Bibliothèque Tour du Valat

Se connecter

Mot de passe oublié ?
Pas encore inscrit ?

La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Détail

Ajouter au panier

Ajouter au panier

Lien vers la notice

Titre :	The occurrence of Bewick's Swan Cygnus bewickii in the Hunte lowland near Oldenburg (NW Lower Saxony)
Auteurs :	Thorsten Krueger, Auteur
Type de document :	Article
Dans :	Vogelwelt (Die) (129(1) 2008)
Article en page(s) :	15-33
Résumé :	The lowland of the river Hunte, east of Oldenburg, is a traditional staging and wintering site for Bewick's Swans. First documented in 1861, the species has been reported regularly from the area since 1870. From the total study area of 65 km(2), most of which are managed grasslands (92%), a portion of 11km(2) was declared a Special Protection Area (SPA) in 1983 for this reason. As late as the 1950s and 1960s, most winters brought accumulations of up to 600 Bewick's Swans in the area, making it one of the most significant staging and wintering sites in Lower Saxony and, in fact, in Germany at that time. Main indicator for the significance of the area is the presence of roosting Bewick's Swans and their recorded maximum numbers. Owing to direct and indirect losses of habitats through hydrological measures and widespread agricultural amelioration, numbers declined drastically in subsequent years. After having remained fairly small for years, numbers rose to 250 Bewick's Swans in the winter of 1998/99 and, with 216 and 283 birds recorded in the following winters, stayed well above average, thus fulfilling criteria for international importance. Subsequently, however, numbers dropped considerably again. In spite of this development, numbers of swan-days have risen quite significantly, owing to the fact that Bewick's Swans have been wintering (again) in the area since the mid 1990s.Depicted in the paper presented here are also phenology, spatial utilisation (e.g. as foraging habitat) of the area, variations in flock size and proportions of juveniles during winter seasons. Records of colour-ringed swans are also collated and evaluated, indicating that some birds show remarkable staging resp. wintering site fidelity. They were found to have returned in up to eleven consecutive winters. Starting in 2001/02 already, spatial utilisation of the Hunte lowland by the birds changed dramatically from 2004 on, paralleled by yet another decline in maximum numbers. Possible causes are extensively discussed. As early as 2001, measures to scare away swans from the SPA were perceived. At least from 2007/08 onwards, these were extended towards White-fronted, Barnacle, Greylag and Bean Geese, which had risen sharply in numbers since 1998/99. Local farmers and hunters have formed a sort of "(anti) geese militia" to systematically scaring away the birds. It is thus most likely that all parts of the SPA not having the status of a nature reserve were and still are subjected to targeted disturbances, so as not to attract the birds any longer.Conditions in the Hunte floodplain and especially at its very core, the SPA, are characterised by the fact that certain bird species like Great Cormorant, crows or Grey Heron are not only not tolerated by landowners and parts of the local citizens, but are actively scared away - which is blatantly contrary to goals and provisions of the EU Birds Directive and are a striking example for the wearisome process of finding acceptance in implementing NATURA 2000.

FAQ

Infos pratiques

Heures d'ouverture et contact

Lundi , mardi et jeudi de 9h à 12h et de 13h à 17h00 : ouverture au public ...

Liens utiles

A-
A
A+