das“Repowering” als Chance gesehen wird, die Erzeugung von elektrischem Strom mit Hilfe des Windes dennoch zu steigern.

Die Erhebung von ökofaunistischen Grundlagen­daten(großräumige Arten- und Verhaltenserfas­sungen) kann für die Beurteilung der Eignungs­gebiete für WKA nicht erst mit dem Genehmigungs­verfahren erfolgen. Die Finanzierung der vorausei­lenden ökofaunistischen Erfassungen bedarf noch der rechtlichen Regelung.

9 Summary

The influence of wind energy facilities(WEF) on birds was studied in the Niederlausitz region, fede­ral state of Brandenburg, from 2003 until 2005. The studies were of breeding birds on 11 operating wind farms in an area of 2,643 hectares. The conditions before and after the construction of 4 of the wind farms were known. The frequency of widespread species was calculated and the occurrence of natio­nal(German) or regional(Brandenburg) red list species was mapped precisely. The occurrence of se­lected large bird species in the vicinity was also registered.

Outside the breeding season the occurrence of birds on passage and winter visitors on the wind farms and their immediate vicinity was recorded throughout the year, with the priority being given to flocks of migrants. The relationship of Common Crane and geese to surrounding roost waters was also taken into consideration. Mortality through collision of bird and bat species with the turbines was also recorded.

General avoidance of wind farms by breeding birds was not evident. In the areas studied there was no negative trend in before and after figures. Where the facility infrastructure permitted, the ground for­ming part of the territory of song birds in the im­mediate area of the masts was used without any timidity. Large birds usually kept a minimum stand-off distance of 100 m. A stand-off distance exceeding 200 m was only evident for a few sensiti­ve species which possibly included Honey Buzzard and Nightjar. After the construction of the wind farms there were a number of cases where the Hobby abandoned its traditional breeding site; but the pairs returned after two to three years.

This rapid adaptation to the presence of the turbi­nes led to collision mortality among breeding birds. This also included adult birds with flight experien­ce, which led to abandonment of the brood. Fledged young birds also fell victim to the turbines. A total of 34 dead birds of 20 species were recovered from under the turbines. The spectrum of these species ranged from White-tailed Eagle , Red Kite and White

A„Otis 15(2007), Sonderheft

Stork to Skylark, Great Tit and Goldcrest. As the vegetation under the turbines was dense and tall up to the foot of the masts, it is likely that only a small percentage of mortalities was found. This definitely applies to the smaller bat species of which 19 mor­talities of 4 species were recovered,

In contrast to breeding birds, some birds on pas­sage and winter visitors were recorded as avoiding the wind farms. Of these only small birds passed close to the turbines at ground level or foraged for food on the ground or in the hedgerows. Medium sized birds, such as the Golden Plover, often however also Lapwing and Curlew, kept a stand-off distance of some 300m to the turbines. Some bird species showed no shyness however. These included Kestrel, Sparrowhawk , Common Buzzard , Red Kite and Raven. Geese and Common Crane were however very careful. Whereas the Greylag Goose approa­ched the turbines to within 250 m, Bean and White­ fronted Goose kept a minimum stand-off distance of 500 m and the Common Crane 1,000 m. Only smaller groups occasionally approached closer than these distances. In the middle of the wind farms these species were never observed and they seldom overflew the turbines. As a rule, migrating geese, cranes and other large birds avoided the wind parks by some considerable distance. Even North Euro­ pean birds of prey which hunt close to the ground such as Merlin, Hen Harrier and Rough-legged Buz­zard, were only observed within the area of the wind farms when the food supply was exceptionally good.

In conclusion, the wind farms have only a minimal influence on the distribution of breeding birds in the Niederlausitz . Those species within and close to the wind farms are exposed to a greater degree of endangerment. This can lead to a lasting decrease in reproduction success for those species most affec­ted, such as White Stork , White-tailed Eagle and Red Kite .

In addition, the suitability of the region as a resting habitat for northern visiting species(prima­rily Common Crane , arctic geese, Golden Plover, Lapwing and possibly Curlew, Merlin, Rough-legged Buzzard and Hen Harrier) can be affected. In the case of geese and cranes, feeding on farmland free of turbines can lead to increased conflict with far­mers(increased damage potential).

In principle, compensatory measures for the con­struction of wind energy facilities must be taken outside the confines of the wind farms. Efforts must be made here to improve the habitat of birds and bats in order to achieve a increase in the reproduc­tion rate which compensates for the deficits arising within the wind farms. The strict rules for and com­pliance with species-specific stand-off criteria is the most workable method for determining suitable sites, or for the selection of appropriate areas for