Rapid decline of Common Cuckoo Cuculus canorus parasitism in Red-backed Shrikes Lanius collurio.

This article discusses a study which examined temporal changes in parasitism rate by the Common Cuckoo on one of its regular hosts, the Red-backed Shrike Lanius collurio. In the Czech Republic, the Red-backed Shrike is one of the most commonly ringed bird species. The parasitism rate in this study was calculated by administrative districts within the country. Results of the study showed that there was a mean parasitism rate of 1.04% during 1964-2006. The study also found a significant drop in the parasitism rate of Shrike nests during the same period. It also identified two districts with the highest rates of parasitism.