Quirós on the Ruta del Oso

The Senda del Oso branch in Quirós

The Quirós branch is the arm of the Senda del Oso that climbs from Caranga de Abajo to Santa Marina: between 8 and 10 km opened to the public in 1999, completing a network of some 30 km of greenway.

It is also the only stretch of the greenway with a gradient you notice, so the logic of the day is simple: climb steadily on the way out and roll back down barely pedalling.

The surface is the same as on the main axis, compacted gravel and zero cars, because what you are riding is the trackbed of the Quirós mining railway. That narrow-gauge line (750 mm) was proposed in 1863, obtained its concession in 1874 and opened in 1884 to carry coal out of the municipality's hills.

In its best year, 1912, it moved 33,000 tonnes with 244 workers; it closed in 1963 and the greenway reclaimed the trackbed in phases: Tuñón-Proaza in 1995, Caranga-Entrago in 1996 and this branch in 1999.

At Caranga the branch joins the Entrago-Tuñón axis, 22 km with an average gradient of 1.5%. To place every piece you have the full section map, and the ride that shares its start with the branch is covered in the Entrago-Caranga guide.

Ride the branch from Caranga to Santa Marina in the morning, uphill and in the cool, and save the descent beside the Valdemurio reservoir for the way back. On an August Saturday you will see a fraction of the crowds that fill the main axis.

What to see

The must-see in Quirós is the Valdemurio reservoir and its wooden boardwalk, the most photogenic corner of the branch: the greenway runs beside the sheet of water and it is the natural stop halfway up. Leave the bike, walk the shore and you will understand why this is the valley's postcard.

In Bárzana, the municipality's capital, the cultural stop is the Quirós Ethnographic Museum.

This municipal museum stands where the smelting furnaces that worked from the late 19th to the early 20th century once stood, and is split across two buildings: one recreates the traditional farmhouse, and the whole explains how mining transformed that way of life, with an hórreo (the traditional raised granary), a fountain, a wash-house and a school completing the visit.

It opens on different schedules depending on the season, so confirm them at turismoasturias.es before heading up.

With half a day more, the plan rounds off downstream. At km 19 of the main axis (counting from Entrago) is the Fernanchín bear enclosure, 40,000 m² where Molina lives: the outdoor viewpoint is free and the best windows to see her are 9 to 11 am and 5 to 7 pm, with a 70% chance.

And at km 14, Proaza has its old quarter 200 metres from the greenway and the Casa del Oso (Bear House), headquarters of the Fundación Oso de Asturias.

On timing: May-June and September are the sweet spots; in summer it pays to start early and in winter there are frosts, so save it for sunny days. The detail is in the guide to the best time to do the route.