Rob Robinson

The species breeds in various types of well-vegetated wetlands – both natural (lakes, marshes, rivers) and artificial (fish-ponds) (Gochfeld et al. 2020). It has discontinuous distribution across Eurasia, Africa and Australia. In Europe, the species occurs mostly in the E part, some populations present also in the W. The bulk of European population (ca. 65%) is found in Romania, Belarus, Ukraine, Russia and Azerbaijan (Keller et al. 2020).

Eurasian-African migrant. African wintering grounds are mainly N of the equator. Low number of birds are resident in S Europe.

Its population trend in Europe is increasing. Evaluated as “Least Concern” (BirdLife International 2021).

Season of assessment

B

Population trendIncreasing
Population size
(min-max, best estimate)		117000-294000,177000
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 Whiskered Tern

European populations are migratory. A few hundred birds winter regularly in SW Europe (Gochfeld et al. 2020).

Birds breeding in W Europe migrate mostly SW with encounters in the Iberian Peninsula. Iberian population takes S routes towards its wintering grounds in W Africa (Ghana); spring encounters exist both from W Africa – both inland (Mali) and coastal (Senegal), as well as from the C Mediterranean and even C Europe.

C European breeders are encountered during winter in E Africa and the Middle East. Birds marked in SC Europe have been found during migration in N Africa (Libya, Algeria - Spina & Volponi, 2008) and while wintering S of the equator (Angola).

Long-distance recoveries in Africa comparatively scarce. Recoveries from the species’ strongholds in SE & E Europe are almost lacking as well.

Recoveries by Condition for Whiskered Tern

Most encounters are obtained during the late 2010s. Majority of them are recorded in C Europe (92%), primarily during the period Jun-Aug (87%). Just couple of encounters prior to 1960. The encounters based on dead birds markedly decreased over time: from 71% during 1961-1990 to less than 1% after 1991; those based on alive birds considerably increased from 3% in 1961-1990 to 99% after 1991. The latter is mostly due to ringing recoveries, and especially to colour ring resightings. Shooting was an important factor in the past only (34% of all recoveries during the period 1961-1990).

Annual Movements for Whiskered Tern

Post-breeding dispersal and autumn migration movements start in late Jul (Gochfeld et al. 2020) but are more evident in Aug-Sep – by this time W European breeders are encountered SW from their breeding grounds, mostly in Spain, some birds remaining in SW Europe until Nov. Birds breeding in SW Europe are encountered in W Africa as early as Aug (Mali), the wintering grounds near the Gulf of Guinea (Ghana) are reached in Sep with encounters until Nov. Spring encounters from Apr (Senegal) and May (Mali) indicate possible return migration routes; spring records exist also from Tunisia (Mar), Italy (Apr) and Hungary (May). Local short-distance movement in Dec suggests wintering in S Spain.

C European breeders migrate mostly SE, with encounters during migration and winter in Israel (Sep, Jan) and E Africa (Kenya, Dec).

Connectivity by Month by Region for Whiskered Tern

Genetic evidence supports the existence of two distinct (W & E) subpopulations in Europe, which markedly differ in wintering distribution and seasonal migratory routes (Dayton et al. 2017). Dispersal movements are prominent from late summer. W European population takes SW routes, with encounters mainly in Spain, sometimes until late autumn. SW European breeders migrate mostly S towards W Africa where are encountered from late summer to mid-autumn. Return migration records (early to late spring) are spread from W Africa to C Mediterranean and C Europe. Local encounters in Spain in Dec indicate overwintering. Long-distance recoveries of the birds breeding in C Europe suggest SE direction of autumn migration, with winter encounters in the E Mediterranean & E Africa.

Return migration is mostly mid- to late spring.

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.
BirdLife International 2021 . Species factsheet: Chlidonias hybrida. Downloaded from http://www.birdlife.org on 24/09/2021.
Dayton, J., Ledwoń, M., Paillisson, J.-M., Atamas, N. & Szczys, P. 2017 . Genetic Diversity and Population Structure of the Eurasian Whiskered Tern (Chlidonias hybrida hybrida), a Species Exhibiting Range Expansion. Waterbirds 40: 105–117
Gochfeld, M., J. Burger, G. M. Kirwan, and E. F. J. Garcia2020 . Whiskered Tern (Chlidonias hybrida), version 1.0. In Birds of the World Link to Article (DOI: https://doi.org/10.2173/bow.whiter2.01) Cornell Lab of Ornithology, Ithaca, NY, USA
Spina, F., Volponi, S. 2008 . Atlante della Migrazione degli Uccelli in Italia. 2. Passeriformi. Ministero dell’Ambiente e della Tutela del Territorio e del Mare, Instituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Tipografia SCR-Roma

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