Gerrit J. Gerritsen & Jan van Dooren (2024) Spring staging of Whimbrels Numenius phaeopus phaeopus on the Landschotse Heide: results of large numbers ringed in 1975-93. LIMOSA 97 (3): 129-136.

The Whimbrel is a numerous breeding bird in Northern Europe and Russia, with an estimated population size of 240 000-390 000 birds. It has a stable trend. In the Netherlands and Belgium important stop-over-sites are found during spring migration. Simultaneous night roost counts in 1975-79 revealed that most birds stayed in the northeast part of the Netherlands (16 000) and a smaller number in the border area between Belgium and the Netherlands (5100). The numbers in this border area dropped seriously after 1979, probably because wet habitats have dried out at these sandy soils. In 1975-93 2659 Whimbrels were caught with wader nets and sound lure on a roost on the Landschotse Heide. This represents 75% of the total number of Whimbrel ringed in the Netherlands. From 593 birds (22% of the grand total) wing, bill and tarsus length were measured. Based on these biometrics we conclude that there was no difference in the timing of migration of males and females.
14 Whimbrels were recaptured during the same spring, at an average interval of 8 days (minimum 7 and maximum 15 days). 62 (2.3%) were recaptured in subsequent springs, showing that individuals are faithful to their spring staging sites to some extent. Most frequent were recaptures one (32%) or two (31%) year(s) later, the maximum interval was nine years.
There are five recoveries from Finnish breeding grounds between 62.32° and 67.16° N and one from Russia. The Russian bird was shot on the first of July, 3125 km east of the Landschotse Heide. We received 11 recoveries from Africa: 3 from Morocco (13 April 1984, 19 April 1990 en 15 May 1992), 1 from Guinea-Bissau (20 Oktober 1992), 1 from Guinea-Conakry (23 August 1980), 2 from Sierra Leone (10 August 1983 and 7 January 1991), 1 from Ivory Coast (28 November 1992), 1 from Ghana (10 September 1985), 1 from Benin (12 September 1982) and 1 from Gabon (14 December 1980). The recovery from Gabon is the most southern one (5793 km).
Several questions about the spring migration of Whimbrels remain. How many stops do Whimbrels make during spring migration? How frequently do Whimbrel switch between the route along the Atlantic coast and the more inland route through Italy? These questions might be resolved by the GPS-tracking studies recently initiated by French and Dutch researchers.

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