Spring migration of Turnstones from the Banc d’Arguin in Mauritania

The majority of the Turnstones Arenaria interpres wintering on the Banc d’Arguin, Mauritania, probably breeds in N. Scandinavia and NW. Russia, but a sizeable proportion may be derived from Greenland and NE. Canada. Juveniles did not prepare to migrate to the breeding grounds, but in the course of spring they moved away from the study site to unknown destinations, probably nearby. The majority of adults had moulted into summer plumage by the end of April and departure was concentrated in the last week of April and the first week of May. Some immigrations of Turnstones wintering further south may have occurred. It was calculated from the number of recaptured birds that approximately 1000 Turnstones return year after year to winter at the major catching site and its immediate vicinity. During March and the beginning of April adults gained mass slowly, which may be linked to the concomitant moult into summer plumage. Calculations of the rate of body mass gain of adults recaptured in different years indicated an increase in the rate of body mass gain by the end of April. Probable departure masses vary between 130 and 140 g. From current knowledge it cannot be decided whether the Turnstones need more than one additional spring staging site to reach their breeding grounds.

Ens B.J., Duiven P., Smit C.J. & Van Spanje T.M., ARDEA 78 (12): 301-314.