Das Projekt "Die Verteilungsmuster von Vogelgilden an Wald - Oekozonen" wird vom Umweltbundesamt gefördert und von Universite Fribourg, Institut de Zoologie durchgeführt. How do species that are members of the same guild share space in non-homogeneous riparian forests? Is the overlap between territories less than random? To answer these questions, one can compare the observed spatial distribution of territories of members of a guild with the distribution of randomly distributed territories. This null model must take in account (a) the probability of detecting a bird relative to the distance to the observer (the detection function), (b) the effect of the vegetation on the species composition and abundance, and (c) the effect of edges on the spatial distribution of birds. Edges between forest and open area and between types of vegetation with different cover percentage of trees have the greatest overall effect. Almost half of all species show a statistically insignificant response to the edge between forest and open area, a quarter of them a positive and another quarter a negative response. The edges formed by a differing cover percentage of trees are attractive upon most species. All woodpeckers and the Short-toed Tree Creeper have a neutral response to edges. The other species segregate more or less well along the perpendicular distance to forest-open area edges. The biological meaning of the attraction or repulsion effect of interior-forest edges remains to be explored.