Data Zone
Justification of Red List category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >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.
Population justification
The global population is estimated to number between 838,000–1,660,000 mature individuals, or 1,257,000–2,490,000 total individuals, derived from flyway population estimates (Wetlands International, 2021). The European population is estimated at 519,000–1,070,000 mature individuals (BirdLife International in prep.). This species breeds mostly in Iceland, a population that was once believed to make up 60-70% of the global population (Costa et al. 2019); now, Iceland holds the majority in Europe (41%) but not globally due to increases elsewhere. Europe holds more than 90% of the global population.
Trend justification
This species was previously thought to be declining at a rate of 25-29% over three generations (c. 43 years). This was based largely on information from Iceland, which at that time was considered to hold c. 60% of the global breeding population, and where a national decline of 17% had been estimated between counts in 1983-1986 and 2006-2008 (Gardarsson et al., 2019), as well as a 45% decline in world's largest colony (Látrabjarg) between 2006-2009 (G. Gudmundsson in litt. 2015). Since then, however, monitoring of selected colonies between 2009 and 2017 has revealed a significant increase at Látrabjarg and a slow increase elsewhere (Kolbeinsson & Poraninsson, 2017). The population at Stora Karlsö, Sweden, has been increasing since the 1970s and now hosts up to 30% of the Baltic Sea population (Olsson & Hentati-Sundberg, 2017). It has also been suggested that the earlier decline at least partly reflected a temporary redistribution, with some birds moving from Látrabjarg to Grimsey and beyond (Skarpheoinsson, 2018).
New data collated from across Europe for the 2021 European Red List of Birds (BirdLife International in prep.) indicate that the species has increased significantly across its European range, with nine countries holding 90% of the European population reporting increases this century, and none reporting declines. Iceland still holds the largest single population in Europe (41%), but increases elsewhere (especially in the UK, Sweden, Ireland and Finland) mean it no longer holds the majority. As Europe holds >90% of the global population, and there is no sign that the small North American population is declining (Lavers et al., 2020), there is no evidence to suggest that the population is declining overall, let alone at a rate approaching 30% over three generations.
The species breeds on islands, rocky shores and cliffs on northern Atlantic coasts, in eastern North America as far south as Maine (U.S.A.), and in western Europe from north-west Russia to north-west France. North American birds migrate offshore and south, ranging from the Grand Banks of Newfoundland (Canada) to New England and New York (U.S.A.) (Nettleship 1996). Eurasian birds also winter at sea, with some moving south as far as the western Mediterranean and North Africa (Nettleship 1996, Merne and Mitchell 2004).
The species lives on rocky sea coasts, breeding on cliff ledges and under boulders in boreal or low Arctic waters where sea-surface temperatures <15°C (Nettleship, 1996; Lavers et al. 2020). It is a pursuit diver that propels itself through the water with its wings. Razorbills are capable of diving to 120 m depth, but mostly forage nearer the surface. They spend most of their lives at sea, only arriving ashore to reproduce. They mainly overwinter within the boreal water zone either side of the Atlantic (Lavers et al., 2020). This species has been described as coastal rather than pelagic (Huettman et al. 2005), and birds tend to be concentrated within 10 km of the shore (BirdLife International, 2000, Huettman et al., 2005). They are known to consume Krill, Sprat Sprattus sprattus, Sandeels Ammondytes spp. and Capelin amongst other prey (Nettleship, 1996).
The major threats for the razorbill are current and future impacts of climate change, decreasing prey availability, bycatch in gillnets and driftnets, and unregulated hunting (Costa et al. 2019). As a pursuit diver, the species is at risk from being caught in gill-nets and drift-nets, with gill-net fisheries in the North and Baltic Seas known to catch significant numbers (Žydelis et al. 2009, 2013; Skov et al. 2011). Overfishing of important prey species in the Gulf of St Lawrence, east Newfoundland and Grand Banks, Georges Bank, North Sea and Barents Sea is also a threat due to reduction in prey populations (Nettleship, 2018). The role of IUU fishing in prey reductions has not been evaluated (Costa et al. 2019). Razorbills are also at risk from climate change related reductions in the abundance of prey such as Sandeels due to their restricted diet (Sandvik et al. 2005). Past food shortages have coincided with declines in productivity in the North-east of the UK, as well as a decrease in energy content of fish brought to chicks on the Isle of May (Wanless et al. 2005). There are indications that the decline in Sandeel stocks is linked to increasing sea surface temperatures (Heath et al. 2009). A significant negative relationship between productivity and spring sea surface temperature, lagged by one year, has been found, this has been linked to the availability of mid-trophic level forage fish (Lauria et al. 2012). However, a study by Gaston and Woo (2008) showed Razorbills were able to track changes in preferred prey, implying a capability to adapt to climate change. The species is vulnerable to extreme weather, primarily winter storms, which have been linked to large scale mortality in the past (Underwood and Stowe, 1984), due to strong winds preventing feeding and weakening adults. Razorbills are also potentially vulnerable to future sea level rises that may cause flooding in some parts of its range (Sandvik, 2005).
Hunting of adults occurs throughout range, with between 2,000 and 200,000 birds killed each year in Iceland, 20% of which are taken illegally (BirdLife International, 2017). Unregulated hunting occurs in Labrador, Newfoundland, Greenland, Faroe Islands, and Norway (Nettleship et al. 2018). Egg collection is thought to have caused declines in the past (Nettleship et al. 2018), but is not considered only a minor issue in the Norwegian North Sea and Skagerrak (TemaNord 2010). This species is considered to be at moderate risk of displacement by offshore windfarms in the UK, but at low risk of collision mortality (Bradbury et al. 2014), with windfarms having a low impact in general (Furness et al. 2013). Studies on the effects of offshore windfarms on Razorbills return variable results, with the population declining around some and remaining stable or increasing around other (Dierschke et al. 2016). An investigation into the potential impacts of offshore windfarms by van Kooten et al. (2018) returned annual population declines of 0.939 and 0.926 for extreme scenarios, while worst-case and best-estimates showed median annual population increases. The effects are thought to depend on the distance to breeding and foraging grounds and effect on prey populations (Vanerman et al. 2015). However, Razorbills were highlighted as one of the more vulnerable species to the adverse effects of tidal turbines off Scottish waters (Furness et al. 2012).
Invasive mammalian predators, especially rats and American mink (Neovison vison), represent a threat to Razorbill populations. Presence of rat activity has been linked with declines in Razorbill productivity through disturbance on Calf of Man, U.K. (O'Hanlon and Lambert 2017). The Isle of Canna, West coast Scotland, has also seen declines in Razorbills since early 1990 with introduction of Norway rats which have been observed predating eggs and chicks (Swann 2002). Numbers of Razorbill increased following successful rat eradication on the island in 2005/06 (Swann et al. 2016). Colonies suffer local declines due to American mink and are at high risk of predation, e.g. a decline of 60% was seen in SW Finland after introduction of mink in the 1970s, with the removal of mink being followed by return of breeding colonies (Nordstrom et al. 2003). American mink have had a 'verified impact' in Finland and Sweden (Bonesi & Palazon 2007). Excessive predation by mink can cause exceptionally low chick mean survival rates (Barrett 2015).
Razorbills spend the majority of their time at and below the water surface, leading them to be highlighted as vulnerable to habitat degradation, species mortality and loss of reproductive success due to oilspills. Oiling affects Razorbills’ ability to feed and fly (Biliavskiy and Golod 2012). An assessment of the threat that marine aggregate mining poses to Razorbill around the UK suggests that operations would cause disturbance, potentially restrict access to some foraging sites and that the Firth of Forth colonies (ca 2,700 pairs) would be exposed to direct effects through reduced prey availability (Cook and Burton 2010). At present the threat is likely to be at a very minor scale and to have minimal severity, but many areas of the Arctic are opening up to mining developments that may pose a threat to breeding seabirds (Chardine and Mendenhall 1998). High levels of mercury (Hg) found in Razorbills recovered from 2014 winter wreck. Although levels were unlikely to be directly responsible for the high mortality observed, it was concluded to be a major aggravating stress factor for emaciated birds on the edge, with evidence suggesting that stranded seabirds were highly contaminated compared to birds in normal conditions (Fort et al. 2015).
Conservation and Research Actions Underway
The species is listed on the African-Eurasian Waterbird Agreement. There are 91 Important Bird Areas across the region for this species. Within the EU there are 91 Special Protected Areas for this species, recognised as a regularly occurring migratory species. The species is considered in the Nordic Action Plan for seabirds in Western-Nordic areas (TemaNord 2010).
Conservation and Research Actions Proposed
Establish international monitoring system, especially of illegal killing and collate robust data (Nettleship, 1996; Brochet et al., 2019). Continue to identify important sites for this species, particularly in offshore regions, and designate as marine protected areas. Identify the risks of different activities on seabirds, and locations sensitive to seabirds. Continue eradication of invasive predators from breeding colonies. Manage fisheries to ensure long-term sustainability of key stocks (e.g. sandeels). Establish observer schemes for bycatch and prepare National/Regional plans of action on seabird bycatch. Develop codes-of-conduct for more organised activities (e.g. tourism). Ensure that appropriate protection (national laws and international agreements) applies to new areas and times in case of changes in seabird migration routes and times. Ensure that existing legislation is adequately implemented and complied with/enforced on the ground (Brochet et al. 2019).
37-39 cm. Black upperparts, tail, wings and head which contrast with white underparts. Blackish legs. Thick black bill with broken transverse white line across both mandibles and prominent white line extending from base of culmen to eye (Nettleship 1996). In winter, birds have white throat, cheeks and ear-coverts and no horizontal white line on bill. Juvenile similar to winter adult.
Text account compilers
McGonigle, K.
Contributors
Bourne, W.R.P., Gudmundsson, G.A., Martin, R., Palmer-Newton, A., Pople, R., Ashpole, J, Wheatley, H., Hatchett, J., Calvert, R., Butchart, S., Ekstrom, J., Tarzia, M, Ieronymidou, C., Burfield, I., Wright, L & Stuart, A.
Recommended citation
BirdLife International (2024) Species factsheet: Razorbill Alca torda. Downloaded from
https://datazone.birdlife.org/species/factsheet/razorbill-alca-torda on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.