Compte rendu ornithologique camarguais pour les années 1980 et 1981

Résumé En

This bird report for the Camargue, Crau and Alpilles (Rhône delta, S. France), covers the years 1980 and 1981. It has been compiled partly from observations communicated by visiting naturalists but particularly from resident ornithologists attached to the «Fondation Tour du Valat», the «Centre d’Ecologie de Camargue» (C.N.R.S.), the «Réserve Nationale de Camargue» (S.N.P.N.) and the «Centre de Recherches Ornithologiques de Provence » (C.R.O.P.). As with the previous reports only the results of censuses and unusual observations are given. As a baseline, readers are advised to consult the recently published guide to the birds of the Camargue by Blondel and Isenmann (1981) in which are mentioned all 337 species recorded in the area to date. The climatological report shows a cold spell in December 1980, with subzero temperatures recorded on 18 days. Total rainfall in autumn and winter was below, but in spring and summer higher, than normal. 1981 was even more unusual, with 25 nights of frost in January, low rainfall, long hours of sunlight and much northerly wind. In contrast, the winter ended (March) mild and wet. April was mild and dry, May cold and wet. The variable summer and autumn weather was characterised by a dry spell (excepting September) with no rain in October/November. De¬ cember was mild and wet. A first complete census of wintering cormorants revealed 4,000 in 1980 and 6,000 in 1981 against a formerly estimated maximum of about 2,000. This increase has meant that the delta has become one of the most important wintering areas for the species in western Europe. The Grey Heron population continues to increase with 438 nests in 1980 and 515 in 1981 (table I). In contrast, Purple Herons have decreased in number in the delta over the last decade, probably as a result of a reduction in the available breeding habitat. Large colonies still exist just outside the delta, and the region continues to be the most important breeding area for Purple Herons in France. The population of Cattle Egrets, after being stable from 1977 to 1979 (table II), increased by 48 % in 1980 before decreasing in 1981. This drop was undoubtedly attributable to the cold winter. A nest of Little Bittern was found in 1981 and there is a summer record of a Reef Heron in 1980. A pair of White Storks again bred, raising 3 young in both years. The adult pair are sedentary whilst the young migrate in autumn. Flamingos again bred in large numbers, with 7,500 prs. in 1980 and 9,500 prs. in 1981, although this latter figure was reduced to 8,170 prs. by heavy rains. These raised 3,730 and 4,000 chicks respectively. The colour-ringing programme continued and a further 1,358 chicks were marked during the two years, bringing the total of individually recognisable birds to 3,316. Of these, 1,724 (52 %) have since been identified throughout the West Mediterranean, whilst the total number of sightings exceeds 11,000. Both Greylag Goose and Gannet have been attracted to the Flamingo colony, the latter bird staying for three months, displaying and occupying a nest cone and accompanying the flamingos up to 14 kms inland. Bewick’s Swans continue to be winter visitors with 52 in 1979-1980 and 82 in 1980-1981, with a record high of 23 juveniles. The breeding population of Shelduck, a species extending its range in the south of France, was censused in 1980, with 350 chicks (42 families) in the Salins de Giraud and 700 (86 families) in the Salins d’Aigues-Mortes. A further 111 were colour-ringed as part of a study on the movements of the West Mediterranean population which has now been shown to moult in the same area as the North West European population, in North West Germany, a distance of 1,200 kms north of the Camargue. Winter counts have revealed peaks of 1,354 birds in 1980 and 1,035 in 1981, in each case representing over 80 % of the total number recorded in the south of France. For other species of ducks the peak 1980-1981 winter count was of 143,000 in November. Instead of increasing in December, as is usually the case, the cold spell of early December resulted in a decrease of 25 % mostly caused by a high hunting mortality within the delta. Amongst the major changes in numbers compared to former winters has been a decrease of Pintail and Tufted Ducks and an increase of Shoveler and Gadwall. Diving ducks (Tufted and Pochard) are gradually decreasing in the Camargue because there are more attractive areas further north, whilst some of the surface-feeders tend to increase, Mallard and Teal together regularly forming 50-60 % of the total Anatidae. Amongst the sea-ducks, a concentration of 1,000 Scoters, mostly or solely Velvets, was quite exceptional. The area is one of the most remarkable in Europe for raptors at all seasons. Booted Eagles were again regularly recorded in 1980 and a Sea Eagle appeared in both years. Wintering Marsh Harriers are at a remarkably high density with 280 counted at 3 roosts, probably only about half of the total in the area. There were two observations of Eleonora’s Falcon in 1981. The average number of wintering coots has recently decreased from about 25,000 (1964-1968) to 20,000 in 1980-1981. Sample censuses of the breeding population indicate a relatively low density of 3.7 nests per 10 ha. In the Crau, the wintering Little Bustards have been estimated at 1,000 -1,100, which corresponds with the breeding population of about 500 prs. The third record of a Pectoral Sandpiper was a bird shot in September 1979. There is a second winter record of a Great Skua in 1981 and a remarkable observation of 22 Long-tailed Skuas together in the Gulf of Beauduc in May 1980. A pair of Mediterranean Gulls successfully bred in both 1980 and 1981 whilst the Slender-billed Gull was not found breeding either year. The former of these two species occurs in large numbers outside the breeding season with maximum counts of 250 in March 1980 and 700 in September 1981. Two pairs of Black Terns nested in 1980, the first breeding record since 1931. Whiskered Terns bred in 1981 (120 prs.). This species was formerly abundant in the area but had not been recorded breeding since 1974. The Long-eared Owl, which forms winter roosts of up to 20 birds, was found breeding in 1980 for only the fifth time. There are several spring records of Red-rumped Swallows whilst those of the common Swallow in December may indicate a possible attempt at wintering. Richard’s Pipit was recorded for the first time in October 1981 with a second record one month later, whilst the May 1980 record of a Red-throated Pipit was only the sixth in the past 30 years. The Stonechat seems now to be well re-established as a breeding species and there is a possible return of the Penduline Tit with one nest found in each of the two years.