THE S.A. ORNITHOLOGIST 87 THE COMMON TERN IN SOUTII AUSTRALIA By JOHN -ECKERT On January 26, 1967 a flock of about study skin, the other three being taken to 50 Crested Terns (Sterna bergii) were the S.A. Museum intact. resting on the sand near the Murray Mouth. Later in February, John Endersby found With them were 12 to 20 smaller terns with some of these terns present in the same area black bills and black caps, but with the but a further visit by myself on March 27 forehead white. I assumed that they must was unsuccessful. However a bird of similar be immature Fairy Terns (Sterna nereis), appearance was in the same vicinity on but took two as specimens. When measuring October 22 and a week later at least two these birds later, it became obvious from were present at a freshwater swamp on their length of 13 inches that they could 'Poltalloch Plains,' 9 miles south of Welling­ not be Fairy Terns. The long forked tails ton. These were among a flock of some ruled out the possibility of either the Marsh 5,000 Marsh Terns and 20 Crested Terns. Tern (Chlidonias hybrida) or White-winged They were distinguishable from the Marsh Black Tern (C. leucopteris). Although my Terns by their slightly larger size and long, knowledge of the rarer terns was almost nil, deeply forked tails. They showed a willing­ I had made a copy of diagrams of primary ness to perch on posts in the water, a habit feathers shown by Hitchcock (1965a). From shared by the Crested but not the Marsh these I was able to deduce that the birds Terns. A specimen was secured and it were either the Common Tern (Sterna proved to be similar to those previously hirundo) or the Arctic Tern (S. paradisea) taken. These specimens had been identified but my copying of the diagrams had not as Common Terns by the Curator of Birds at been accurate enough for me to be certain. the S.A. Museum, Mr. H. T. Condon, on On January 28, in company with R. the basis of the broadness of the dark band Cleggett, I again went to the Murray mouth. on the first primary feather. Twelve of the terns were present, again sitting with Crested Terns. They were After reading W. B. Hitchcock's paper studied for a considerable time, but although 'Geography and Seasonal Movements of the they occasionally shifted position, none was Common Tern in Australia' (1965b), I had observed to flyaway to feed, nor were they become curious to know to which race these joined by any more of the same species. birds belonged. Accordingly the skin of the The wing-tips of the sitting birds extended bird taken on February 1 was sent to Hitch­ beyond the tail by about half an inch and cock for examination. With his reply he the dark crown came forward of the eye enclosed a copy of a paper by Stegmann by about a similar distance. The area (1936) on the Palaearctic races of the around the eye was dark as was the shoulder Common Tern. Stegmann accepted five area. One bird seemed to differ slightly races of the species, the extremes being the from the others in having grey instead of nominate race hirundo of Europe with its blackish primaries. However, when collected dark-tipped red bill and longipennis, a black­ it proved to be of the same species as the billed form from north-eastern Asia, these other two specimens, the lighter colour of being separated by a somewhat intermediate the primaries apparently being due to recent race, minussensis. The race tibetana inhabits moult. the high country in and around Tibet while the slightly smaller turkestanica comes from Another visit was made to the locality on the vicinity of Turkestan. February 1. The water level which had been high on my first visit had now dropped Hitchcock has since examined all the considerably and bird-life in the area was above specimens except that collected greatly reduced. Only one of the terns was October 22, and an additional two collected present but it seemed to differ slightly from from a flock of 30 at Boggy Lake, the most those seen previously in that the black of the northerly arm of Lake Alexandrina, a female head came a little further down behind the on February 24, 1968, and a male on March eye. This bird was taken and made into a 13, 1968. A few birds were still present until 88 THE S.A. ORNITHOLOGIST April 7, but none obviously in breeding February and March, 1964 and March-April, plumage. 1965, by J. B. Hood, H. Bakker and himself, Hitchcock informs me (in litt. 1-5-68) with a specimen being taken on April 3, that he is unable to say with certainty to 1965, and forwarded to the S.A. Museum. I what subspecies these birds belong, but is have examined this specimen, together with fairly sure they are not referable to longi­ the Buckland Park bird and those taken by pennis because in some specimens the bill is myself, and although its coloration is similar not entirely black. The latest reviser of to that of the Common Tern, I consider Sterna hirundo, Vaurie (1965), states (p. the bird to be an immature Marsh Tern, 493) "Geographical variation is elinal in the because of its smaller size, shorter bill, short Palaearctic region. The wing length in­ comparatively square-cut tail and the pattern creases and the coloration of the plumage of the primary feathers, which is identical becomes darker from west to east and also to that of the Marsh Tern but not the on the high plateaux of central Asia (S.h. Common. The dark blotches on the back tibetana}, the elinal variation affecting also of this bird are, in my opinion, a sign of during the breeding season the colour of the immaturity, and the bird matches quite well bill and that of the legs and feet. At this two other immature Marsh Terns in the season, the bill is red, tipped with black, Museum collection, one from Newscastle and the legs and feet are red in the western Waters (2-5-1962) and another from Mul­ race (nominate hirundo) and in the one of gundawa (4-1-1965). From its bill length cen.t1:al Asia (tibetana), but the bill becomes and coloration Attiwill's specimen would darker, more invaded with black in western probably be the most mature of these three. Siberia, the preponderance of dark billed From examination of Museum specimens it birds increasing eastwards, until the bill be­ would appear that the bill length of the comes wholly black in virtually all the birds immature Marsh Tern is shorter than that (longipennis) of eastern Siberia..." Vaurie of adults. further states (p. 494). "This elinal va­ If my opinion of the Naracoorte bireI's riation makes it impossible to define with identity is correct, then the only positive certainty the reciprocal limits of the breeding evidence of the Common Tern away from ranges, and most migrants or winter visitors the sea in this State would be the two birds to southern Asia cannot be identified to sub­ seen south of Wellington and the flock fre­ species." quenting the Boggy Lake during autumn Vaurie does not recognise the race turkes­ 1968. These birds would have been about tanica, so that the subspecific identity of the 30 miles from the nearest part of the coast. first South Australian specimen, which was provisionally referred to that race by Hitch­ SUMMARY cock (loc. cit.), must also remain. in doubt. The Common Tern has been recorded At the time of Hitchcock's paper in the from three separate areas. in South Australia: Emu (1965b), only two records of the Buckland Park (specimens October, Decem­ Common Tern had been reported for South ber), Kangaroo Island (skeleton, September) Australia. The first was a bird taken by and Lake Alexandrina (specimens October, A. H. Lendon and R. W. McKechnie at January, February and March and observed Buckland Park on December 31, 1956 (Len­ until April 7 one year, 1968). The sub­ don, 1957). This bird had been seen in specific identity of South Australian birds is the locality for some weeks before it was still debatable but they are probably not secured. The second was a part skeleton referable to longipennis; this question can found on Kangaroo Island by members of only by settled by the collection of specimens the 1959 R.A.O.U. Campout (Wheeler, in breeding plumage. 1960). It could not be subspecifically iden­ tified. ACKNOWLEDGMENTS Since then the only occurrences of the I wish to express sincere thanks to Mr. Common Tern in this State other than those H. T. Condon for his help with identification stated above are one taken at Port Gawler of the birds and at whose instigation this (Museum party October 29, 1962), and paper was commenced, and special thanks those of Attiwill (1966) in the Naracoorte to Mr. W. B. Hitchcock for his help in and Lucindale areas-sightings during examining specimens and for his advice and THE S.A. ORNITHOLOGIST 89 considerable assistance with the manuscript Wheeler, J. R. (1960). 'The R.A.O.U. Campout itself. at Kangaroo Island, South Australia, 1959.' Emu vol, 60, 273. REFERENCES Attiwill, A. R. (1966). 'Common Terns at Nara­ AN ADDITIONAL RECORD OF THE coorte.' S. Aust. Orn. vol. 24, 94. Hitchcock, W. B. (1965a). Australian Bird COMMON TERN Bander, March. On July 27, 1960, a dead tern was found Hitchcock, W.