Although this species has a small range, it is thought to be stable and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Loxia crossbills are conifer seed specialists for which there is an increasing body of evidence to show that bill morphology and overall body size, the main morphological features by which forms vary, are intimately linked to the cone structure and size of the particular conifer species (or mosaics of species) upon which they feed. There is also increasing evidence that different populations of crossbills show differences in flight and excitement calls which co-vary with bill shape, and hence with the distributions of their main food sources (e.g. Borras et al. 2008, Edelaar 2008a, 2008b). This evidence is especially well developed in the case of the Scottish Crossbill Loxia scotica by Summers et al. (2002, 2007) to support treatment of L. scotica as a species distinct from both Common Crossbill L. curvirostra and Parrot Crossbill L. pytyopsittacus. In particular, Summers et al. (2007) present data to show that, in areas of broad sympatry in Scotland, these forms largely breed assortatively. Although they do show some degree of hybridisation, in the view of Summers et al. (2007) this is insufficient not to warrant recognition as species, despite overlaps in morphology and the lack of any genetic differentiation. Some uncertainty remains regarding the status of this form, and an alternative approach is to regard different vocal types as components of a single resource-polymorphic species. Assortative mating by voice-type could prove to be a consequence of post-pairing vocal copying. More generally, increasing numbers of vocal types are being discovered among sympatric populations of crossbills whenever sufficiently detailed studies are carried out. The American Ornithologists' Union (BirdLife's taxonomic source for North America) has yet to recognise any of the nine North American 'vocal types' as species, although the case for the first of these was made over twenty years ago (Groth 1988). Nevertheless, given the evidence currently available and associated uncertainties, BirdLife continues to follow the Association of European Rarities Committees in treating L. scotica as a species distinct from L. curvirostra and L. pytyopsittacus.
Related state of the world's birds case studies
Summers Ron W.; Buckland Stephen T. 2011. A first survey of the global population size and distribution of the Scottish Crossbill Loxia scotica. Bird Conservation International 21(2): 186-198.
Summers, R. W.; Dawson, R. J. G.; Phillips, R. E. 2007. Assortative mating and patterns of inheritance indicate that the three crossbill taxa in Scotland are species. Journal of Avian Biology 38(2): 153-162.
Summers, R. W.; Jardine, D. C.; Dawson, R. J. G. 2004. The distribution of the Scottish Crossbill, 1995-2003. Scottish Birds 24(2): 11-16.
Tucker, G. M.; Heath, M. F. 1994. Birds in Europe: their conservation status. BirdLife International, Cambridge, U.K.
Further web sources of information
Action Plan for the Scottish Crossbill in Europe
Text account compilers
Calvert, R., Capper, D. & Symes, A.
Bainbridge, I. & Summers, R.
IUCN Red List evaluators
Butchart, S., Symes, A.
BirdLife International (2014) Species factsheet: Loxia scotica. Downloaded from http://www.birdlife.org on 13/07/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 13/07/2014.
This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.
To provide new information to update this factsheet or to correct any errors, please email BirdLife
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|Current IUCN Red List category||Least Concern|
|Family||Fringillidae (Finches and Hawaiian honeycreepers)|
|Species name author||Hartert, 1904|
|Population size||13600 mature individuals|
|Distribution size (breeding/resident)||13,700 km2|
|Links to further information|
|- Additional Information on this species|