Compte rendu ornithologique camarguais pour les années 1978 et 1979

Abstract

This bird report covers the years 1978 and 1979 and completes a period of 30 years of observations by a contingent of resident and visiting ornithologists in the Rhône delta and neighbouring Crau and Alpilles. It presents not only observations of rare species or unusual numbers of birds, but also indicates the results of several long term monitoring programmes concerning in particular, waterfowl and allied species. A climatological report summarizes the most important meteorological phenomena of the two years, the most striking of which were the very wet spring of 1978 and the dry summer of 1979. The winter of 1978-1979 must surely be remembered in northern and central Europe as one of the most severe this century. In the Mediterranean, however, it was much less severe and, fortunately, had none of the disastrous effects of the previous hard winters of 1956 and 1962-1963. “ La Crau ”, a unique stony desert area and former delta of the River Durance, is suffering seriously from the spread of industry and from agricultural reclamation. Some of the first census work to be carried out here shows just how important the area is for breeding Stone Curlews, Little Bustards and Pin-tailed Sandgrouse in particular. The sandgrouse population is an isolated one, the species occurring elsewhere in Europe only in parts of Spain. Observations of sea birds are not carried out systematically and more thorough sea-watching would probably show that many of the species mentioned here are regularly wintering in the “ Golfe du Lion ”. Unusually high numbers of Black-necked Grebes appear each autumn in the saline “ Etang de Lavalduc ” (up to 4,500), which makes it an internationally important site for this species. Whilst the herons as a group maintain their numbers, several notable changes have taken place in recent years. The reed-nesting Grey Heron continues to increase whilst the Purple clearly shows the opposite trend. The Cattle Egret, occuring only as an accidental visitor less than 15 years ago, appears now to have reached the peak of colonisation with the numbers of breeding pairs levelling off. Autumn roost counts show the total of individuals at close to 2,000. The first indications of roughly how many Bitterns breed in the Camargue are given whilst the second only record of White Storks breeding in the delta involved one semi-captive male and a wild female carrying a ring. This was a chick transplanted from Morocco to a nest in Alsace as part of a reintroduction programme in 1975. The flamingos again had two successful breeding seasons and the summer population for the south coast of France peaked at over 35,000 birds both years. Particularly interesting data are being gathered from the sightings of “ Darvic-ringed ” birds, 1858 of which have thus been marked over the past three years. 24 % of these have already been read outside France. Amongst the Anseriiformes, the wintering Bewick’s Swan population was the highest yet recorded with a maximum of 85 in January 1979. During this same period four species of geese were present with Greylags and Bean’s both reaching one hundred or more individuals. Counts of Shelducks have shown how important the salines are both as a breeding area and winter quarters, and a ringing programme has thrown some light on their movements. For other ducks the overall wintering population has been quite high with a peak of 122,000 in January 1979. In general the number of diving ducks was below average but this was compensated for by several of the surface feeders being present in large numbers, in particular Teal, Gadwall and Shoveler. The list of raptor observations is as impressive as ever and includes a second estimate of the breeding Marsh Harrier population with results slightly superior to those obtained ten years earlier. The eighth complete census of breeding Laro-limicoles was carried out in the brackish and salt water zone of the greater Camargue area. All species are maintaining their numbers and attention is drawn to the increasing populations of Mediterranean and Slender-billed Gulls. Nearctic waders already observed in the delta included sightings of Buff-breasted Sandpiper and Wilson’s Phalarope whilst the Pectoral was only the second reported. Eagle Owls in “ Les Alpilles ” appear to be increasing with 30 pairs recorded. Passerines have not been ignored entirely ; the continued increase of breeding Stonechats is encouraging whilst the successful nesting of a pair of Bed-billed Quelea in the Camargue adds an exotic flavour to this report.