Phenology
| Year | Migration site | First | Migration site | Last | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2021 |  |
VRS Castricum | 7 October | |
VRS Castricum | 7 October | |||
| 2018 | |
VRS Castricum | 7 October | |
VRS Castricum | 15 October | |||
| 2017 | |
VRS Castricum | 15 October | |
VRS Castricum | 3 November | |||
| 2016 | |
VRS Castricum | 12 September | |
VRS Castricum | 12 September | |||
| 2015 | |
VRS Castricum | 30 September | |
VRS Castricum | 30 September | |||
| 2013 | |
VRS Castricum | 13 September | |
VRS Castricum | 13 September | |||
| 1998 | |
VRS Castricum | 7 November | |
VRS Castricum | 7 November | |||
| 1986 | |
VRS Castricum | 30 November | |
VRS Castricum | 30 November |
