Larus audouinii -- Payraudeau, 1826 ANIMALIA -- CHORDATA -- AVES -- CHARADRIIFORMES -- LARIDAE Common names: Audouin's Gull; Goéland d'Audouin 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., Wheatley, H. & Wright, L. Assessment Rationale European regional assessment: Least Concern (LC) EU27 regional assessment: Least Concern (LC) At both European and EU27 scales, although this species may have a small 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 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 within both Europe and the EU27. Occurrence Countries/Territories of Occurrence Native: Croatia; Cyprus; France; Greece; Italy; Portugal; Spain; Turkey; Gibraltar (to UK) Origin Uncertain: Albania; Bosnia and Herzegovina; Montenegro; Slovenia Vagrant: Bulgaria; Czech Republic; Georgia; Germany; Macedonia, the former Yugoslav Republic of; Malta; Switzerland; United Kingdom Population The European population is estimated at 21,600-22,000 pairs, which equates to 43,100-44,000 mature individuals. The population in the EU27 is estimated at 21,500-21,800 pairs, which equates to 42,900-43,600 mature individuals. For details of national estimates, see Supplementary PDF. Trend In Europe and the EU27 the population size is estimated to be fluctuating. In Spain, which holds nearly 90% of the European population, the population size was estimated to be increasing during 1981-2007 and fluctuating during 2000-2010. For details of national estimates, see Supplementary PDF. Habitats and Ecology This coastal species rarely occurs inland. Colonies are located on exposed rocky cliffs and on offshore islands or islets, normally not more than 50 m above sea level. Characteristics of habitats used differ from region to region and even within the same areas in different years: altitude ranges from close to sea-level to 100 m, vegetation cover from bare rocks to 85% bush cover, and slope from 0–90°. During the non-breeding season the species prefers sheltered bays, either flat with shingle or sand or with cliffed margins (Cramp and Simmons 1983). It breeds in large monospecific colonies ranging from 10 up to 10,000 pairs. Egg-laying takes place in the second half of April until the beginning of May, and peak hatching occurs in late May (Burger and Gochfeld 1996), with fledging mainly in the first two weeks of July (Mañosa et al. 2004). The nest is a shallow scrape lined with available debris and vegetation (Cramp and Simmons 1983). It is placed among rocks and vegetation. Clutches normally have three eggs (Burger and Gochfeld 1996). It has a large foraging range while breeding, and has been recorded up to 200 km from the colony. The diet consists mostly of epipelagic fish, especially Clupeiformes (Mañosa et al. 2004). It is also known to take some aquatic and terrestrial invertebrates, small birds and plant material such as the peanut (Arachis), olive (Olea), and grain (Cramp and Simmons 1983). It is partially migratory and dispersive (Burger and Gochfeld 1996). After breeding the birds disperse widely around the Mediterranean coast (Sanpera et al. 2007, Burger and Gochfeld 1996). Almost all juveniles and some adults migrate past Gibraltar during July-October (Olsen and Larsson 2003), peaking in August (Guitiérrez and Guinart 2008), to winter on the North African coast (Burger and Gochfeld 1996). Habitats & Altitude Habitat (level 1 - level 2) Importance Occurrence Marine Coastal/Supratidal - Sea Cliffs and Rocky Offshore Islands major breeding Marine Intertidal - Rocky Shoreline suitable breeding Marine Intertidal - Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc suitable breeding Marine Intertidal - Shingle and/or Pebble Shoreline and/or Beaches suitable breeding Marine Intertidal - Shingle and/or Pebble Shoreline and/or Beaches suitable non-breeding Marine Intertidal - Tidepools suitable breeding Marine Neritic - Macroalgal/Kelp major breeding Marine Neritic - Macroalgal/Kelp major non-breeding Marine Neritic - Pelagic major breeding Marine Neritic - Pelagic major 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 Rocky areas (eg. inland cliffs, mountain peaks) suitable breeding Altitude 0-100 m Occasional altitudinal limits Threats The trawling fishery off the Ebro Delta is regarded as unsustainable and its collapse would probably result in a decline in the breeding population due to the increase in density-dependence (Oro et al. 2004, Tavecchia et al. 2007, Barov and Derhé 2011). A similar outcome would arise if waste from the trawlers were used industrially to produce food for domestic animals, as occurs in other areas, rather than being dumped near the Ebro colony. More important could be the reduction of small-pelagic fish stocks, the main natural prey for the species, due to increasingly high fishing pressure around the breeding grounds, owing partly to high demand by tuna-farming (Arcos et al. 2008). Other important threats include coastal tourism developments, regulation of the river Ebro, mortality due to entanglement in fishing gear (mainly longlines and sporting lines) (Belda and Sánchez 2001, Cooper et al. 2003) and predation by terrestrial predators, such as Red Fox (Vulpes vulpes), Badger (Meles meles) and domestic dogs (Oro et al. 1999, Tavecchia et al. 2007). Predation by sympatric Yellow-legged Gull (Larus michahellis) can be high at some breeding colonies, especially when densities of Audouin's Gulls are low (Bonaccorsi 2003, Travichon 2004, Oro et al. 2006, Paracuellos and Nevado 2010). Predation on chicks by Black Rats (Rattus rattus) has a negative impact at some breeding colonies (Jones et al. 2008). Nevertheless this species shows a very nomadic breeding site selection and high dispersal rates from year to year, probably avoiding large densities of L. michahellis (Genovart et al. 2003, Martínez-Abraín et al. 2003, Oro and Matínez-Abraín 2007). Peregrines (Falco peregrinus), other raptors, some herons and snakes can also prey on adults and nests but only accidentally and locally (Oro 1996, 1997). Very high levels of mercury and other pollutants are found in this species (Sanpera et al. 2007), partly due to the consumption of discards (Arcos et al. 2002), thus posing a potential threat, although no negative effects have been demonstrated. Current marine wind-farm projects, particularly around the main breeding colony (Ebro Delta), could also represent a serious threat. Overgrazing of some islets by goats in the east of its breeding range may reduce breeding success. Natal and breeding dispersal are extremely high ensuring genetic mixing and buffering against bad local environmental conditions through emigration and colonisation (Oro and Ruxton 2001, Oro et al. 2004). Threats & Impacts Threat (level 1) Threat (level 2) Impact and Stresses Biological resource Fishing & harvesting Timing Scope Severity Impact use aquatic resources Future Majority (50-90%) Rapid Declines Low Impact (unintentional effects: (large scale) Stresses [harvest]) Indirect ecosystem effects Energy production Renewable energy Timing Scope Severity Impact & mining Future Majority (50-90%) Unknown Unknown Stresses Species mortality Human intrusions & Recreational Timing Scope Severity Impact disturbance activities Ongoing Minority (<50%) Slow, Significant Low Impact Declines Stresses Species disturbance Invasive and other Black Rat (Rattus Timing Scope Severity Impact problematic rattus) Ongoing Minority (<50%) Slow, Significant Low Impact species, genes & Declines diseases Stresses Reduced reproductive success Invasive and other Goat (Capra hircus) Timing Scope Severity Impact problematic Ongoing Minority (<50%) Slow, Significant Low Impact species, genes & Declines diseases Stresses Ecosystem degradation Invasive and other Unspecified species Timing Scope Severity Impact problematic Ongoing Majority (50-90%) Slow, Significant Medium Impact species, genes & Declines diseases Stresses Species mortality Natural system Dams (size Timing Scope Severity Impact modifications unknown) Ongoing Majority (50-90%) Unknown Unknown Stresses Ecosystem conversion; Ecosystem degradation Pollution Industrial & military Timing Scope Severity Impact effluents (type Ongoing Majority (50-90%) Unknown Unknown unknown/ unrecorded) Stresses Species mortality Residential & Tourism & Timing Scope Severity Impact commercial recreation areas Ongoing Majority (50-90%) Slow, Significant Medium Impact development Declines Stresses Ecosystem conversion;