Phenology
| Year | Migration site | First | Migration site | Last | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2021 |  |
VRS Castricum | 23 April | |
VRS Castricum | 30 April | |||
| 2019 | |
VRS Castricum | 20 April | |
VRS Castricum | 20 April | |||
| 2018 | |
VRS Castricum | 7 February | |
VRS Castricum | 21 November | |||
| 1994 | |
VRS Castricum | 25 August | |
VRS Castricum | 19 September | |||
| 1992 | |
VRS Castricum | 29 August | |
VRS Castricum | 29 August | |||
| 1990 | |
VRS Castricum | 3 September | |
VRS Castricum | 3 September | |||
| 1973 | |
VRS Castricum | 25 August | |
VRS Castricum | 25 August | |||
| 1971 | |
VRS Castricum | 13 August | |
VRS Castricum | 13 August |
