Sam Franks

The smallest of the divers, with a large circumpolar breeding range north of the 60th latitude. Nests solitarily on shores and islands of freshwater pools and lakes in open moorland, bog and peatland habitats, also on well-vegetated tundra lakes. Diet consists of fish, crustaceans, molluscs, frogs, insects, worms and plant matter. Fully migratory, moving to coast and south after breeding. Winters offshore along sheltered coasts, occasionally inland on lakes, pools, reservoirs and rivers. European population is estimated at 42,100-93,000 pairs, trend decreasing.

Season of assessment

B

Population trendUnknown
Population size
(min-max, best estimate)		91100-146000,115000
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 Red-throated Diver

Birds from Scotland move between SW and SE to coasts of UK, W France and occasionally Norway and Netherlands. Birds from Fennoscandia and N. Baltic all move SW to West coast of UK, France, Netherlands, S Baltic and occasionally Spain, Italy, Albania. Three long-distance recoveries in Russia during breeding of birds wintering in Finland and the Netherlands, as well as a bird in SW Finland during breeding. Some within-winter movements in C. Europe.

Recoveries by Condition for Red-throated Diver

Two thirds of encounters are from birds reported dead, without geographical pattern. Few shot or intentionally taken, mostly in France, but 16% drowned in fishing nets. Oil victims decreased from 40% pre-1960 to few percent now. Remarkably for this species, almost one third of recoveries refer to ringing recoveries, all on Shetlands, or birds of which rings were read in the field, nearly all in Finland.

Annual Movements for Red-throated Diver

From November to end March, birds are scattered along coasts of UK and W Europe, occasionally on inland waters in C Europe. From mid-April, birds concentrate in S Finland and N.  Scotland and Shetland, wintering sites in UK and W Europe largely vacated. From mid-May also at scattered locations further N in Fennoscandia. Begin Sept first birds move S, begin Oct Fennoscandia vacated, small concentration in Skagerak. Begin November all birds in wintering areas again.

Connectivity by Month by Region for Red-throated Diver

Birds early in the breeding season in May, June in NW and N Europe mainly connect to relatively close-by sites within the season, representing post-fledging or (post-)breeding dispersal. Birds later in the breeding season in July, Aug in NW and N Europe connect to wintering sites in UK and W Europe in Nov-Mar, occasionally later (Apr-Jun). Birds wintering in Denmark Sep-mar connect to breeding site in Sweden in Jul-Aug and Finland in May-Aug. Winter dispersal in C Europe limited to Nov-Feb.

Henk van der Jeugd

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries