OUWENEEL GL (1978) The occurrence of the Marsh Harder Circus aeruginosus in the Hollandsch. LIMOSA 51 (3): 81-87.

Western Marsh Harrier Circus aeruginosus Between 1970 and 1977 the number of breeding-pairs of the Marsh Harrier Circus aeruginosus in the Hollandsch Diep-Haringvliet area increased from 3-6 to 23-25 pairs. In 1977 four extensive reedlands along the Haringvliet held 14 nests. One of these areas, the Scheelhoek, had the remarkable density of 5 nests on 100 hectares, with moreover one nest of the Hen Harrier Circus cyaneus. In 1976 and 1977 there were several successful couples which had their nests in reed areas of less than one hectare. In 1976 8 couples reared 24 juveniles, an average of 3,0. In 1977 19 couples reared42 juveniles, an average of nearly 2,2. In The Netherlands the Marsh Harrier has regained its numbers somewhat the last few years. It is believed that recolonization offormely haunts, is the principal reason of the recent development. Besides, small rodents increased in numbers on the grounds outside the dikes after the closure of the Haringvliet in 1970.

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