Seasonal occurrences and abundances of six common migratory waders in Botany Bay, 1942-1966, a documentation and analysis of Arnold McGill's long-term data set Allen Keast Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada ABSTRACT Times of occurrence and abundances of five Palearctic, and one New Zealand, migratory waders in Botany Bay over the period 1942 to 1966, are documented from Arnold McGill's unique data set. The Sharp-tailed Sandpiper occurred from early September to the end of February; Red-necked Stint from beginning of September to early March; Bar-tailed Godwit from September to April; Golden Plover, October-April; and Double-banded Plover from late March to late August. Taking into account birds on passage the sandpiper was most abundant in the first years, the stint from 1952 to 1959; godwit from 1952 to 1959: curlew sandpiper from 1957 to 1966; numbers of the two plover species were relatively constant. It is suggested that the variation reflects level of success on the breeding grounds, not changes in the quality of the Botany Bay habitat since degradational changes In the latter had not then occurred. The study emphasizes the great importance of Botany Bay as a wader habitat; it is still a good place to "see" waders but only future quantitative munts will show its current status. Data on quality of the feeding habitat, in addition to dlanges in area, is needed. Future wader conserva- tion necessitates a simultaneous study of aN major feeding grounds for waders along the east mast. INTRODUCTION and shape of the bill, it was possible to identify these otherwise similar-looking birds. It was Botany Bay and, especially the wide sand- Keith Hindwood who introduced Arnold and flats at the northern end between Cooks River 1 to the Botany Bay flats. The earlier trips and La Perouse, have long been recognized as were multi-person affairs with Keith one of the most important feeding areas on Hindwood, Arnold and myself, Ernie Hoskin, the New South Wales coast for migratory and others taking part. I was a regular waders. The width of the flats exposed at low companion of Arnold for his first couple of tide was about 400 m, and their length in years. Several of Arnold's trips each year excess of a kilometre. They were visibly rich would be with Keith Hindwood after that and, in invertebrate life, with a small green jointly, they worked out the identities of some oligochaete having a density of up to 10 per of the rarer and more difficult species. Arnold square metre (pers. obs.). was ultimately to become perhaps Australia's From the 1940s onwards the waders of the most knowledgeable wader expert. Early flats were the focus of attention by Sydney papers by the Sydney "wader group" included ornithologists. Arnold McGill was pre-eminent Hindwood (1942), McGill (1943, 1947), and in the studies and from 1942 to 1965 made McGill and Keast (1945) some 200 surveys, alone or with Keith Hindwood, Ernie Hoskins, and myself. It is METHODS important that the results of these surveys be put on permanent record and here I take The flats would be visited just as the tide Arnold McGill's field lists and incorporate was running out so that maximum time would some additional data by myself and others. be spent with the birds as they fed. The counts Making the data available is important in that would start from immediately adjacent to the the area has been severely impinged upon by Cooks River mouth. Walking slowly eastwards airport and shipping container port develop- we would identify and count each group of ment. It provides a basis relative to which waders. As the waders flushed the direction of modern counts can be assessed. flight would be noted so as not to count the Interest in migratory waders in the Sydney same flocks twice. A kilometre would be so ornithological community surged in the late covered and then the remaining stretch of 1930s when Serventy (1938) showed how, by sand explored long-distance by field-glasses to studying the distribution of white on the tail confirm proportions of species and make the and on the wing, colour of the legs, and length count as complete as possible. 34 Australian Zoologisf, Vol. 30(1) The greatest number of visits were made SHARP-TAILED SANDPIPER - Botany Bay in 1942 and 1943. with 13 and 15 visits 700 respectively by Arnold or Arnold jointly with 600 1942- 43 500 others of us, and six and sevena dditional visits No. lrips = 56 400 by myself. During the 1944-1945 wartime 300 years with severe petrol rationing Arnold was 210000 .l-t.-. rlrhll.,. only able to make a few visits to the flats. From 0 o 700 1947 onwards the number of visits a year to l 600 E:>500 the flats was 15-20, 75-80% of them being by E 400 Arnold or with Arnold as a member of the = 300 200 group. In any year three-quarters would be 100 '*''i'_.1 made during the August-April period when E= 3000 il the northern migrants were passing through z 200. *=oo on passageo r summering in the Bay, with the 1000.. -h tr - remainder being directed at the Double- 210000.. 1957-59 N=s8 banded Dotterel or Plover Charad,riusb icinctus. -.r.ll I l. .lt I .h 200. a winter visitor from New Zealand. 100. Because the visits were rather scattered in JUL AUG SEPTO CTNOVDECJ AN FEB MAH APR MAY time I have consolidated the data into series Date of two (1942-1943) and three (other years) averages. In doing so, if a single seven-day period was only visited once during the two or RED-NECKEDS TINT- Botany Bay three years, its counts stand, if twice or more '* an average for the particular period is struck. cord I 300 This objective is both to give the most accurate .:" l.r-h| . .,r,i,,,=" 200 average picture of arrival and departure 100 (including "passage"d ates),a nd bestb ring out 0 any longer-term shifts in abundance. In the 200 1946-48 N=34 100 | .r I hrrl ll --.-, latter obviously the summer data is more q 0 G valid, it representing the period of stability: at 1952- 54 migration times numbers fluctuate greatly as il, l,hil l flocks arrive and depart. In the graphs, data from 1942 and 1943 (when most trips were E made) is grouped, as is that from 1946 to zl 1948, 1952t o 1954, 1957t o 1959,a nd 1964 .r i,;i;, .li,ll ,|hril,rt,l, , to 1966.T oo few trips were made in the other years for the data to warrant inclusion. Data is given only for the six common "ffi1,,1,,.,1',l,rll,l species: Sharp-tailed Sandpiper Erolia -t. -,.,,-l=" acuminata, Red-necked Stint E. rufcollis, Bar- tailed Godwit Lirnosal apponica,G olden Plover JULY AUG SEP OCT NOVD ECJ AN FEB IVIARA PR MAY Pluaialis fulua, Curlew Sandpiper Calid,ris Date fenuginea, and the Double-banded Dotterel. Fzg. 1. Seasonal occurrences and abundances, Sharp-tailed RESULTS Sandpiper and Red-necked Stint, Botany Bay mud- flats, five clusters of years from 1942 to 1966. Seasonal occurrences and abundances of the various speciesw ere as follows: Sharpaailed Sandpiper: Typically this species in small numbers of 50 to 100. Large numbers arrived in the first week of September, with a appeared again in January: possibly represent- major influx occurring in the second week. ing birds from further south, or in response Then there tended to be a numerical drop, to improved resources. Usually the bulk and a second peak in early October. In contrast disappeared by the end of February, but in to the others this species did not exclusively some years small numbers lingered on into utilize the flats; a more favoured summering March, and even early April. None were ever habitat was saltmarsh and muddy creeks recorded between April and early August. entering the bay (writer's data). From late Presumably the late August birds recorded in October until early January flocks of birds 1942-1943 represented early returnees, and were continuously present on the flats but not over-wintering birds. Decembe1r9 95 Australian Zoologist, Vol. 30(1) 35 It is difficult to draw any conclusions about BAR- TAILEDG ODWIT- Botany Bay long-term population changes from this data 'l1-::l"j although far more birds *ere recorded on "]'*"' | . te42-43 No.riP=ss 6 ,.l.lllll.rl r,,,-.rr-.r I rrr northward passagei n 1942-1948 than sub- sequently. 1946-48 N=34 r _l l. r - -.1-..-.- Red,-nechcSd# n/; This was throughout a rather more abundant species, occuriing in larger t00 flocks. There was commonly a Jma[ over- ,,ll,ilflLrfrlhl',lirli ,,,'l,,,rrrl wintering nucleus of birds, usually less than q 50 birds. The major influx of migranrs from 't ethaer lyn,oSrethp toecmcbuerrl.e dS autb tsheeq eunedn tolyf yAeuagiu-tsot- yaenadr Ict _ ovffibrlng ',,''- abundances varied, but there wai commonlv o N=58 another_ peak in October. High number's E occurred all summer: thus the flats represented zf r,;,,| lh||,ilfllu,t illlllltrLlrrl,r,,, major habitat. I never found them in the salt 50 marshes. Return migration was initiated in late February--early March. It was g-radual; 'll small numbers remained into April. 50 t' ,l',.I lNt=6l12l,.,, . lllltu r trh- .r.-,, , The.overview projected by the graphs is of 0 a significant population increasd in lgb2_ AUG SEP OCT NOV DEC JAN FEB MAB APR MAY 1959 relative ro earlier years, with numbers Date averaging smaller during the l964-1966 period. GOLDENP LOVER- BotanyB ay Bar-tailed,G odwit: There was regularly an over- 6800 1942 - 4g ' indi@t6s ho r*ord ll No.r ips = so wintering nucleus in this speciEs.p eak return 4200 ..r.--..I t,l.lll.llul r migration occurred in September. The flats '.. "=" were a majoq summer feeding area, with the . l. r.l, ht,nli,lll. l drop in numbers occurring in April. @ G Long-term variations in numbers occurred. pf, 11446000 Abundances in 1957-1959 were very high, oc 11220000 those of 1952 to 1954 less so; numbers were 60 1952-54 small from 1942 ro 1948 and in 1964 to 1966. o 40 .l.rr. ,rillll,ll ll, E 20 The differences are real. The increase in zf 80 numbers from 1952 ro lgbg presumably 1es57e' I N=sa 40 indicates high success on thi breeding 20. ,ll .lrr.llll r --l.r grounds. 0. 1964-66 *=" -t--, r-r.r llrrr ll -ilh Gold,enP loaer: The year-to-year abundances varied with numbers of birds usually being JUL AUG SEP OCT NOV DEC JAN FEB MAR APB MAY small. The annual influx occurred in October] Date JFleebreru awrya.s pao rpeuglualtaiorlny, owccituhr rinig bNuoivldeumpb eri-n Fig. 2.G Sodeawsito naanl do Gccoulrdreenn cpelso vaenr,d Baobtaunnyd aBnacey,s ,1 9B4a2r__1ta9il6e6d. numbers in the latter month, and u peik i., March be.fore department in March--April. Characteristically no birds over-winteied. residents all summer. There was a clearcut From time to time I found Golden plover feeding flocks on the grassed Barton park numerical drop at the end of January, but in some years they remained during February fpreormio d-st haen dF t1hye,r eb w.rat st nhoe yp aottnelryn sint aiyheedir btirmieef aMnadr,c _he. sNpeoc imalelyimn btehres 1o9f 6t4h-i1s9 6sp6e-pceieriso odv, eirn- of appearance. Populations in the area were wintered. relatively constant bver the 20-year period. During 19-42.-1943r he Curlew Sandpiper lurlew Sandpiper: This species was recorded occurred only in modest numbers but there- in August but there was a striking influx of after was an abundant summer species. migrants aj t!t" end of Septeirber--early Highest numbers occurred in the^ later October. The birds were abundant feeding years. 36 AustraliaZno ologistV, ot.3 0(t) December 1995 CURLEWS ANDPIPER- BotanY BaY Double-bandedD otterel (Ploaer): This species arrived at the end of March and tended 150 1942-43 I .ind€tsrcre@rd to remain in good numbers until late May. 100 No. rrips - 56 Thereafter there was a drop in numbers, with the time of this varying, followed by high 200 numbers from late June to the end of 1945- 48 August. Presumably there was some seasonal |lr,.,l. .l ,l, N=34 adjustment during the stay in response to resources. lrL| Numbers were relatively uniform from N=44 1942t o 1966. | , l,,l',h., , -.1l,- t. DISCUSSION o 150 The arrival and departure times of the six t00 rrilil1r.i.l,.1.N=5,8 , speciesa re fairly constant but showed year to year variation by a couple of weeks.T his could 0 partly be an artifact of the way the data was 150 100 1964- 66 l,lrf|i|i|li,,l'r,, N,=62 collected. However, in all cases there was obviously a spread in times, i.e., in the arrival 50 I-rr I and departure of flocks. Numbers of birds were highest at times of passage.T he major JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY status of Botany Bay as a residence area for Date waders is amply confirmed. Small numbers of stints and godwits overwintered and did not return north to breed. DOUBLE- BANDEDD OTTEREL- Botany Bay Duration of stay in the bay varied with the species;S eptember-Februaryw ith the Sharp- tailed Sandpiper; Curlew Sandpiper, October- No. lrips = 48 1942-4 3 Februarv. The stav of six and five months in these speciesw as eclipsedb y the eight to nine months of the Bar-tailed Godwit. The stayw as ,.,rlr.,l,l ,ll l I five months with the Double-banded Plover. which was present at the opposite time of the year to the other species. o 1946- 48 hlN=2l4 The mid-seasonc ounts can be used to assess E changes in abundance. The Sharp-tailed pf 30 1.,1. l,h Sandpiper (though numbers on northward E passages howed a drop after the first years), .c Golden Plover, and Double-banded Plover, o '=" maintained fairly constant populations Lq) res2-s4 I throughout the period. Increasesi n numbers -o tl E of Red-necked Stints and Bar-tailed Godwits = z | -,-,tlll,ll-l.l.h. over the 1952-1959 period are indicated; and the Curlew Sandpiper numbers increased in 50 tl the final years. - ll 40 1957- 59 "=* 30 lrrrrlllrlll,'1, Because flocks may pass through quickly, more regular counts than those made here 0 would be necessaryt o assessn umbers of birds 0 66 on passage.I t would be valuable to know how 1964- 20 .lhl h..llhhru-="long migrating flocks stay in the Bay. It is 10 likely that southward moving flocks stay JAN FEB MAR APRM AYJ UN JULA UG SEP longer than the reverse, as is the case with passerines in the Northern Hemisphere, Date associatedw ith the need to establishb reeding territories. Doubtless many flocks over-flew Fig. 3. Seasonal occurrences and abundances, Curlew Botany Bay and would not be included in the Sandpiper and Double-banded Dotterel, Botany Bay, 1942-1966. counts. Decembe1r 995 AustralianZ oologist, VoL 30(1) 37 Differences in numbers of birds summering one or two areas might not matter; progressive in the Bay over the 20-year period reflects, degradation of feeding places throughout I suspect, varying reproductive successes on would be serious. the breeding grounds rather than conditions Botany Bay, the prime wader area, like the in Australia. Unfortunately no data was Hunter, continues to be under intense develop- gathered on year-to-year variation in the prey mental pressure. It would be interesting to resource base in Australia: resolution of the know the extent to which the extension of the matter would require this. Cooks River breakwater well out into the bay, and interruption to the inlet flow from the BOTANY BAY AS A PRESENT Eastlakes Ponds, has affected nutrient loading AND FUTURE WADER HABITAT at the north end of the Bay. Has the over-use The present data set, as a basis for making of natural resources (over-harvesting of comparisons with contemporary numbers of prawns and fish) indirectly affected wader waders, should be used with caution. The area habitat? There is a need for quantitative covered in the surveys was not precisely studies at all levels. measured: indeed it would have been difficult The Bay remains a "good area to see to do better because the flocks ranged widely. waders and, recently at the south end, I saw This was, however, taken into consideration good populations of godwits, sandpipers, throughout the surveys and the count-area plovers, and tattlers. Some remain along the kept sufficiently large to accommodate this. north shore. It is hoped that a contract let Unfortunately, the feeding wader popula- recently to study current wader populations tions at the southern end of Botany Bay, will reveal something of current over-all e.g., in Quibrey and Yowie Bays, were not wader status in the Bay. Ultimately, of course, simultaneously monitored: we had all we total surveys of the entire east coast habitat could handle with the high numbers at the and abundances is critical. northern end. This would make it impossible to compare total Botany Bay wader popula- tions then and now. It would be worth while ACKNOWLEDGEMENT developing numbers as a ratio of available This article was written whilst the writer held feeding area in 1940 with that of today. The a Canadian National Science and Engineering smaller area of feeding habitat now remaining Research Council Grant: the costs of develop- could, however, represent the "best" or ing the diagrams is from that source. I should "worst" section of the old habitat: what is left like to thank this body. could, alternatively, have become secondarily nutritionally enriched or have become a "desert". REFERENCES Obviously the health of our migratory wader Hindwood, K. A, 1942. The birds of Long Reef, New South populations cannot be assessed just in terms Wales. Proc. Zool. Soc. NSW 1942: 1633. of Botany Bay studies. Southward moving McGill, A. R., 1943. Bird movements in rhe Lower Cooks waders have a series of potential feeding areas River District. Emu 42: 174. available to them, separated by long gaps: McGill. A. R.. 1947. Unra\,elline the Knots. Notes on the sections of Cape York, the Cairns waterfront, occurrence of the genus Caidris in Australia. Emu 47: Moreton Bay, the Hunter, Botany Bay, and 137-46. Lake Illawarra. Presumably they will linger in McGill, A. R. and Keast, A., 1945. The Mongolian Sand- any one area proportionately to their immediate dotterel in Australia. Emu 45: 202-16. nutritional needs and to the quality and Serventy, D. L., 1938 A guide to the identification of the amount of food available. Presumably loss of waders. Emu 38: 65-76. 38 Australian Zoologisf, Vo1. 30(1)