Thalasseus sandvicensis sandvicensis
Length: 37 – 46 cm
Wingspan: 85 – 105 cm
Weight: 180 – 300 g
Appearance: medium/large-sized tern with an ash grey coat, black legs, and long black beak with yellow tip. White tail prolonged by two long nets and erectile hoopoe extending its black cap.
Distinguishing characteristics: longer and thinner bill than Gull-billed tern, which is also black but without the yellow tip.
Flight: monotonous light wingbeat; acrobatic flights during parade.
Sound: loud grating and discordant call « kirrèk kirrèk » when flying; guttural « krak krak » during parade, with beak pointing towards the sky.
Ecology and habitat
Nest: hole in the ground, sometimes lined with grass, on low and stony or sandy coasts, with sparse vegetation, near the coast.
Diet: mainly small fish (98% of the diet) such as sandeels, sprats and whiting.
Behaviour at sea: rarely seen at sea or far from the coasts.
* This map indicates coastal nesting sites in the Mediterranean and adjacent Seas.
Distribution and movement
Breeding: this subspecies breeds on coasts of the Atlantic Ocean (including North and Baltic Sea), the Mediterranean and Black Sea, and the Caspian Sea. The bulk of the Mediterranean population is concentrated in the Western sub-region (France, Spain, Italy and, to a lesser extent, Greece). Breeding occurs also in the Black Sea (Bulgaria, Romania and Ukraine).
Wintering: to South Africa
Phenology: Laying: May-June; one to three eggs. Incubation: 23 days. Chick-rearing. Fledging: 5 weeks after hatching.
Global population estimate: 490,000 – 640,000 individuals. European population: 79,900 – 148,000 pairs.
Threats: habitat destruction and modification, anthropogenic disturbance (eggs abandon), predation by foxes on colonies, decrease of fishing resources.
Protection level: Barcelona Convention: Annex II; Bern Convention: Appendix II, African Eurasian Waterbird Agreement; Convention on Migratory Species: Appendix II; EU Birds Directive: Annex II; IUCN Red List: Least Concern.
Some key references
BirdLife International (2021) Species factsheet: Thalasseus sandvicensis.
Efe M. A., Tavares E. S., Baker A. J., Bonatto S. L. 2009. Multigene phylogeny and DNA barcoding indicate that the Sandwich tern complex (Thalasseus sandvicensis, Laridae, Sternini) comprises two species. Molecular Phylogenetics and Evolution 52(1): 263-267.
Oro D., Bertolero A., Vilalta A. M., López, M. A. 2004. The biology of the Little Tern in the Ebro Delta (northwestern Mediterranean). Waterbirds 27(4): 434-440.