas,
but most preferred the large delta barrier shelf (Areas G and I). My maximum count was 750 (on
7 April 1983), but totals of 1000 birds have previously been recorded (Gibson 1977).
The Grey Teal Anas gibberifrons was by far the most common duck. In the first ten counts
the maximum number of birds was 2820, but on the last two censuses numbers had dropped
dramatically following good rains in the Murray -Darling region on 19 and 20 March 1983. The
response of this species to rainfall was discussed by Frith (1982) who argued that it can detect
heavy rains more than 100 kms away and will move to newly flooded areas within a few days
Approximately half of the Grey Teal censused were resting on mud and sand banks along
margins with extensive growth of common reed Phragmites sp., the remainder were either
loafing or feeding in shallow water Areas G, I and K often contained large numbers. My survey3891
was conducted during a period of severe drought over much of inland Australia; the large
numbers of Grey Teal (consistently approaching or exceeding 2000 birds) frequenting the lake
throughout the survey, together with the abrupt decline following good rains in the interior,
strongly suggests that Lake Illawarra is an important drought refuge for this species.
The less common Chestnut Tea IA. castanea was found in greatest numbers in Areas D and
E. Most were feeding. The aquatic plants Ruppia and Lamprothamnium predominate in Area I,
and Gracilaria in Areas D and E (Anon. 1976). Delroy (1974) reported that in the saline habitat of
the Coorong, South Australia, both Chestnut and Grey Teal fed almost exclusively on tubers of
Lamprothamnium and Ruppia, while Norman and Mumford (1982) also found that Ruppia was
well represented in the diet of Chestnut Teal shot in the saline Gippsland Lakes, Victoria. This
teal’s preference for the Gracilaria-rich Areas D and E during my survey suggests that this plant
may also be an important food for Chestnut Teal at Lake Illawarra. Unlike the Grey Teal,
numbers of Chestnut Teal did not markedly decrease after the rains of 19 and 20 March 1983,
which is consistent with the view that the Chestnut Teal is a sedentary species showing little
dispersal associated with rainfall (Frith 1982).
The Pacific Black Duck A. superciliosa was observed on nine censuses but in relatively
small numbers (average count 6). The birds did not appear to favour any particular area, and
were recorded in all but three. 20-30 Blue -winged Shovelers A. rhynchotis were present
between May and October 1982, mostly in Griffins Bay, their presence also no doubt drought –
induced, since their preference is normally for freshwater swamps (Gibson 1977, Frith 1982).
Musk Ducks Biziura lobata preferred the deeper water of Koonawarra and Haywards Bays and
were seen on five censuses, always in small numbers (max. 5).
Mallard A. platyrhynchos, Pink -eared Duck Malacorhynchus membranaceus, Hardhead
Aythya austra/is, Maned Duck Chenonetta jubata and Australian Shelduck Tadorna tador-
noides were each recorded only once. Both Pink -eared and Maned Duck flocks were seen on
separate occasions after heavy rain in the catchment area. Four Pink -eared Duck had been seen
for some time previously at nearby freshwater Kanohooka Lagoon and its rise in water level may
have caused them to search elsewhere for food. Similarly, Hardheads were almost always
present on Kanohooka lagoon and the only sighting on the lake (10 birds in nearby Koonawarra
Bay on 30 May 1982) may have been birds temporarily disturbed from this more permanent
freshwater habitat. Howarth & Grant (1982) mention two Australian Shelducks which
frequented the lake for several days in 1979, but recorded the species only once flock of 14
seen in February 1983. I am not aware of any record on the lake since. In contrast, I regularly
saw several on nearby Albion Park Lagoon throughout the summer of 1983-84.
All ducks, except Musk Duck, that were sighted on the water were resting or feeding at
depths less than about one metre.
Griffins Bay is very shallow (with depths gradually increasing from its eastern shore to 1 5 m),
supports diverse aquatic vegetation (including algae), and is shielded from disturbance fromAUSTRALIAN BIRDS 19 (2) 29
nearby heavy vehicular traffic by beds of common reed, Phragmites sp. Rallids were seen only in
this bay during the survey, except for a single record of the Australian Spotted Crake Porzana
fluminea in Cudgaree Bay. Dusky Moorhens Gallinula tenebrosa and Eurasian Coots Fulica atra
were seen on every census in consistent numbers (average counts 8 and 34 respectively). The
presence of three juvenile Dusky Moorhens in company with adult birds on 17 December 1982,
and markedly lower counts in October (presumably due to adults being hidden at nests)
indicates that this species successfully bred in the reeds in late 1982. Eurasian Coots fed in
shallow water close to the eastern shore. The sighting of a lone Purple Swamphen Porphyrio
porphyrio also in Griffins Bay in February 1983 coincided with the drying up of nearby
Coomaditchy Lagoon, which normally supports a small resident population. The Australian
Spotted Crake was seen only when the water level was low, in late afternoon or on overcast
days, but it is certainly locally more common than previously thought (Gibson 1977
(Addendum), and Morris, McGill & Holmes 1981). The Banded Landrail (Rallus philippensis,
Lewin’s Rail Rallus pectoralis and Marsh Crake Porzana pusilla have each been observed prior
to this study but were not recorded during it, although Banded Landrails (max. 6) were
subsequently seen often during February 1985 foraging among rotting Zostera near Hooka Park
(Area F). When disturbed they took cover in adjacent rushes Juncus spp.
PAINTED SNIPE (Rostratulidae)
The Painted Snipe Rostratula benghalensis was not recorded during the survey, and can trace
only a single previous record, in March 1970 (Gibson 1977).
OYSTERCATCHERS (Haematopodidae)
Pied Oystercatchers Haematopus longirostris, which show a marked preference for the local
estuarine habitats, were present on eight of the twelve censuses, always in small numbers and
usually on the estuary shoals east of Windang Bridge and the western foreshores around Hooka
Point, Tallawarra Point, Macquarie Rivulet delta and Koona Bay am aware of only one record
of the Sooty Oystercatcher H. fuliginosus on the lake (R.N. Imisides pers. comm.).
PLOVERS (Charadriidae)
Three resident and five migrant species were recorded. Noted on all censuses (average count
15), Masked Lapwings Vane//us miles breed and feed on open fields nearby and were
commonly seen loafing or preening on the lake. Red -capped Plovers Charadrius rufica-pil /us
were also seen during all censuses (average count 12), but were found in only two areas the
entrance shoals east of Windang Bridge, and the sand bar off Hooka Point (Areas H and L).
Distraction displays and the presence of dependent young indicated that the species bred at or
close to these areas. Although previously recorded, the Black -fronted Plover C. me/anops was
not noted during this study and my only (subsequent) observation is of two birds at Kully Bay
during dredging operations in July 1984. It normally prefers freshwater margins.AUSTRALIAN BIRDS 19 (2)
The Lesser Golden Plover Pluvialis dominica, Grey Plover P. squatarola, Mongolian Plover
C. mongolus, and Large Sand Plover C. leschenaultii are Palaearctic migrants arriving in the
region during September -October and departing April -May Though not recorded during the
survey, Large Sand Plovers have been seen on the entrance shoals in the past (Gibson 1977).
Some 30-35 Lesser Golden Plovers were present between October 1982 and March 1983
(maximum count 60 on 10 March 1983), preferring the samphire flats at the north-western end
of Koona Bay where 20-25 birds were regularly seen. The Grey Plover, though rare in NSW, was
seen twice on the entrance shoals. Although previously recorded in good numbers (for example,
Gibson (1977) recorded 100 birds on the entrance shoals in 1974), only one Mongolian Plover
was seen during the survey period. I have noted an abrupt decline in the number of this species
since about 1978, and a corresponding increase in disturbance from dogs, trail bikes and other
vehicles. The species is still recorded in good numbers in other comparable coastal areas in
New South Wales, e.g. Shoalhaven Heads (Pegler, 1983), Port Stephens (Pegler, 1980) and
Boat Harbour (pers. obs.), which suggests that Mongolian Plovers are extremely vulnerable to
human disturbance.
Approximately 20 Double -banded Plovers C. bicinctus were found regularly from April to
September, mostly either at the Hooka Point sand bar or the eastern entrance shoals (Areas H
and L). Similar in habits to Mongolian Plovers, these birds are present during the winter months
when human disturbance is much reduced.
AVOCETS AND STILTS (Recurvirostridae)
Black -winged Stilts Himantopus himantopus were found in small numbers (max. 8) on six
censuses when salinity was lower than normal. They preferred the foreshore of Windang Road
and Griffins Bay. Neither the Banded Stilt Cladorhynchus leucocephalus nor the Red -necked
Avocet Recurvirostra novaehollandiae were recorded during the survey, but the former has
been recorded on a few previous occasions (Gibson 1977), and a group of 21 Red -necked
Avocets -w as seen on the east entrance shoals on 7 July 1984 (L.E. Smith and others, pers.
comm.) the first record of the species in the Illawarra region.
WADERS (Scolopacidae)
Three Palaearctic migrant waders (Eastern Curlew Numenius madagascariensis, Bar -tailed
Godwit Limosa lapponica and Greenshank Tringa nebularia) were recorded on every census,
even during the (austral) winter when most individuals are at their breeding grounds in the
northern hemisphere. In particular, substantial numbers of Bar -tailed Godwits over -wintered;
that this is a regular occurrence is indicated by my sightings of 75+ off Hooka Point throughout
July and August 1981 during my preliminary work at the lake. Numbers of Greenshanks and
Bar -tailed Godwits were markedly higher in spring than at other times, but counts of Eastern
Curlews were much more stable throughout the year (average count 12, range 1 -32). A total of
61 Greenshanks, an unusually large number, was seen on 10 February 1983, when the lake
was lower than normal; 55 of these were scattered around the south and west margins ofAUSTRALIAN BIRDS 19(21 31
Bevans Island feeding actively on a dense congregation of aquatic insects In general, the
waders showed no obvious preference for one area over another
Whimbrels N. phaeopus were not seen and know of only one previous record, in 1955
(McGill & Lane 1955). This species prefers mangrove mud flats and rocky platforms and shores
in coastal New South Wales and there is little suitable habitat at Lake Illawarra. A lone
Black -tailed Godwit L. limosa was seen on seven occasions during April and May 1983, mainly
on the entrance shoals east of Windang Bridge. Grey -tailed Tattlers T. brevipes were present on
most censuses but in small numbers (max. 10). The birds showed a distinct preference for
feeding and loafing on the southern flats on Picnic and Berageree Islands. Ruddy Turnstones
Arenaria interpres prefer the rocky tidal headland at Bellambi Point (Mills 1984) and the Five
Islands but in the survey area a flock of 16 was found on rocks at Kanahooka Point in September
1982, four were recorded during the census of 30 October 1982 and eight were seen in
September 1982 at Boonarah Point.
Sharp -tailed Sandpipers Ca/idris acuminata, Curlew Sandpipers C. ferruginea, and Red –
necked Stints C. rufico//is occurred in mixed flocks. They were low in over -wintering numbers
but built up to a substantial population in summer. The Sharp -tailed Sandpiper was the fifth
most numerous species overall. They were found all around the lake during the summer
months, but concentrations formed in some localities depending on water level (and therefore
food supply). Together with Curlew Sandpipers, they were often found feeding amongst rotting
sea grass on sandy flats at the east entrance (near the northern bank protected byPhragmites);
south of Picnic Island; north-west of Bevans Island; at Hooka Point sand bar, and Koonawarra
Bay. Although some Red -necked Stints associated with Sharp -tailed Sandpipers and Curlew
Sandpipers all around the lake, most preferred the sandy, less weedy, estuarine shoals to the
east of Windang Bridge. Here they often associated with plovers.
Sanderlings C. a/ba were seen regularly on the entrance shoals during February, March,
and April 1983, often in company with Red -necked Stints. In the past, Sanderlings have been
considered scarce with only a few records of one to four birds in the survey area at Windang
(Gibson 1977). Most of the 1983 sightings occurred either during or soon after heavy seas.
Red Knots C canutus were found only during September and October 1982, and in
relatively small numbers. In addition to the sightings on census days, found 10 birds on 4
October and 22 birds on 13 October 1982. In all cases, the Red Knots were feeding with
Bar -tailed Godwits in Areas G or H. During preliminary investigation in 1981, also noticed Red
Knots in small numbers during these months and in similar circumstances. Thus Red Knots,
though common elsewhere in coastal New South Wales throughout the summer (Morris,
McGill & Holmes 1981), apparently occur at Lake Illawarra predominantly in early spring.
Six other waders (Japanese Snipe Gallinago hardwickii, Common Sandpiper T. hypo-
/eucos, Terek Sandpiper T terek, Great Knot C. tenuirostris, Pectoral Sandpiper C. me/anotos
and Broad -billed Sandpiper Limicola falcine//us) are rare on the lake None was recorded duringAUSTRALIAN BIRDS 19 (2,
the survey except for a single Japanese Snipe which I flushed from low samphire Sarcocornia
sp. at the north-western end of Koona Bay on 8 October 1982
recorded 11 species, the most common of which was the Silver Gull Larus novaehollandiae
which breeds in large numbers on the nearby Five Islands in late spring. In 1978, Gibson (1979)
estimated that the Five Islands supported a breeding population of 50,000 pairs, this number
having grown from about 1,000 pairs in 1940. My counts at Lake Illawarra were below 2250
until December 1982, but my largest counts (of 4000+. mainly comprising adults and
immatures at rest along the north-western foreshores) were between February and April 1983.
This increase late in the survey is attributed to post -breeding dispersal from the Five Islands and
a new food source resulting from the establishment nearby, late in 1982, of the Unanderra
waste disposal depot.
The Kelp Gull L. dominicanus, which also breeds at the Five Islands where it is gradually
increasing in numbers (Lane 1979), was found on seven censuses in small numbers, usually at
the east entrance (Area H). During the survey, it was most common on the entrance shoals after
the breeding season. Juveniles comprised more than half of birds counted in the last four
Crested Terns Sterna bergii also breed at Five Islands (Lane 1979), and were found on all
censuses. Numbers were relatively stable (average count 20, range 30-60), but 900 birds were
counted on 8 October 1982; all of these were on sand flats near the mouth of the lake and some
were engaged in courtship behaviour.
The Little Tern S. albifrons was found in reasonable numbers throughout the summer, with
a distinct peak in December 1982. Some were in breeding plumage. Little Terns were found
only in Area H (the east entrance), with two exceptions: 100 were found on the sand bar to the
north-west of Bevans Island on Saturday, 30 October 1982, in company with many waders.
None were found on the east entrance shoals on this day, and a similar effect was noted during
the only other Saturday census; that of 30 May 1982. I attribute this to the extremely high level
of human recreational activity at the most easterly entrance shoals on weekends, which
severely disrupts the normal activities of birds in this area and highlights the importance of the
shallow sand bar to the north-west of Bevans Island as a refuge.
Caspian Terns Hydroprogne caspia were present on all counts in small numbers (average
count 15), showing a preference for the entrance and western foreshores. Unusually high
numbers occurred during April 1983 (about 30-40 birds), in contrast to a maximum of only three
birds sighted at any time during the previous three months. The census of 30 October 1982
provided the only record of Whiskered Terns Chlidonias hybrida when a total of 33 birds was
found, most resting on weed in Griffins Bay. Most were in part -breeding plumage. White –

fronted Terns S. striata were recorded twice on the east entrance shoals (7 on 1 September, andAUSTRALIAN BIRDS 19 (2) 33

100 on 8 October 1982), while the Common Tern S. hirundo was recorded only once two
birds on the east entrance shoals on February 1983. have found these migratory terns more
common in some years than others.
On 15 December 1984Iobserved a single White -winged Tern C. leucoptera resting on the
eastern estuary shoals in company with 170+ Little Terns and 33 Common Terns, the first
record of the species for Lake Illawarra and the Country of Camden (Gibson 1977, Morris,
McGill & Holmes 1981). The Pacific Gull L. pacificus, Fairy Tern S. nereis and Gull -billed Tern
Ge/ochelidon nilotica have each been recorded occasionally in the past but were not found
during the survey
Surve Period
Figure 3 Fluctuation in numbers of species (bottom) and number of individuals (of all species
combined, top) at Lake Illawarra, May 1982- -April 1983AUSTRALIAN BIRDS 19(21
Figures 3 and 4 summarize my census data through time and between areas. Areas G, I, K and J
contained the largest numbers of individuals (totals of all species surveyed) but there was little
variation in the number of species recorded between areas. Area K, though poor in species, was
among the most productive areas in total number of birds (although this result is heavily
influenced by the large number of Silver Gulls frequenting the area), while Area A was poor in
both species and individuals. In general, the richest areas were at the northern end of the lake
the western entrance shoals around Bevans Island, the delta barrier shelf, Griffins Bay, the
northern shoreline adjacent to Northcliffe Drive, and Koongburry Bay.
There was little fluctuation in total number of species recorded through the year, and
species lists for each census ranged only from 31 to 38. The total number of individuals,
however, did fluctuate markedly, approximately doubling from a low of 4184 in September to a
peak of 9312 in the following February.
As already noted, almost all birds were seen in water depths of less than two metres, a
region which comprises about 30 per cent of the total lake area of 32 km2. Figure 3 thus implies
that, at least occasionally, bird populations on Lake Illawarra may approach a total of 10,000
individuals at a density of nearly 1000 birds per km2. While a very large proportion of this total
consisted of Silver Gulls, and useful comparative data with other Australian wetlands seem
scanty, this density appears high, especially in view of the marked concentration in the
north-eastern sector of the lake (Areas K, J, I and G).
The entrance shoals to the west of Windang Bridge (Area G) appear very similar to those to
the east of the bridge (Area H), and the species lists compiled for the two areas over the survey
period were almost identical, yet Area G contained well over twice as many individuals as Area
H. I have no data on comparative prey abundance between the two areas, but the only obvious
difference between them is that human recreational activity is very much more intense at Area
H. If the two areas are really as similar as they appear, then this might reflect the unfavourable
effects of human activities on bird populations at the lake.
Results of surveys of water birds in other wetlands of south-eastern Australia have been
published by Loyn (1978), Pegler (1980 and 1983) and Gosper (1981). Table III compares these
surveys and includes the wader densities of the areas studied, the predominant species, and (in
particular) the population of Sharp -tailed Sandpipers. This comparison suggests that Lake
Illawarra has a relatively high wader population, especially of Sharp -tailed Sandpipers.
National wader counts coordinated by the Royal Australasian Ornithologists Union in February
of each year since 1981 has resulted in estimates (of the total Australian wintering population)AUSTRALIAN BIRDS 1912) 35
2, 2
0 0
30 30
20 20
10 J 10
F G 14 K L
Figure 4. Total number of species and of individuals (of all species combined) for each census
area at Lake Illawarra, May 1982-April 1983AUSTRALIAN BIRDS 19 (2)
for Sharp -tailed Sandpipers of 62,010 in 1981, 99,066 in 1982, 37,101 in 1983 and 36,338 in
1984 (Lane & Jessop 1984). These estimates were obtained by methods which seem
comparable with my own. If 37,101 is accepted as the population of Sharp -tailed Sandpipers in
Australia during the summer of 1982-83 (concurrent with my survey), then my peak count at
Lake Illawarra of 782 (on 17 December 1982) represents about 2.1 per cent of the total. Further
census work is desirable and this comparison must be treated with some caution; but it
nevertheless suggests that Lake Illawarra may be important as a wintering area for Sharp –
tailed Sandpipers. Under the terms of the Ramsar Convention, any wetland which holds greater
than one per cent of the national known population of a wader species is considered to be of
international significance.
TABLE 3. Comparison of Lake Illawarra with other coastal wetlands in south-eastern Australia.
wetland census total estimated wader population population
period wader intertidal density of 2 most of
population area (birds/km 1 abundant Sharp -tailed
(max) (km 2 ) species Sandpipers
Westernport Oct 1973- 17000 270 60 CS 5600 1000
Bay Oct 1974 RNS 5300
Hunter River Feb 1970- 8620 14.6 590 CS 1200* 720*
estuary Jan 1973 BTG 1050*
Richmond River Dec 1972- 1870 5.7 330 BIG 330* 74.
estuary Jan 1974 RNS 210*
Lake May 1982- 1594 3.8 420 STS 782 782
Illawarra Apr 1983 RNS 190
Shoaihaven-Crookhaven Dec 1981 1067 3.5 310 BIG 300 35
RNS 282
Port Stephens Dec 1979- 978 4 250 BIG 266 4
(northern shore) Jan 1980 GTT 245
key: CS = Curlew Sandpiper
RNS = Red -necked Stint
BTG = Bar -tailed Godwit
STS = Sharp -tailed Sandpiper
GTT = Grey -tailed Tattler
Records marked (.) from D.G. Gosper (pers. comm.); other data from Loyn 1978 (Westernport Bay); Gosper 1981
(Hunter and Richmond estuaries); Pegier 1980 (Port Stephens); Pegler 1983 (Shoaihaven-Crookhaven estuary);
and this study.AUSTRALIAN BIRDS 19 (2) 37
This study indicates that Lake Illawarra is of considerable ornithological importance, and
among the most important wetlands in the region (see also Howarth & Grant 1982). A total of 87
species have been reported, of which 55 were encountered on my regular censuses during
1982-83. Twenty-two species appeared on every census, and 43 were seen on two or more
counts. Ten species (Silver Gull, Grey Teal, Hoary -headed Grebe, Crested Tern, Sharp -tailed
Sandpiper, Black Swan, Little Pied Cormorant, Chestnut Teal, Australian Pelican, Little Black
Cormorant and Little Tern) reached populations exceeding 200 individuals at least once during
the survey. Howarth & Grant (loc. cit.) encountered 24 species in their surveys in 1979, all but
one of which also regularly encountered. They did not, however, extend their surveys to
include the Charadriiformes; if this group is deleted, my own comparable list (i.e. recorded on
regular counts) was 30 species.
Lake Illawarra makes an important contribution to maintaining Palaearctic waders in
south-eastern Australia, especially Sharp -tailed Sandpipers, and a significant number of
waterfowl use the lake as a refuge in periods of drought in the interior. Most birds utilise the
shallow margins (to about the 2 -metre contour, or about 30 per cent of the total surface area)
rather than deeper waters at the centre. The entrance shoals and the eastern and northern
shores are especially important in terms of numbers of individuals. Species diversity is nearly
constant in all areas, although several species exhibit distinct habitat preferences within the
lake. The entrance shoals, Griffins Bay and Koongburry Bay are especially important when the
number of individuals and of species are considered together. Bird populations seem adversely
affected by human disturbance, especially that resulting from such factors as trail bikes,
vehicles and dogs.
found that wader feeding grounds are almost always available on the margins and estuary
of the lake and, unlike most other tidal wetlands in New South Wales, flock roosting does not
occur at high tide. I hope that Lake Illawarra will be preserved in its present state because in the
coastal areas of New South Wales, Goodrick (1970) has shown that 60 per cent of the prime
water -and shore -bird habitat has already been destroyed.
am very grateful to my wife for checking the original manuscript and giving me the support and
encouragement to persevere with this study. sincerely thank A.R. McGill and T.R. Lindsey for
their help with earlier drafts of this paper, and the following for their observations: C.J. Chafer,
A.W. Colemane, T Dunlea, W.G. Emery, R.N. Imisides, A.R. McGill, M. Parkinson, A. Salvadori,
R.A. Simcock, and L.E. SmithAUSTRALIAN BIRDS 19 (2)
Anonymous. 1976. An Environmental Assessment of Lake Illawarra. Wollongong City Council & The
University of Wollongong
Anonymous. 1982. Lake Illawarra Entrance Study. NSW Public Works Department
Delroy, L.B. 1974. The food of Waterfowl (Anatidae) in the southern Coorong Saltwater habitat of S.A. S
Aust. Ornith. 26: 157-166
Frith, H.J. 1982. Waterfowl in Australia. Angus & Robertson: Sydney (2nd ed.)
Gibson, J.D. 1977. Birds of the County of Camden. Aust. Birds 11: 41-80
Gibson, J.D. 1979. Growth in population of the Silver Gull on the Five Islands Group, New South Wales.
Corella 3: 103-104
Goodrick, G.N. 1970. A survey of wetlands of coastal N.S.W. CSIRO Div. Wildlife Res. Tech. Mem. No. 5
Gosper, D.G. 1981. Survey of birds on floodplain-estuarine wetlands on the Hunter and Richmond Rivers in
northern N.S.W. Corella 5: 10-18
Howarth, D.M. & T.R. Grant. 1982. Species diversity of waterbirds on Lake Illawarra, Coomaditchy Lagoon
and the Cordeaux Storage Dams, New South Wales. Emu 82: 106-108
Lane, B. & A. Jessop. 1984. National Wader Count, Summer 1984: report to participants. Australasian
Wader Studies Group, RAOU: Melbourne
Lane, S.G. 1979. Summary of the breeding seabirds on New South Wales coastal islands. Corella 3: 7-10
Loyn, R.H. 1978. A survey of birds in Westernport Bay, Victoria 1973-74. Emu 78: 11-19
McGill, A.R. & S.G. Lane. 1955. Mt. Keira camp -out. Emu 55: 49-71
Mills, K. 1984. Seasonal fluctuation of numbers of Ruddy Turnstones at Bellambi Point, Wollongong, NSW
Aust. Birds 18: 80-82
Morris, A.K.; A.R. McGill & G. Holmes. 1981. Handlist of Birds in New South Wales. NSW Field Ornith. Club:
Norman, F.I. & L. Mumford. 1982. Food of the Chestnut Teal (Anas castanea) in the Gippsland Lakes Region
of Victoria. Aust. Wildlife Res. 9: 151-155
Pegler, J.M. 1980. A wader survey of the northern shores of Port Stephens and lower Myall River. Aust.
Birds 14: 68-72
Pegler, J.M. 1983.A brief survey of the water birds in the Shoalhaven-Crookhaven Estuary. Aust. Birds 17.
Kevin Wood, 7 Eastern Avenue, Mangerton NSW 2500AUSTRALIAN BIRDS 1912, 39
On 26 March 1983, during a Canberra Ornithologists Group field trip to the Wollongong area,
we located a Wandering Tattler Tringa incana feeding on tideline rocks at Windang Island, off
the mouth of Lake lllawarra, NSW The bird was initially seen in the company of a small party of
Grey -tailed Tattlers Tringa brevipes, but when this group was flushed the Wandering Tattler
separated from it A few minutes later the bird was found further along the shore, this time
feeding alone It was then observed closely for about twenty minutes and during this time it
became less active and allowed us to approach to about ten metres; excellent views were
obtained through at 25x tripod -mounted telescope and a detailed field description was taken.
Field Description:
SIZE AND SHAPE Slightly larger than accompanying Grey -tailed Tattlers, but very similar in
PLUMAGE Crown, back of neck, and entire dorsum plain slaty grey, the crown very slightly
darker than the neck and back Superciliary white, distinct in front of the eye but faint
behind it. Eyestripe grey, almost black in front of eye. Ear coverts and chin streaked grey
and white, the streaking merging into barring on the breast. Breast, upper belly and flanks
barred in a distinct zig-zag pattern, slaty grey and white; these markings much more
distinct (both heavier and darker) than those of the Grey -tailed Tattlers. Centre of belly,
from legs to vent, plain white Undertail coverts barred slate grey on white, the bars very
distinct A patch of uniform grey on the flank in front of the undertail coverts. Eyelids
FLANK PATTERN Uniform grey on back, wings and tail
BARE PARTS Legs yellow. Bill straight, fairly stout, about 1.25 times as long as the head, dark
grey shading to dull pink at the base of the lower mandible. Nasal aperture (naris) long and
triangular; the nasal groove, which could be seen clearly when viewing the inactive bird
through the telescope at ten metres, extended about two-thirds of the way along the
length of the bill.
BEHAVIOUR Fed actively on wave -washed rocks, or perched quietly on the top of a boulder a
metre or two back from the water’s edge Occasionally bobbed its tail
VOICE When flushed, gave a rapid sequence of about eight short whistles40 AUSTRALIAN BIRDS 19 (2)
The bird can be identified as a Wandering Tattler in almost full breeding plumage by the
heavy dark barring of the underparts, and especially of the undertail coverts; the commoner
Grey -tailed Tattler has white undertail coverts, even when in breeding plumage (Pizzey, 1980).
The identification is confirmed by the call: in the calls of the Grey -tailed Tattler the notes are
fewer and longer. The comparatively large size and the long nasal groove also indicate that the
bird was a Wandering Tattler.
The Wandering Tattler is a rare but probably regular non -breeding summer visitor to the
coast of eastern Australia (Pizzey /oc. cit.). The only previous record for the Illawarra district is a
specimen taken at Five Islands (about ten kilometres north-east of Windang Island) in 1913
(Gibson 1977); this is the southernmost locality at which it has been recorded in New South
Wales (Morris, McGill & Holmes 1981), or indeed in Australia (Blakers, Davies & Reilly 1984).
Our bird was thus at the extreme southern limit of its distribution in Australia. Wandering
Tattlers may be under -recorded, however, as they are difficult to separate from Grey -tailed
Tattlers in the field. We thank A.K. Morris, A.E.F Rogers, E.S. Hoskin, A.P. McBride and T.R
Lindsey for their comments on an earlier draft of this note.
Blakers, M., S.J.J.F. Davies & P.N. Reilly. 1984. The atlas of Australian birds. RAOU (Melbourne University
Press), Melbourne
Gibson, J.D. 1977. Birds of the County of Camden (including the Illawarra District). Aust. Birds 11 41-80
Morris, A.K., A.R. McGill & G. Holmes. 1981 A handlist of birds in New South Wales, NSW Field Ornith
Ciub, Sydney
Pizzey, G. 1980. A field guide to the birds of Australia. Collins, Sydney
M. Doyle, V.A. Drake and D. von Behrens. C/- Canberra Ornithologists Group, PO Box 301, Civic
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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
13 Acknowledgements to other individuals should include Christian names or initialsVol 19 No 2 April 1985
Wood, K A survey of the waterfowl and waders of Lake Illawarra, NSW 17
Doyle, M. A Wandering Tattler at Windang Island. NSW 39
V.A Drake &
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