Biodiversity and Conservation

, Volume 25, Issue 11, pp 2171–2186 | Cite as

Increased mammalian predators and climate ch1ange predict declines in breeding success and density of Capercaillie tetrao urogallus, an old stand specialist, in fragmented Scottish forests

  • David Baines
  • Nicholas J. Aebischer
  • Allan Macleod
Original Paper


Low breeding success has been associated with declines in population and range of the re-introduced Capercaillie Tetrao urogallus in Scotland. Annual breeding success from 26 Scottish forests surveyed between 1991 and 2009 averaged only 0.6 chicks per female, the lowest rate recorded in 16 previous studies. Reduced breeding success was due to proportionally fewer females rearing chicks rather than a reduction in brood size. Birds bred less well in Perthshire at the southern edge of the range, where declines in indices of female and male density were highest. Only at the core of the range (Strathspey), where birds bred better, were female densities stable. Two weather variables, April temperature in the pre-breeding period (APRTEMP), and temperature at chick hatch in June (HATCHTEMP), increased over the study period. Indices of Pine Marten Martes martes increased 3.9-fold since 1995, and those of Red Fox Vulpes vulpes by 2.2-fold, whereas those of Carrion Crow Corvus corone, raptors and forest floor vegetation showed no change. Neither forest type nor forest ground vegetation appeared to influence breeding success. Instead, females reared more chicks in years when hatch time in June was drier, and in forests with lower marten and crow indices. In addition, more females reared broods in years when Aprils were cooler. Brood size was unaffected by any of the measured variables. Densities of adult birds were lower in forests with higher fox indices. Increased predation of clutches and chicks by martens and crows within these small, fragmented forests, as well as changes in climate, may explain reductions in breeding success and hence contribute to continued declines. Successful conservation of Capercaillie in remaining Strathspey strongholds may require better predator management, including a licensed removal of martens to test the hypotheses that martens contribute to reduced breeding success. This short-medium term approach will inform longer-term predator management policies and complement aspirations to increase the area and connectivity of forest habitat to benefit Capercaillie in-part through mitigating against any impact of increasing forest-edge predators.


Pine Marten Bilberry Crow Breeding success Forest management 



We thank land managers for access. Field assistance was provided by Mark Andrew, Paul Baker, Mick Canham, Norman Cobley, Kathy Fletcher, Isla Graham, Rupert Hawley, Andrew Hoodless, David Howarth, David Lambie, Fiona Leckie, Robert Moss, Raymond Parr, Adam Smith, Philip Warren, John Woods and staff at RSPB Abernethy & Craigmore. Stewart A’Hara of Forest Research analysed DNA from mammalian scats. Weather data were provided to Melanie Brown by the UK Meteorological Office supplied through Natural Environmental Research Council Data Centres for her undergraduate thesis. Jerry Wilson, Ron Summers (RSPB), Kenny Kortland (Forest Enterprise Scotland), Megan Davies, Susan Haysom (Scottish Natural Heritage). Funding was from SNH and GWCT.

Supplementary material

10531_2016_1185_MOESM1_ESM.docx (12 kb)
Supplementary material 1 (DOCX 12 kb)


  1. Aebischer NJ, Davey PD, Kingdon NG (2011) National gamebag census: mammal trends to 2009. Game & Wildlife Conservation Trust, Fordingbridge (
  2. Baines D, Wilson IA, Beeley G (1996) Timing of breeding in black grouse tetrao tetrix and Capercaillie tetrao urogallus and distribution of insect food for the chicks. Ibis 138:181–187CrossRefGoogle Scholar
  3. Baines D, Moss R, Dugan D (2004) Capercaillie breeding success in relation to forest habitat and predator abundance. J Appl Ecol 41:59–71CrossRefGoogle Scholar
  4. Baines D, Aebischer NJ, MacLeod A, Woods J (2013) Pine marten and red fox sign indices in Scottish forests: population change and reliability of field identification of scats. Wildl Biol 19:490–495CrossRefGoogle Scholar
  5. Borchtchevski VG (1993) Population biology of the capercaillie, principles of the structural organisation. Central Laboratory of the Management and Hunting of Nature Reserves, MoscowGoogle Scholar
  6. Borchtchevski VG, Hjelford O, Wegge P, Sivkov AV (2003) Does fragmentation by logging reduce grouse reproductive success in boreal forests? Wildl Biol 9:275–282Google Scholar
  7. Browne WJ, Subramanian SV, Jones K, Goldstein H (2005) Variance partitioning in multi-level logistic models that exhibit overdispersion. J R Stat Soc A 168:599–613CrossRefGoogle Scholar
  8. Catt DC, Baines D, Picozzi N, Moss R, Summers RW (1998) Abundance and distribution of Capercaillie tetrao urogallus in Scotland 1992–1994. Biol Conserv 85:257–267CrossRefGoogle Scholar
  9. Croose E, Birks JDS, Schofield HW (2013) Expansion zone survey of pine marten (Martes martes) distribution in Scotland. Scottish Natural Heritage Commissioned Report no. 520Google Scholar
  10. Davison A, Birks JDS, Brookes RC, Braithwaite TC, Messenger JE (2002) On the origin of faeces: morphological versus molecular methods for surveying rare carnivores from their scats. J Zool 257:141–143CrossRefGoogle Scholar
  11. Elston DA, Moss R, Boulinier T, Arrowsmith C, Lambin X (2001) Analysis of aggregation, a worked example: numbers of ticks on red grouse chicks. Parasitology 122:563–569CrossRefPubMedGoogle Scholar
  12. Ewing S, Eaton MA, Poole TF, Davies M, Haysom S (2012) The size of the Scottish population of Capercaillie tetrao urogallus: results of the fourth national survey. Bird Study 59:126–138CrossRefGoogle Scholar
  13. Fletcher K, Howarth D, Kirby A, Dunn R, Smith A (2013) Effect of climate change on breeding phenology, clutch size and chick survival of an upland bird. Ibis 155:456–463CrossRefGoogle Scholar
  14. GenStat (2009) Genstat GenStat 12th edn. RothamstedGoogle Scholar
  15. Goldstein H (1999) Multilevel statistical models. Edward Arnold, LondonGoogle Scholar
  16. Gregory RD, Marchant JH (1995) Population trends of jays, magpies, jackdaws and carrion crows in the United Kingdom. Bird Study 43:28–37CrossRefGoogle Scholar
  17. Kauhala K, Helle P, Helle E (2000) Predator control and the reproductive success of grouse populations in Finland. Ecography 23:161–168CrossRefGoogle Scholar
  18. Kenward MG, Roger JH (1997) Small sample inference for fixed effects from restricted maximum likelihood. Biometrics 53:983–997CrossRefPubMedGoogle Scholar
  19. Kurki S, Helle P, Linden H, Nikula A (1997) Breeding success of black grouse and capercaillie in relation to mammalian predator densities on two spatial scales. Oikos 79:301–310CrossRefGoogle Scholar
  20. Kurki S, Nikula A, Helle P, Linden H (1998) Abundances of red fox and pine marten in relation to the composition of boreal forest landscapes. J Anim Ecol 67:874–886CrossRefPubMedGoogle Scholar
  21. Kurki S, Nikula A, Helle P, Linden H (2000) Landscape fragmentation and forest composition effects on grouse breeding success in boreal forests. Ecology 81:1985–1997Google Scholar
  22. Lever C (1977) The naturalised animals of the British Isles. Hutchinson, LondonGoogle Scholar
  23. Ludwig GX, Alatalo RV, Helle P, Linden H, Lindstrom J, Siitari H (2006) Short and long-term population dynamical consequences of asymmetric climate change in black grouse. Proc R Soc B 273:2009–2016CrossRefPubMedPubMedCentralGoogle Scholar
  24. Marcstrom V, Kenward RE, Engren E (1988) The impacts of predation on boreal tetraonids during vole cycles: an experimental study. J Anim Ecol 57:859–872CrossRefGoogle Scholar
  25. Moss R (1985) Rain, breeding success and distribution of Capercaillie tetrao urogallus and black grouse tetrao tetrix in Scotland. Ibis 128:65–72CrossRefGoogle Scholar
  26. Moss R, Picozzi N, Summers R, Baines D (2000) Capercaillie tetrao urogallus in Scotland—demography of a declining population. Ibis 142:159–167Google Scholar
  27. Moss R, Oswald J, Baines D (2001) Climate change and breeding success: decline of the capercaillie in Scotland. J Anim Ecol 70:47–61CrossRefGoogle Scholar
  28. Murtaugh PA (2009) Performance of several variable-selection methods applied to real ecological data. Ecol Letters 12:1061–1068CrossRefGoogle Scholar
  29. Perrins CM (1991) Tits and their caterpillar food supply. Ibis 133:49–54CrossRefGoogle Scholar
  30. Picozzi N, Catt DC, Moss R (1992) Evaluation of capercaillie habitat. J Appl Ecol 29:751–762CrossRefGoogle Scholar
  31. Picozzi N, Moss R, Kortland K (1999) Diet and survival of Capercaillie tetrao urogallus chicks in Scotland. Wildl Biol 5:11–23Google Scholar
  32. Rolstad J, Wegge P (1987) Distribution and size of capercaillie leks in relation to old forest fragmentation. Oecol 72:389–394CrossRefGoogle Scholar
  33. Storch I (1993) Habitat selection of capercaillie in summer and autumn: is bilberry important? Oecol 95:257–265CrossRefGoogle Scholar
  34. Summers RW, Green RE, Proctor R, Dugan D, Lambie D, Moncrieff R, Moss R, Baines D (2004) An experimental study of the effects of predation on the breeding productivity of capercaillie and black grouse. J Appl Ecol 41:513–525CrossRefGoogle Scholar
  35. Summers RW, Willi J, Selvidge J (2009) Capercaillie tetrao urogallus nest loss and attendance at Abernethy Forest, Scotland. Wildl Biol 15:319–327CrossRefGoogle Scholar
  36. Summers RW, Dugan D, Proctor R (2010) Numbers and breeding success of capercaillies and black grouse at Abernethy Forest, Scotland. Bird Study 57:437–446CrossRefGoogle Scholar
  37. Summers RW, Golder P,Wallace N, Iason G, Wilson J (2015) Correlates of capercaillie productivity in Scots pinewoods in Strathspey. Scottish Natural Heritage Commissioned Report no. 742Google Scholar
  38. Tapper S (1992) Game heritage. The Game Conservancy Trust, FordingbridgeGoogle Scholar
  39. Verbeke G, Molenberghs G (2000) Linear mixed models for longitudinal data. Springer, New YorkGoogle Scholar
  40. Wegge P, Kastdalen L (2007) Pattern and causes of natural mortality of capercaillie tetrao urogallus chicks in a fragmented boreal forest. Ann Zool Fenn 44:141–151Google Scholar
  41. Wegge P, Kastdalen L (2008) Habitat and diet of young grouse broods: resource partitioning between Capercaillie tetrao urogallus and black grouse tetrao tetrix in boreal forests. J Ornith 149:237–244CrossRefGoogle Scholar
  42. Wegge P, Rolstad J (2011) Clearcutting forestry and Eurasian boreal foreal grouse: long-term monitoring of sympatric Capercaillie tetrao urogallus and black grouse tetrao tetrix reveals unexpected effects in their population performance. For Ecol Manag 262:1520–1529CrossRefGoogle Scholar
  43. Wegge P, Vesteras T, Rolstad J (2010) Does timing of breeding and subsequent hatching in boreal forest grouse match the phenology of insect food for the chicks. Ann Zool Fenn 47:251–260CrossRefGoogle Scholar
  44. Wooldridge JM (2008) Introductory econometrics: a modern approach, 4th edn. South-Western, MasonGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.The Game & Wildlife Conservation TrustCo. DurhamUK
  2. 2.The Game & Wildlife Conservation TrustFordingbridgeUK
  3. 3.The Game & Wildlife Conservation TrustDalwhinnieUK

Personalised recommendations