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Sandwich tern migration Thalasseus sandvicensis
ⶠFollow the Sandwich tern across the big globe
Press ⶠto play the year. Line: a simplified typical route, joining the main cluster of GBIF records in each month (adjusted for observer effort).
| Scientific name | Thalasseus sandvicensis |
|---|---|
| Wingspan | 100 cm |
| IUCN status | Least concern |
| Records mapped | 970,356 (GBIF) |
| GPS / geolocator tracks | none with an open licence yet |
Facts from Wikidata Q27547 (CC0).
When does the Sandwich tern arrive in the UK?
A summer visitor in the records: sightings rise sharply from late March, are near their peak by late June, and fall away after mid October.
Bars: this speciesâ share of all UK bird records in GBIF (CC0/CC BY), by month, scaled to the peak month. Based on 91,570 UK records. Weekly counts from the GBIF occurrence search API (country=GB). Dates are read from records, not from a survey, so treat them as a guide.
When do they arrive in and leave the UK? â
Migration in the data
970,356 GBIF records (CC0 and CC BY 4.0 licences only) are mapped here, in 1.41° grid cells, month by month.
In Europe and Africa, the centre of the records (adjusted for observer effort) is furthest north in July (about 45°N) and furthest south in February (about 27°N).
Month by month: centre of records in Europe and Africa
| Month | Centre (latitude) | South of the Equator |
|---|---|---|
| January | 28°N | 10% |
| February | 27°N | 12% |
| March | 29°N | 10% |
| April | 38°N | 6% |
| May | 41°N | 5% |
| June | 42°N | 6% |
| July | 45°N | 4% |
| August | 43°N | 5% |
| September | 40°N | 6% |
| October | 33°N | 9% |
| November | 28°N | 11% |
| December | 27°N | 12% |
Tracked birds
No openly licensed (CC0 / CC BY) tracking data package for this species was found in the Movebank Data Repository yet, so only records are shown.
About the Sandwich tern
The Sandwich tern is a tern in the family Laridae. It is very closely related to the lesser crested tern, Chinese crested tern, Cabot's tern, and elegant tern and has been known to interbreed with both elegant and lesser crested terns. It breeds in the Palearctic from Europe to the Caspian Sea, and winters in the Mediterranean and on the coasts of Africa, India, and Sri Lanka.
From the Wikipedia article âSandwich ternâ (revision 1371756884), CC BY-SA 4.0.
Sources
GBIF occurrence records, licence CC0 1.0 or CC BY 4.0 only, observations only (no specimens), filtered with: taxonKey=2481240&license=CC0_1_0&license=CC_BY_4_0&occurrenceStatus=PRESENT&hasGeospatialIssue=false&basisOfRecord=HUMAN_OBSERVATION&basisOfRecord=MACHINE_OBSERVATION&basisOfRecord=OBSERVATION. Monthly queries: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec. GBIF.org (23 October 2026) occurrence data accessed via the GBIF API; a GBIF download DOI is still to be added. Contributing datasets.