Phenology
| Year | Migration site | First | Migration site | Last | |||||
|---|---|---|---|---|---|---|---|---|---|
| 2021 |  |
VRS Castricum | 11 February | |
VRS Castricum | 5 August | |||
| 2020 | |
VRS Castricum | 25 June | |
VRS Castricum | 25 June | |||
| 2018 | |
VRS Castricum | 26 June | |
VRS Castricum | 2 September | |||
| 2017 | |
VRS Castricum | 12 February | |
VRS Castricum | 12 February | |||
| 2016 | |
VRS Castricum | 18 August | |
VRS Castricum | 18 August | |||
| 2013 | |
VRS Castricum | 2 July | |
VRS Castricum | 25 July | |||
| 2012 | |
VRS Castricum | 4 June | |
VRS Castricum | 22 July | |||
| 2011 | |
VRS Castricum | 17 November | |
VRS Castricum | 17 November | |||
| 2010 | |
VRS Castricum | 29 June | |
VRS Castricum | 29 June | |||
| 2009 | |
VRS Castricum | 11 January | |
VRS Castricum | 11 January | |||
| 2007 | |
VRS Castricum | 19 June | |
VRS Castricum | 19 June | |||
| 2006 | |
VRS Castricum | 9 July | |
VRS Castricum | 26 August | |||
| 2005 | |
VRS Castricum | 14 July | |
VRS Castricum | 27 November | |||
| 2000 | |
VRS Castricum | 9 June | |
VRS Castricum | 9 June | |||
| 1996 | |
VRS Castricum | 3 January | |
VRS Castricum | 3 January | |||
| 1993 | |
VRS Castricum | 3 January | |
VRS Castricum | 3 January | |||
| 1987 | |
VRS Castricum | 17 January | |
VRS Castricum | 20 January | |||
| 1985 | |
VRS Castricum | 16 February | |
VRS Castricum | 16 February | |||
| 1982 | |
VRS Castricum | 12 January | |
VRS Castricum | 14 January | |||
| 1980 | |
VRS Castricum | 8 November | |
VRS Castricum | 8 November | |||
| 1978 | |
VRS Castricum | 8 December | |
VRS Castricum | 8 December |
