| Titre : | The Black Tern Chlidonias niger in the floodplains of river Elbe of the Hannover Wendland. |
| Auteurs : | Wilhelm Meier-Peithmann, Auteur |
| Type de document : | Article |
| Dans : | Vogelwelt (Die) (126(3) 2005) |
| Article en page(s) : | 219-225 |
| Résumé : | The population of Black Terns breeding in the Hannover Wendland (NE Lower Saxony) continuously decreased from (40-)50-60 pairs in the second half of the 1960s and tile beginning of the 1970s to an all time low of five pairs in 1996. Since then the population slightly increased and stabilised at about 20 pairs. In the same period the number of colonies decreased from 14 to 1(-2). In addition there were two small colonies on artificial breeding rafts in neighbouring parts of the Elbe valley. Whilst Black Terns originally mostly settled on foreshore waters in the Gartow and Dannenberg marshes of river Elbe, they meanwhile only breed on embanked oxbow lakes in the western Dannenberg river bend. They changed breeding habitats and swapped tussocks of reed and sedges in the flood zones against rhizome islands of Nuphar lutea in flood-free areas. The circular rhizome islands created by underwater springs in Lake Penkefitz are one of the last natural breeding habitats in western Europe. Clay pits in the neighbourhood offer easily available fish as food. In 1997-2002 only about 45% of broods hatched. On average 1 each pair raised 0.81 fleglings per year. In years with changes of colony site during the breeding period this figure dropped to 0.25-0.62, but in other years it was as high as 1.00-1.16. In order to protect and enlarge the Black Tern population breeding at the middle reaches of River Elbe recommendations for protection and habitat management are presented, |



