During the time and for the territories observed by Henne, three times a crane formerly bound with a mate has changed his mate (1991/94 Fb; 1994/ 95 and 1995/96 Ss). This would be equivalent to a rate of about 10% per year and crane pair, but also almost 30% of the crane pairs during the observation period, and (as shown in Ss) not necessarily because of the death of the partner. Also, a territorial pair with longer tradition may be displaced by a new one and find a different territory nearby.
In 4 cases (about 15%) a new pair appears in a territory originally owned by another pair (1991, 1995 and 1998 in Fb, 1993 Zb, 1995 Ss).
We started a broad acoustic monitoring program in connection to the ongoing banding program (in the biosphere preserve "Schorfheide-Chorin" which the a.m. crane territories belong to) with a recording weekend in 2001 during which 116 pairs had been identified. Due to organisatorical problems, no recording were taken in 2002, but new recordings had been made (but not yet completely analysed) in 2003. Results will be published at an appropriate time.