The Cantabrian capercaillie (Tetrao urogallus cantabricus) is a subspecies of the western capercaillie in the grouse tribe Tetraonini. It is one of two subspecies found in Spain.
Description The capercaillie is a large grouse, in length, with the female much smaller than the male. It has dark grey plumage with fine blackish vermiculation (wavelike pattern) around the head and neck. The breast is glossy greenish-black. It has a long, rounded tail, an ivory-white bill, and a scarlet crest.World Association of Zoos and Aquaria (WAZA). 2009. WAZA's virtual zoo – Western Capercaillie. Downloaded from World Association of Zoos and Aquaria website on 10/29/2009.
Distribution and habitat The subspecies once ranged the length of the Cantabrian Mountains from northern Portugal, through Galicia, Asturias and León, to Cantabria in northern Spain (IUCN Redbook 1979, p. 1). Its range has since contracted to the mountains in northwest Spain. It inhabits an area of , and is separated from the nearest neighbouring subspecies (T. u. aquitanicus) in the Pyrenees by a distance of more than .Quevedo, M., J.M. Bañuelos, O. Sáez, and J.R. Obeso. 2006. Habitat selection by Cantabrian capercaillie Tetroa urogallus cantabrius at the edge of the species' distribution. Wildlife Biology 12(3): 267–276.
Capercaillies are able to digest conifer needles, and their typical habitat is often described as old coniferous forest. However, the Cantabrian subspecies is not as reliant as other Western capercaillies on pine forest, a type of habitat which is relatively scarce in the Cantabrian mountains.Disappearance Of Pine Trees In Spain's Cantabrian Mountains Threatens Cantabrian Capercaillie Bird, Plataforma SINC (2008, 21 November). ScienceDaily. Retrieved 19 September 2011, from https://www.sciencedaily.com/releases/2008/11/081121151920.htm The Cantabrian capercaillie feeds in deciduous woodland, and occurs in mature beech forest and mixed forests of beech and oaks (at elevations ranging from . The capercaillie also uses other microhabitat types such as broom, meadow and heath selectively throughout the year. It feeds on beech buds, birch catkins, and holly leaves. It also feeds on bilberry, a common component of its diet (Rodriguez and Obeso 2000 as reported in.Pollo, C.J., L. Robles, J.M. Seijas, Á. García-Miranda, and R. Otero. (2005). Trends in the abundance of Cantabrian Capercaillie Tetrao urogallus cantabricus at leks on the southern slope of the Cantabrian Mountains, north-west Spain. Bird Conservation International 15:397–409.
Conservation and status Storch et al. (2006) estimates the population to be 627 birds, of which approximately 500 are adults, according to the most recent population data collected from 2000 through 2003. Population estimates for species of grouse are commonly assessed by counting males that gather during the leks (traditional places where males assemble during the mating season and engage in competitive displays that attract females). Pollo et al. (2005) estimated a 60–70 percent decline in the number of male leks since 1981. This is equivalent to an average decline of 3 percent per year, or 22 percent over 8 years. There is also evidence of a 30-percent decline in lek occupancy in the northern watershed of the species' range between 2000 and 2005.
Based on data collected between 2000 and 2003 by Pollo et al. (2005), the distribution of Cantabrian capercaillie on the southern slope of the Cantabrian Mountains is fragmented into 13 small subpopulations: four in the western area and 9 in the eastern. Six subpopulations (5 in the eastern and 1 in the western) contained only one singing male, which indicates a very small subpopulation, since presence of singing males is a direct correlate to population numbers.
The area occupied by Cantabrian capercaillie in 1981–1982 covered up to approximately of the southern slope in the west and in the east). Between 2000 and 2003, the area of occupancy had declined to , specifically in the west and in the east. Thus, over a 22–year period, there was a 66-percent reduction in the areas occupied by this subspecies on the southern slope of the Cantabrian Mountains.
Based on this data, the subpopulation in the eastern portion of the range appears to be declining at a faster rate than the subpopulation in the western portion of the range.
Although Storch, et al. (2006) noted that the Cantabrian capercaillie meets the criteria to be listed as "Endangered" on the IUCN Red List due to "rapid population declines, small population size, and severely fragmented range", it is not classified as such by the IUCN. The species is classified as "Endangered" in Spain under the National Catalog of Endangered Species. The species has not been formally considered for listing in the CITES Appendices (http://www.cites.org).
In 2011, United States Fish and Wildlife Service listed the Cantabrian capercaillie as an endangered species.
Threats
Habitat destruction Numerous limiting factors influence the population dynamics of the capercaillie throughout its range, including habitat degradation, loss, and fragmentation (Storch 2000, p. 83; 2007, p. 96).Storch, I., (2000). Grouse: Status Survey and conservation Action Plan 2000-2004. IUCN, Gland, Switzerland / World Pheasant Association, Reading, UK, 116p. Forest structure plays an important role in determining habitat suitability and occupancy. Quevedo et al. (2006) found that open forest structure with well-distributed bilberry shrubs were the preferred habitat type of Cantabrian capercaillie. Management of forest resources for timber production has caused and continues to cause significant changes in forest structure such as: species composition, density and height of trees, forest patch size, and understory vegetation.
The historic range occupied by this subspecies has declined by more than 50 percent. The current range is severely fragmented, with low forest habitat cover (22 percent of the landscape) and most of the suitable habitat remaining in small patches less than .Garcia, D., M. Quevedo, R. Obeso, and A. Abajo. (2005). Fragmentation patterns and protection of montane forest in Cantabrian range (NW Spain). Forest Ecology and Management 208: 29-43. Patches of good-quality habitat are scarce and discontinuous, particularly in the central parts of the range, and leks in the smaller forest patches have been abandoned during the last few decades. The leks that remain occupied are now located farther from forest edges than those occupied in the 1980s.
Based on population surveys, forest fragments containing occupied leks in 2000 were significantly larger than fragments containing leks in the 1980s that have since been abandoned. The forest fragments from which the Cantabrian capercaillie has disappeared since the 1980s are small in size, and are the most isolated from other forest patches. In addition, the Cantabrian capercaillie have disappeared from forest patches located closest to the edge of the range in both the eastern and western subpopulations of the south slope of the Cantabrian Mountains, suggesting that forest fragmentation is playing an important role in the population dynamics of this subspecies. Research conducted on other subspecies of capercaillie indicate that the size of forest patches is correlated to the number of males that gather in leks to display, and that below a certain forest patch size, leks are abandoned. In highly fragmented landscapes, forest patches are embedded in a matrix of other habitats, and forest dwellers like capercaillies frequently encounter open areas within their home range. Quevedo et al. (2005)Quevedo, M., M.J. Bañuelos, and J.R. Obeso. (2005). The decline of Cantabrian capercaillie: How much does habitat configuration matter? Biological Conservation 27(2): 190–200. developed a habitat suitability model for the Cantarian capercaillie that assessed the relationship between forest patch size and occupancy. He determined that the subspecies still remains in habitat units that show habitat suitability indices below the cut-off values of the two best predictive models (decline and general), which may indicate a high risk of local extinction. Other researchers suggested that, should further habitat or connectivity loss occur, the Cantabrian capercaillie population may become so disaggregated that the few isolated subpopulations will be too small to ensure their own long-term persistence (Grimm and Storch 2000, p. 224).Grimm, V. and I. Storch. (2000). Minimum viable population size of capercaillie Tetrao Urogallus: results from a stochastic model. Wildlife Biology 6(4): 219–225.
A demographic model based on Bavarian alpine populations of capercaillie suggest a minimum viable population size of the order of 500 birds. However, genetic data show clear signs of reduced variability in populations with numbers of individuals in the range of fewer than 1000 birds, which indicates that a demographic minimum population of 500 birds may be too small to maintain high genetic variability.Segelbacher, G., J. Höglund, and I. Storch. (2003). From connectivity to isolation: genetic consequences of population fragmentation in capercaillie across Europe. Molecular Ecology 12: 1773–1780. Genetic consequences of habitat fragmentation exist for this species in the form of increased genetic differentiation due to increased isolation of populations. Therefore, anthropogenic habitat deterioration and fragmentation not only leads to range contractions and extinctions, but may also have significant genetic, and thus, evolutionary consequences for the surviving populations.
Recent population surveys show this subspecies is continuing to decline throughout its current range, and subpopulations may be isolated from one another due to range contractions in the eastern and western portions of its range, leaving the central portion of the subspecies range abandoned. Some remaining populations may already have a high risk of local extinction. Management of forest resources for timber production continues to negatively affect forest structure, thereby affecting the quality, quantity, and distribution of suitable habitat available for this subspecies. In addition, the structure of the matrix of habitats located between forest patches is likely affecting the ability of capercaillies to disperse between subpopulations. Therefore, we find that present or threatened destruction, modification, or curtailment of the habitat or range is a threat to the continued existence of the Cantabrian capercaillie throughout its range.
Overhunting
Currently hunting of the Cantabrian capercaillie is illegal in Spain; however, illegal hunting still occurs (storch 2007, p. 96). Because this species congregates in leks, individuals are particularly easy targets, and poaching of protected grouse is considered common (Storch 2000, p. 15). It is unknown what the incidence of poaching is or what impact it is having on this subspecies; however, given the limited number of birds remaining and the reduced genetic variability already evident at current population levels, the further loss of breeding adults could have substantial impact on the subspecies.
Disease and predation