VOLUME 30 - N. 1/2

Abstract:

Breeding ecology of the cuckoo Cuculus canorus in Central Italy. In this study I present the results of a 14-years survey (1992- 2005) of cuckoo parasitism towards breeding warblers in the lake of Massaciuccoli, a large wetland area in Central Italy. Data about density of singing cuckoo males, characteristics of parasitized nests, parasite eggs, and breeding success have been collected. A mean density of 4.2 singing males/km2 was found. Cuckoo exclusively parasitized nests built on Phragmites australis. Parasitized nests were mainly sited in dense reed-beds close to open water. Minimum distance between two active and parasitized nests was 350 m. Cuckoo egglaying, occurring between April 28th and July 27th (median date 4th June), coincided with the laying period of selected host species. Parasitism frequencies resulted to be 8.9% for the reed warbler Acrocephalus scirpaceus, 13.9% for great reed warbler A. arundinaceus and 0.8% for moustached warbler A. melanopogon. A single cuckoo egg was found in 93.5% of parasitized nests and two eggs in the remaining 6.5%. The eggs laid in great reed warbler’s nests were larger than the ones laid in reed warbler’s nests. Mean duration of incubation of cuckoo eggs was 11.7 days. Hatching success was 63.6%, breeding success was 56.1%. Mean fledging period was equal to 19.9 days. Feeding rates of cuckoo nestlings varied from 20.6/h for 10-day old nestlings to 51.4/h for 20-day old nestlings.