Breeding of the Water Rail Rallus aquaticus in Cladium mariscus vegetation

Abstract

We have studied breeding habitats of the Water Rail Rallus aquaticus in Cladium mariscus (Galingale) vegetation at Botshol (Abcoude, 51°52'N;5°04'E) in The Netherlands and on Öland in Sweden. Water Rails were localised by day by provoking vocal responses with a cassette recorder, using three typical call types that indicate breeding status of the rails. We found 21 territories and five nests in Cladium mariscus vegetation. In the territories and around the nests we measured the degree of plant cover, frequency of different plant species, height of vegetation, and water depth. No rails were heard in pure reed (Phragmites australis) vegetation. In all territories and around all nests Cladium mariscus was dominant. Cladium mariscus was also the most common nest material. The soil and the vegetation mat were inundated. The water depth was usually below 50 cm. This study seems to be the first one documenting Water Rails breeding in Cladium mariscus vegetation.