Phenology
| Year | Migration site | First | Migration site | Last | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2021 |  |
VRS Castricum | 29 May | |
VRS Castricum | 4 June | |||
| 2019 | |
VRS Castricum | 10 September | |
VRS Castricum | 10 September | |||
| 2018 | |
VRS Castricum | 6 September | |
VRS Castricum | 20 October | |||
| 2017 | |
VRS Castricum | 25 September | |
VRS Castricum | 25 September | |||
| 2016 | |
VRS Castricum | 8 September | |
VRS Castricum | 8 September | |||
| 2013 | |
VRS Castricum | 4 August | |
VRS Castricum | 27 September | |||
| 2012 | |
VRS Castricum | 21 October | |
VRS Castricum | 9 November | |||
| 2010 | |
VRS Castricum | 9 July | |
VRS Castricum | 1 October | |||
| 2007 | |
VRS Castricum | 12 September | |
VRS Castricum | 20 October | |||
| 2003 | |
VRS Castricum | 30 September | |
VRS Castricum | 30 September |
