European Shag Phalacrocorax aristotelis

Status;  International importance;  Population estimates;  Distribution;  Annual abundance/ productivity; Phenology/diet/survival

 

Description

European Shag vignette

The following has been adapted from original text by Sarah Wanless and Mike P. Harris in Seabird Populations of Britain and Ireland (with permission from A&C Black, London).

 

The European shag is endemic to the northeast Atlantic and the Mediterranean. An inshore species that is almost never observed out of sight of land, it takes a wide range of small fish that it catches on or near the seabed over both sandy and rocky substrates. The species nests on offshore islands or on cliffs and colonies range in size from a few to several thousand pairs.


Conservation status

 

European shag is currently identified as a conservation priority in the following:

EC Birds Directive - migratory species

Amber listed in Birds of Conservation Concern 3 (2009 update)

(further information on Conservation Designations for UK Taxa)

Amber listed in Birds of Conservation Concern in Ireland 2008-2013 (2013 update)

 


International importance

 

UK Population % Biogeographic Population % World Population
26,600 AON* 38.3 (ssp. aristotelis) 34.1

 

*AON = Apparently Occupied Nests

The UK population figure (rounded to the nearest hundred) was derived from data in Mitchell, P.I., Newton, S.F., Ratcliffe, N. and Dunn, T.E. (eds.) 2004. Seabird Populations of Britain and Ireland. Poyser, London. This was also the source of figures for the Biogeographic and World populations.

 


UK population estimates and change 1969-2002 (census data)

 

European shags build large conspicuous nests which superficially appear straightforward to count, but there are, however, several major problems associated with a widespread survey of this species: i) detection of nests - these can be hidden among boulders and in caves, or can easily be overlooked when present at low densities among other species in large cliff nesting colonies; ii) a prolonged and variable breeding season - in Britain eggs have been laid in every month of the year except September and October; iii) occasional years when many adults do not breed - however, such events tend to be localised and did not appear to be a problem during census years. Seabird 2000 aimed to overcome the second problem by conducting a single count in the period of maximum nest occupancy (1 May-25 June). Previous censuses probably suffered from similar problems, so these will all have led to the underestimation of the absolute size of the breeding population.

 

 

Operation Seafarer

(1969-70)

Seabird Colony Register

(1985-88)

Seabird 2000

(1998-2002)

UK Population estimate (AON*) 29,956 36,276 26,565
% change since previous census N/a +21 -27

 

*AON = Apparently Occupied Nests

For census results for individual countries and Ireland, the Channel Islands and the Isle of Man see under relevant sections below.

 


Distribution/abundance

 

The Seabird 2000 census provides the most comprehensive recent assessment of the distribution and abundance of breeding seabirds. Numbers of European shag found in different regions, and a map showing the location and size of colonies, is provided in the Seabird 2000 European shag results page (PDF, 2.0 mb).

 

An interactive map is available on the NBN Gateway, where you can filter to display only the Seabird 2000 data.  For more recent, but less comprehensive, coverage view the distribution on the NBN with all available contributing datasets.

 

The locations sampled during the annual Seabird Monitoring Programme provide some information on distribution and are accessible via the Seabird Monitoring Programme online database.

 


Annual abundance and productivity by geographical area

 

With reference to the regional accounts below please note the following.

Breeding abundance: graphs of abundance index with 95% CLs are only shown for a region where the trend produced has been deemed accurate (see methods of analysis). Where a trend was thought to be inaccurate, graphs of abundance at major colonies in a region may be shown instead, particularly if such colonies hold greater than 10% of the regional population, are monitored frequently and may thus help illustrate regional population fluctuations outwith national censuses. Occasionally, too few data have been collected regionally to produce either of these.

Productivity: graphs of productivity are only shown if analysis of breeding success data produced a significant result for regional and/or year effects (again see methods of analysis). If results were not significant, then a regional mean productivity value is given. However, on some occasions, too few data are available from which to provide a meaningful average. Furthermore, for 11 species where the quality of monitoring data available was considered high, population viability analysis was undertaken at the UK level and the results of this are also reported.   

 



 

Breeding abundance

 

Shag abundance in UK 2013

Figure 1: Trend in UK abundance index (solid line) of European shag 1986-2013 with 95% confidence limits (dotted lines). Based on SMP data; view the methods of analysis (PDF 158 kb).

 

The UK shag population increased slightly from 1969-70 (30,000 pairs) to 1985-88 (36,000 pairs), possibly as a result of better coverage of previously inaccessible coastlines through the use of inflatable craft, increased legal protection (e.g. under the Wildlife and Countryside Act 1981) and reduced persecution. However, numbers had fallen by 27% by the time of Seabird 2000. Data collected by the SMP show an initial steep rise in the index up to 1987 probably due to many adults choosing not to breed in 1986 (e.g. on Canna and the Isle of May); thus, counts at many colonies were low that year. The trend also shows how breeding abundance is heavily affected by the incidence of mass mortality events – or ‘wrecks’  – which occur during prolonged periods of onshore gales, when species such as shag find it hard to forage. Severe events, such as those in the winter of 1993/19941 (also preceded by a year when many pairs took a year off from breeding) and 2004/2005, considerably affected populations on the east coast of the UK. Subsequent recovery from the 1994 wreck was slow with breeding numbers not fully restored before the wreck in 2005 occurred. There appears to have been no recovery before the 'wreck' during winter 2012/3, when over 650 corpses were recovered between Orkney and Suffolk. It is therefore not surprising that the index value for 2013 (at 52% below the baseline) is the lowest yet recorded. Measures of the return rates of shags to the Isle of May show the impact of such 'wrecks' (see Figure 4 below). Predictions of increased storminess due to climate change suggest such mortality events may become more frequent and have significant effects on population size3.  Predation of eggs and chicks by invasive mammalian predators is known to have localised effects on shag population size.

 

Productivity

 

Shag productivity in the UK 2013

Figure 2: Trend in UK productivity (no. of chicks fledged per pair) of European shag 1986-2013. Based on SMP data; view the methods of analysis (PDF 158 kb).

 

Shags are heavily reliant on sandeels2 and food shortages are likely to have contributed to periodic low productivity and population decline. Sandeel abundance is thought to have declined as a result of increases in sea surface temperature that changed the abundance and composition of plankton and reduced sandeel recruitment. However shag productivity in 2009 and 2010, which were better years for sandeels, was comparatively high, in common with other sandeel specialists.

 

Analysis of the SMP dataset by Cook and Robinson4 found mean breeding success of European shags at monitored nests was 1.21 chicks per nest per year between 1986 and 2008, and was relatively stable throughout the period. The quality of the dataset meant a decline in breeding success of 5% or greater could be detected with confidence. Were existing levels of breeding success to be maintained, population viability analysis (using available life history information such as population size, clutch size, age at first breeding and survival rates of different age classes) suggests the national population may decline by a modest 9% over 25 years. Breeding success would need to fall to 1.10 for a decline in abundance of 25% over 25 years to occur. For the UK population to decline by over 50% in 25 years success would need to fall to 0.90.

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 27,077 31,560 21,487
% change since previous census    N/a +17 -32

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

Shag abundance in Scotland 2013

Figure 1: Trend in abundance index (solid line) of European shag in Scotland, 1986-2013 with 95% confidence limits (dotted lines). Based on SMP data; view the methods of analysis (PDF 158 kb).

 

Long-term census data show an increase of 17% between Operation Seafarer and the Seabird Colony Register after which numbers fell by nearly one-third by Seabird 2000. Scotland holds about 80% of the European shags found nesting in the UK so it is unsurprising that the post-1986 trends shown for both are similar. Common features are the initial steep rise to 1987 due to many adults choosing not to breed in 1986 (e.g. on Canna and the Isle of May) and the dips in abundance in 1994 and 2005 due to 'wrecks' along the east coast in the preceding winters, from which numbers have been slow to recover (1994-2004) or appear not have recovered at all (2005 to present). Yet another 'wreck' during the 2012-13 winter, centred on Aberdeenshire and the Firth of Forth, further lowered numbers breeding in east coast colonies. Fourteen east coast colonies between Orkney and Berwickshire counted in 2013 held 1,872 AON compared to 3,433 AON during 2004, when abundance would have been near its highest during the last 20 years (Figure 1), representing a fall of 45% over the last decade.

 

In Shetland, numbers breeding at colonies also fell in 2013 although not in response to the 'wreck' (few shags were recorded from beached bird surveys in Shetland during the winter of 2012-13). Non-breeding in colonies in the south-east Mainland, recorded in 2011 and 2012, was even more extensive. Distinguishing non-breeding from early failure is not straightforward but may be indicated by paired adults standing at empty nest sites, or declining nest counts, over successive visits to a colony during the breeding season5. Counts from Sumburgh Head north to Mousa found 72% fewer nests (244) than in 2010 (877) with the number of active nests also declining from 97% to 51% over the same period. Breeding appeared more normal in southeast Yell where counts of nests (137, 91% active) were 22% lower than in 2009 (176 nests, 99% active). Along two stretches of coast on Fetlar, counts of nests (105, 72% active) were 17% lower than on the previous survey in 2002 (126 nests, 94% active)5. On Fair Isle, a whole colony count in 2013 recorded 204 AON, compared to 235 AON in 2008 and 732 AON and in 2003. In addition, data not previously submitted to the SMP concerned the large colony on Foula, which held approximately 2,300 AON in 2000. A survey in 2007 recorded 154 AON along the north, east and south coasts, directly comparable to 451 AON there in 2000. Along the west coast of Foula, 104 AON recorded in 2007 excluded some boulder beaches, so some caution is needed comparing this figure with approximately 1,830 AON recorded in these areas in 2000. Nevertheless, it is clear there has been a major decline in numbers nesting on the island.

 

As a result of these 'wrecks', non-breeding events and general declines, the abundance index value for Scotland in 2013 is now almost 68% lower than the peak in 1987.

 

 

Productivity

 

Productivity of shag in Scotland 2013

Figure 2: Trend in productivity (no. of chicks fledged per pair) of European shag in Scotland, 1986-2013. Based on SMP data; view the methods of analysis (PDF 158 kb).

 

Data from Scottish shag colonies have generally shown productivity to be high; usually, more than one chick is fledged per pair each year, although productivity has apparently been declining with time. Productivity can be affected by a variety of factors. For example, detailed monitoring on the Isle of May in 1990 revealed that over-winter survival (from 1989) was low, the breeding season was incredibly late, many shags did not breed or even construct nests and that only two-thirds that did have nests laid eggs. In addition, adults also appeared to have trouble finding sufficient quality food during the season with few sandeels of any size available. Various combinations of these factors, together with inclement summer weather, have reduced overall productivity in other years.

 

However, regional variation exists within years. In 2013, shags in south-west Scotland had a successful breeding season fledging 2.14 chicks per AON. Colonies in Orkney (1.63) and north Scotland (1.77) also had reasonable breeding seasons. In south-east Scotland, breeding success was 1.09, similar to that recorded in 2012 (1.08) which was the lowest value recorded since 2004 and 2005 in this relatively productive region. In north-west Scotland, breeding success (0.82) was low due to a variety of reasons, e.g. by predation of nests by mink and adults by gulls. On Shetland, where non-breeding in south-east Mainland was even more extensive than in 2012 (0.68), European shags fledged only 0.54 chicks per nest5, although success there has been as low in several other years.

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 2,111 3,491 3,863
% change since previous census    N/a +65 +11

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

Shag abundance in England 2013

Figure 1: Trend in abundance index (solid line) of European shag in England, 1986-2013 with 95% confidence limits (dotted lines; drawing of upper limit restricted to preserve detail in the abundance index). Based on SMP data; view the methods of analysis (PDF 158 kb).

 

National census data indicate a large increase in numbers had occurred between 1969-70 and 1985-88 but numbers were then stable between 1985-88 and 1998-2002. Detail provided by data collection for the SMP show the affects of winter 'wrecks' in the abundance indices for England in 1994, 2005 and in 2013. Prior to the first two events indices had generally been rising but were stable in the years immediately before the most recent 'wreck'. However, recovery from the 1994 crash was slow and still incomplete before the next slump in 2005. For example, on the Farne Islands (Northumberland), the largest and most frequently monitored colony in England, numbers fell from 1,948 to 771 AON between 1993 and 1994. Partial recovery then saw numbers increase to 1,678 AON in 2003 before another sharp decline to 937 AON by 2005. There had been no further recovery up to 2012 when 965 AON were recorded in this colony and numbers in 2013 fell steeply to 582 AON. The national index value for 2013 lies 44% below that for 1986 although the confidence limits are wide.

 

Productivity

 

Shag productivity in England 2013

Figure 2: Trend in productivity (no. of chicks fledged per pair) of European shag in England, 1986-2013. Based on SMP data; view the methods of analysis (PDF 158 kb).

 

Productivity of European shags at English colonies had generally been falling since recording began but reached a nadir in 2004 when an average of only 0.41 chicks were fledged per pair. Since 2004, productivity has improved most years, with 2010 the most successful year on record. Most data have been collected on the Farne Islands, where low levels of breeding success in 2004 (the effects of which are evident in the graph above) was in response to poor weather and low food availability during the chick rearing stage, combined with predation of nest contents by gulls early in the season, after which few replacement clutches were laid. Good (though unquantified) feeding conditions around the Farne Islands in 2012 ensured adequate numbers of chicks fledged despite inclement weather throughout much of the breeding season. Unfortunately, no data were submitted for 2013.

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 550 785 914
% change since previous census    N/a +43 +16

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

Shag abundance in Wales 2013

Figure 1: Trend in abundance index (solid line) of European shag in Wales, 1986-2013 with 95% confidence limits (dotted lines). Based on SMP data; view the methods of analysis (PDF 158 kb).

 

European shag populations in Wales, in common with those in England and Scotland, increased between the first two national censuses. In contrast to that seen in England, the abundance index of the Welsh population underwent a steady decline until the early 1990s, as was the case in Scotland. Thereafter, the trend was generally upward until 2001, but with no discernible pattern, and relatively stable from then on. The 'wrecks' preceding the 1994 and 2005 breeding seasons, common to both the Scottish and English indices, do not feature in the Welsh index. However, the 'wreck' during the 2012-2013 winter may have had an effect on numbers as the index value has fallen to its lowest point since 1998.

 

Productivity

 

Analysis of productivity data from European shags collected at colonies in Wales revealed there was no statistically significant variation over time. Overall, shags in Wales are the most productive in the UK, fledging an estimated 2.14 chicks per pair per year between 1987 and 2013

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 218 440 301
% change since previous census    N/a +102 -32

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

Census data show numbers of European shags in Northern Ireland doubled between Operation Seafarer and the Seabird Colony Register but then declined by one-third by Seabird 2000. Very few sites holding European shags in Northern Ireland are monitored regularly so it is difficult to assess the species' current status. Counts at Gun's Island, near Strangford Lough, the most frequently monitored colony, ranged from eight to 22 between the Seabird Colony Register and Seabird 2000. However, recently this colony has declined with none breeding by 2007. On Rathlin Island, only 46 and 47 pairs were found in 2007 and 2011, respectively, compared with over 100 during the Seabird Colony Register. In 2013, an increase was recorded on Muck (21 AON compared to 3 in 1987) and at The Gobbins numbers were stable (20 AON compared to 18 in 1987). Three new breeding colonies, holding 7 AON, were also found. Based on this limited and conflicting information, it is difficult to predict whether the national population has increased or declined since Seabird 2000.   

 

Productivity

 

Data submitted to the SMP on the productivity of European shags in Northern Ireland are sparse; thus, no meaningful average productivity value can be given.

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 2,783 4,676 3,426
% change since previous census    N/a +68 -36

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

Abundance of shag in ROI 2013

Figure 1: Abundance of European shag on Lambay, 1986-2013.

 

Over the longer-term, national census data collected during Seabird 2000 indicated numbers had increased since Operation Seafarer in 1969-70, although numbers are currently lower than was recorded by the Seabird Colony Register in 1985-88. Few data have been collected at colonies since Seabird 2000, so it is difficult to assess the species' current status. Numbers at Lambay (Figure 1), the largest colony (holding about one-third of the national population) and most frequently monitored, have fluctuated. Surveys in 2009 and 2010 (no data were collected there from 2011 to 2013) recorded several hundred fewer nests compared to those in 2004 and 2007, although figures were on a par with counts during the 1990s. The cause of these changes is unknown.

 

Productivity

 

Few data on the productivity of European shags at colonies in the Republic of Ireland have been collected as part of the SMP. On average, productivity measured 1.17 chicks per pair per year between 1996 and 2011 (although no data were submitted in several years during this period).

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 3,001 5,116 3,727
% change since previous census    N/a +70 -37

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

Few data have been collected throughout the whole of Ireland as part of the SMP. Therefore it is difficult to present a coherent picture on the current trend in numbers of the European shag for All Ireland. Please refer to entries for Northern Ireland and the Republic of Ireland instead. Over the longer-term, national census data collected during Seabird 2000 indicated numbers had increased since Operation Seafarer in 1969-70, although a decline was recorded since the Seabird Colony Register in 1985-88.

 

Productivity

 

No data on the productivity of European shags have been collected at colonies in Northern Ireland and few data have been submitted from colonies in the Republic of Ireland as part of the SMP. On average, monitored colonies fledged 1.17 chicks per pair per year between 1996 and 2011; no data have been submitted for 2012 and 2013.

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 567 575 912
% change since previous census    N/a +1 +59

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

Long-term national census data show little change in numbers of European shags on the Isle of Man between 1969-70 and 1985-88 but an increase of 60% thereafter by the time of Seabird 2000 during 1998-2002. Few colonies are monitored regularly as part of the SMP. The most frequently counted and largest colony is on the Calf of Man where close to 40% of the Manx population was recorded during the SCR (225 AON in 1986). Numbers increased up to 1994 when 337 AON were counted. During Seabird 2000, 218 AON were recorded although counts were only done from land (land and sea during 1986 and 1994). Other land-based counts immediately after Seabird 2000 suggested numbers were stable at this colony; 220 AON counted in 2000, 208 AON in 2001 and 205 AON in 2002. Thereafter, the only accurate count is from 2010, when 132 AON were recorded, again from land and sea, representing a decline of 41% since the SCR census (and of at least 40% since Seabird 2000). No data have been forthcoming from this colony, nor from any other Manx colonies, since then so the species current status is unknown.   

 

Productivity

 

Data submitted to the SMP on the productivity of European shags on the Isle of Man are sparse; thus, no meaningful average productivity value can be given.

 

 

Population estimates and change 1969-2002 (census data)

 

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998-2002)

Population estimate (AON*) 570 1,443 1,403
% change since previous census    N/a +153 -3

 

* AON = Apparently Occupied Nests

 

Breeding Abundance

 

National census data show that the numbers of European shags in the Channel Islands recorded during 1998-2002 had more than doubled since 1969-70 from 570 pairs to 1,403, although there had been almost no change over the latter half of this period since the Seabird Colony Register in 1985-88. Few data have been collected since Seabird 2000. On Burhou, which held 47 AON during Seabird 2000 (c.3% of the population) annual monitoring between 2007 and 2013 recorded a minimum of 19 and a maximum of 24 AON. However, in 2013, colonies were recorded on Little Burhou and Coque Lihou holding 35 and 77 AON respectively. With no data apparently available for these latter two colonies from Seabird 2000 the current status of European shag on the Channel Islands is unknown.  

 

Productivity

 

Data submitted to the SMP on the productivity of European shags in the Channel Islands are sparse; thus, no meaningful average productivity value can be given.

 

 


UK phenology, diet, survival rates

 

Phenology

 

No systematic data on phenology (timing of life-cycle events) have been collected as part of the SMP.

 

Diet

 

Figure 3 shows a marked decline in the proportion by weight of sandeels in the diet of European shag chicks on the Isle of May, especially between 2004 and 2009, although during most of this period this had no clear negative effect on productivity; in fact, 2008 and 2009 were two of the most productive breeding seasons on record. In these years, although sandeels still comprised the greatest single constituent, the remainder comprised gadids (members of the cod family, including whiting and rockling), clupeids (such as sprat), goby, butterfish and wrasse. In 2013, the most frequent prey (by occurrence in a regurgitate) in the 13 regurgitations collected on the Isle of May was butterfish, which occurred in 53.8% of samples. Sandeels constituted only 28.2% of the biomass, the joint lowest percentage on record. The remains of other items found were Cottidae (2 samples), flatfish (1), Gadidae (1), dragonet (1) and crustacea (1). Again, the lack of sandeels does not seem to have impacted hugely on breeding success; the breeding success of European shags on the Isle of May in 2013 was just above average at 1.20 chicks per nest built (1986-2012 average = 1.07; CI=0.86-1.27)6.

 

Percentage of sandeels in IOM shag diet 2013

Figure 3: Percentage of sandeels (by weight) in the diet of young shags at the Isle of May (North-east Fife), 1987-2013.

 

Return rates and survival rates

Important notes on interpretation: Estimation of European shag adult return rate is currently only undertaken at one site within the Seabird Monitoring Programme - the Isle of May (North-east Fife). Return rates are based on sightings of individually colour-ringed birds and are calculated as the proportion of marked birds present in year one that is seen in the following year. Because not every adult alive is seen each year, return rates for 2013 presented need to be treated as a minimum estimate of survival of birds seen alive in 2012. In contrast, survival estimates (not currently undertaken for shag) do take into account birds that are not seen one year but which re-appear in following years.

 

No clear trend in return rate is evident from the Isle of May data although the return rate for 2012 (92.9%) was markedly above the long-term average (79.4%, 95% CI = 71.9-86.8). A notable feature of European shag biology is their susceptibility to die from periods of low food availability caused by unusually prolonged periods of strong onshore winds, which makes foraging difficult. Such 'wrecks' occurred around eastern Britain during the winters of 1994/95, 2004/05 and again in 2012/13 and are reflected in the very low return rates in the following breeding seasons. The 'wreck' during winter 2012/13 resulted in over 650 corpses being recovered from beaches between Orkney and Suffolk. It is therefore not surprising that the return rate for the Isle of May fell in 2013, although not all corpses recovered would have been from this colony. Measures of the return rates of shags to the Isle of May show the impact of such 'wrecks' (Figure 4).

 

Predictions of increased storminess due to climate change suggest such mortality events may become more frequent and have important impacts on population size3. In addition, European shags often take a year off breeding, which is manifested in return rates because, although they have not died, they are not seen at the breeding colony in the second year of a pair.

 

Figure 4: Annual return rate of European shag breeding on the Isle of May (North-east Fife), 1987-2013.

 


References

1 Harris, M.P. and Wanless, S. 1996. Differential responses of guillemot Uria aalge and shag Phalacrocorax aristotelis to a late winter wreck. Bird Study 43: 220-230.

2 Harris, M.P. and Wanless, S. 1991. The importance of the lesser sandeel Ammodytes marinus in the diet of the shag Phalacrocorax aristotelis. Ornis Scand. 22: 375-82.

3 Frederiksen, M., Daunt, F., Harris, M.P. and Wanless, S. 2008. The demographic impact of extreme events: stochastic weather drives survival and population dynamics in a long-lived seabird. Journal of Animal Ecology 77 (5). 1020-1029.

4 Cook, A.S.C.P. and Robinson, R.A. 2010. How representative is the current monitoring of breeding success in the UK? BTO Research Report No. 573, BTO, Thetford.

5 Heubeck, M. and Mellor, M. 2014. SOTEAG Ornithological Monitoring Programme: 2013 Summary Report. Aberdeen Institute of Coastal Science and Management, University of Aberdeen.

6 Newell, M., Harris, M.P., Gunn, C.M., Burthe, S., Wanless, S. and & Daunt, F.  2014. Isle of May seabird studies in 2013. Unpublished report. JNCC, Aberdeen.

 


Partners

Data have been provided to the SMP by the generous contributions of its partners, other organisations and volunteers throughout Britain and Ireland. Partners to the SMP are: BirdWatch Ireland; The British Trust for Ornithology; Centre for Ecology and Hydrology; Natural Resources Wales; Department of Agriculture, Fisheries and Forestry (Isle of Man); Department of Environment, Heritage and Local Government (Republic of Ireland); States of Guernsey Government; JNCC; Manx Birdlife; Manx National Heritage; The National Trust; National Trust for Scotland; Natural England; Northern Ireland Environment Agency; The Royal Society for the Protection of Birds; Scottish Natural Heritage; Seabird Group; Shetland Oil Terminal Environmental Advisory Group; Scottish Wildlife Trust.  More about the SMP partners >>

 
European shag image appears courtesy of Ian Rendall ©, is subject to international copyright law and may not be reproduced in any form whatsoever.