Bestaat West-Drentse populatie van Grauwe Klauwieren Lanius collurio bij de gratie van lokale reproductie?

In western Drenthe, a small population of Red-Backed Shrikes became established in the early 1990s, increasing to 6 pairs (and 3 unpaired males) in 1998. Males normally arrived ahead of females, mean arrival dates being respectively 10 and 12 May (Table 1). Over the years, the pairs produced 46 clutches, resulting in 124 fledglings (2.7/pair, including failures; Table 2). This reproduction should suffice to replace mortality. No indications were found that recruits from the large population in SE-Drenthe settle in western Drenthe; 2 ringed birds in western Drenthe were probably locally produced fledglings.