Tom Cadwallender

Entirely marine species which breeds on rocky, sandy or coral islands, preferring densely vegetated sites in temperate regions but barren sites in the tropics (Gochfeld & Burger 2020). It has wide but fragmented distribution across the globe, occurring mostly in the tropical and subtropical belt worldwide, with some populations at temperate latitudes. European distribution includes primarily the British Isles, W France and the Azores (Keller et al. 2020), with birds migrating to Africa (mainly W Africa) for the winter.

Season of assessment

B

Population trendIncreasing
Population size
(min-max, best estimate)		4900-6200,5500
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 Roseate Tern

General movement pattern in the breeding populations of NW & W Europe follows N-S direction. Migration is along the Atlantic coast of W & SW Europe and W Africa, with the main wintering grounds in the Gulf of Guinea (especially Ghana). There are at least three transatlantic, breeding-season encounters in NE USA and Canada. A wintering bird was found in E Brazil. Birds breeding in the Azores mainly winter in the Gulf of Guinea in W Africa, although some migrate to Brazil, thus showing an unusual dichotomous migration pattern (Hays et al. 2002).

Recoveries by Condition for Roseate Tern

Ringing started in mid-20th century, but most encounters are from the late 1980s and the early 1990s and are mainly in the breeding season - 79% in Jun-Aug (52% in Jul alone). The majority of encounters (77%) are in NW Europe. The percentage of dead recoveries has decreased over time - from 90% pre-1961 to 16% from 1991; with live recoveries increasing from 7% pre-1961 to 81% since1991. The latter is mostly due to recaptures, particularly to metal ring readings in the field; only 4% are colour-mark encounters. Before 1961 37% of recoveries were of shot birds, but there are now almost none. Birds have been locally trapped in W Africa for sport, food and income by boys using baited hooks or nooses (Wernham et al. 2002).

Annual Movements for Roseate Tern

Post-breeding dispersal in the British Isles breeding population starts in Aug. A number of recoveires from Sep-Oct are spread along the Atlantic coastline of W & SW Europe, as well as W Africa. Numerous recoveries show that birds are mostly in Ghana, Togo and the Ivory Coast in winter. Birds return to the breeding grounds as early as May. Most first-year birds remain in W Africa during the summer, while many second-year birds return to their European colonies in Jun-Jul, but rarely breed (Wernham et al. 2002). The transatlantic encounters relate both to the breeding season (Jul) - North America, and winter (Jan) - Brazil. Birds from the Azores breeding population winter in the same region of the Gulf of Guinea (Oct-Jan); return movements are marked by recoveries in Apr in Senegal and the Canaries.

Connectivity by Month by Region for Roseate Tern

Dispersal movements after the breeding season in NW & W Europe are evident from late summer. Numerous encounters along the coast of France, the Iberian Peninsula and W Africa (incl. the Canary Islands) in early to mid-autumn indicate the migratory route towards the wintering grounds in the Gulf of Guinea. The latter are shared with most of the birds originating from the Azores. Return movements take place mostly mid- to late spring. A few recoveries from E Brazil in winter show that some birds breeding in the Azores, and a few British Isles breeders cross the Atlantic. Upwelling systems along the W Africa coast are vital for migratory staging, particularly on the slower return migration (Redfern et al. 2020).

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.
Gochfeld, M., Burger, J. 2020 . Roseate Tern (Sterna dougallii), version 1.0. In Birds of the World Link to Article (DOI: https://doi.org/10.2173/bow.roster.01) Cornell Lab of Ornithology, Ithaca, NY, USA
Hays, H., Neves, V., Lima, P. 2002 . Banded Roseate Terns from different continents trapped in the Azores. Journal of Field Ornithology 73: 180–184
Redfern, C.P.F., Kinchin-Smith, D., Newton, S. Morrison, P., Bolton, M. & Piec, D. 2020 . Upwelling systems in the migration ecology of Roseate Terns (Sterna dougallii) breeding in northwest Europe. Ibis Link to Article (DOI: https://doi.org/10.1111/ibi.12915)

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