This reserve is managed through an agreement between Camargo Town Hall, Santander Town Hall and a concession of Coast Demarcation in Cantabria

Marshes of Alday are the vestige of what was once a big marsh. Today is a very anthropized area surrounded by infrastructure such as highways, lines FEVE and RENFE, and the mall Valle Real de Maliaño, in whose parking is sited the House of Nature of Nature and Man Foundation. The via of FEVE crosses the marsh splitting it in two areas: the Salada area and Dulce area.

Despite the humanization of the area, la Marisma de Alday has a great ornithological and environmental interest, being habitat for numerous aquatic birds and place of temporary residence and refuge of other species during the migrations that occur each year.

It is an intertidal plain where, time ago, the waters of the Ria de Raos and channel Alday used to mix with the waters of the Cantabrian sea, although nowadays only the salty area is influenced by tidal. The most common plant species are rushes, reeds and cattails. At the edges of the paths appear plants also associated with wetlands or riparian forests as hazel, willow, birch and ash. It is noteworthy the presence of areas damaged by invasive species such as pampas grass (Cortaderia selloana) and eastern baccharis (Baccharis halimifolia) on which have been developed tasks for eradication. In recent years has been reduced significantly the area colonized by these species.

Two different options have been used to eradicate these species. The first is the manual or mechanical removal of invasive species through the clearing of land (shoots and root systems). The other option is by using “Losinos” horses and Spanish donkeys who feed on the tender shoots. This way they prevent the proliferation of these species. This method is very effective and it keeps the marsh in perfect conditions. The “Losino” horse is an endangered species from the Valle de Losa, north of the province of Burgos.

Over the past decade, an intense work has been developed in the recovery of much of the marshes that were badly damaged due to its location in a highly urbanized environment. Thanks to a better management and implementation of corrective measures, currently the marshes play an important role for avifauna, complementary to other marshy areas on the Cantabrian coast. Alday is an important stop on the migratory route for many species of waterfowl, herons, waders and birds of prey.

Its greatest wealth appears during the winter, when it is easy to see a large number of migratory species. During the summer nesting birds and some sedentary can be observed. Examples are, herons, cormorants, the Common Sandpiper, plovers, ducks, etc.

This reserve has three observatories and a viewpoint that facilitate observation of the birds of the marsh, there is also an extensive network of paths connecting the different viewpoints.

The visit to the Marshes allows access to the Salada area through the House of Nature located in the parking in Valle Real Mall. While the entrance to the Dulce area is located in the vicinity of Makro. Nonetheless, a walkway has recently been installed on the halt of FEVE in the shopping center, which allows joining the two areas of the marsh in a pedestrian and easy way.

In addition the marsh of Alday can be visited using public transport. The FEVE line Santander-Liérganes, stops at Valle Real, a few hundred meters from the entrance to the marsh.


  • Camargo Town Hall
  • Santander Town Hall
  • Ministry of Agriculture, Food and Environment. Coast Demarcation in Cantabria
  • General Direction of Sustainability of the Coast and the Sea
  • Caja Madrid Social and Cultural Work
  • Citroen Auto Gomas Citroën official concessionaire
  • Counselling of the Environment of the Regional Government of Cantabria

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