Compte rendu ornithologique camarguais pour les années 1984-1985

Abstract

This paper continues the series of publications reporting interesting observations and data collected in the Camargue and neighbouring areas (Crau, Alpilles) since 1930. For several species and groups of birds long-term monitoring is carried out and this is done primarily by ornithologists from the Tour du Valat, the C.N.R.S. Ecology Centre and the National Nature Reserve. From the climatological report it can be seen that there was a severe cold spell in January 1985, with freezing conditions lasting two weeks. Flamingos were severely affected as were several species of ducks (Figure 3), herons and waders. Of the two mainly sedentary warblers Fan-tailed seem to have suffered more than Cetti’s. This cold spell caused the sharp decline in the numbers of breeding Little egrets (Table I) and Cattle egrets though this was probably exacerbated for the former species by the drought which persists in the Sahel where some birds winter. In 1985 the numbers of breeding Grey herons (Table II) were the highest yet recorded, as were the numbers of wintering Great white herons. During the cold spell, this former rarity to the delta outnumbered the Little egret, and in December 1985 an outstanding total of 42 individuals was recorded (Figure 2). On the other hand, the breeding population of Purple herons was the lowest recorded (in 1985) for the previous six years. In spite of the cold spell in January 1985 and the fact that the species also bred in Spain, the number of Flamingos which nested at the Etang du Fangassier was the second highest on record, with 13,500 pairs and 7,800 chicks raised in 1985. An intensive research programme continues on this species based largely on the re-sightings of individually marked birds and a further 1,333 chicks were «Darvic»-ringed in these two years. Even prior to the cold spell the numbers of waterfowl wintering in the delta, or passing through, were lower than usual, and coupled with the effects of the cold weather, the 1984-85 season proved to be the worst in the 21 years since records began. The following winter also revealed low numbers of most species ; all except the Gadwall have gradually decreased in numbers since the index years of 1964-65 to 1966-67. The tendency for birds to concentrate in areas free from hunting is greater now than it was at the end of the 70’s. No similar decrease in numbers at the other major wintering areas along the same flyway has been noted and it would therefore appear that it is the Rhone delta which is no longer as attractive to the ducks as it formerly was. This trend could be reversed by an extension of the feeding areas under protection and a lowering of the shooting pressure throughout the region where the annual bag is still around 150,000 ducks. The list of raptors observed in the area is still very impressive, but the populations of two of those which breed give cause for alarm. In spite of conservation actions by several organisations and societies the 15 pairs of Bonelli’s eagles under observation in Provence raised only 0.79 and 0.86 chicks per pair on average in 1984 and 1985 respectively, as opposed to an average of 1.03 per year since 1974. Also now a rarity is the Lesser kestrel ; the only place in France where the species still breeds is the Crau with only 2 and 4 prs. respectively in 1984 and 1985. The tenth complete census since 1956 of the waders, gulls and terns breeding in the brackish and saline lagoons of the greater Camargue area was carried out in 1985. Most species maintained their normal population levels although Avocet numbers were low. Herring gull numbers are kept down by culling whilst the scarcer Slender-billed and Mediterranean gulls both maintained a good foothold in the delta, the latter species showing signs of increasing with a record 23 pairs in 1985. Outside the breeding season, there were three records of Terek sandpiper in 1984 and observations the same year of Audouin’s and Glaucous gulls, all rarities in the delta.