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WILDLIFE OF NORTHERN ENGLAND

State of birds 2017----Headlines

Climate change will provide opportunities for some species, while others will be more vulnerable.
•  Birds in the UK are showing changes in abundance and distribution, predominantly moving northwards, in a way that is consistent with a changing climate.
•  Migratory birds are arriving earlier and egg-laying dates have advanced  such that swallows, for example, are arriving in the UK 15 days earlier,  and breeding 11 days earlier, than they did in the 1960s.
•  A large number of bird species are likely to have opportunities for colonisation and range expansion in the UK under projected climate change. Potential colonists include a number of wetland species such as little bittern and night heron. A considerable list of southerly-distributed species have already shown substantial increases in recent years, including garganey, quail and little egret

 Climate change will increase the pressures on species already in decline.  A number of our declining rare breeding birds, including dotterel, whimbrel, common scoter and Slavonian grebe, are likely to be at a higher risk of extinction in the UK, based on projections of how climate  will become less suitable for them.
•  The UK’s kittiwake population has declined by 70% since 1986 because of falling breeding success and adult survival. Climate change has reduced the availability of the sandeels they rely upon in the breeding season.  Other species that feed largely on sandeels, such as Arctic skua, Arctic tern and puffin, are at high risk of climate-related decline.
•  National surveys provided updated population estimates for capercaillie and hen harrier and revealed declines for both species.
•  In the UK Overseas Territories, there are positive signs of recovery for four endemic land birds on Henderson Island and updates on a successful translocation project for the cahow

Wild bird indicators

The UK wild bird indicators are high-level measures of the state of bird populations. They show relative changes in the abundance of common and widespread native birds of farmland, woodland, freshwater and marine habitats. In conjunction with indicators for other well-monitored groups, such as butterflies and bats, they are used as a proxy for the overall state of biodiversity, to
track progress towards targets for conserving the natural environment and for sustainable development goals.
The indicators are shown by habitat type. They present the average population trends for breeding bird species associated with farmland, woodland and wetlands, and for seabirds (page 25) and wintering waterbirds
(page 41). The bar chart provided alongside each habitat chart (see opposite) shows the percentage of species within that indicator that have increased, decreased or shown no change. While the indicators communicate broad trends and are a good tool for summarising these changes,  it is important to note that there is considerable variation in the individual species’ trends that  go into the indicator.

 

Farmland woodland and wetland.

Trends in common and widespread breeding birds are included in the farmland, woodland and wetland indicators.
•  The farmland indicator remains at less than half its 1970 starting value, while over the short term, between 2010 and 2015, the smoothed index has decreased by 9%. Agricultural
management during the period has had a greater impact on farmland birds than other factors such as climate change. •  The woodland bird indicator is 23% lower than its 1970 level, showing no significant change over the short term. The climatic conditions of woodlands in the UK might
become more suitable for some species in the indicator, such as the lesser spotted woodpecker and nightingale. But such changes are unlikely to counterbalance other negative drivers causing declines in woodland birds. Other species, particularly long-distance migrants, such as the pied flycatcher and tree pipit, may be vulnerable to ongoing changes in the timing of insect availability on their breeding grounds, and the impacts of climate change on their wintering grounds affecting overwinter survival. •  The water and wetland bird index is 8% lower than the 1975 starting value, having remained relatively stable until the mid-2000s. The smoothed index was 2% lower in 2015 than it was in 2010. The arrival and subsequent population expansion of Cetti’s warblers breeding in the UK since 1973 is seen as an example of the northward shift in distribution of some species as a result of climate change.

Lesser spotted woodpecker numbers have fallen since the 1970s.

 
2. For five riverine species a smoothed trend for both time periods is calculated by combining the WBS and WBBS data as follows: 1975–2015 for grey wagtails, dippers, kingfishers and common sandpipers and 1978–2015 for sand martins. For grey herons, the trend is based on the Heronries Census (1982– 2015) (page 52).
3. Long-term trends cover shorter time periods for three species due to the later availability of reliable data, as follows: 1972–2015 for collared doves, 1975–2015 for sparrowhawks and 1977–2015 for house sparrows.
na = trends not available
More details on the BBS,  including The Breeding Bird  Survey 2016 report,  can be found at bto.org/bbs
BTO/JNCC/RSPB Breeding Bird Survey and Waterways Breeding Bird Survey data were provided by a partnership jointly funded by the BTO, RSPB and JNCC, with fieldwork conducted by volunteers. The Waterways Breeding Bird Survey received significant previous support from the Environment Agency.
More details on the BBS, including the Breeding Bird Survey 2016 report, can be found at bto.org/bbs
Species
Long-term trend % (1970–2015)
BBS trend % (1995–2015)
BoCC4
Mute swan 192 26 Greylag goose na 232 Canada goose na 75 Shelduck1 131 -5 Mandarin na 405 Gadwall na 131 Mallard 100 18 Tufted duck na 43 Goosander na 21 Red grouse na 13 Red-legged partridge -26 6 Grey partridge -92 -60 Pheasant1 70 29 Grey heron2 -5 -17 Little grebe na 42 Great crested grebe na 10 Red kite na 1231 Sparrowhawk3 65 -16 Buzzard1 465 84 Kestrel1 -50 -38 Hobby na -12 Peregrine na -13 Moorhen -27 -12 Coot 56 17 Oystercatcher na -23 Golden plover na -20 Lapwing -64 -43 Snipe na 19 Curlew1 -65 -48 Common sandpiper2 -46 -34 Redshank na -38 Feral pigeon na -21 Stock dove1 113 20 Woodpigeon 123 35 Collared dove3 311 3 Turtle dove -98 -94 Ring-necked parakeet na 1455 Cuckoo1 -56 -43 Barn owl na 217 Little owl -64 -57 Tawny owl -37 -28 Swift na -51 Kingfisher2 -17 -4 Green woodpecker1 100 31 Great spotted woodpecker 349 130 Magpie 97 -2 Jay 8 19 Jackdaw 149 54 Rook na -20 Carrion crow1 98 18 Hooded crow na 17 Raven na 46 Goldcrest1 -15 11 Blue tit 21 1

 For most species, long-term trends and short-term trends are based on smoothed estimates of change in the UK between 1970 and 2015, and 1995 and 2015 respectively. Although all data, including the most recent from 2016, are included in analyses, we report measures of change to the penultimate year (2015), to avoid unreliable effects due to smoothing at the endpoints of time series.
Exceptions to these time periods are identified in the table and explained below: 1. For most species, the long-term trends are based on the smoothed estimates of change between 1970 and 2015 in a combined CBC–BBS analysis. However, for species with evidence of marked differences in the populations monitored by the BBS and its predecessor the CBC, we use the CBC results to 1994 anchored to the BBS from 1994 to 2015. Hence, long-term trends for these species may not be representative of the UK population prior to 1994, due to the more limited geographical and habitat coverage of the CBC (mainly farmland and woodland sites in England).
2. For five riverine species a smoothed trend for both time periods is calculated by combining the WBS and WBBS data as follows: 1975–2015 for grey wagtails, dippers, kingfishers and common sandpipers and 1978–2015 for sand martins. For grey herons, the trend is based on the Heronries Census (1982

 Keeping tabs on population changes in our common and widespread birds allows us to gain an insight into the overall health of the environment around us, as shown by the regular summaries of trends presented in the UK wild bird indicators (see page 9). However, knowing how individual species are faring is essential for directing conservation efforts and monitoring the effectiveness of this work.
Common and widespread  breeding birds
Data from the Breeding Bird Survey (BBS) and its predecessor survey, the Common Birds Census (CBC), can be combined to provide long-term population trends dating back to the 1960s.
In 2016, Breeding Bird Survey data alone enabled population trends to be calculated for 111 species of breeding birds, monitoring population change since 1994. In order to obtain
these data, 2,796 volunteers surveyed a record breaking  3,837 1-km BBS squares.
The Waterways Breeding Bird Survey (WBBS) and its predecessor survey, the Waterways Bird Survey (WBS), fill a gap in our knowledge of specialist species of linear waterways, such as grey wagtails, sand martins, dippers, kingfishers and common sandpipers. Population trends can be calculated since 1970 using WBBS and WBS data combined. Although the BBS does report trends, the WBBS is thought to provide a better measure of population change in these species, which are very much dependent on waterways habitats. In addition, for these species and others, we can make informative comparisons between trends across all habitats (from BBS) and the waterway-specific trends produced by WBBS.
The table opposite (continued overleaf) presents trends in 108 breeding bird species, along with notes about the sources of data. Where possible, trends are given for two periods: long term (1970–2015) and BBS trend (1995–2015). As well as the CBC, BBS, WBS and WBBS, trends in the grey heron population are reported using the oldest single species  survey in the world: the BTO Heronries Census, which has been monitoring grey herons since 1928.

11 The state of the UK’s birds 2017
Common and widespread breeding birds
For most species, long-term trends and short-term trends are based on smoothed estimates of change in the UK between 1970 and 2015, and 1995 and 2015 respectively. Although all data, including the most recent from 2016, are included in analyses, we report measures of change to the penultimate year (2015), to avoid unreliable effects due to smoothing at the endpoints of time series.
Exceptions to these time periods are identified in the table and explained below: 1. For most species, the long-term trends are based on the smoothed estimates of change between 1970 and 2015 in a combined CBC–BBS analysis. However, for species with evidence of marked differences in the populations monitored by the BBS and its predecessor the CBC, we use the CBC results to 1994 anchored to the BBS from 1994 to 2015. Hence, long-term trends for these species may not be representative of the UK population prior to 1994, due to the more limited geographical and habitat coverage of the CBC (mainly farmland and woodland sites in England).
2. For five riverine species a smoothed trend for both time periods is calculated by combining the WBS and WBBS data as follows: 1975–2015 for grey wagtails, dippers, kingfishers and common sandpipers and 1978–2015 for sand martins. For grey herons, the trend is based on the Heronries Census (1982– 2015) (page 52).
3. Long-term trends cover shorter time periods for three species due to the later availability of reliable data, as follows: 1972–2015 for collared doves, 1975–2015 for sparrowhawks and 1977–2015 for house sparrows.
na = trends not available
More details on the BBS,  including The Breeding Bird  Survey 2016 report,  can be found at bto.org/bbs
BTO/JNCC/RSPB Breeding Bird Survey and Waterways Breeding Bird Survey data were provided by a partnership jointly funded by the BTO, RSPB and JNCC, with fieldwork conducted by volunteers. The Waterways Breeding Bird Survey received significant previous support from the Environment Agency.
More details on the BBS, including the Breeding Bird Survey 2016 report, can be found at bto.org/bbs
Species
Long-term trend % (1970–2015)
BBS trend % (1995–2015)
BoCC4
Mute swan 192 26 Greylag goose na 232 Canada goose na 75 Shelduck1 131 -5 Mandarin na 405 Gadwall na 131 Mallard 100 18 Tufted duck na 43 Goosander na 21 Red grouse na 13 Red-legged partridge -26 6 Grey partridge -92 -60 Pheasant1 70 29 Grey heron2 -5 -17 Little grebe na 42 Great crested grebe na 10 Red kite na 1231 Sparrowhawk3 65 -16 Buzzard1 465 84 Kestrel1 -50 -38 Hobby na -12 Peregrine na -13 Moorhen -27 -12 Coot 56 17 Oystercatcher na -23 Golden plover na -20 Lapwing -64 -43 Snipe na 19 Curlew1 -65 -48 Common sandpiper2 -46 -34 Redshank na -38 Feral pigeon na -21 Stock dove1 113 20 Woodpigeon 123 35 Collared dove3 311 3 Turtle dove -98 -94 Ring-necked parakeet na 1455 Cuckoo1 -56 -43 Barn owl na 217 Little owl -64 -57 Tawny owl -37 -28 Swift na -51 Kingfisher2 -17 -4 Green woodpecker1 100 31 Great spotted woodpecker 349 130 Magpie 97 -2 Jay 8 19 Jackdaw 149 54 Rook na -20 Carrion crow1 98 18 Hooded crow na 17 Raven na 46 Goldcrest1 -15 11 Blue tit 21 1
Keeping tabs on population changes in our common and widespread birds allows us to gain an insight into the overall health of the environment around us, as shown by the regular summaries of trends presented in the UK wild bird indicators (see page 9). However, knowing how individual species are faring is essential for directing conservation efforts and monitoring the effectiveness of this work.
Common and widespread  breeding birds
Data from the Breeding Bird Survey (BBS) and its predecessor survey, the Common Birds Census (CBC), can be combined to provide long-term population trends dating back to the 1960s.
In 2016, Breeding Bird Survey data alone enabled population trends to be calculated for 111 species of breeding birds, monitoring population change since 1994. In order to obtain
these data, 2,796 volunteers surveyed a record breaking  3,837 1-km BBS squares.
The Waterways Breeding Bird Survey (WBBS) and its predecessor survey, the Waterways Bird Survey (WBS), fill a gap in our knowledge of specialist species of linear waterways, such as grey wagtails, sand martins, dippers, kingfishers and common sandpipers. Population trends can be calculated since 1970 using WBBS and WBS data combined. Although the BBS does report trends, the WBBS is thought to provide a better measure of population change in these species, which are very much dependent on waterways habitats. In addition, for these species and others, we can make informative comparisons between trends across all habitats (from BBS) and the waterway-specific trends produced by WBBS.
The table opposite (continued overleaf) presents trends in 108 breeding bird species, along with notes about the sources of data. Where possible, trends are given for two periods: long term (1970–2015) and BBS trend (1995–2015). As well as the CBC, BBS, WBS and WBBS, trends in the grey heron population are reported using the oldest single species  survey in the world: the BTO Heronries Census, which has been monitoring grey herons since 1928.
Ben Andrew (rspb-images.com)
The Waterways Breeding Bird Survey provides information on kingfishers.
Species
Long-term trend % (1970–2015)
BBS trend % (1995–2015)
BoCC4
Great tit 81 37 Coal tit 16 0 Willow tit -93 -80 Marsh tit -75 -41 Skylark1 -59 -22 Sand martin2 7 -30 Swallow 8 18 House martin1 -48 -11 Long-tailed tit1 98 17 Wood warbler na -57 Chiffchaff 104 109 Willow warbler1 -44 -11 Blackcap 289 145 Garden warbler -10 -23 Lesser whitethroat 22 6 Whitethroat 6 30 Grasshopper warbler na -17 Sedge warbler -28 -9 Reed warbler 112 17 Nuthatch 252 90 Treecreeper -10 9 Wren 68 32 Starling1 -81 -51 Dipper2 -22 -6 Blackbird -16 22 Song thrush -50 22 Mistle thrush -55 -25 Spotted flycatcher -85 -38 Robin 55 25 Nightingale na -48 Pied flycatcher na -41 Redstart 72 43 Whinchat na -51 Stonechat na 53 Wheatear na -16 Dunnock -29 23 House sparrow3 -66 -6 Tree sparrow1 -90 119 Yellow wagtail -67 -42 Grey wagtail2 -39 4 Pied wagtail 39 0 Tree pipit -69 8 Meadow pipit1 -34 -7 Chaffinch 21 -2 Greenfinch -46 -46 Goldfinch1 159 122 Siskin na 61 Linnet1 -55 -21 Lesser redpoll1 -87 27 Common crossbill na -2 Bullfinch -39 10 Yellowhammer -56 -16 Reed bunting -31 31 Corn bunting -89 -34

Adapting to climate change

 As the climate changes, adaptability will be essential in enabling bird populations to persist. The great tit is one of a number of species, including swallows, chiffchaffs and willow warblers, to have advanced its egg-laying date; great tits lay their eggs on average 11 days earlier than they did in 1968. Despite these changes in timing, there remains the potential for a mismatch in the timing of the peak food demands of breeding birds and peak invertebrate prey availability. To date, this has not been directly linked to population declines or reduced breeding success in the UK (see pages 28–40).
The ability to adapt to a changing environment varies between species. Cuckoos populations declined by 43% in the UK between 1995 and 2015.
Whilst some have suggested that this could be due to advances in the egg-laying date of host species such as dunnocks and reed warblers, there is little evidence for this in the UK. Other factors during migration, as well as a decrease in food availability on UK breeding grounds, may be more important. Notably, cuckoos are faring better in Scotland, with an increasing trend of 33% between 1995 and 2015. This pattern is also shown by a number of our Afro-Palearctic migrants, including
willow warblers, house martins and tree pipits.
Habitat extent and distribution will change as a result of climate change as well as other factors, and this has implications for the ability of species to respond. While a species may be able to alter the timing of life history events for instance, the availability of suitable habitat will ultimately determine whether a species can persist in a particular area, as well as its capacity to colonise new areas. As the climate changes, adaptability will be essential in enabling bird populations to persist. The great tit is one of a number of species, including swallows, chiffchaffs and willow warblers, to have advanced its egg-laying date; great tits lay their eggs on average 11 days earlier than they did in 1968. Despite these changes in timing, there remains the potential for a mismatch in the timing of the peak food demands of breeding birds and peak invertebrate prey availability. To date, this has not been directly linked to population declines or reduced breeding success in the UK (see pages 28–40).
The ability to adapt to a changing environment varies between species. Cuckoos populations declined by 43% in the UK between 1995 and 2015.
Whilst some have suggested that this could be due to advances in the egg-laying date of host species such as dunnocks and reed warblers, there is little evidence for this in the UK. Other factors during migration, as well as a decrease in food availability on UK breeding grounds, may be more important. Notably, cuckoos are faring better in Scotland, with an increasing trend of 33% between 1995 and 2015. This pattern is also shown by a number of our Afro-Palearctic migrants, including
willow warblers, house martins and tree pipits.
Habitat extent and distribution will change as a result of climate change as well as other factors, and this has implications for the ability of species to respond. While a species may be able to alter the timing of life history events for instance, the availability of suitable habitat will ultimately determine whether a species can persist in a particular area, as well as its capacity to colonise new areas.

Expanding northwards---As the climate changes, adaptability will be essential in enabling bird populations to persist. The great tit is one of a number of species, including swallows, chiffchaffs and willow warblers, to have advanced its egg-laying date; great tits lay their eggs on average 11 days earlier than they did in 1968. Despite these changes in timing, there remains the potential for a mismatch in the timing of the peak food demands of breeding birds and peak invertebrate prey availability. To date, this has not been directly linked to population declines or reduced breeding success in the UK  The ability to adapt to a changing environment varies between species. Cuckoos populations declined by 43% in the UK between 1995 and 2015.
Whilst some have suggested that this could be due to advances in the egg-laying date of host species such as dunnocks and reed warblers, there is little evidence for this in the UK. Other factors during migration, as well as a decrease in food availability on UK breeding grounds, may be more important. Notably, cuckoos are faring better in Scotland, with an increasing trend of 33% between 1995 and 2015. This pattern is also shown by a number of our Afro-Palearctic migrants, including
willow warblers, house martins and tree pipits.
Habitat extent and distribution will change as a result of climate change as well as other factors, and this has implications for the ability of species to respond. While a species may be able to alter the timing of life history events for instance, the availability of suitable habitat will ultimately determine whether a species can persist in a particular area, as well as its capacity to colonise new areas.

Pressures on upland birds 

 The decline in the curlew population is of great concern, especially when it is considered that the UK supports around a quarter of the global breeding population. Afforestation, overgrazing and predation are likely to be key drivers of decline.
In addition, the drying of soils on the breeding grounds, which is already a problem due to the drainage of lowland meadows and upland bogs, may be exacerbated by climate change. Wetter areas are important sources of insects which breeding waders, such as
curlews and golden plovers, feed to their young. Curlews have declined by 65% between 1970 and 2015 across the UK, and golden plovers by 31% between 1995 and 2015 in Scotland.

 

 

 

Scarce and rare breeding birds.

The Breeding Bird Survey allows us to monitor trends in more than 100 of our most common and widespread breeding birds. However, its non-targeted approach means that rarer breeding species, or those with restricted ranges, are encountered too infrequently for population trends to be derived.
Different approaches are needed to ensure that these species, many of which are high conservation priorities, are monitored. Much of the data on these species is collated by the Rare Breeding Birds Panel (RBBP), for the most part based on the records collected by volunteer birdwatchers. In some
cases, the RBBP simply reports the efforts of focused annual monitoring on species of high conservation interest, such as bitterns and Slavonian grebes, but in many cases it provides a unique synthesis by compiling data from many sources.
The degree to which species are monitored adequately by the RBBP varies considerably between species; for some it is complete, or virtually so, whereas for others, data are available for only a small proportion of the population, may vary between years, or are biased in other ways. This is particularly true for some of the scarce species covered by the RBBP, and those that have
distributions away from reserves, popular birdwatching locations, and well-populated areas.
For such species, bespoke surveys repeated at regular intervals, such as those conducted under the Statutory Conservation Agency and RSPB Annual Breeding Bird Scheme (SCARABBS), provide the data required to inform conservation decision-making. Here we collate information from the most appropriate sources to give an update on trends in scarce and rare breeding birds. In addition, we consider the impact that climate change might have upon these species, for better or worse.

Climate change continued

There is now considerable evidence for changes in abundance and population trends of birds. The observed and predicted changes in climate suitability and recent species population trends have been shown to be correlated across continental Europe (Gregory et al. 2009; Stephens et al. 2016).    Many resident species, such as wren, treecreeper, nuthatch, robin and dunnock, have shown long-term increases in abundance, which have been linked to increases in winter and spring temperatures.    Populations of long-distance migrants (for example  ring ouzel) may suffer negative consequences from warmer, drier conditions during the spring and summer potentially influencing food availability and abundance (Beale et al. 2006). Migratory populations are also sensitive to changes in weather conditions on their wintering grounds, where lower rainfall affects survival rates (Johnston et al. 2016).    Long-term changes in internationally important waterbird populations are also partly explained by climate change (Johnston et al. 2013). Improved survival as a result of milder winters has been reported for several species including dunlins, redshanks and golden plovers.    A number of breeding seabird species, eg kittiwakes and shags, show declines caused by declining productivity associated with warming seas and changes to food abundance and availability (see kittiwake case study on page 34).
Community change
Collectively, these responses mean that birds in the countryside around us are changing in response to climate change. Southerly-distributed species, resident species and habitat generalists are increasing relative to northern or upland species, long-distance migrants and habitat specialists (Davey et al. 2012).
Across Europe, warm-associated species are becoming more common relative to coldassociated species (Devictor et al. 2012), and bird communities are becoming more similar to each other (Le Viol et al. 2012, Sullivan et al. 2016). For birds,  the decline in cold-adapted, northern species is the key  driver of change in community composition across England, contrasting with the situation for butterflies, where the change is being driven by an increase in southern, warm-adapted species (Oliver et al. 2017).
Changes in timing
The spring arrival dates for 11 of 14 common migrants have got earlier and egg-laying dates have advanced with the result that swallows, for example, are arriving in the UK 15 days earlier and breeding 11 days earlier than they did in the 1960s (Newson  et al. 2016).
However, timings vary annually in relation to spring temperatures and conditions on migration. Blackcaps and chiffchaffs bred significantly later in 2016 than they have in recent years, probably as a result of lower April temperatures (NRS report 2016).
Timing of departure has become slightly delayed in some species,
including short distance/partial migrants, eg blackcaps and chiffchaffs, and long distance migrants, eg garden warblers.
As a result of earlier arrival and later departure, migratory species are staying longer in the UK. For example sand martins and whitethroats, now spend around two weeks longer in the UK than in the 1960s, and garden warblers four weeks longer.
Species that have extended their stay in the UK show more positive trends in abundance over the period studied (1960s–2010), compared to species that had not altered their timing of migration, for example cuckoos and turtle doves (Newson et al. 2016).
However, timings events vary between taxonomic groups. Across a wide range of species of plants and insects, timing has advanced on average by about four days for a 1°C increase in temperature, compared to birds which have advanced by an average of two days. This presents a potential problem of mismatch between peak prey availability and birds’ peak prey requirem

To read the full report in pdf form 

To read the full report visit 

 

2017 - rspb.org.uk

https://www.rspb.org.uk/.../sukb-2017---web-version.pdf
 
 
The above information is courtesy of the RSPB. 

 

 The state of the UK’s birds 2017
Scarce and rare breeding birds
The Breeding Bird Survey allows us to monitor trends in more than 100 of our most common and widespread breeding birds. However, its non-targeted approach means that rarer breeding species, or those with restricted ranges, are encountered too infrequently for population trends to be derived.
Different approaches are needed to ensure that these species, many of which are high conservation priorities, are monitored. Much of the data on these species is collated by the Rare Breeding Birds Panel (RBBP), for the most part based on the records collected by volunteer birdwatchers. In some
cases, the RBBP simply reports the efforts of focused annual monitoring on species of high conservation interest, such as bitterns and Slavonian grebes, but in many cases it provides a unique synthesis by compiling data from many sources.
The degree to which species are monitored adequately by the RBBP varies considerably between species; for some it is complete, or virtually so, whereas for others, data are available for only a small proportion of the population, may vary between years, or are biased in other ways. This is particularly true for some of the scarce species covered by the RBBP, and those that have
distributions away from reserves, popular birdwatching locations, and well-populated areas.
For such species, bespoke surveys repeated at regular intervals, such as those conducted under the Statutory Conservation Agency and RSPB Annual Breeding Bird Scheme (SCARABBS), provide the data required to inform conservation decision-making. Here we collate information from the most appropriate sources to give an update on trends in scarce and rare breeding birds. In addition, we consider the impact that climate change might have upon these species, for better or worse.
Mark Sisson (rspb-images.com)
The UK’s Slavonian grebe population declined by 61% over 25 years.
David Kjaer (rspb-images.com)
The UK was home  to 164 booming  male bitterns  in 2017.
19The state of the UK’s birds 2017
Scarce and rare breeding birds
Notes for table (opposite)   1 Trends for three rare breeding seabirds – Arctic skuas, roseate terns and little terns – are presented on page 27.
2 Population estimates are based on the most recent survey results (with the year of origin in parentheses), or means of RBBP or annual survey totals from the five years 2011–2015. For species for which RBBP totals may underestimate numbers, we have used alternative estimates from the Avian Population Estimates Panel (Musgrove, et al. (2013) British Birds 106: 64–100). For those well-monitored species with increasing populations, we have used the most recently available year of data. Numbers are pairs, territories or units which are likely to be equivalent to breeding pairs, but for the RBBP, numbers are based on possible breeding attempts and include, for example, single territorial male birds and so do not necessarily equate to successful breeding attempts. Thus for the golden oriole we present an average population of two, based on the continued occurrence of small numbers of unpaired birds each spring. The estimate for the capercaillie is individuals counted in the winter.
3 RBBP and annual survey trends are five year means calculated for a 25-year period between 1986–1990 and 2011–2015. The trend periods for those species covered by periodic surveys, such as under SCARABBS, are given. RBBP trends for common scoters and spotted crakes have been given despite SCARABBS coverage, as they allow a 25-year trend to be given rather than just 12 years between surveys. Species that have colonised the UK since the start of the 25-year period cannot have percentage figures calculated, so we have just noted that an increase  has occurred.
Chris Gomersall (rspb-images.com)
Red-throated divers breed on remote lochs in north and west Scotland.
18 The state of the UK’s birds 2017
Species1 Population estimate2 Trend (% change) Trend source and period3 BoCC4
Whooper swan 26 584 RBBP Pintail 25 -14 RBBP Garganey 97 35 RBBP Pochard 685 157 RBBP Common scoter 37 -43 RBBP Goldeneye 200 (APEP) Increase RBBP Quail 728 43 RBBP Black grouse 5,100 (2005) -80 SCARABBS (1991/92-2005) Capercaillie 1,114 (2015/16) -49 SCARABBS (1992/93/94-2015/16) Red-throated diver 1,300 (2006) 38 SCARABBS (1994-2006) Black-throated diver 220 (2006) 16 SCARABBS (1985-2006) Bittern 164 (2017) 604 Annual surveys (1988/92-2013/17) Little egret 921 Large increase RBBP Spoonbill 12 Increase RBBP Slavonian grebe 28 -57 Annual surveys Black-necked grebe 54 44 RBBP Honey buzzard 40 219 RBBP White-tailed eagle 102 (2016) 902 Annual surveys (1987/91-2012/16) Marsh harrier 365 479 RBBP Hen harrier 545 (2016) 2 SCARABBS (1988/89-2016) Montagu's harrier 10 -15 RBBP Goshawk 542 274 RBBP Golden eagle 508 (2015) 16 SCARABBS (1982-2015) Osprey 225 342 RBBP Spotted crake 29 16 RBBP Corn crake 1200 146 Annual surveys (1993-2011/2015) Crane 24 1,883 RBBP Stone-curlew 399 196 RBBP Avocet 1,791 368 RBBP Dotterel 423 (2011) -57 SCARABBS (1987/88-2011) Little ringed plover 1,200 (2007) 80 Surveys (1984-2007) Whimbrel 300 (2009) >-50 Surveys (1995-2009) Black-tailed godwit 54 -1 RBBP Ruff 8 -72 RBBP Purple sandpiper 1 -50 RBBP Red-necked phalarope 49 195 RBBP Green sandpiper 3 Increase RBBP Wood sandpiper 29 663 RBBP Mediterranean gull 889 9,158 RBBP Yellow-legged gull 3 Increase RBBP Lesser-spotted woodpecker 1,000-2,000 (APEP) -83 CBC-BBS joint trend (1970-2015) Merlin 1,100 (2008) 94 SCARABBS (1983/84-2008) Hobby 2,800 (APEP) 172 RBBP Peregrine falcon 1,505 (2014) 5 SCARABBS (1992-2014) Golden oriole 2 -93 RBBP Red-backed shrike 4 -50 RBBP Chough 354 (2014) -1 SCARABBS (1982-2014) Firecrest 981 1063 RBBP Bearded tit 595 64 RBBP Woodlark 3,100 (2006) 1,086 SCARABBS (1986-2006) Cetti's warbler 1,827 718 RBBP Dartford warbler 3,200 (2006) 70 RBBP Savi's warbler 5 -65 RBBP Marsh warbler 8 -66 RBBP Ring Ouzel 5,332 (2012) -72 Atlas & SCARABBS (1988/91-2012) Fieldfare 2 -80 RBBP Redwing 19 -54 RBBP Black redstart 56 -45 RBBP Cirl bunting 1,079 (2016) 814