NT
Razorbill Alca torda



Justification

Justification of Red List Category
This species has undergone moderate declines in Europe, including very rapid declines in Iceland since 2005. Crashes in sandeel stocks around Iceland may be a contributing factor in the declines. The species is, therefore, listed as Near Threatened as it almost meets the requirements for listing as threatened under criterion A4ab.

Population justification
The European population is estimated at 979,000-1,020,000 mature individuals (BirdLife International 2015).

Trend justification
Although a number of populations are increasing within Europe, a recent sharp decline was observed in Iceland (where more than 60% of the European population is found) since 2005 (BirdLife International 2015). Two comprehensive surveys of the species in Iceland suggest that the population declined by 18% between 1983-1986 (Gardarsson 1995) and 2005-2009 (Gardarsson et al. in press) from 378,000 pairs to 313,000 pairs. However, more frequent monitoring of a subset of colonies (every five years) between 1985 and 2005 suggests the population decline only started in 2005 and prior to this the population was stable, demonstrating that the decline has been much more rapid. Evidence of a very rapid decline in the Icelandic population is supported by data from the largest colony of this species in the world, Látrabjarg, which declined by 45% in only three years (160,000 pairs in 2006 to 89,000 pairs in 2009) (G. Gudmundsson in litt. 2015). The 2005 decline occurred around the same time that sandeel stocks crashed around Iceland, suggesting that a lack of food may have influenced the decline (Gardarsson et al. in press). As a result of the reported decline in Iceland, the estimated and projected rate of decline of the European population size over the period 2005-2046 (three generations) is 25-29%.

The population trend is increasing in North America (based on BBS/CBC data: Butcher and Niven 2007). Europe is thought to hold c. 95% of the global population, based on latest population estimates (Merne and Mitchell 2004, Berglund and Hentati-Sundberg 2014). Thus, the European decline is of global significance.

Distribution and population

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).

Ecology

The species lives on rocky sea coasts, breeding on cliff ledges and under boulders in boreal or low Arctic waters (Nettleship 1996). 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. 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).

Threats

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). 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 Wade and Masden 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). 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 more vulnerable species to the adverse effects of tidal turbines off Scottish waters (Furness et al. 2012).

Invasive mammalian predators, especially rats and mink, 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 mink and are at high risk of predation, e.g. a decline of 60% was seen in SW Finland after introduction of mink in 1970s, with the removal of mink being followed by return of breeding colonies (Nordstrom et al. 2003). 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’s ability to feed and fly (Biliavskiy and Golod 2012) and this species is known to have been impacted by oiling in the past (Furness 2013). 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 (c. 2,700 pairs) would be exposed to direct effects through reduced prey availability (Cook et al. 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 actions

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 (Nettleship 1996). 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.

Identification

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.

Acknowledgements

Text account compilers
Pople, R., Wright, L, Palmer-Newton, A., Stuart, A., Martin, R., Ekstrom, J., Hatchett, J., Calvert, R., Butchart, S., Tarzia, M, Wheatley, H., Ieronymidou, C., Ashpole, J, Burfield, I.

Contributors
Gudmundsson, G., Bourne, W.R.P.


Recommended citation
BirdLife International (2019) Species factsheet: Alca torda. Downloaded from http://www.birdlife.org on 16/02/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/02/2019.