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Estimated Ring Ouzel (Turdus torquatus) Population in the North York Moors

by Ken Hutchinson and Vic Fairbrother

North York Moors

The North York Moors are located in north-east England, to the south-east of Middlesbrough and to the north-east of York. It is predominantly an upland area, dominated by open heather moorland that is intersected by long valleys (dales) that are largely orientated north-west to south-east. The North York Moors contain the largest continuous tract of open heather moorland in England and Wales and has SSSI and SPA status. The habitat favoured by the Ring Ouzel lies in the western half of the upland area, where land elevation rises significantly above the 250 metres contour. The moorland area covers around 490 km2 of which up to 288 km2 (59%) could contain suitable breeding habitat for the Ring Ouzel. The North York Moors is the most easterly breeding ground for the Ring Ouzel in Great Britain and stands isolated from the nearest population in the Yorkshire Dales some 50 km to the west.

National Population and Trend

The British breeding population of Ring Ouzels has been in decline since the early twentieth century and a 27% reduction in the British breeding range was apparent between the two national atlases of 1968-72 and 1988-91 (Sharrock 1976; Gibbons et al. 1993). The first national Ring Ouzel survey in 1999 estimated the UK population at 6,157-7,549 pairs (1,523-1,654 pairs in England), with further range contraction and a likely 58% decline in population numbers since the 2nd atlas (Wotton et al. 2002). This resulted in the Ring Ouzel being Red-listed in 2003 and made a priority Bio-diversity Action Plan species in the UK.

North York Moors Population and Trend

The national survey data indicated that there was a North York Moors decrease in distribution between the two atlases of 38% with the number of 10km squares where confirmed and probable breeding had been recorded falling from 9 to 5. Provisional data from the 2007-11 3rd atlas suggests a continuing downward trend.

There are a number of problems in trying to arrive at a reliable estimate of Ring Ouzel population and trends on the North York Moors.

There is a surprising shortage of published accounts of Ring Ouzel records from the North York Moors and no dedicated study to use as a benchmark. Survey work for the two national atlases required field workers to record data for all bird species during their visits and data was published only at the 10km square level. Whilst appropriate and the only viable approach for a national survey, this methodology provides an incomplete local picture.

The first national Ring Ouzel survey in 1999 was inevitably restricted to a random selection of squares so coverage on the North York Moors was quite limited and not all squares selected were surveyed.

An elusive upland species like the Ring Ouzel which frequently nests in remote areas, often not easy to access, is a difficult and time consuming species to monitor. A dedicated survey, preferably by a field worker with experience of the species is clearly beneficial if a reliable population estimate is to be obtained.

North York Moors Study

In view of the national decline and the paucity of data on Ring Ouzel numbers and distribution on the North York Moors a local study was commenced in 1999. Records were sought in tetrads containing suitable habitat throughout the area but a core study area was identified in Rosedale in order to monitor this discrete population more intensively over a long time period.

This approach produced extensive and detailed records for 5 tetrads but information on distribution and numbers for the remaining tetrads in the North York Moors was limited to and dependent on a smaller number of occasional records from the study members and casual records from interested contacts.

The offer of help from a volunteer seeking a sabbatical project in 2010 provided an opportunity to significantly enhance the wider records. Provided with grid references of all previous locations a detailed search was carried out across the North York Moors to identify suitable breeding sites and to record Ring Ouzel sightings and breeding status (Tyas 2010). This effort updated and added considerably to existing tetrad records and provided an excellent opportunity to produce a realistic estimate of the Ring Ouzel population on the North York Moors for the first time.

Findings of the 2010 Survey

Annex 1 shows the criteria used to assess the breeding status.

Annex 2 shows all Ring Ouzel records for the North York Moors between 1999 and 2011 combined with data from the 2010 survey.

The map at Annex 3 shows the tetrads that contain suitable breeding habitat and where Ring Ouzel sightings were recorded in 2010. From this it can be seen that in 2010 Ring Ouzels were recorded in 25 of the 72 tetrads (35%) assessed as having some suitable breeding habitat. Breeding was Confirmed in 6 (24%) of the 25 tetrads, Probable in 9 (36%) and Possible in 10 (40%). The map also shows those tetrads where nothing was found during the 2010 survey but where records show breeding had taken place over a number of years between 1999 and 2011.

Annex 4 shows the location of all the territories recorded in Rosedale between 1999 and 2011.

North York Moors Population Estimate

A total of 28 Confirmed and Probable breeding pairs were recorded in 15 tetrads during 2010 - an average breeding density of 1.86 pairs per tetrad. When the records of Possible breeding in 2010 are considered, then a further 16 pairs could be added putting the total number of breeding pairs at 44.

In the 2010 survey it was not possible to visit or conduct a thorough search of all tetrads containing suitable habitat and many tetrads only received one visit. As a consequence some breeding pairs may have escaped detection. Given the 2010 survey found nothing in 47 (65%) of the tetrads considered to have suitable breeding habitat, the population estimate is likely to be higher than the above suggests.

If those tetrads are taken into consideration where nothing was found in 2010 but where breeding has been evident for a number of years during the study period, then a further 10 occupied tetrads could be considered. At a density of 1.86 pairs per tetrad this would increase the number of breeding pairs by 19 to 63.

Combining the data obtained in 2010 with the data and experience gained over the 13 years of the study then a conservative …

population estimate for the North York Moors lies within the range 44 to 65 breeding pairs

… representing about 1% of the breeding population in Great Britain and 4% of the population in England.


The 12 territories recorded in the Rosedale core study area in 2010 were slightly higher than the average of 11.5 recorded between 2004 and 2010.

A breeding density of 0.47 pairs/km2 (1.86 pairs per tetrad) recorded in 2010 is low compared to figures given for populations in Scotland where densities of 4.2 to 6.4 pairs/km2 were recorded in Glen Esk and 0.9 to 1.2 pairs/km2 in the contrasting Moorfoots between 1998-2000 (Burfield 2002).

In Wales an average density of 1.2 to1.4 pairs/km2 were recorded in the more recent 2009/10 Snowdonia survey (Driver 2011).

The greatest density found in the Rosedale core study area was 3 pairs/km2 recorded in 2010 and 2011; this was confined to just one 1km square in the north of the dale. Similar density levels of 2-4 pairs/km2 were found in some areas of Snowdonia.

Due to the low-lying nature of the terrain when compared with other study areas, most territories in the North York Moors are confined to a narrow altitudinal band lying between the 250 and 400 metre contours. The highest point lies at 454 metres on Urra Moor. In the Rosedale study area the lowest nest was found at 245 metres and the highest at 362 metres with the mean altitude being 313 metres. Climate change is likely to pose serious problems for the North York Moors population.

Finally, it is instructive to consider the ring ouzel carrying capacity of the North York Moors based on the above data. Taking the 72 tetrads identified as having suitable breeding habitat, then at a breeding density of 1.86 pairs per tetrad the minimum number of breeding ring ouzels that the North York Moors could support is put at 134 pairs. However, if it is assumed that the 37 currently unoccupied tetrads are somewhat less suitable for breeding than the occupied tetrads then the breeding density in these squares may be less than the current average of 1.86 pairs. In that case an estimated carrying capacity of 134 pairs would be a little high. Conversely and to offset this, there is no evidence to suggest that the occupied territories have reached full capacity, even in the more densely populated tetrads found in Rosedale. Evidence from other studies suggests that there could still be additional capacity in the occupied tetrads and if the marginal outlying tetrads which have held breeding pairs in the past but were not included in the current population estimate are taken into consideration, then the potential carrying capacity could conceivably be greater than the estimated 134 pairs. To conclude, the above evidence suggests that in the North York Moors the breeding habitat is unlikely to be a restraining factor to an expanding ring ouzel population.


The authors wish to acknowledge the considerable help given by Chris Tyas.


Burfield, I.J. 2002. The breeding ecology and conservation of the Ring Ouzel Turdus torquatus in Britain. Unpublished PhD thesis, University of Cambridge.

Driver, J. 2011. Population census of Ring Ouzels Turdus torquatus breeding in Snowdonia, 2009-10. Birds in Wales 8/1 September 2011.

Gibbons,D.W., Reid J.B. & Chapman R.A. 1993. The New atlas of Breeding Birds in Britain and Ireland. 1988-1991. Poyser. London.

Sharrock, J.T.R. (ed.) 1976. The Atlas of Breeding Birds in Britain and Ireland. Poyser, Calton.

Wotton, S.R., Langston, R.H. & Gregory, R.D. 2002. The breeding status of the Ring Ouzel Turdus torquatus in the UK in 1999. Bird Study 49: 26-34.

Annex 1

  • Single bird observed in suitable nesting habitat.
  • Male seen or heard singing on one survey date only.
  • Male observed singing on two different days in a week or more at the same place.
  • Territorial behaviour observed on two or more days.
  • Pair observed in suitable nesting habitat.
  • Nest-building activity.
  • Nest found with eggs or chicks.
  • Recently fledged young seen.
  • Adult seen carrying food.

Annex 2


Tetrad GridRef Place Date Comment
SE49V 494919 Thorodale Head 04/05/2000 Pair.
  485913 Kepwick Quarry 12/05/2003 Pair.
  486914   10/04/2009 6 males. Passage?
  486909 Clarke Scars north. 24/04/2010 Five RZs.
  486914   24/04/2010 1m & 1f.
SE49W 491928 White Gill Head 04/05/2000 Pair.
  484922 Kepwick Moor 19/05/2008 1male.
  491931   10/04/2009 Male to lure.
  487929   10/04/2009 Male to lure.
  487928 Whitestone Scar 31/03/2010 Male.
  482934 Whitestone Scar, gill NW. 24/04/2010 Single call.
  497923 West of Wild Middle. 08/05/2010 Male.
SE49Y 491971 Osmotherley Moor. 20/04/2000 Female.
SE49Z 495992 Piper Grain. 20/05/2002 Pair.
NZ50F 529015 Staindale Farm. 15/04/2003 2 pairs.
  529015 Staindale Farm. 10/05/2006 Pair.
NZ50V 591003 North Gill, sheepfold. 12/04/2010 Pair.
  593002 Tripsdale Head 12/04/2010 Pair in flight.
NZ50W 581021 Cowkill Well. 13/06/2002 Male.
  581021   01/05/2010 Male.
NZ51V 595111 Great Ayton Moor. 19/04/2000 Pair.
  599117   19/04/2000 Male.
SE59A 511915 Harker Yates. 10/04/2009 Male.
SE59B 507930 Arden Great Moor. 10/04/2009 Male.
  502931 Arden Great Moor. 10/04/2009 Male.
  503931 Gill above Locker Woods. 24/04/2010 Pair.
  502935 Arden Great Moor. 24/04/2010 Male song.
  508921 East of Harker Yates. 24/04/2010 Pair.
SE59D 520969 Proddale Sike 29/04/2010 Male.
SE59H 537955 Parci Gill mid. 30/04/2010 Male.
SE59I 535971 Head House. 14/04/2000 Pair.
  535971   19/07/2000 Pair & juvenile.
  537974   14/04/2000 Pair.
  534967   22/04/2003 Four RZs.
  538975   10/05/2006 Pair cf.
  534971   10/05/2006 Male.
  536974   11/04/2009 Male to lure.
  535973   29/04/2010 Pair & five RZs.
SE59M 553947 Wetherhouse in-bye 30/04/2010 Pair.
SE59N 554971 Crookleth Crags west. 30/04/2010 Male.
  551960 Bilsdale Mast. 2009 RZs all season.
SE59Z 582995 Middlehead 13/06/2002 Pair.
  587998 Tripsdale Head east gully. 12/04/2010 Male.
NZ60A 615009 Blowarth Gill 01/05/2010 Pair.
  616015 Blowarth Crossing. 01/05/2010 Three m. & two f.
NZ60B 618036 Armouth Wath. 01/04/2000 Pair.
  605036 Greenhow Bank. 01/05/2000 Pair.
  618036 Armouth Wath. 22/04/2002 2 pairs.
  604034 Greenhow Bank. 01/05/2010 RZ.
  606031 Greenhow Bank. 2009 RZ.
NZ60C 601048 Ingleby Moor 24/04/2006 Pair.
NZ60F 631018 Middle Head east gill. 13/04/2010 Male.
  634014   13/04/2010 Male.
  629010 Middle head Crags. 13/04/2010 Pair.
  628011 Middle head Crags. 29/04/2011 Male/Female.
  635013 East of Middle head Crags. 29/04/2011 Male singing.
NZ60K 659014 Esklets Crag. 18/04/2002 Pair.
  660014   2004 RZ.
NZ60L 649027 Westerdale High House 06/04/2000 Pair.
  649027   18/04/2002 Pair.
NZ60M 645050 Stockdale north slope. 15/04/2010 Pair.
NZ60Q 661019 Esklets Crags middle. 14/04/2010 Male song.
  662015 Esklets Crags south. 14/04/2010 Pair.
  661010 Sweet Banks Gill 14/04/2010 Male.
NZ60R 676033 Stone Rook Hill. 2009 Male song.
NZ60W 684036 High Crag St Helena. 21/04/2010 14 RZ on passage.
NZ61A 600112 Great Ayton Moor 16/04/2002 Male.
  601117   16/04/2002 Pair.
NZ61K 656108 Commondale 26/04/2007 Male - on passage?
NZ61L 646134 Tidkinhow Gully 16/04/2002 Male - on passage?
SE69B 610934 Bonfield Gill/Cinderhill Wath 1999  
  611931 Pockley Moor. 2005  
      04/05/2010 Male with food.
  610934 Bonfield Gill 11/04/2010 Male.
  610939 Bonfield Gill 28/04/2011 Male singing.
SE69C 609942 Bonfield Gill. 1999  
      29/04/2009 Pair.
      09/05/2009 Pair.
SE69E 606982 Stump Cross    
SE69H 639946 Ousegill Bridge. 1999 Pair every year.
  635955 Shaw Rigg. 1999  
  635955 Shaw Rigg. 2004  
  639944 Ousegill Bridge south. 12/06/2010 Nest 5 eggs.
  639949 Ousegill. 12/06/2010 5 eggs, 3 pulli.
  640951 Ousegill. 03/05/2010 3 fledged.
  640947 Ousegill Bridge. 02/05/2011 4eggs, predated.
SE69I 634960 Shaw Rigg. 18/04/2009 Male, pair late Apr.
SE69L 656937 Bog House Rudland Rigg. 2005 RZ.
SE69M 650955 Rudland Rigg. 2005 RZ.
SE69P 658999 Hillhouse Nab 29/04/2011 Male.
SE69U 672997 Gill Wath. 1999  
  670999   05/05/2006 RZ.
  672997   30/04/2009 Pair.
  669996 Gill Wath SW Crag. 23/04/2010 Male.
  677992 Round Crag 23/04/2010 Male.
  677993 Round Crag 29/04/2011 Male.
  672997 Gill Wath 29/04/2011 Male.
NZ70B 708035 Danby Rigg, Raven Hill. 08/04/2000 Male.
  714028 Mark Nab. 21/04/2010 Female?
  707028 West of Mark Nab 02/05/2011 Male.
NZ70A 715015 Yew Grain Scar 09/05/2009 Pair.
  715018   05/05/2010 Male.
  713019 Trough Gill 02/05/2011 Male singing.
  705018 Trough Gill. 01/07/2011 F. with food.
NZ71K 744110 Betta Dale Slack 18/04/2007 Pair, passage?

  680010  Dalehead North
99   02   04       08   10 11

  680008  Dalehead West
    02 03 04 05 06 07   09   11

  686009  Dalehead East
      03 04              

  682005  Dalehead South

  685006  Dalehead Quarry South
                   10 11

  683008  Dalehead Quarry North
                   10 11

  691007  Reeking Gill
99 00 02     05 06 07 08 09 10 11

  688007  Reeking Gill Cutting
              07 08   10  

  691007  Nab Scar North
  00   03 04 05 06 07   09 10 11

  697963  Sherrif’s Pit
99 00 02   04 05 06   08 09 10 11

  698961  Sherrif’s Pit South
            06 07        

  694968  Round Hill South
    02 03 04 05 06 07 08 09    

  694970  Round Hill Central
    02 03 04     07 08 09 10 11

  693974  Round Hill North
    02         07       11

  691978  Sledge Shoe
  00 02 03 04 05 06     09   11

  688983  Matty Carr
      03 04 05 06 07 08   10 11

  690980  Matty Carr South
          05   07        

  681999  Lion Inn
  00 02 03   05   07        

  685998  Blakey Swang

  699000  Sturdy Bank
99 00 02 03         08 09 10 11

  716930  Spindle Thorn
    02         07        

  715934  Loskey Ridge 1
  00 02 03     06          

  713931  Loskey Ridge 2
      03 04 05            

  714954  Hob Crag
  00 02 03 04 05 06 07 08 09 10 11

  709958  Thorgill Bank
    02      06          

  720951  Bank Top
99 00 02 03     06         11

  705989  East Mine

  718996  North Dale, West Gill
99               08      

  725945  Bank Top East
      03   05            

  725998  North Dale, North Gill
99     03         08      

Annex 3

annotated map

Annex 4

annotated map

© 2012 Ken Hitchinson and Vic Fairbrother

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