Anne Cotton

Colonially breeding species, which occupies sparsely vegetated low-lying areas in exclusively coastal habitats, preferring sandy, muddy, gravelly or bare coral substrates. Widely, but patchily, distributed along the coasts of Europe, E North America, Caribbean region and South America (Shealer et al. 2020). European strongholds are in the Netherlands, the British Isles, Russia and Ukraine (Keller et al. 2020). Populations in Europe are migratory, the wintering grounds being largely in the Mediterranean region and along the coasts of W Africa.

Season of assessment

B

Population trendIncreasing
Population size
(min-max, best estimate)		160000-320000,258000
Red List categoryLC
Franks, S., Fiedler, W., Arizaga, J., Jiguet, F., Nikolov, B., van der Jeugd, Ambrosini, R, Aizpurua, O., Bairlein, F., Clark, J., Fattorini, N, Hammond, M., Higgins, D, Levering, H., Skellorn, W., Spina, F, Thorup, K. Walker, J., Woodward, I. and Baillie, S.R. (1) (2022) Online Atlas of the movements of European bird populations. https://migrationatlas.org EURING/CMS (1) Principal investigator
Map

Overall Connectivity for Sandwich Tern

Birds breeding in N, NW, W & C Europe migrate S & SW mostly along the Atlantic coast of W & SW Europe, to a lesser extent through the W & C Mediterranean. Multiple encounters of wintering birds are spread along the whole Atlantic coastline of W & S Africa, reaching the Indian Ocean close to Mozambique. Wintering birds are encountered in the Macaronesian islands (single stragglers) and even as far as North America. Very few birds from N & C Europe take SE routes towards the Black Sea region. SC European breeders (Italy) migrate and overwinter both in the Mediterranean and along the W & S Africa coasts. The Black Sea breeding population mainly migrates to the Mediterranean Sea during winter, moving E-W. A bird marked by the Caspian Sea was recovered during winter in Sri Lanka.

Recoveries by Condition for Sandwich Tern

Most recoveries occur during the breeding season, peaking in Jun (ca. 42%). The bulk of encounters (ca. 80% in total) come from W  (32%), NW (17%), N (16%) and C Europe (15%). Recoveries of dead birds have  decreased over time: from 74%  before1961 to 14% since 1991; recoveries of live birds increased considerably from 9% before 1961 to 80% since 1991. The latter is mostly due to recaptures; especially metal rings read in the field and colour-ring resightings. Shooting was an important factor in the past (26% of all recoveries before 1961 and 6% 1961-1990). Birds have been locally trapped in W Africa by children using baited hooks or nooses (Wernham et al. 2002).

Annual Movements for Sandwich Tern

The populations around the North Sea show no prevailing direction for post-breeding dispersal (Jul-Aug; Møller 1981a). There is pronounced autumn migration mainly from Aug and especially in Sep. The wintering grounds along the W & S African coasts (even the furthest ones, in S Africa; Tree 2011) are reached as early as Sep; overwintering birds are encountered until Mar-Apr. Many of them depend on the local upwellings for food provisioning (Møller 1981b). Some birds from NW, W & C Europe are encountered in C Mediterranean (Italy) in autumn (mainly Sep-Oct) and spring (Apr-May). Most birds breeding in the Black Sea region migrate to the Mediterranean Sea (from Spain to Israel), where are encountered mainly Oct-Mar; some continue as far as W & S Africa. Spring movements are mainly undertaken in Mar-Apr, sometimes until May.

Connectivity by Month by Region for Sandwich Tern

Dispersal movements after the breeding season take place in mid- to late summer, migration is more evident from early autumn. Wintering birds in W & S Africa are encountered mostly between early autumn and mid-spring. Most first-year and some 2-3-year-old birds spend the summer in the winter quarters (Møller 1981b). Some birds from the populations around the North Sea migrate through Italy. The Black Sea breeding population moves E-W and overwinters mostly within the Mediterranean region (Popov et al. 2012), some birds reach the Canaries (Mar). Spring migration takes place mostly early to mid-spring. Spring movements from the wintering sites in Namibia to the colonies in the Netherlands last 30-45 days (Keijl 2003). Large-scale connectivity between NW European colonies has been suggested (Fijn et al. 2014).

Boris Nikolov

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries
References Map
2020 . European Breeding Bird Atlas 2: Distribution, Abundance and Change. European Bird Census Council & Lynx Edicions, BarcelonaEditor(s): Keller, V., S. Herrando, P. Voříšek, et al.
2002 . The Migration Atlas: movements of the birds of Britain and Ireland. T. & A.D. Poyser, LondonEditor(s): Wernham, C.V., Toms, M.P., Marchant, J.H., Clark, J.A., Siriwardena, G.M., Baillie, S.R.
Fijn, R. C., Wolf, P., Courtens, W., Verstraete, H.,. Stienen, E. W. M, Iliszko, L. & Poot, M. J. M.2014 . Post-breeding prospecting trips of adult Sandwich Terns Thalasseus sandvicensis. Bird Study 61: 566–571
Møller, A. P.1981 . The migration of European Sandwich Tems Sterna s. sandvicensis. II. Vogelwarte 31: 149–168
Møller, A. P.1981 . The migration of European Sandwich Tems Sterna s. sandvicensis. I. Vogelwarte 31: 74–94
Popov, D., Kirov, D., Zhelev, P.2012 . Results from Marking of Sandwich Terns (Sterna sandvicensis) with Colour Rings and Radio Transmitters at Pomorie Lake. Acta zoologica bulgarica : 147–154
Shealer, D., J. S. Liechty, A. R. Pierce, P. Pyle, and M. A. Patten2020 . Sandwich Tern (Thalasseus sandvicensis), version 1.0. In Birds of the World Link to Article (DOI: https://doi.org/10.2173/bow.santer1.01) Cornell Lab of Ornithology, Ithaca, NY, USA
Tree, A. J. 2011 . Origins, occurrence and movements of Sandwich Tern Thalasseus sandvicensis in southern Africa. Marine Ornithology 39: 173–181

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