TOMBEUR FLL (1994) Short contributions: Strong autumn migration of Marsh Harriers Circus aeruginosus. LIMOSA 67 (3): 110-111.

During early-morning counts of visible landbird migration, 31 Marsh Harriers passed within 3.5 h near Sas van Gent, Zeeuws-Vlaanderen, Delta area, SW-Netherlands on September 18, 1993. Seven more birds were observed migrating south during the following three days. Altogether, three males, five females, 26 subadults and four birds of unknown sex and age were recorded in four days. All birds flew rather high, and between SE and SSW. The observation site is situated in the middle of flat, open arable land, far from any feature that could influence raptor migration. An explanation for this relatively large number of migrating Marsh Harriers in a single day in this type of landscape is sought in meteorology. Through September 17, it was completely overcast and rainy, with SW wind. By the 18th, weather had changed drastically: blue sky, dry and NE wind. Supposedly, Marsh Harriers interrupted their migration until better weather-conditions prevailed Western Marsh Harrier Circus aeruginosus

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