Phenology
| Year | Migration site | First | Migration site | Last | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2020 |  |
VRS Castricum | 27 August | |
VRS Castricum | 27 August | |||
| 2018 | |
VRS Castricum | 21 August | |
VRS Castricum | 21 August | |||
| 2016 | |
VRS Castricum | 14 August | |
VRS Castricum | 23 August | |||
| 1996 | |
VRS Castricum | 16 April | |
VRS Castricum | 25 May | |||
| 1995 | |
VRS Castricum | 20 April | |
VRS Castricum | 20 April | |||
| 1993 | |
VRS Castricum | 11 May | |
VRS Castricum | 11 May | |||
| 1990 | |
VRS Castricum | 3 May | |
VRS Castricum | 8 September | |||
| 1989 | |
VRS Castricum | 3 May | |
VRS Castricum | 3 May | |||
| 1987 | |
VRS Castricum | 24 April | |
VRS Castricum | 7 May | |||
| 1986 | |
VRS Castricum | 17 April | |
VRS Castricum | 17 April | |||
| 1981 | |
VRS Castricum | 12 April | |
VRS Castricum | 12 April |
