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Black-legged kittiwake (Rissa tridactyla)

The following has been adapted from original text by Martin Heubeck in Seabird Populations of Britain and Ireland (with permission from A&C Black, London).

 

As well as being the most numerous species of gull in the world, the black-legged kittiwake is the most oceanic in its habits and most adapted to nesting on vertical rocky sea-cliffs. In Britain and Ireland, the largest and most numerous colonies are found along the North Sea coasts of Britain, around Orkney and Shetland, and off north-west Scotland. Colony size varies from less than ten pairs to tens of thousands, but the locations of colonies tend to be traditional over many decades. Although most colonies are on sheer cliffs, in a few instances man-made structures such as buildings, bridges, sea walls and even offshore oil installations have been utilised. During the breeding season, black-legged kittiwakes feed mainly on small pelagic shoaling fish; around the British Isles these consist of energy-rich species such as sandeels, sprats and young herring. However, kittiwakes will also scavenge for offal and discards around fishing boats, which can be an important food source in years when their preferred prey species are less abundant. Outside the breeding season the species is essentially oceanic, and it is probable that populations from many different breeding localities mix together in the North Atlantic and North Sea during winter, with some birds from British and Irish colonies (especially first-winter and immature birds) spending time off the eastern seaboard of North America.

Conservation status

Black-legged kittiwake is currently identified as a conservation priority in the following:

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International importance

UK Population

Biogeographic Population

% World Population

378,800 AON*

13.8 (ssp. tridactyla)

8.0

*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.

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UK population estimates and change 1969–2008

Geographical coverage of black-legged kittiwake colonies in the UK was complete during all three national censuses. In some years, in response to a scarcity of food in spring, nest building can be delayed by 2–3 weeks. Under such conditions a high proportion of pairs (up to 40%) may begin nest building but not complete a structure which qualifies as an apparently occupied nest (AON), the preferred count unit, or progress to laying. This phenomenon was documented for Shetland in 2002 but did not affect counts for Seabird 2000. Counts outwith the recommended count period (June) may also underestimate figures but, as this applied to only approximately 5% of UK counts, it is unlikely that such ‘out-of-season’ counts had much influence on gross estimates of population change.

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

UK Population estimate (AON*)

407,417

504,055

378,847

% change since previous census   

n/a

+24

-25

*AON = Apparently Occupied Nests

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Distribution/abundance

The Seabird 2000 census provides the most comprehensive recent assessment of the distribution and abundance of breeding seabirds. Numbers of Black-legged kittiwake found in different regions, and a map showing the location and size of colonies, is provided in the Seabird 2000 Black-legged kittiwake results page.

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

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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% confidence limits 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.

 

United Kingdom

Breeding abundance

Kittiwake UK breeding abundance.jpg

Figure 1. Trend in UK abundance index (solid line) of black-legged kittiwake 1986–2018 with 95% confidence limits (dotted lines). Based on SMP data; view the methods of analysis.

 

Over the longer term, combining census results with the SMP sample indicates that, while black-legged kittiwake numbers increased by around 24% between the late 1960s and the mid-1980s (see UK population estimate table above), there are probably now around 50% fewer than in the late 1960s (Figure 1). The UK kittiwake abundance index has declined rapidly since the early 1990s, such that by 2004 the index was 47% below what it was in 1986. By 2013, it had decreased to 70% below the 1986 baseline but appears to have been more stable since then. In 2018, the index was located at 65% below the baseline.

Table 1 shows how numbers have changed at some of the most important UK colonies (those in the SPA network) in the period since they were surveyed for Seabird 2000. Some of the largest declines recorded since Seabird 2000 have been at colonies in the north and north-west. Colonies in Shetland have been declining at an average rate of 16.0% per annum, those in Orkney at 9.7% and those in the North West at 11.9%. Along the east coast of the UK, and in the Minch and Irish Sea, the average rate of decline is much slower at an estimated 2.3%, 3.8% and 3.7% per annum, respectively.

Table 1. Recent counts of the number of black-legged kittiwake (AON) recorded in Special Protection Areas (SPAs) in Britain and Ireland compared to the number recorded in them during Seabird 2000. The percentage that each colony has fallen by, and the per annum change, is also provided. Note: data at St Abb's Head relate to only part of the SPA.

 

Area

SPA Name

Seabird 2000

Count (Year)

Change (%)

per annum

Shetland

Noss

2,395 2000

44 2017

-98

-21.0

Shetland

Foula

1,934 2000

277 2015

-86

-12.2

Shetland

Fair Isle

8,204 2001

859 2015

-90

-14.9

Orkney

West Westray Cliffs

33,281 1999

12,055 2007

-64

-11.9

Orkney

Copinsay

4,256 1999

955 2015

-78

-8.9

Orkney

Marwick Head

5,573 1999

906 2018

-84

-9.1

East Coast

Troup, Pennan and Lion's Heads

18,482 2001

10,503 2007

-43

-3.5

East Coast

Buchan Ness to Collieston Coast

14,091 2001

12,542 2007

-11

-1.9

East Coast

Fowlsheugh

18,800 1999

14,039 2018

-25

-1.5

East Coast

Forth Islands

6,632 2000

3,514 2018

-47

-3.5

East Coast

St Abb's Head NNR

11,077 2000

3,244 2018

-71

-6.6

East Coast

Farne Islands

5,096 1998

5,327 2017

4

0.2

East Coast

Flamborough Head and Bempton Cliffs

42,582 2000

45,504 2017

7

0.4

North West

North Rona and Sula Sgeir

4,119 1998

1,253 2012

-70

-8.1

North West

St Kilda

4,268 1999

276 2015

-94

-15.7

The Minch

Handa

7,013 1999

3,749 2018

-47

-3.2

The Minch

Shiant Isles

2,006 1999

1,075 2015

-46

-3.8

The Minch

Canna and Sanday

1,274 1999

1,069 2018

-16

-0.9

The Minch

Mingulay and Berneray

5,511 1998

1,627 2015

-70

-7.3

Irish Sea

Ailsa Craig

1,675 2001

275 2018

-84

-10.1

Irish Sea

Skomer and Skokholm

2,257 2000

1,336 2017

-41

-3.0

Irish Sea

Rathlin Island

9,917 1999

7,922 2011

-20

-1.9

Irish Sea

Lambay Island

4,091 1999

3,320 2017

-19

-1.2

 

Given the magnitude of the fall in the abundance index (Figure 1) between 1999 and 2013, and the fact that during Seabird 2000 these SPAs held over 50% of the black-legged kittiwakes nesting in the UK, it is possible that the national population now lies between 150,000 and 250,000 AON – far below the figure recorded during Operation Seafarer in 1969-70. A more accurate estimate will be provided when the results from the current census, 'Seabirds Count', are published. Given the declining trend in productivity recorded for much of the period since 1986 (Figure 2), coupled with low survival and return rates (see below), it is likely that declines will continue.

 

Productivity

Kittiwake UK productivity.jpg

Figure 2. Trend in UK productivity (no. of chicks fledged per pair) of black-legged kittiwake 1986–2018. Based on SMP data; view the methods of analysis.

 

Black-legged kittiwake productivity in the UK has declined and then stabilised over the course of the SMP (Figure 2). This would appear to be related to declines in abundance of their sandeel prey which in certain regions is negatively correlated with sea surface temperatures1 that have risen due to climate change. Productivity (and adult survival) has also been negatively affected by the presence of a sandeel fishery that operated off SE Scotland from 1990 to 20002,3,4. Species such as kittiwakes are particularly vulnerable to food shortages as they can take prey only when it occurs at or near the surface of the sea, unlike diving species such as auks which have access to a greater variety of prey in the water column. This has exacerbated the effects of low prey abundance5.

Lesser sandeels Ammodytes marinus constitute a significant proportion of kittiwake diet during the breeding season2,4,6,7,8,9,10. Consequently, kittiwakes are highly sensitive to fluctuations in sandeel abundance. Warming of waters around the UK over the last three decades (between 0.1 and 0.5 ̊C per decade11) has led to substantial changes in species composition and abundance at lower trophic levels12,13,14,15,16, with detrimental effects on sandeels14,16. Lesser sandeels are sensitive to changes in SST1,14 and have restricted capacity to shift distribution17,18. In the North Sea, significant changes in the timing of key life history events of sandeels and their copepod prey19 have resulted in changes in their length, and therefore energy value16,20,21,22. Kittiwakes and other seabirds have not kept pace with these changes and, as a result, are now relying on prey of lower calorific value during the chick rearing period when energy demands are highest16,23. This trophic mismatch appears to be prevalent within the North Sea pelagic food web, however, important regional differences are apparent, with these effects appearing stronger in the North Sea than the Irish Sea, the Celtic Sea and the English Channel24,25,26. In addition, over-winter survival of adult black-legged kittiwakes breeding in eastern Scotland was lower following winters with higher SST, and breeding success one year later was reduced2,27,28,29. This relationship, though varying greatly between colonies, has also been demonstrated at other kittiwake colonies along the North Sea coast30,31. There is evidence that breeding success is positively related to sandeel abundance32,33. Effects of climate on these bottom-up processes is likely to intensify if warming continues.

In addition to kittiwake productivity being correlated with sandeel availability23,34, diet composition can also impact on chick growth and survival. A study in Norway showed that whilst adult black-legged kittiwakes are foraging on energy rich prey items in both the oceanic habitat and the fjords, a diet dominated by sandeel Ammodytes spp. resulted in higher growth and survival of chicks compared to a diet consisting of mesopelagic fish (i.e. glacier lantern fish Benthosema glaciale, spotted barracudina Arctozenus risso and silvery lightfish Maurolicus muelleri)35. Data collected at the Isle of May (one of the SMP key sites) also show a correlation between the proportion of sandeels in the diet of black-legged kittiwake chicks and breeding success5,28,36,37.

SMP sample data show that average productivity between 2014 and 2018 (0.63 chicks fledged per pair) was higher than it had been for a number of years. This increase in productivity could contribute to a larger number of birds being recruited to the breeding population in future years.

 

Scotland

Population estimates and change 1969–2002 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

Population estimate (AON*)

346,097

359,425

282,213

% change since previous census

n/a

+4

-21

*AON = Apparently Occupied Nests

 

Breeding abundance

Kittiwake Scotland breeding abundance.jpg

Figure 3. Trend in abundance index (solid line) of black-legged kittiwake in Scotland, 1986–2018 with 95% confidence limits (dotted lines). Based on SMP data; view the methods of analysis.

 

Census results indicate black-legged kittiwake numbers in Scotland changed little between Operation Seafarer and the Seabird Colony Register (SCR), but fell thereafter so that Seabird 2000 recorded 21% fewer AON than the SCR. Data collected by the SMP indicate a steady decline since the late 1980s, with the index in 2018 69% below the 1986 baseline (a slight rise compared to its lowest point in 2013 at 76% below).

 

Productivity

Kittiwake Scotland productivity.jpg

Figure 4. Trend in productivity (no. of chicks fledged per pair) of black-legged kittiwake in Scotland, 1986–2018. Based on SMP data; view the methods of analysis.

 

Black-legged kittiwakes breeding in Scotland underwent a sustained decline in productivity from 1986, culminating in a very poor breeding season in 2008 when very few chicks fledged. Productivity between 2009 and 2018 was higher than it had been for a number of years, possibly due to increased availability of sandeels in those years. However, this increased production was not sustained in 2013 which was again a poor breeding season.

Between 1980 and 2010, Sea Surface Temperature (SST) in the Forth and Tay region increased significantly, however, in the last decade cooler conditions have led to a decrease in SST. This decrease in SST is thought to have had a direct positive effect on the number of black-legged kittiwake chicks that were fledged on the east coast of Scotland from 2009 to 2017 (average 0.98)10 which is apparent in Figure 4.

 

England

Population estimates and change 1969–2002 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

Population estimate (AON*)

49,676

125,819

76,281

% change since previous census

n/a

+153

-39

*AON = Apparently Occupied Nests

 

Breeding abundance

Kittiwake England breeding abundance.jpg

Figure 5. Trend in abundance index (solid line) of black-legged kittiwake in England, 1986–2018 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.

 

In England, the peak in abundance index was reached in 1992 (cf. 1989 in Scotland). A gradual decline is apparent after 1995, but over much of the last decade the index has been relatively stable. The abundance index has not fallen to the extent seen in Scotland but – in 2018 – lay at 32% below the 1986 baseline. Another difference between the two countries is that, between Operation Seafarer and the Seabird Colony Register, the English population more than doubled, as opposed to showing little change, but the proportional size of decline from the Seabird Colony Register to Seabird 2000 was nearly twice that recorded to the north. Causes of change are probably the same for both countries (see UK section) but are clearly now having a greater impact in Scotland where the estimated rate of decline is greater.

Recent studies have indicated that regional variation in the effects of climate change on seabirds is apparent. In particular, there is growing evidence that the climate impacts recorded in the North Sea are not replicated elsewhere. The negative effect of winter SST on black-legged kittiwake productivity outlined in the Scotland section above is not apparent throughout the UK30 and analyses of the Irish Sea, the Celtic Sea and the English Channel have found only weak climate effects on seabird demography25,26.

 

Productivity

Kittiwake England productivity.jpg

Figure 6. Trend in productivity (no. of chicks fledged per pair) of black-legged kittiwake in England, 1986–2018. Based on SMP data; view the methods of analysis.

 

Productivity at English colonies, usually more successful than those in Scotland, has been generally decreasing since 1986. The lowest point was reached in 2004, when productivity averaged just 0.34 chicks per nest fledged but has improved since. Monitored colonies were least productive in 1998, 2004 and 2008 and to some extend in 2016. However, 2009 to 2012 inclusive were four of the more successful breeding seasons in the last decade. After an increase the previous year, productivity fell again in 2018 (0.51 chicks fledged per pair).

The relatively high productivity in England compared to Scotland, despite a declining trend, may explain why the species' abundance has not fallen to the same extent. The reasons for higher mean productivity in English colonies could be related to recent findings about weaker climate effects on seabird demography which is not apparent throughout the UK25,26,28.

 

Wales

Population estimates and change 1969–2002 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

Population estimate (AON*)

6,891

8,771

7,293

% change since previous census   

n/a

+27

-20

*AON = Apparently Occupied Nests

 

Breeding abundance

Kittiwake Wales breeding abundance.jpg

Figure 7. Trend in abundance index (solid line) of black-legged kittiwake in Wales, 1986–2018 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.

 

National censuses found that black-legged kittiwake numbers in Wales had changed little between Operation Seafarer and Seabird 2000, but recent measures of abundance suggest the current population is lower than in 1969-70. Factors affecting colonies in other countries in the UK, appear to have had less impact in Wales but the reasons for this are not well understood. Compared with Scotland, the abundance index for black-legged kittiwakes in Wales has been relatively stable since 1986 but is similar to that shown for England with a slow decline since the mid-1990s. However, in recent years, the index has fallen below the previous low point of 2004. Currently, the index is 49% below the 1986 baseline; 15 colonies surveyed in 2018 held 3,377 AON, 43% fewer than was recorded during Seabird 2000 (4,965 AON).

 

Productivity

Kittiwake Wales productivity.jpg

Figure 8. Trend in productivity (no. of chicks fledged per pair) of black-legged kittiwake in Wales, 1986–2018. Based on SMP data; view the methods of analysis.

 

The productivity of black-legged kittiwakes in Wales has fluctuated widely over the recording period with no clear trend, although productivity appears to have been depressed over much of the last decade. In general, Welsh colonies are less productive than those in England and there are more years when productivity falls below 0.50 chicks per pair compared with both England and Scotland. Productivity in 2017 was particularly low in Wales, although details as to why are limited. On Skomer, one of four colonies regularly monitored, low breeding success of 0.33 chicks fledged per pair in 2017 was partly attributed to above average rainfall (twice the normal amount for Pembrokeshire in June). All of the study plots had a lower productivity than reported in 2016, with the greatest reduction recorded at High Cliff, where only one chick fledged. Similar low productivity values have been reported previously in 2001 (0.34) and 2012 (0.33). In 2013, 132 fewer black-legged kittiwake nests were built in study plots on the island compared to 2012 (632), with the breeding season described as disrupted, unusually extended and unsynchronised. In 2018, productivity had increased to 0.55 chicks fledged per pair.

 

Northern Ireland

Population estimates and change 1969–2002 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

Population estimate (AON*)

4,753

10,040

13,060

% change since previous census   

n/a

+111

+30

*AON = Apparently Occupied Nests

 

Breeding abundance

There are approximately 13 colonies of black-legged kittiwake in Northern Ireland, but few are monitored regularly. The largest colony is Rathlin Island which held 76% of the national population, some 9,917 AON, during Seabird 2000. In 2007, numbers there were similar, with 9,896 AON recorded. However, numbers had declined to 7,922 AON in 2011 (a fall of 20%)38. In 2017, four smaller colonies (The Gobbins, Muck, Portrush and Maggie’s Leap) held 1,592 AON compared to 1,250 AON during Seabird 2000. In 2018, the same four colonies held 1,358 AON, a decline of 15% since 2017. There was, however, considerable fluctuation between colonies, e.g. The Gobbins held just 64% of the 2017 total but numbers at Portrush had increased by 24% (although one less site was surveyed there); this may have been in response to local feeding conditions. A new survey of Rathlin Island will, however, be required to gain a better understanding of the current status the Northern Ireland black-legged kittiwake population.

 

Productivity

Kittiwake NI productivity.jpg

Figure 9. Trend in productivity (no. of chicks fledged per pair) of black-legged kittiwake in Northern Ireland, 1986–2018. Based on SMP data; view the methods of analysis.

 

In Northern Ireland, few data on the productivity of black-legged kittiwake have been collected as part of the SMP since 2014. Data were sparse before 1997, with productivity thereafter extremely variable, so no clear trend was visible. In 2018, breeding success at The Gobbins was 0.57 chicks fledged per pair, the lowest since 2014. This was due to predation by a mixed pair of hooded Corvus cornix and carrion crows Corvus corone5. Only 29 chicks fledged from 121 monitored nests at this colony. Muck Island also had a low productivity with 0.62 chicks fledged per nest, the lowest since 2013. Counter to the poor breeding season at The Gobbins and Muck Island, breeding success at Maggy’s Leap (0.79 chicks fledged per pair) was higher than in 2017. Productivity was even higher on the north coast, where Rathlin Island produced 1.28 chicks fledged per pair and Portrush produced 1.01 chicks fledged per pair39.

 

Republic of Ireland

Population estimates and change 1969–2018 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

 

 Republic of Ireland Census

(2015-18)

Population estimate (AON*)

39,630

34,180

36,100

24,728

% change since previous census   

n/a

-14

+6

-32

*AON = Apparently Occupied Nests

 

Breeding abundance

In the Republic of Ireland, Operation Seafarer found 39,630 AON of black-legged kittiwake. Numbers had decreased slightly by the second national census, but Seabird 2000 recorded similar numbers to the Seabird Colony Register. The recent Republic of Ireland Seabird Census (2015–2018) recorded a total of 24,728 AON, a decrease of 32% compared to Seabird 200040. At the Cliffs of Moher and Lambay Island (the largest colonies in the country), only 7,698 AON and 3,320 AON were recorded, a decline of 48% and 19%, respectively since Seabird 2000. There were insufficient data from the Republic of Ireland to allow trends to be generated.

 

Productivity

Kittiwake ROI productivity.jpg

Figure 10. Trend in productivity (no. of chicks fledged per pair) of black-legged kittiwake in the Republic of Ireland, 1986–2015. Based on SMP data; view the methods of analysis.

 

Black-legged kittiwakes in the Republic of Ireland have had few years with high levels of productivity. In most years, productivity was below 0.80 chicks fledged per pair and often below 0.60. Productivity was lowest in 2008, which was a very wet summer in Ireland that is likely to have impacted on young birds in nests. Annual black-legged kittiwake productivity estimates at Rockabill fell from 1.2 chicks per pair (1999–2007) to 0.61 chicks per pair in 2018. The practice of pair-trawling of spawning inshore sprat has increased in recent years and a herring fishery is operating in the Irish and Celtic Seas. The existence of these fisheries, operating within the foraging areas of black-legged kittiwakes, may have an impact on the productivity of this species along these coasts, particularly if the fisheries target young sprat Sprattus sprattus41. No black-legged kittiwake productivity data have been submitted to the SMP since the 2015.

 

All Ireland

Population estimates and change 1969–2002 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

Population estimate (AON*)

44,383

44,220

49,160

% change since previous census   

n/a

<-1

+11

*AON = Apparently Occupied Nests

 

Breeding abundance

In the whole of Ireland, Operation Seafarer and the Seabird Colony Register both recorded a little over 44,000 black-legged kittiwake AON. Numbers had increased by 11% to 49,160 AON by the time of Seabird 2000. The largest colony on Rathlin Island held 76% of the national population, some 9,917 AON, during Seabird 2000. In 2007, numbers there were similar, with 9,896 AON recorded. However, numbers had declined to 7,922 AON in 2011 (a fall of 20%)38. In 2018, four smaller colonies (The Gobbins, Muck, Portrush and Maggie’s Leap) held 1,358 AON combined, an increase of 9% AON compared to 1,250 AON during Seabird 2000. In contrast, in the Republic of Ireland, all black-legged kittiwake colonies were counted between 2015 and 2018. A total of 24,728 compared to 36,100 AON during Seabird 2000 were recorded, representing a decline of 32%40. In the whole of Ireland, it is highly likely that black-legged kittiwake numbers have declined since Seabird 2000, although a survey of Rathlin Island is required to allow a robust estimate of the size of this decline to be made. There were insufficient data from all-Ireland to allow trends to be generated.

 

Productivity

Kittiwake Eire productivity.jpg (1)

Figure 11. Trend in productivity (no. of chicks fledged per pair) of black-legged kittiwake throughout Ireland, 1986–2015. Based on SMP data; view the methods of analysis.

 

The trend in productivity of black-legged kittiwakes throughout Ireland is similar to that shown for the Republic of Ireland where most data have been collected. There are few years when productivity is higher than 0.80 chicks fledged per pair. A particularly poor breeding season was recorded in 2008, probably due to the very wet summer that year impacting on young birds in nests. Such low levels of productivity may now be having an effect on abundance. Annual productivity estimates at Rockabill Island fell to 0.61 chicks per pair in 2018 compared to an average of 1.2 chicks from 1999–2007. The practice of pair-trawling of spawning inshore sprat has increased in recent years and a herring fishery is operating in the Irish and Celtic Seas. The existence of these fisheries, operating within the foraging areas of black-legged kittiwakes, may have an impact on the productivity of this species along these coasts, particularly if the fisheries target young sprat41. There were insufficient data from all-Ireland to allow trends to be generated.

 

Isle of Man

Population estimates and change 1969–2018 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

 

 Isle of Man Census

(2017-18)

Population estimate (AON*)

908

1,376

1,045

672

% change since previous census   

n/a

+51

-24

-36

*AON = Apparently Occupied Nests

 

Breeding abundance

Kittiwake Calf of Man breeding abundance.jpg

Figure 12. Abundance of black-legged kittiwake on the Calf of Man, 1986–2017.

 

Black-legged kittiwake shows a steady declining trend on the Isle of Man. Full censuses recorded 908 AON during Operation Seafarer, increasing by 50% to 1,376 AON during the Seabird Colony Register. A decline then occurred with Seabird 2000 recording 1,045 AON. In 2017, a census of the Isle of Man recorded 672 AON, a decline of 36% since Seabird 2000. During Seabird 2000, 182 black-legged kittiwake AON were recorded on the Calf of Man, declining to 104 in 2006, then 8 in 2010, and by 2017 the colony was extirpated (Figure 12). The stronghold of birds, however, is located at the Sugar Loaf, which held 580 AON during Seabird 2000 and had it increased by 5% in 2017 to 553 AON42.

 

Productivity

No data have been submitted to the SMP recently, but between 1986 and 2005 there was no statistically significant effect of year in the productivity of black-legged kittiwakes nesting on the Isle of Man; an average of 0.27 chicks were fledged per nest each year.

 

Channel Islands

Population estimates and change 1969–2016 (census data)

 

Operation Seafarer    

(1969-70)

Seabird Colony Register    

(1985-88)

Seabird 2000    

(1998–2002)

Channel Islands Census

(2015-16)

Population estimate (AON*)

12

34

3

0

% change since previous census   

n/a

+183

-91

0

*AON = Apparently Occupied Nests

 

Breeding abundance

The black-legged kittiwake had only a small breeding presence in the Channel Islands during the last three censuses. Three AON were recorded during Seabird 2000, 34 during the Seabird Colony Register when the population was at its peak and 12 nests during Operation Seafarer. Further to the decline noted during Seabird 2000, no breeding was recorded during a seabird census in 2015-16, and local populations are now believed to be extinct43.

 

Productivity

No systematic data on the productivity of black-legged kittiwakes on the Channel Islands have been submitted to the SMP.

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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

 

Kittiwake percentage of sandeels Isle of May.jpg

Figure 13. Percentage of sandeels (by weight) in the diet of young black-legged kittiwakes at the Isle of May, 1987–2018.

 

Sandeels are an energy-rich food source compared with some alternative prey and the proportion of sandeels by weight can be used as a measure of 'diet quality'. Figure 13 shows that the percentage of sandeels in the diet of black-legged kittiwakes on the Isle of May has been high for the majority of years but since 2012 has declined considerably (from 87% to 58%). A recent study on the seabirds of the Isle of May found that the proportion of sandeels in their diet has declined in both the summer and winter over the last three decades, linked to trends in SST5. The amount of sandeels fed to chicks, (particularly the size 1+ group fish) has decreased, and a shift from size 1+ group to 0 group sandeels has occured5. Black-legged klittiwake chicks were fed clupeids, predominantly sprat Sprattus sprattus, indicating a potential reduction in their reliance on sandeels and a diet composition shift5. Therefore, sandeel abundance might be still important to black-legged kittiwakes but less so when there are alternative prey in poor sandeel years, as appears to be the case around the Isle of May.

 

Return rates and survival rates

Estimation of kittiwake adult return rate and survival rate is currently undertaken at two sites within the SMP - the Isle of May (south-east Scotland) and Skomer (south-west Wales). Return rates are based on sightings of individually colour-ringed birds and calculated as the proportion of marked birds present in year one that are seen the following year. As not every adult alive is seen each year, return rates for 2018 presented here for Isle of May need to be treated as minimum estimates of survival of birds seen in 2017. In contrast, survival estimates – as presented here for Skomer – do consider birds that are not seen one year but which re-appear in following years.

Kittiwake annual return rate Isle of May.jpg

Figure 14. Annual return rate of black-legged kittiwakes breeding on the Isle of May, 1987–2018.

 

The return rate of black-legged kittiwakes on the Isle of May (Figure 14) declined between 1986 and 1998 and then typically fluctuated at a low level until 2009, however, return rate has improved since then. Particularly low rates occurred in 2007-2009 but in 2010 the return rate (89.0%), the highest since 1989 and well above the average for the period prior to this (77.7, 95% CI =74.5–81.0). In 2018, the return rate of black-legged kittiwakes (87.6%) was above average (1986–2017 average = 79.3%). Adult survival was likely to have been negatively affected by the presence of a sandeel fishery that operated off south-east Scotland1 between 1990 and 19992.

The new EU Common Fisheries Policy came into effect in 2014. It included the obligation that all catches of regulated commercial species had to be landed and counted against quota. From 2015 to 2019, the landing obligation was phased in across the majority of EU fisheries. This is likely to impact on seabird populations that feed on discards. Species native to the north-east Atlantic that are currently extensively exploiting fishery discards are kittiwake, herring gull, lesser black-backed gull, great black-backed gull, great skua, northern fulmar and the northern gannet44.

 

Kittiwake adult survival rate Skomer.jpg

Figure 15. Estimated adult survival rate of black-legged kittiwakes on Skomer, 1986–2017.

 

Survival rate of kittiwakes on Skomer (Figure 5) declined between 1991 and 1997 and then increased up to 2002, after which another decline is evident. The survival rate in 2007 was particularly low (70.4). Over the period of the long-term study (1978–2017), survival of breeding adults averages 0.85. There continues to be a cyclic fluctuation in adult breeding survival over the course of the study, despite a consistently high probability of re-sighting live birds (>90% encounter probability in the last ten years). The survival rate of breeding adult black-legged kittiwakes in 2016-17 was 0.96, a continued recovery in recent years. An upturn that may indicate the continuation of the apparently decadal cycles of adult survival since 1978, rather than a consistent decline in adult survival45.

The waters around the UK have been warming since the 1980s, and recent studies have demonstrated links between kittiwake adult survival and climate46,47,48,49. Adult survival is largely affected by winter mortality, and additionally by the carry-over effects of the previous breeding season. These effects may become increasingly important for all seabirds since most climate models predict that future warming will be associated with increasing climate variability and hence frequency of extreme weather events50,51. A recent study using geolocation data loggers to examine the non-breeding season distribution of kittiwakes found tagged birds from Skomer (and Rathlin) remained relatively near the colony but those from the Isle of May migrated more widely with the main areas of use split between the North Sea and the Central and West Atlantic52. Based on the longer distance to the breeding grounds, black-legged kittiwakes may, therefore, be at higher risk of winter mortality and lower adult survival based on environmental conditions in the West Atlantic. Any major changes in food availability in this part of the west Atlantic (e.g. projected changes in distribution of C. finmarchicus; could affect the entire Atlantic population53.

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References

1 Arnott, S. A. and Ruxton, G. D. 2002. Sandeel recruitment in the North Sea: demographic, climatic and trophic effects. Marine Ecology Progress Series, 238, 199–210.

2 Frederiksen, M., Harris, M.P., Daunt, F., Rothery, P. and Wanless, S. 2004. The role of industrial fisheries and oceanographic change in the decline of North Sea black-legged kittiwakes. Journal of Applied Ecology, 41, 1129–1139.

3 Daunt, F., Benvenuti, S., Harris, M.P., Dall’Antonia, L., Elston, D.A. and Wanless, S. 2002. Foraging strategies of the black-legged kittiwake Rissa tridactyla at a North Sea colony: evidence for a maximum foraging range. Marine Ecology Progress Series, 245, 239–247.

4 Wanless, S., Harris, M.P. and Greenstreet, S.P.R. 1998. Summer sandeel consumption by seabirds breeding in the Firth of Forth, south-east Scotland. ICES Journal of Marine Science, 55, 1141–1151.

5 Wanless, S., Harris, M.P., Newell, M.A., Speakman, J.R. and Daunt F. 2018. Community-wide decline in the occurrence of lesser sandeels Ammodytes marinus in seabird chick diets at a North Sea colony. Marine Ecology Progress Series, 600, 193–206.

6 Furness, R.W. and Tasker, M.L. 2000. Seabird-fishery interactions: quantifying the sensitivity of seabirds to reductions in sandeel abundance, and identification of key areas for sensitive seabirds in the North Sea. Marine Ecology Progress Series, 202, 253–264

7 Furness, R. W. 2002. Management implications of interactions between fisheries and sandeel-dependent seabirds and seals in the North Sea. ICES Journal of Marine Science, 59, 261–269.

8 Sandvik, H., Erikstad, K.E., Barrett, R.T. and Yoccoz, N.G. 2005. The effect of climate on adult survival in five species of North Atlantic seabirds. Journal of Animal Ecology, 74, 817-831.

9 Lahoz-Monfort, J.J., Morgan, B.J.T., Harris, M.P., Wanless, S. and Freeman, S.N. 2011. A capture-recapture model for exploring multi-species synchrony in survival. Methods in Ecology and Evolution, 2, 116–124.

10 Newell, M, Harris, M.P., Burthe, S., Bennett, S., Gunn, C.M., Wanless S. and Daunt, F. 2019. Isle of May seabird studies in 2018. Unpublished JNCC Report, Peterborough.

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13 Kirby, R. R. and Beaugrand, G. 2009. Trophic amplification of climate warming. Proceedings of the Royal Society B, 276, 4095–4103.

14 van Deurs, M., van Hal, R., Tomczak, M. T., Jónasdóttir, S. H., and Dolmer, P. 2009. Recruitment of lesser sandeel Ammodytes marinus in relation to density dependence and zooplankton composition. Marine Ecology Progress Series, 381, 249–258.

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16 MacDonald, A., Heath, M.R., Edwards, M., Furness, R.W. Pinnegar, J.K., Wanless, S., Speirs, D.C. and Greenstreet, S.P.R. 2015. Climate driven trophic cascades affecting seabirds around the British Isles. Oceanography and Marine Biology. An Annual Review, 53, 55–80.

17 Wright, P. J., Jensen, H. and Tuck, I. 2000. The influence of sediment type on the distribution of the lesser sandeel, Ammodytes marinus. Journal of Sea Research, 44, 243–256.

18 Heath, M.R., Rasmussen, J., Bailey, M.C., Dunn, J., Fraser, J., Gallego, A., Hay, S.J., Inglis, M. and Robinson, S. 2012. Larval mortality rates and population dynamics of lesser sandeel (Ammodytes marinus) in the north western North Sea. Journal of Marine Systems, 94, 47–57.

19 Régnier, T., Gibb, F.M. and Wright, P.J. 2019. Understanding temperature effects on recruitment in the context of trophic mismatch. Scientific Reports, 9(1), Article number: 15179.

20 Wanless, S., Wright, P.J., Harris, M.P. and Elston, D.A. 2004. Evidence for decrease in size of lesser sandeels Ammodytes marinus in a North Sea aggregation over a 30-yr period. Marine Ecology Progress Series, 279, 237–246.

21 Frederiksen, M., Elston, D.A., Edwards, M., Mann, A.D. and Wanless, S. 2011. Mechanisms of long-term decline in size of lesser sandeels in the North Sea explored using a growth and phenology model. Marine Ecology Progress Series, 432, 137−147.

22 MacDonald, A., Speirs, D.C., Greenstreet, S.P.R., Boulcott, P. and Heath, M.R. 2019. Trends in Sandeel Growth and Abundance off the East Coast of Scotland. Frontiers in Marine Science, 6, 201.

23 Burthe, S., Daunt, F., Butler, A., Elston, D.A., Frederiksen, M, Johns, D., Newell, M., Thackeray, S.J. and Wanless, S. 2012. Phenological trends and trophic mismatch across multiple levels of a North Sea pelagic food web. Marine Ecology Progress Series, 454, 119–133.

24 Frederiksen, M., Edwards, M., Richardson, A.J., Hallyday, N.C., Wanless, S. 2006. From plankton to top predators: bottom-up control of a marine food web across four trophic levels. Journal of Animal Ecology, 75, 1259−1268.

25 Lauria, V., Attrill, M.J., Pinnegar, J.K., Brown, A., Edwards, M., Votier, S.C. 2012. Influence of climate change and trophic coupling across four trophic levels in the Celtic Sea. PLoS ONE, 7, e47408.

26 Lauria, V., Attrill, M.J., Brown, A., Edwards, M. and Votier, S.C. 2013. Regional variation in the impact of climate change: evidence that bottom-up regulation from plankton to seabirds is weak in parts of the Northeast Atlantic. Marine Ecology Progress Series, 488, 11–22.

27 Frederiksen, M., Wright, P.J., Heubeck, M., Harris, M.P., Mavor, R.A. & Wanless, S. 2005. Regional patterns of kittiwake Rissa tridactyla breeding success are related to variability in sandeel recruitment. Marine Ecology Progress Series, 300, 201–211.

28 Frederiksen, M., Furness, R.W. and Wanless, S. 2007. Regional variation in the role of bottom-up and top-down processes in controlling sandeel abundance in the North Sea. Marine Ecology Progress Series, 337, 279–286.

29 Frederiksen, M. 2014. Environmental demography – Exploring the links between vital rates and a fluctuating environment. Doctor’s dissertation. Aarhus University, Department of Bioscience, Denmark. 80 pp.

30 Cook, A.S.C.P., Dadam, D., Mitchell, I., Ross-Smith, V.H. and Robinson RA 2014. Indicators of seabird reproductive performance demonstrate the impact of commercial fisheries on seabird populations in the North Sea. Ecological Indicators, 38, 1–11.

31 Cook, A.S.C.P., Dadam, D. and Robinson, R.A. 2014. Development of MSFD Indicators, Baselines and Target for the Annual breeding Success of Kittiwakes in the UK 2012. JNCC Report, No. 538. Joint Nature Conservation Committee, Peterborough.

32 Daunt, F., Wanless, S., Greenstreet, S.P.R., Jensen, H., Hamer, K.C., Harris, M.P. 2008. The impact of the sandeel fishery closure in the northwestern North Sea on seabird food consumption, distribution and productivity. Canadian Journal of Fish Aquatic Science, 65, 362−381.

33 Eerkes-Medrano, D., Fryer, R. J., Cook, K. B. and Wright, P. J. 2017. Are simple environmental indicators of food web dynamics reliable: Exploring the kittiwake-temperature relationship. Ecological Indicators, 75, 36–47.

34 Monaghan, P. 1992. Seabirds and sandeels: the conflict between exploitation and conservation in the northern North Sea. Biodiversity Conservation, 1, 98−111

35 Christensen-Dalsgaard, S., May, R.F., Barrett, R., Langset, M., Sandercock, B., Lorentsen and Håkon, S.H.. 2018. Prevailing weather conditions and diet composition affect chick growth and survival in the black-legged kittiwake. Marine Ecology Progress Series, 604, 237–249.

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41 Cummins, S., Lewis, L.J. and Egan, S. 2016. Life on the Edge - Seabird and Fisheries in Irish Waters. A BirdWatch Ireland Report.

42 Hill, R.W., Morris, N. G., Bowman, and K. A., Wright, D. 2019. The Isle of Man Seabird Census: Report on the census of breeding seabirds in the Isle of Man 2017-18. Manx BirdLife. Laxey, Isle of Man.

43 Veron, M. and Veron, C. 2016. Seabird Count 2015; monitoring the status of Guernsey’s Seabirds. La Société Transactions, Channel Islands.

44 Bicknell, A.W. J., Oro, D., Camphuysen, J.C. and Votier, S.C. 2013. Potential consequences of discard reform for seabird communities. Journal of Applied Ecology, 50, 649–658.

45 Stubbings, E.M., Büche, B.I., Riordan, J.A.,Baker, B. and Wood, M.J. 2018. Seabird monitoring on Skomer Island in 2018. Unpublished JNCC Report. Joint Nature Conservation Committee, Peterborough.

46 Oro, D. and Furness, R. W. 2002. Influences of food availability and predation on survival of Kittiwakes. Ecology, 83, 2516–2528.

47 Sandvik, H., Erikstad, K.E., Barrett, R.T. & Yoccoz, N.G. 2005. The effect of climate on adult survival in five species of North Atlantic seabirds. Journal of Animal Ecology, 74, 817–831.

48 Lewis, S., Elston, D.A., Cheney, B., Daunt, F. and Thompson, P.M. 2009. Extrinsic and intrinsic effects on reproductive success in a long-lived seabird. Oikos, 118, 518–528.

49 Burthe, S., Wanless, S., Newell, M.A., Butler, A. and Daunt, F. 2014 Assessing the vulnerability of the marine bird community in the western North Sea to climate change and other anthropogenic impacts. Marine Ecology Progress Series, 507, 277–295.

50 Solomon, S. 2007. Climate change 2007: the physical science basis: contribution of Working Group I to the fourth assessment report of the Intergovernamental Panel on Climate Change. Cambridge University Press, Cambridge.

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52 Frederiksen, M., Moe, B., Daunt, F., Phillips, R.A., Barrett, R.T., Bogdanova, M.I., Boulinier, T., Chardine, J.W., Chastel, O., Chivers, L.S., Christensen-Dalsgaard, S., Clément-Chastel, C., Colhoun, K., Freeman, R., Gaston, A.J., González-Solís, J., Goutte, A., Grémillet, D., Guilford, T., Jensen, G.H., Krasnov, Y., Lorentsen, S.-H., Mallory, M.L., Newell, M., Olsen, B., Shaw, D., Steen, H., Strøm, H., Systad, G.H., Thórarinsson, T.L. and Anker-Nilssen, T. 2012. Multi-colony tracking reveals the winter distribution of a pelagic seabird on an ocean basin scale. Diversity and Distributions, 18, 530–542.

53 Reygondeau, G. and Beaugrand. G. 2011. Future climate-driven shifts in distribution of Calanus finmarchicus. Global Change Biology, 17, 756–766.

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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; UK Centre for Ecology and Hydrology; Natural Resources Wales; Department of Environment, Food and Agriculture (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 Department of Agriculture, Environment and Rural Affairs; 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 >>

 

Image of Black-legged kittiwake appears courtesy of Ian Rendall ©, is subject to international copyright law and may not be reproduced in any form whatsoever.

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SMP Report 1986–2018

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