Take our virtual guided tour of Horcajo de la Sierra and Aoslos
Both Horcajo and Aoslos lie on soils made up of gneiss and metamorphic rocks of slaty aspect, composed of quartz, feldspar, and mica, that generate a pretty rough orography. As an example, let us consider the difference in altitude between the valley of the Madarquillos and the Cebollera Nueva peak. Owing to this disparity of altitudes, in Horcajo's lands we can find a great diversity of fauna and flora.
If we follow the river course, we will go through several poplar and walnut tree groves, also encountering different fruit trees and bushes. We will also come across what might be the largest walnut tree in Madrid Community, measuring more than 16 meters of height, and with a trunk perimeter of 3 meters.
Keeping close to the river, it is possible to see the kingfisher in action, and listen to serins, robins and the cuckoo with its special chant, while the tawny and little owls dominate the nocturnal landscape. Foxes and ginets might also come close to the river banks, always watched upon by the swimming trout, mullets and carps. Some claim to have spotted an otter, and it is still easy to hear the croaking of frogs.
As we walk to higher altitudes, the landscape changes, and elm, oak and ash trees dominate the land, together with plum trees and other bushes that form hedges separating meadows and old flax fields. We will also be able to see great variety of blackberry bushes and blackthorns, that serve as shelter to blackbirds, starlings and rooks. Sharing the sky with them, swallows and sparrows fly above our heads. At night, the inhabitants change, and hedgehogs, shrews and rabbits will come out for a walk, being closely watched upon by the owls. The omnipresent stock flies over these lands to take food to its chicks, who await in the nest on top of Madarcos church's steeple.
Continuing our ascent, we enter the Dehesa (communal lands traditionally used for grazing), where oaks give shelter to shrikes and jays, as well as to the rare golden orioles and the beautiful bee-eaters. Dominating the sky with their majestic flight, we can see birds of prey such as the booted eagle, the kite, the bussard or the goshawk. The low bush surrounds us with its intense aroma of thyme, wild marjoram and Spanish lavender. Here, during the winter, we will be able to spot wild boars and even one or two roe-deer.

