"In terms of conventional physics, the grouse represents only a millionth of either the mass or the energy of an acre. Yet subtract the grouse and the whole thing is dead". Aldo Leopold (1949) A sand county almanac and sketches from here and there. Oxford University Press
The Cantabrian Capercaillie constitutes an isolated and endangered population of Tetrao urogallus. Living in the forests of the Cantabrian Mountains (NW Spain), above 800 m a.s.l., in the south-western border of the species distribution, this grouse is isolated from its nearest neighbors of the Pyrenees by more than 300 km, and constrained to an occupancy area smaller than 2000km2.
At the SW edge of the Eurosiberian biogeographical region, the Cantabrian Mountains are nowadays the only place in the world where capercaillies live 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. The result is that forests are a threatened landscape themselves, covering about 22% of the montane landscape.
A serious 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. 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, Bańuelos & 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, mostly lek-centered (Obeso & Bańuelos 2003, 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. This latter point may be particularly important, given that poor recruitment has been reported for the population (Obeso & Bańuelos 2003).
We can only protect efficiently what we really understand. Therefore, the picture of the requirements of this grouse population has to be completed before we can establish sound conservation strategies to stop its decline and, ultimately, to avoid its extinction.