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Titre :	[Occurrence of Dotterel Charadrius morinellus in Denmark in 1981-1999]
Auteurs :	Egon Ostergaard, Auteur
Type de document :	Article
Dans :	Dansk Ornitologisk Forenings Tidsskrift (95(1) 2001)
Article en page(s) :	1-8
Langues:	Anglais
Résumé :	During the period 1981-1999 Dotterels were recorded on 570 days. Adding the daily maxima yields a total of 10 429, 97.8% of which were seen in spring, between 16 April and 9 June (Table 1). There has been an increasing number of records per year compared with the period before 1980, probably largely owing to an increased ornithological activity during the last 20 years. Most Dotterels are seen in western Jutland (Fig. 3), and the 8 known spring staging sites (Table 3) are all located in this area, on open fields without crops or with germinating cereals or peas. The largest of the sites, Skjern Enge with an average of 88 birds per year, has been known as a staging site for more than 100 years, as has the site at Hanstholm/Raehr. The spring phenology in Denmark is shown in Fig. 4. The summed maximum records have been 50-200 birds each year but increased in 1997-1999 to 300-560 birds (Fig. 5). Only 225 Dotterels have been recorded in autumn (late August - late September) during the study period; 86% of these were single and most of them juveniles. Three flocks of 25, 25 and 35 birds, respectively, were the only ones with more than four. The distribution in autumn is largely coastal and not concentrated to West Jutland as in spring (Fig. 1). One hundred years ago the Dotterel was a fairly common spring migrant, especially in western Jutland. It is not known why the number of staging birds decreased. The species was hunted intensively until it was legally protected in 1922, but has failed to recover since then. Other possibilities are 1) A general change in spring migration from a stopover-strategy to a non-stop strategy. Cultivation of the heathlands in Jutland in the 19th and 20th century has probably improved the conditions for Dotterels feeding on manured fields. Subsequent planting of windbreaks and plantations may have rendered the previously open farmland less suitable for Dotterels. Hunting could also have played a role in the change. 2) A general decrease of the Scandinavian Dotterel populations. Although still considerable (11 000-23 000 pairs) they may have undergone a decrease similar to that reported from Finland (Sari 1995). The birds staging in Denmark probably belong to the Norwegian population. 3) A decrease of a particular (northern?) population which, contrary to other populations, used stopover sites in Denmark during spring migration.

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