Recent changes in the diet and breeding parameters of the Purple Heron Ardea purpurea in southern France

The Purple Heron population in southern France suffered a 46% decline between 1981 and 1994. A study of breeding biology was instigated in 1997 in order to examine potential changes in the main breeding parameters between the early 1980s and the late 1990s. Here, we present data on the breeding biology and diet of breeding Purple Herons in the Camargue, southern France, collected from 1997 to 1999. These results were compared with those from a similar study conducted between 1979 and 1982. No difference in first spring arrival date on breeding grounds was noted between these two periods. Mean first egg date was 22 April during 1979–82, in contrast to 6 May during 1997–99. Mean colony size was c. 118 breeding pairs during 1979–82, but only c. 59 during 1997–99. For broods of three and four chicks, linear growth rates for rank A (first hatched) chicks were higher during 1979–82 than during 1997–99. For broods of four chicks linear growth rates were also higher for rank B (second hatched) chicks and tended t...