July J HOBBS, Mice Plague 43 r971 who made the first general ornithological collection in the area. That man, a young fellow named George Harper, who had reached Australia from Britain about 1820 with letters of recom­ mendation from Sir Walter Scott, was given a grant of land at Picton, whence he appears to have ranged considerably in amas­ sing natural history material. In consequence, according to the Sydney Gazette of February 3, 1827, he was then able to take to Britain a great many specimens, including no fewer than 1675 bird­ skins, as well as two living Emus that rather alarmed Sir Walter Scott. Some of Harper's bird-skins were bought by Sir William Jardine; others were acquired by the Edinburgh Museum. It would be interesting now, 140-odd years later, to have news of those specimens.

A Plague of Mice at Warren By J. N. HOBBS, Katoomba, New South Wales INTRODUCTION It is generally accepted that certain species of birds will con­ gregate at plagues of insects or rodents, but more detailed docu­ mentations of such visitations are rare. House Mice, Mus musculus were in plague proportions in many parts of the wheat belt of eastern and southern Australia in the autumn and early winter of 1970. In May 1970, I made a short visit to Warren, New South Wales, one of the areas overrun by the mice. I had been there also in December 1969, before the build-up in the numbers of mice, and, therefore, was able to malEagle, the Brown Hawk and the Nankeen Kestrel. The first named was breeding and probably some incubating birds were overlooked. The increase in the Black Kite was probably due to the mice. The count for the Square-tailed Kite was too low fo r significance to be attached to it. In my experience this species preys mostly on birds and the contents of their nests. The Brown Goshawk is often very secretive and easily over­ looked but the May increase is large enough to indicate a definite influx. The conclusion that this occurred because of the mice is unavoidable. The same conclusion must be drawn over the very large rise in numbers of the Little Eagle. I usually associate this bird with rabbits but few were about the district at the time. Apparently, the Little Eagle is not ashamed to stoop to such small prey as a mouse, unlike the much larger Wedge-tailed Eagle which apparently vacated the district, finding no attraction in the readily available supply of tit-bits. The Spotted Harrier is generally considered to be a summer visitor to the southern parts of its range and the count bears this out. The mice do not appear to have caused it to remain, although the numbers seen in December were very low and any that were still about in May could have been missed. This bird also prefers to hunt over tall vegetation, grass or crops. Those seen in Decem­ ber were watched catching locusts. The Swamp-Harrier is a bird known to vacate much of its more southern range in winter, par­ ticularly moving north out of Tasmania. The increase in May could either reflect this movement or be due to the increase in mice. Those falcons which prey primarily on birds, the Grey, July ] HOBBS, Mice Plague 45 1971

Black and Peregrine, did not move into the district after the mice. The Black Falcons seen in December were watched catching locusts by running after them on foot along a bitumen road! No observing was carried out at night so perhaps little sig­ nificance should be attached to the counts of the owls, although the day sightings of the Boobook showed quite a large increase. The remaining species listed all show quite large increases in numbers in May, which increases could well be related to the mice plague. The Grey Butcherbird is accepted as a partial migrant and may have been in the district as such and not attracted by the mice. I found the number of Kookaburras to increase quite sub­ stantially in winter along the Murray River, in southern New South Wales, and perhaps it may be a winter visitor to the Warren area too. The Raven and Little Raven are known nomads, the first more so as a juvenile, and were probably in the area because of the mice. Two Little Ravens, after picking meat out of freshwater mussels opened earlier by White-winged Choughs, flew to the top of a red gum-tree, some 60 feet above ground level. Here they engaged in idle mutual preening and pecking and scraping at the bark on a dead limb. A piece of the bark fell to the ground dis­ closing a mouse surprised in its lofty hideaway. One of the Little Ravens took it by the neck, thoroughly bashed it against the limb, and swallowed it. Research carried out to date on the Black-backed Magpie indicates it to be a sedentary species, neither migratory or nomadic. The substantial increase in the numbers in May possibly indicates that not all is known about this bird's movements or apparent Jack of such. COMPARATIVE COUNTS DECEMBER MAY SPECIES 1969 1970 *Black-shouldered Kite, Elanus notatus 4 32 Black Kite, Milvus migrans 6 22 Square-tailed Kite, Lophoictinia isura 1 4 *Whistling Eagle, Haliastur sphenurus 8 76 Brown Goshawk, Accipiter fasciatus 0 8 Little Eagle, Hieraaetus morphnoides 1 32 Wedge-tailed Eagle, Aquila audax 5 0 Spotted Harrier, Circus assimilis 3 0 Swamp-Harrier, Circus approximans 2 12 Grey Falcon, Falco hypoleucos 1 0 Black Falcon, Falco subniger 3 4 Peregrine Falcon, Falco peregrinus 1 0 *Brown Hawk, Falco berigora 39 114 *Nankeen Kestrel, Falco cenchroides 40 384 Barn Owl, Tyto alba 0 2 Boobook Owl, Ninox novaeseelandiae 1 10 *Laughing Kookaburra Dacelo gigas 9 56 46 BERULDSEN, Letter-winged Kite [ Bird Watcher

*White-winged Chough Corcorax melanorhamphus 384 266 *Pied Butcherbird, Cracticus nigrogularis 43 114 Grey Butcherbird, Cracticus torquatus 2 30 Raven, Corvus coronoides 28 200 *Little Raven, Corvus mellori 98 260 *Black-backed Magpie, Gymnorhina tibicen 160 464

The Letter-winged Kite, Elanus scriptus. By GORDON R . BERULDSEN, Glenalta, South Australia SUMMARY The Letter-winged Kite, Elanus scriptus, is a species about which little has been written and only fragmentary details of its habits and habitats are known. Rarely does it enter settled areas and rarer still does it remain long enough to allow any study. However, one such occasion did present itself during June and July, 1970, in the settled areas of South Australia's lower north, when numbers of this species arrived and bred. The author seized the opportunity to learn something of their habits and although time was limited, much information was gained. OCCURRENCE At a meeting of The Adelaide Ornithologists Club in May, 1970, it was announced that a number of Letter-winged Kites had recently been seen at Willowie, approximately 170 miles north of Adelaide, and between Wilmington and Orroroo. A further speci­ men had been shot on the west coast near Streaky Bay, and it was thought that there may have been others in that area. Several members of the club had visited the Willowie area on April 11 and 12; had seen the birds, and photographed them roosting and flying. At 5.30 p.m. on the 11th three birds were noted resting in foliaged trees, and fifteen minutes later 21 were observed perching atop a group of dead roadside sugargums. At dusk these bi rds were noted to fly in to the township of Willowie and perch on other dead trees. It was presumed then that they flew there to roost for the night. However, it would appear now that they went there to feed during the night on the large numbers of mice present around the town. It transpires that although mice in the fields were then not in exceptionally great numbers, although they were plentiful, they were in great numbers around the towns. At 8.30 a.m. the next morning 15 birds were noted in the dead sugargums and when disturbed, dispersed and did not return. Although a day was spent driving around the district no further Letter-winged Kites were seen flying or perched. I am of the opinion now that when they dispersed after being disturbed, they flew to foliaged trees to roost for the day. Towards the end of May the author had an opportunity to make a trip north, and on June 9, two of us left by car. We