Phenology
| Year | Migration site | First | Migration site | Last | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2021 |  |
VRS Castricum | 9 October | |
VRS Castricum | 16 November | |||
| 2018 | |
VRS Castricum | 18 October | |
VRS Castricum | 18 October | |||
| 2017 | |
VRS Castricum | 16 September | |
VRS Castricum | 16 September | |||
| 2016 | |
VRS Castricum | 6 October | |
VRS Castricum | 6 October | |||
| 2014 | |
VRS Castricum | 16 October | |
VRS Castricum | 16 October | |||
| 2013 | |
VRS Castricum | 27 September | |
VRS Castricum | 5 November | |||
| 2012 | |
VRS Castricum | 8 October | |
VRS Castricum | 20 October | |||
| 2011 | |
VRS Castricum | 15 October | |
VRS Castricum | 15 October | |||
| 2009 | |
VRS Castricum | 4 November | |
VRS Castricum | 4 November | |||
| 2007 | |
VRS Castricum | 21 October | |
VRS Castricum | 21 October | |||
| 2004 | |
VRS Castricum | 8 October | |
VRS Castricum | 8 October | |||
| 1990 | |
VRS Castricum | 10 November | |
VRS Castricum | 10 November | |||
| 1987 | |
VRS Castricum | 5 November | |
VRS Castricum | 5 November | |||
| 1986 | |
VRS Castricum | 12 November | |
VRS Castricum | 12 November | |||
| 1978 | |
VRS Castricum | 26 October | |
VRS Castricum | 26 October | |||
| 1977 | |
VRS Castricum | 27 September | |
VRS Castricum | 27 September |
