Sandwich Tern

Sterna sandvicensis

Order: Charadriiformes
Family: Laridae
Presence in the Strait: Seasonal
Abundance: common
Protection in Spain: Special protection (List)
In Spanish: Charrán patinegro

Photograph: Stanley Davis, CC BY, vía iNaturalist

Length: 36–41 cm
Wingspan: 98–105 cm
Weight: 250 g

Presence in the Strait

Common winter visitor to coasts (<200) with some birds staying for the summer.

Identification

Similar size to a Black-headed Gull but more slender. Black bill with yellow tip, short black legs, uniform light-grey upperparts, white rump and forked tail. Summer plumage shows black forehead, crest and crown. In winter plumage, less obvious white-streaked crest and white forehead. Juveniles are like winter adults but with dark markings on wings, back and tail, Sternidae Pagaza Piconegra ad.E Pagaza Piquirroja ad.E ad.W ad.E Charrán Patinegro juv. ad.W ad.E and lacks yellow bill-tip. They dive into the water to catch their prey. Gregarious.

Movements

Peaks in 1st hf. April and 1st hf. September.

Ring recoveries

United Kingdom (9), Ukraine (2), Russia (2), Germany (2), Holland (1), Sweden (1) and Ireland (1).

Bioestrecho editorial text. Last revised: 8 September 2026.

Photographs from iNaturalist observations with the licence checked file by file. Those marked “Strait” were taken within the area; place and date are those of each observation.

Calendar in the Strait

15 %

Peak in October. Observations under CC0 or CC BY licences. The distribution also reflects observation effort.

Where it is seen

Open records from the atlas database, in cells of about 3.6 km. Opacity follows the square root of the count, and also reflects where people observe most.

See on the map

First open record: 25 February 1966
Latest record: 15 February 2026

The oldest and the most recent open observation in the extended area. A recent first observation does not mean the species is new: it means nobody had published it openly before.

Conservation

The catalogues, Andalusian and Spanish, are what binds; the Red Book assesses the Spanish population with IUCN criteria, and the global Red List is the context.

LCNTVUENCR

Andalusian Catalogue: Special protection (List)
Spanish Catalogue: Special protection (List)
Red Book of the Birds of Spain 2021: VU · Vulnerable · breeding
Global Red List (IUCN): LC · Least concern

Annex I of the Birds Directive

Andalusian Catalogue: Junta de Andalucía, list of 24 April 2025. Spanish Catalogue: MITECO, table of 30 June 2025. Red Book: SEO/BirdLife, 2021 (Annex I). IUCN: via GBIF, 6 September 2026. Red Book and IUCN categories are assessments; catalogue categories are legal obligations.

Phenology compared

Monthly distribution in proportion, by decade. It shows whether the passage is getting earlier or later.

1990–1999

2000–2009

2010–2026

Proportions, not totals: observation effort grew faster than any population.

Where they come from

18 birds ringed in other countries and recovered in the area.

United Kingdom9
Ukraine2
Russia2
Germany2
Netherlands1
Sweden1

See the journey on the map

Same genus in the Strait

Lesser Crested Tern35–37 cm · Migrant · overlapping size
Roseate Tern33–38 cm · Vagrant · overlapping size
Forster´s Tern33–36 cm · Vagrant · overlapping size
Common Tern31–35 cm · Migrant
Caspian Tern47–54 cm · Seasonal

Species of the same genus that also occur here, ordered by how close they are in size. Being relatives does not mean they are confused in the field, but that is where the doubts start: compare size and season.

Classification

Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Laridae
GBIF taxon key: 2481240

Sources

Distribution and calendar: Bioestrecho's own database, ingested from GBIF and OBIS
Photograph: Stanley Davis, CC BY, vía iNaturalist
Taxonomy: GBIF backbone, pending WoRMS for marine taxa
Editorial text: written by Bioestrecho
Last revised: 8 September 2026

Sandwich Tern

Presence in the Strait

Identification

Movements

Ring recoveries

Gallery