Phenology
| Year | Migration site | First | Migration site | Last | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2021 |  |
VRS Castricum | 14 February | |
VRS Castricum | 19 February | |||
| 2019 | |
VRS Castricum | 17 February | |
VRS Castricum | 30 March | |||
| 2018 | |
VRS Castricum | 27 February | |
VRS Castricum | 15 November | |||
| 2016 | |
VRS Castricum | 9 November | |
VRS Castricum | 9 November |
