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 :	Annual and diurnal phenology of birdcall activity above the German Bight (2012)
Auteurs :	Kathrin Hueppop, Auteur ; Jochen Dierschke, Auteur ; Reinhold Hill, Auteur ; Ommo Hueppop, Auteur
Type de document :	Article
Dans :	Vogelwarte (50(2) MAY 2012)
Article en page(s) :	87-108
Langues:	Allemand
Résumé :	With regard to potential sites for the construction of offshore wind farms and to their possible threats for birds it is essential to enlarge the current knowledge on bird migration above the sea - especially during the night. Within a comprehensive study for the evaluation of offshore wind farms bird calls were registered automatically on a research platform in the south-eastern North Sea. The species identification of nocturnally migrating birds is almost exclusively possible only by means of their calls. Here, we present species-specific bird occurrence near an anthropogenic offshore structure in the total daily and yearly course on the basis of automatically registered calls.From 2004 to 2007, a total of 100 species was identified. Calls from 95,318 individuals (excluding the large gulls) were used for analyses. Three quarters were passerines (predominantly thrushes), furthermore mainly waders, terns and smaller gulls were detected. 79.4% of all individuals were registered during the night. High numbers of individuals, mostly of several species occurring together, were concentrated in only a few days/nights or even hours. Bird occurrence was much higher during autumn migration than during spring migration. A maximum of 5,236 birds of different species (corresponding to 392 Ind./h) was identified in the night from 28th to 29th October 2005. The migration periods of the short-/medium distance migrants were clearly distinguishable, otherwise not those of the long-distance passerine migrants, presumably due to their much minor ambition to call. In July mainly smaller gulls and terns, in August above all terns and waders (especially Redshank) and in winter some late smaller gulls and thrushes were registered. Generally, numbers increased continually with the beginning of the night and reached a maximum before sunrise. The fewest birds were detected in the late afternoon.Despite methodological constraints, the shown species-specific phenologies broadly match the migration times in the offshore area of the German Bight as recovered by trapping and/or by scheduled or coincidental visual observations of bird migration. Like these methods the acoustic recording cannot cover the whole occurrence of birds. Presumably, the number of birds is underestimated during fine and overestimated during adverse weather when birds reduce flight altitude. However, we assume that the birds registered acoustically on the platform reflect at least the low flying proportion of the calling species in the course of the year and in their daily variability.The opportunity to estimate numbers of low and thereby close to an anthropogenic obstruction flying birds using calls is - with regard to the evaluation of its collision risk and the introduction of mitigation and avoidance measures (site, short-term shutdown of the construction and optimization of illumination) - not exiguous.

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+