JANSEN FH (1979) Some aspects of migration of the Dunlin Calidris alpina off Scheveningen. LIMOSA 52 (1): 34-52.

Dunlin Calidris alpina = Calidris alpina schinzii Visible migration of Dunlins Calidris a/pina is strongest when the direction of wind is opposite to the intended direction of migration. This is probably the result from the fact thatwindforces are much weaker at the lowest level than at higher altitudes. 2. In opposing winds with windforce 3 in autumn and windforce 5 in spring (Scale of Beaufort) more Dunlins are seen migrating; the urgency to migrate is obviously stronger in spring. 3. More Dunlins are seen migrating under an almost clear sky than in more cloudy weather, 4. Additionally, strong visible migration occurs with strong northwesterly winds in autumn, possibly as a result of (voluntary?) drift. Migratory routes of the Dunlin are better understood when describing them as loxodromes, that's to say as the shortest routes between two places, appearing as straight lines on a gnomonic projection. All important wintering residences are more or less situated on a single straight line. As a result the migratory routes take shape of a narrow corridor coinciding with the EuropeanlNorth African coast-line. 6. Occurrence of peaks in the visible migration of Dunlins off Scheveningen coincides with strong fluctuations of numbers of Dunlins staying at various residences in the North Sea area. 7. An explanation is offered for the different patterns in visible migration in spring at various observatories along the Dutch coast. It is therefore assumed that the migrating birds arrive from various origins.

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