Notes Foot-slapping by Coots During 1978, at reservoirs and flooded gravel-pits in Northamptonshire, I began to notice single Coots Fulica atra standing on mats of flooded vegetation at the water's edge and slapping the s'urface with one foot. The Coot would stand hunched and slap regularly and deliberately about five or six times, the noise carrying across land for at least 100m. Although I first noticed this behaviour at the beginning of the breeding season, I have observed it throughout the year. It became obvious that, as it was always triggered by the approach of a human being, it served as a warning to other Coots of possible danger: it can be likened somewhat to foot-stamping by rabbits Oryctolagus cuniculus. I have not yet determined whether one specific individual of a group of Coots continued....

126 Notes 127 feeding at the water's edge acts as a guard, or whether it is the Coot nearest to a suitable slapping area that reacts; on one occasion, however, a Coot swam towards an approaching human being, hauled itself out of the water, ran to a weed-patch and began slapping. P, W. RICHARDSON 10 Bedford Cottages, Great Brington, Northampton NN74JE Terrestrial foot-slapping on the nest is mentioned in BH'P volume 2, although its significance is not known. Dr K. E. L. Simmons has commented that Mr Richardson's observations appear to add a new dimension to the foot-slapping display by this species, which is also performed by the Moorhen Gallinula chloropm. EDS

Grey Plovers associating with inland Golden Plover flocks During a study of Golden Plovers Pluvialis apricaria wintering in Buckinghamshire, we twice observed Grey Plovers P. squatarola associating with them. Both sites are at least 90km from the coast. On 15th December 1974, near Marsh Gibbon, RJF saw a single Grey Plover in a permanent pasture field with about 400 Golden Plovers; it fed on the periphery of the flock for several minutes and, when the flock flew to a nearby field, it flew with them. On 19th March 1979, near Bishopstone, CEY watched two Grey Plovers feeding for about 15 minutes in a flock of 103 Golden Plovers on permanent pasture; they maintained particularly close contact with a sub-group of eight Goldens and flew in the middle of the flock. The two flocks in question had probably arrived in the area very shortly before: the first record came at a time of year when a major influx occurs (Bird Study 26: 37-46); the second was shortly after a period of severe weather during which no large flocks of Golden Plovers were recorded in the study area. Alternatively, perhaps the Grey Plovers were passing over and were attracted to a feeding or roosting flock of Golden Plovers. R.J. FULLER and C. E. YOUNG British Trust jor Ornithology, Beech Grove, Tring, Hertfordshire HP235NR Dr Michael VV. Pienkovvski has commented that mixed Golden Plover-Grey Plover flocks do occur in coastal areas. EDS

Supercilium pattern of immature Pectoral Sandpiper The principal differences between the Sharp-tailed Sandpiper Calidris acuminata and the Pectoral Sandpiper C. melanotos have been well described by D.J. Britton (Brit. Birds 73: 333-345). The distinctions in anterior and posterior supercilium width between the two species were mentioned, but a subsid­ iary difference was not described: the supercilium of the Pectoral Sandpiper typically forks above the eye, creating a distinctly divided (even striped) pattern when the species is viewed head-on. Although subdued on adults, this pattern is frequently prominent on immatures and is well-illustrated in Brit. Birds (68: plate44) and Birds of the World (3: 931). A. R. DEAN 2 Charingworth Road, Solihull, West Midlands B92SHT D. J. Britton has commented that this is probably a useful character, but that, as in the case of Little Stint C. minuta versus Semipalmated Sandpiper C. pusitla, it may not be diagnostic. EDS 128 Notes Eye-ring of Sharp-tailed Sandpiper The only Sharp-tailed Sandpiper Calidris acuminata that I have seen, on 8th May 1980, in Alaska, had a gleaming white eye-ring. None of the thousands of Pectoral Sandpipers C. melanotos that I have observed has exhibited this. Photographs in D. J. Britton's paper {Brit. Birds 73: 333-345, plates 178-188) depict this eye-ring on Sharp-tailed and its absence on Pectoral. Examining specimens in the Field Museum of Natural History, Chicago, I found that Pectoral Sand­ pipers have an off-white or bully eye-ring that does not contrast with the rest of the head colour. Although preparation of study skins sometimes damages the feathering around the eye, obscuring noticeable plumage marks, in life the difference between the gleaming white eye-ring of Sharp- tailed and the dull buff one of Pectoral is marked and startling. While recognising the risks in drawing conclusions from a single observation, further field investigation may confirm the validity of this identification feature. GERALD ROSENBAND 9444 Kedvale, Skokie, Illinois, USA D.J. Britton has commented as Ibllows: 'I wish I had noticed this! Summer adult Sharp- tailed clearly exhibits a pronounced clean pale eye-ring, especially in midsummer. It is less striking in winter, but still more pronounced than in Pectoral (e.g. the original print of Brit. Birds 73: plate 185). Juveniles also share the feature, but their eyes are surrounded by so much white (cheeks and supercilia) that it is oflittle note. I cannot, however, agree that Pectoral entirely lacks this character: an eye-ring, less pronounced than Sharp-tailed's, is evident in over half the photographs I have consulted (e.g. Brit. Birds 67: plate 51 (juvenile); 68: plate 44 (juvenile); 73: plate 178 (juvenile); 74: plate 176 (adult)). To put it in perspective, J doubt that this character would have produced a speedier identification of the Scillv adult Sharp-tailed (see 73: plates 178-188).'EDS

Apparent play by immature Common Gull On the afternoon of 29th March 1979, at Herriotts Pool, Chew Valley Lake, Avon, I watched an immature Common Gull Larus canus indulging in apparent play behaviour. It was carrying a blackish spherical object to a height of about 10m and then allowing it to fall. Usually, the object was caught before it reached the water; if not, the gull alighted to retrieve it, then flew up to repeat the behaviour. This was repeated 20 to 30 times with the same object, and then three other Common Gulls approached. All four then began to toy with an object 10cm long, probably of vegetable origin, in the same way; they appeared to lose interest and alighted on the bank to preen. The sky was heavily overcast with moderately heavy rain. There was no question of food items being involved, although the flight attitude when dropping the object closely resembled that of Herring Gulls L. argentatus dropping shellfish on the shore. Searching British Birds since 1949 (vol. 42), I found references to similar apparently purposeless behaviour by the following species: Black- headed Gull L. ndibundus (44: 69-70; 46: 378); Common Gull (46: 378); Lesser Black-backed Gull L.juscus (57: 326-327); Herring Gull (45: 74); and Carrion Crow COITUScoroiie (43: 333; 46: 378; 66: 400). D. WARDEN Centaur, Ham. Lane, Bishop Sutton, Bristol BS184TZ Notes 129 Identification of juvenile Common, Arctic and Roseate Terns There are some potentially confusing statements in the chapter on 'Field identification of juvenile Common, Arctic and Roseate Terns' by P. J. Grant and R. E. Scott in Frontiers of Bird Identification (1980, pages 96-100). The leg colour of juvenile Arctic Tern Sterna paradisaea is described as orange, no mention being made of the black-legged first-winter colour. By late August, young Arctic Terns reaching Norfolk already have legs rapidly darkening, almost a sooty-red colour, and often black-looking. In Sep­ tember, most legs look black. The statement that juvenile Roseate Tern S. dougallii has black legs unlike the juveniles of the other two species would sway people towards identifying a dark-legged, older juvenile or first- winter plumaged Arctic Tern as a Roseate. The upperparts of juvenile Arctic Tern are described as 'lacking any strong scaling, being virtually uniform'. In fact, they tend to have a broad- barred appearance, a feature well shown in 'Mystery photograph' 57 (Brit. Birds 74: 345). While completely different from the pattern of juvenile Roseate, it does have some similarities to that of the mantle of juvenile Common Tern 5. hirundo. J. B. KEMP / College Farm, Great Massingham, King's Lynn, Norfolk

Common Tern feeding by wading On 19th May 1979, at VVarsash, Hampshire, I watched a Common Tern Sterna hirundo, from about 30m, as it walked about on the shore at low tide and picked up items which it swallowed. For at least five minutes it behaved in this way, both walking on mud/shingle and wading in a pool about 1 cm deep. I could not ascertain the nature of the food it was taking, but there were many very small fishes in the pool and numerous small invertebrates within the total area of about 2m X 2m which it covered. Another Common Tern was standing less than 1 m away and 34 others were standing or plunge-diving along the shore. Eventually, both terns by the pool took flight and started fishing with the others in the normal manner. I can find no reference to Common Terns picking food from the ground, nor to their wading at low tide, in Britain. D. A. CHRISTIE 119 Thornhill Park Road, Thomhill, Southampton SQ26AT

Field characters of first-year White-winged Black Terns In his in­ teresting note describing a tern with mixed characters of Black Chlidonias niger and White-winged Black Terns C. leucopterus (Brit. Birds 73: 223-225), Keith Vinicombe mentioned the lack of definitive plumage descriptions for year-old White-winged Blacks. Individuals in first-summer plumage remained in northeast Saudi Arabia from May to August 1980, up to three being present on one lagoon; two more were present in late April 1981. They did not resemble the individual described by KV, supporting the view that that was a juvenile. 130 Notes

Fig. 1. Impressions of immature White-winged Black Terns Chlidonias leucopterus, Saudi Arabia, 1980-81. Juvenile, late July to November or December (left), juvenile moulting to first-winter, November to February (centre), and first-summer, late April to August (P.J. Grant, based on sketches by Graham Bundy) White-winged Black Terns are fairly common autumn migrants in the coastal zones of the Persian Gulf, with juveniles predominating. Most arrive in August and remain until early February. In mid November, some juveniles start their head and body moult to first-winter plumage and begin to look paler, with less contrasting dark 'saddles' and a faded, whitish panel on the coverts of the inner upperwing. These moulting and fading juveniles can often be seen flying with winter-plumaged adults; some retain quite dark areas on the mantle and scapulars throughout the period. From early February through March and in most of April, White-winged Blacks become unaccountably scarce in the region, so that the complete sequence from juvenile to first-winter to first-summer plumage cannot be followed. In late April, there is an influx of adults in summer plumage and a small arrival of first-summers, the latter sometimes remaining until July or August. The first-summer individuals are like winter-plumaged adults, being essentially pale grey above and white below. They have a variable amount of grey about the head and cheeks; most have a dark patch on the ear^ coverts, and some show dark grey on the crown and nape. As on juveniles, the white collar around the hindneck is not always obvious; it is usually best seen when grounded birds anxiously stretch up their necks when approached. They have a variable amount of dark-grey on the primaries; sometimes, this extended in a dark, almost sooty, wedge along the leading edge of the wing, whereas on others, the primaries looked concolorous with Notes 131 the rest of the wing. The most striking feature on the upperwing is a dark bar on the secondaries, always visible in flight and contrasting with the coverts of the inner upperwing. The rump and tail usually look concolorous with the pale grey upperparts; some examples have slightly darker grey central tail feathers. Two in 1980 showed some blackish 'smudges' on the underwing-coverts, where the adult is strikingly black in summer plumage. Two in late April 1981 had a small dark area at the forward end of the mantle extending to the leading edge of the inner upperwing, but not as far as the carpal joint. Apparently immature (first- or second-summer) Whiskered Terns C. hybridus, resembling adults in summer plumage with sooty caps but with whitish underparts, were present on 5th June and from 18th July 1980. When seen well, the bill of White-winged Black always looks shorter and slighter than the bill of the flatter-crowned Whiskered, the latter often looking 'swollen' at the base. The 'facial expression' of White-winged Black, caused by the head pattern, the higher, more rounded crown, and the neat-looking black bill, is reminiscent of winter-plumaged Little Gull Larus minutus. I am most grateful to Peter Grant and Keith Vinicombe for commenting on the first draft of this note. GRAHAM BUNDY PO Box 98, BAC Ltd, Dhahran, Saudi Arabia

Short-eared Owl apparently feeding on snail At about 14.00 GMT on 13th April 1979,1 watched two Short-eared Owls Asioflammeus hunting over rough ground near Pegwell Bay, Kent. Both stooped frequently, without much apparent success, but, when one dropped suddenly on to a stony bank quite near me, I carefully approached to within about 12m. I could see the owl was feeding on a small object. When I was less than 10m away, the owl flew off; I marked both the precise spot and the actual food item, which it had dropped from its bill. On examination, I was surprised to discover the broken remains of a snail shell, which must originally have been about 30mm in diameter; it was not completely shattered, as are those attacked by a Song Thrush Turdus philomelos, and the owl had clearly been having difficulty in smashing it. I can find no mention in the literature of snails as a prey of any owl species. MALCOLM J. PALMER 29 Hurst Road, Kermington, Ashjord, Kent

Swift impaled on television aerial In July 1973, in Corfu, Greece, while watching a small group of about 15 Swifts Apus apus swooping along the narrow streets at rooftop height, I was most surprised when one suddenly flew into one of the many television aerials and impaled itself on the transverse bars. The Swift was fixed through the lower thorax or upper abdomen, the force of the impact having carried it several centimetres along the bar; it flapped its wings for several seconds before dying. Dr David Lack (1956, Swifts in a Tower) did not mention any similar causes of mortality. IAIN H. LEACH 18Burness Avenue, Alloway, Ayr 132 Notes Skylarks feeding on bread and household scraps A few days after Ken Osborne informed me of his observations of 30th July 1978 (Brit. Birds 74: 98), and at the same spot, I saw a member of the public throwing chopped potato dressed with salad cream over the fence on to the concrete reservoir embankment. After a few minutes, a Skylark Alauda arvensis appeared with a juvenile and started to peck off pieces of potato, which it fed to its begging young. ROYSTON K. COLES 12 Lennard Road, Dunton Green, Sevenoaks, Kent

On 16th May 1953, on Canvey Island, Essex, I saw a Skylark on the sea-wall near some houseboats, carrying a piece of bread. When I approached, it ran along the wall with the bread, and finally carried it away in flight. On 17th August 1974, in the picnic area at Grimes Graves, Norfolk, an adult Skylark fed a juvenile with bread crumbs. R. B. WARREN 103 Larchcrojt Road, Ipswich IP16PQ

I first observed adult Skylarks (of both sexes) taking bread and cake during June 1970, near the top of Cefn Bryn, Gower, West Glamorgan, a site commonly used as a viewing point by motorists. Several of the larks calmly walked about among parked cars, picking up crumbs in such a tame manner that I concluded that the habit was well established long before. DAVID G. P. CHATFIELD 3 Cyncoed Close, Dunvant, Swansea SA2 7RS

From 23rd June to 7th July 1951, at Crosby, Liverpool, up to three Skylarks fed in my garden, a piece of waste ground on the edge of the town next to open country. They frequently ate and took away, presumably to nestlings, bread and cheese scraps; one was once seen to eat a maggot chrysalis and a piece of fried black pudding. On 4th January 1961, following a period of heavy frost and snow, a Skylark ate bread crumbs in the same garden, now cultivated. During a cold spell in December 1962, when the ground was covered with frozen snow, up to five Skylarks fed in a new uncultivated garden at Formby, Merseyside; on 30th, they repeatedly fed on bread crumbs and were seen pecking at lumps of bread. They visited the garden many times until 10th March 1963 and were often seen pecking at, and sometimes eating, bread crumbs. D.J. Low 25 Heatherways, Freshfield, Liverpool L37 7HL

In my book Birds of Town and Suburb (1975), I listed 23 species, including Skylark, which I observed eating bread in the outer suburbs of London. The Skylark observations include one present daily in my garden at Dollis Hill during 5th-9th January 1963 which fed on bread throughout the period. ERIC SIMMS 21 Church Street, South Witham, Grantham, Lincolnshire

The Skylark's relatively catholic tastes in food and occasional exceptional tameness now seem sufficiently documented; further observations will be filed for reference but not published separately. EDS Notes 133 Identification of Pallas's Grasshopper Warbler I read with interest Alan Kitson's comments on Pallas's Grasshopper Warbler Locustella certhmla (Brit. Birds 73: 398-399, plates 203-204). In June 1980, also in Mongolia, 1 saw and photographed (plate 52) Pallas's Grasshopper Warblers, apparently of the race rubescens {Ibis 13: 301-332), to which K. Williamson (1968, Identification jor Ringers 1. The Genera Cellia, Locustella, Acrocephalus andHippolais. BTO Field Guide No. 7) suggested the British and Irish vagrants belong. They were all adults in spring plumage, sometimes in atypically exposed situations, and were readily identifiable, the rufous rump and uppertail and the very pale grey, almost white, tips to the upperside of the tail being quite obvious. A number of other features combine to make the spring adult a much more strikingly plumaged bird than the literature, and especially illustrations, suggest. In shape and manner, the warblers were clearly of the genus Locustella; particularly characteristic was the rodent-like habit of running along the ground. The cold, greyish buff ground colour of the plumage, however, lacked the olive element of Grasshopper Warbler L. naevia. By far the most outstanding feature was the supercilium (so obvious in Kitson's photographs). My own impression of its shape and extent agrees entirely with Kitson's, but I would describe it as white rather than buffy white and as conspicuous as that of Sedge Warbler Acrocephalus schoenobaenus. I also agree with Kitson that this feature effectively rules out confusion between Pallas's Grasshopper Warbler and other members of its genus, and would suggest that confusion is possible only with two other species: Sedge Warbler and Moustached Warbler .4. melanopogon. Pallas's Grasshopper Warbler, however, lacks the conspicuous rusty colour so characteristic of the upperparts of Moustached and, especially, the sooty black crown and very dark lores and ear-coverts of that species. I considered the following to be significant plumage characters of Pallas's Grasshopper Warbler:

HEAD Besides supercilium (sec above), crown Ear-coverts and lores at least as dark as on darker and more heavily streaked than on Sedge, not obviously streaked in distant Sedge, especially around side and at back, view, with paler, apparently unstreaked Ibrehead. LOWER NAPE Lower nape and upper back

52. Pallas's Grasshopper Warbler Ucusltlla crr/liiola, Mongolia, June 1980 (.1/. Dens/er) 134 Notes area very pale, seemingly unmarked greyish- line of scales or chequers across wing (with buff, creating a well marked 'shawl', con- much the same effect as dark-centred, pale- trasting well with both darker mantle and edged median coverts of'Tawny Pipit Anthus head, giving definite capped appearance, campestris); this feature may also extend to (Similar unmarked pale area sometimes some of the median coverts, as it certainly present on Sedge Warbler, but contrast does to inner secondaries and tertials. between it and mantle and head does not Strikingly pale, almost white, outer fringe to appear as great.) second and probably third primary feathers. WING-COVERTS Contrast between some of UNDERPARTS Chin, throat and upper breast wing-coverts and rest of the generally areas striking white, forming very noticeable medium grey-brown wing very striking, gorget or 'apron'. Similar white area under Primary coverts appear virtually black in the tail, forming triangular-shaped patch. Rest field, creating a conspicuous black spot on of underparts pale, seemingly unmarked the wing, especially in flight. Greater coverts greyish-buff, much the same colour as shawl, also appear virtually black, but with Contrast between white and darker areas practically white fringes, creating striking very marked. The literature seems not to draw attention to any of the wing features, but the last two points noted show well in Kitson's photographs. A number of observers and reference works have commented on elements of the under­ parts, but none, to my mind, has placed the required degree of emphasis, nor correctly defined the areas. M. DENSLEY 60 Saffron Crescent, Tickhill, Doncaster Bullfinches eating flesh During severe weather in January and February 1979, at my former home at Hartest, Suffolk, a number of birds visited the open-fronted glass verandah in which I provided them daily with food: household scraps, broken corn and weed seeds scattered on the floor, and a number of cooked chicken and duck carcases and other bones suspended from the roof. A pair of Bullfinches Pyrrhula pyrrhula fed regularly on the seeds but, on 25th January, I saw the female clinging to one of the carcases and eating the flesh with evident relish for some 20 minutes. She did so again the next day, while the male picked up and ate fragments of meat that fell to the ground. Both Bullfinches fed in this way from time to time during the next week or two. On 10th February I hung up a large ham bone. Within a short time the female Bullfinch was clinging to it and eating some of the meat; she repeated this behaviour a few days later. I can find no reference in the literature to Bullfinches eating flesh, apart from insects. WILLIAM H. PAYN Neptunia, Champs Beulai, Aldemey, Channel Islands