Thalasseus\sandvicensis – MOR-WENNOL FWYAF – Passage migrant.
Other records are summarised in Sandwich Tern 1994 and Sandwich Tern 2007
| Year | First | Last | Notes |
| 2000 | 4 April | 26 November | |
| 2001 | 18 March | 1 November | |
| 2002 | 18 March | 5 November | |
| 2003 | 16 March | 11 November | |
| 2004 | 29 March | 25 October | |
| 2005 | 13 March | 25 October | |
| 2006 | 24 March | 31 October | |
| 2007 | 21 April | 28 October | |
| 2008 | 19 March | 15 October | |
| 2009 | 3 April | 27 September | (1) |
| 2010 | 22 March | 19 September | |
| 2011 | 9 April | 7 October | |
| 2012 | 3 March | 4 October | |
| 2013 | 24 March | 5 November | |
| 2014 | 30 March | 19 December | |
| 2015 | 31 March | 22 November | |
| 2016 | 4 April | 4 October | |
| 2017 | 20 March | 17 October | |
| 2018 | 30 March | 25 September | |
| 2019 | 23 March | 15 December | |
| 2020 | 11 April | 14 October |
| Notes | 2009 Two winter records of a single, possibly the same bird, firstly in Fishguard harbour on 19 Jan and then off Broad Haven (N) on 2 Feb. The earliest migrants were 7 off Tenby on 3 April. |
Pattern of occurrence
A distinction between spring and autumn migrants is usually taken as July 1st (week 26/27). However, movements are clouded by immature birds that are in no hurry to get to breeding colonies, and failed breeders that may start wandering southwards before the end of June.
Note – This graph uses records from BirdTrack for Pembrokeshire only, and includes records from the Skomer and Skokholm logs going back to the 1947. There will be additional records submitted only to the county bird recorder.
