The capercaillies living in the Cantabrian Mountains are an isolated, endangered population of Tetrao urogallus. Living in broad-leaved forests above 800 m a.s.l., at the SW border of the species distribution, these capers find no other neighboring population but that in the Pyrenees, more than 300 km away. The present occupancy area, at less than 2000 km2, seems too small.
Cantabrian capercaillie lives also at the SW edge of the Eurosiberian biogeographical region. The population is the only one (extant) living in deciduous forests all year round. Beech Fagus sylvatica, sessile oak Quercus petraea, Pyrenean oak Q. pyrenaica and mountain birch Betula pubescens, still form some quite big forest patches, but fragmentation is the general pattern (see a gallery of habitat pictures).
An acute decline has been going on during the last decades. Local extinctions, particularly at the edges of the distribution range and in lower altitudes, have shrunk not only the number of individuals but also the area of occupancy of the population (see plot below). Besides, the best habitat patches are actually located on opposite ends of the Cantabrian Range (Muniellos and Alto Sil – Sajambre and Ponga), and the connectivity among them does not look too good (Quevedo, Bañuelos & Obeso 2006).
Hunting of capercaillie males at the display grounds was important for quite some time until late 1970’s. That is the main reason why most of the knowledge about this capercaillie population comes from the breeding season, and is mostly lek-centered (e.g. Quevedo et al. 2006). However, the survival of individuals, which are the ultimate conservation unit, depends on successfully accomplishing many other tasks, like foraging, avoiding predators or choosing suitable roosting habitats when the weather is adverse. Furthermore, reproductive success requires choosing safe nesting places and suitable brooding habitats (e.g. Bañuelos et al. 2008). This latter point may be particularly important because the population seem to show lower recruitment than boreal populations.
We can only protect efficiently what we really understand. Therefore, the picture of the requirements of this grouse population has to be completed – and demography is key – before we can establish sound conservation strategies to stop its decline. Still, we already know quite many things that should not be done in capercaillie habitat, both derived from existing specific literature, and from general ecological theory: keeping disturbance to a minimum should be an easy management task, considering that most extant range sustains protected status.