Thalasseus sandvicensis -- (Latham, 1787) ANIMALIA -- CHORDATA -- AVES -- CHARADRIIFORMES -- LARIDAE Common names: Sandwich Tern; Sterne caugek European Red List Assessment European Red List Status LC -- Least Concern, (IUCN version 3.1) Assessment Information Year published: 2015 Date assessed: 2015-03-31 Assessor(s): BirdLife International Reviewer(s): Symes, A. Compiler(s): Ashpole, J., Burfield, I., Ieronymidou, C., Pople, R., Tarzia, M., Wheatley, H. & Wright, L. Assessment Rationale European regional assessment: Least Concern (LC) EU27 regional assessment: Least Concern (LC) In Europe this species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). The population trend appears to be fluctuating, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern in Europe. Within the EU27, although this species may have a restricted range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern in the EU27. Occurrence Countries/Territories of Occurrence Native: Albania; Azerbaijan; Belgium; Bulgaria; Croatia; Cyprus; Denmark; Estonia; France; Germany; Greece; Ireland, Rep. of; Italy; Latvia; Macedonia, the former Yugoslav Republic of; Malta; Netherlands; Norway; Poland; Portugal; Romania; Russian Federation; Slovenia; Spain; Sweden; Switzerland; Turkey; Ukraine; United Kingdom; Gibraltar (to UK) Vagrant: Bosnia and Herzegovina; Czech Republic; Faroe Islands (to DK); Finland; Hungary; Iceland; Montenegro; Svalbard and Jan Mayen (to NO); Serbia; Slovakia Population The European population is estimated at 79,900-148,000 pairs, which equates to 160,000-295,000 mature individuals. The population in the EU27 is estimated at 53,900-63,600 pairs, which equates to 108,000-127,000 mature individuals. For details of national estimates, see Supplementary PDF. Trend In Europe the population size is estimated to be fluctuating. In the EU27 the population size is estimated to be increasing. For details of national estimates, see Supplementary PDF. Habitats and Ecology During the breeding season the species forms colonies on sandy islands, rocky calcareous islets, sand-spits, sand-dunes, shingle beaches and extensive deltas with immediate access to clear waters with shallow sandy substrates rich in surface-level fish (Snow and Perrins 1998). It shows a preference for raised, open, unvegetated sand, gravel, mud or bare coral substrates for nesting. Outside of the breeding season the species frequents sandy or rocky beaches, estuaries, harbours and bays, often feeding over inlets and at sea. It breeds from May to June in dense colonies with other terns or Black-headed Gulls (Larus ridibundus). The nest is a shallow scrape on raised, open, unvegetated sand, gravel, mud or bare coral substrates preferably far from upright vegetation (Gochfeld and Burger 1996) on sandy islands, rocky calcareous islets, sand-spits, sand- dunes and shingle beaches (Snow and Perrins 1998). Clutches are one or two eggs. The species forms very dense colonies during the breeding season in which the eggs of neighbouring pairs may only be 20 cm apart. Its diet consists predominantly of surface-dwelling marine fish (Snow and Perrins 1998) 9–15 cm long, as well as small shrimps, marine worms and shorebird nestlings. This species is migratory, undergoing post- breeding dispersive movements north and south to favoured feeding grounds before migrating southward (Gochfeld and Burger 1996). Habitats & Altitude Habitat (level 1 - level 2) Importance Occurrence Marine Intertidal - Mud Flats and Salt Flats suitable breeding Marine Intertidal - Rocky Shoreline major non-breeding Marine Intertidal - Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc major breeding Marine Intertidal - Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc major non-breeding Marine Intertidal - Shingle and/or Pebble Shoreline and/or Beaches major breeding Marine Neritic - Estuaries suitable breeding Marine Neritic - Estuaries suitable non-breeding Marine Neritic - Macroalgal/Kelp major breeding Marine Neritic - Macroalgal/Kelp major non-breeding Marine Neritic - Pelagic suitable breeding Marine Neritic - Pelagic suitable non-breeding Marine Neritic - Seagrass (Submerged) major breeding Marine Neritic - Seagrass (Submerged) major non-breeding Marine Neritic - Subtidal Loose Rock/pebble/gravel major breeding Marine Neritic - Subtidal Loose Rock/pebble/gravel major non-breeding Marine Neritic - Subtidal Rock and Rocky Reefs major breeding Marine Neritic - Subtidal Rock and Rocky Reefs major non-breeding Marine Neritic - Subtidal Sandy major breeding Marine Neritic - Subtidal Sandy major non-breeding Marine Neritic - Subtidal Sandy-Mud major breeding Marine Neritic - Subtidal Sandy-Mud major non-breeding Marine Oceanic - Epipelagic (m) marginal resident Altitude max. 50 m Occasional altitudinal limits Threats The species is particularly vulnerable to human disturbance (Gochfeld and Burger 1996) (e.g. from tourists) especially near breeding colonies on beaches early in the breeding season (Bourne and Smith 1974). It is also sensitive to disturbance from coastal wind farms (wind turbines) (Garthe and Huppop 2004). It is threatened by the loss or degradation of its favoured breeding habitats through inundation, wind-blown sand and erosion (Gochfeld and Burger 1996), and has suffered previous local declines from exposure to bioaccumulated organochlorine pollutants in marine fish (Koeman et al. 1967, Gochfeld and Burger 1996). Other serious threats include recreational disturbance, coastal developments, pollution, land-use affecting vegetation and predation (Garthe and Flore 2007). Threats & Impacts Threat (level 1) Threat (level 2) Impact and Stresses Agriculture & Marine & Timing Scope Severity Impact aquaculture freshwater Ongoing Unknown Causing/Could Unknown aquaculture (scale cause fluctuations unknown/ unrecorded) Stresses Indirect ecosystem effects Biological resource Fishing & harvesting Timing Scope Severity Impact use aquatic resources Ongoing Majority (50-90%) Slow, Significant Medium Impact (unintentional Declines effects: (large scale) [harvest]) Stresses Indirect ecosystem effects Threats & Impacts Threat (level 1) Threat (level 2) Impact and Stresses Biological resource Hunting & trapping Timing Scope Severity Impact use terrestrial animals Ongoing Minority (<50%) Slow, Significant Low Impact (intentional use - Declines species is the target) Stresses Species mortality Climate change & Droughts Timing Scope Severity Impact severe weather Ongoing Unknown Causing/Could Unknown cause fluctuations Stresses Indirect ecosystem effects Climate change & Habitat shifting & Timing Scope Severity Impact severe weather alteration Ongoing Unknown Unknown Unknown Stresses Indirect ecosystem effects Climate change & Storms & flooding Timing Scope Severity Impact severe weather Ongoing Unknown Rapid Declines Unknown Stresses Indirect ecosystem effects; Species mortality Energy production Renewable energy Timing Scope Severity Impact & mining Ongoing Minority (<50%) Causing/Could Low Impact cause fluctuations Stresses Indirect ecosystem effects; Species mortality; Species disturbance Human intrusions & Recreational Timing Scope Severity Impact disturbance activities Ongoing Unknown Unknown Unknown Stresses Species disturbance Invasive and other Unspecified species Timing Scope Severity Impact problematic Ongoing Majority (50-90%) Causing/Could Medium Impact species, genes & cause fluctuations diseases Stresses Species mortality; Reduced reproductive success Natural system Other ecosystem Timing Scope Severity Impact modifications modifications Ongoing Unknown Unknown Unknown Stresses Ecosystem degradation; Indirect ecosystem effects Pollution Garbage & solid Timing Scope Severity Impact waste Ongoing Whole (>90%) Unknown Unknown Stresses Species mortality Pollution Herbicides and Timing Scope Severity Impact pesticides Ongoing Unknown Unknown Unknown Stresses Species mortality Pollution Industrial & military Timing Scope Severity Impact effluents (type Ongoing Majority (50-90%) Unknown Unknown unknown/ unrecorded) Stresses Ecosystem degradation; Indirect ecosystem effects Pollution Oil spills Timing Scope Severity Impact Past, Likely to Majority (50-90%) Rapid Declines Past Impact Return Stresses Species mortality Transportation & Shipping lanes Timing Scope Severity Impact service corridors Ongoing Majority (50-90%) No decline Low Impact Threats & Impacts Threat (level 1) Threat (level 2) Impact and Stresses Stresses Species disturbance Conservation Conservation Actions Underway CMS Appendix II. EU Birds Directive Annex I. Bern Convention Appendix II. A conservation scheme for the protection of gull and tern breeding colonies in coastal lagoons and deltas (Po Delta, Italy) involves protection from human disturbance, prevention of erosion of islet complexes, habitat maintenance and the creation