Like other bird species predating on large invertebrates the Red-backed Shrike strongly declined in the Dutch coastal dunes. Still common throughout the whole dune area in the fifties, in 1997 and 1998 only one last territory was occupied on AmelandaWadden Sea island. We suppose that affected invertebrate diversity led to deteriorated prey availability that caused this dramatic downfall. Therefore, we compared food ecology data of the 1997 and 1998 breeding pair with data from 1989 on Ameland, with growing population in a Dutch peat moor reserve Bargerveen and (from literature) with a stable population in Germany.
Kuper, J.T., van Duinen, G.A., Nijssen, M., Geertsma, M., & Esselink, H. (2000). Is decline of the red-backed shrike (Lanius collurio) in Dutch coastal dune area caused by decrease in insect diversity? The Ring. Volume 22-1: 11-25.