Cantabrian Capercaillie

Cantabrian Capercaillie: Species Facts

Range & Habitat

The Cantabrian capercaillie, Tetrao urogallus cantabricus, is one of the eight officially recognised subspecies of the western capercaillie, a forest grouse of the boreal and temperate regions of Eurasia, according to a 2023 scientific study. It is the only one whose dominant habitat is not coniferous forest: in the Cantabrian Mountains of north-western Spain it lives mainly in mature deciduous forests of birch, beech (Fagus sylvatica) and several species of oak. Conifer needles, a key winter food for most capercaillie populations, are rare there, so it relies more on understorey food such as bilberry stems, mosses and ferns.^[8]

In June 2025 Spain's environment ministry (MITECO) published the latest full population estimate: 209 capercaillies in the Cantabrian Mountains in 2024 (95 % confidence interval 171–251 birds), 117 males and 92 females, an 8 % rise on the 191 estimated in the previous full survey, in 2019. Individuals were identified genetically from droppings. MITECO called the 2024 results the first in the whole historical series to show a halt in the decline, while warning that it is premature to draw conclusions about the trend from two estimates.^[1]

According to the same 2025 MITECO note, 67 % of the population lives mainly in the León districts of Alto Sil, Laciana and Omaña, with scattered birds in Ancares and El Bierzo, and 33 % in the Asturian municipalities of Degaña, Cangas del Narcea and Ibias.^[1]

Earlier figures, for the record: a 2023 study cites an estimated range of about 5,300 km² in the 1970s and less than 1,000 km² today, a reduction of 83 % in 50 years. A 2014 study cites a coarse estimate of six hundred birds in an area of occupancy of 1,700 km² in the early 2000s, and itself estimated 93 individuals (70–116) at 34 display areas sampled in spring 2009, in five watersheds including Muniellos. MITECO's October 2023 note gave 190 birds for the 2019 estimate.^[2][8][9]

Isolation and taxonomy. A 2014 study describes the Cantabrian population as isolated from other capercaillie long enough to be considered an Evolutionarily Significant Unit, at the rear edge of the species' range. In October 2023 MITECO reported that the Pyrenean and Cantabrian populations form a single evolutionary unit, distinct from the other European populations, and are estimated to have separated from each other about 4,000 years ago. The subspecies was described in the 1960s on the basis of a smaller beak and darker colouring than the Pyrenean birds; a 2024 study argues that it is not supported by recent molecular data.^[2][9][10]

Threats

A long decline. MITECO's October 2023 note describes a sharp regression over recent decades, apparently driven by a combination of changes in habitat quality and human persecution up to the end of the 20th century. A 2023 study lists habitat loss and fragmentation, land-use changes, high densities of domestic ungulates, an increase in predator populations and illegal hunting during the last century among the proposed major threats, which seem to have acted together.^[2][8]

Predation. Of the 17 capercaillies found dead since 2018, MITECO reported in 2025 that 13 were killed by predators, one died in a collision and the cause of death of three is unknown.^[1]

Climate change. Being at the south-western edge of the species' range and restricted to mountains, Cantabrian capercaillies are likely to be among the populations most severely affected by climate change, according to the 2023 study; climate change has already been associated with lower breeding success in the species. Warming is expected to restrict bilberry, a key food and habitat resource, which might reduce the suitable habitat in the region.^[8]

Inbreeding. A 2024 study links the decline to low genetic diversity and high inbreeding. In 32 clutches found in the field, average clutch size has fallen by almost 50 % in the last 70 years, and in the captive-breeding programme only 56 of 204 eggs laid between 2010 and 2017 hatched, and 23 chicks survived. The authors see clear signs of inbreeding depression and argue that a genetic rescue, bringing in genes from other populations, could alleviate the situation.^[10]

Conservation Status & Work

Tetrao urogallus: Least Concern on the IUCN Red List (global assessment of the species, published in 2024). That category describes the western capercaillie as a species across its whole world range. It is not the status of the Cantabrian capercaillie.^[11]

In Spain, the Cantabrian capercaillie was moved in 2005 (Orden MAM/2231/2005) to the category «en peligro de extinción» (in danger of extinction) of the national catalogue of threatened species, because of a marked fall in its population and a pronounced breeding failure; it had been listed as «vulnerable» since 1998. Since Orden TED/339/2023, the Catálogo Español de Especies Amenazadas (Real Decreto 139/2011) lists the western capercaillie, Tetrao urogallus, «formerly Pyrenean capercaillie and Cantabrian capercaillie», as a single entry in that category, so both Spanish populations share it.^[4][5][6]

In 2018 Spain declared Tetrao urogallus cantabricus a taxon in critical situation (situación crítica), by Orden TEC/1078/2018 (BOE of 17 October 2018), together with six other taxa. Under Law 42/2007 that declaration is for species in danger of extinction at imminent risk of extinction; works and projects for their recovery are of general interest and are processed urgently. A working group with representatives of MITECO and of the governments of Asturias, Castilla y León, Cantabria and Galicia coordinates the measures.^[3]

On 13 February 2025 Spain's Conferencia Sectorial de Medio Ambiente approved the Strategy for the Conservation of the Capercaillie (Tetrao urogallus) in Spain, published in the BOE on 5 April 2025. MITECO says the regional governments carry out the work through their official recovery plans, such as that of Castilla y León.^[1][7]

Work on the ground, as reported by MITECO in 2025. Breeding success has risen in recent years thanks to reducing predation pressure from common generalist mesocarnivores, especially the pine marten, with on average 0.5 more chicks per female where that was done; MITECO calls it a ‘last resort’ measure for the short to medium term. Summer counts in 2018–2024 gave an average of 1.14 chicks per female, from 129 hens. Habitat work seeks to reproduce, through forest management, the structure, composition and food resources of the forests that most favour the capercaillie, and more than 50 birds have been radio-tagged in the Cantabrian Mountains over the last ten years.^[1]

Captive breeding. The breeding centres of Valsemana, run by the Junta de Castilla y León, and Sobrescobio, run by the Government of the Principality of Asturias, were finalising breeding techniques and building up their breeding stock: in 2024 they held 38 Iberian capercaillies of Cantabrian and Pyrenean origin. The aim is to release at least 80–100 birds a year once the centres are fully operational, and MITECO said in 2025 that it hoped the first releases could take place in 2026. It also planned a new population estimate, probably in 2027.^[1]