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Urkiola nature parks flora and fauna



Duciduous Woodlands


Deciduous wood in the Urkiola Natural Park. (Increase the size in a new window)


Duciduous forests form part the most complex habitat of the temperate areas of the Earth. Its main feature is the strong seasonal rhythm, to which all its vital processes are exposed, in response to the cold winters. This rhythm manifests itself in the numerous physiologically apparent processes taking place, and showing the most visible signs during autumn falls and leaf sprouting in the spring season.

In the absence of human intervention, the forests would cover practically the total area of Urkiola´s Nature Park, with the exception of specific areas: rock and peat bog areas. Nevertheless, its spreading has been cut down, and at present represents approximately a third of the Parks total area. Even if it shows a scarce surface spreading, a wide variety of forests can be seen

The oak groves are the forest type of the lower areas, where they occupy the depths of the valley, as well as the slopes up to 600 m level, only in the lithosols are they replaced by the Holm oak (Quercus ilex). Presently its presence is very scarce, the forests situated in the fertile plains give way to cultivated fields, the fields in the slopes having been transformed into pastures and its wood cut to supply forges and naval construction industry. In the Park it occupies an area of 35 ha, less than 1% of its total surface. Distributed throughout the Oleta and Mendiola areas.

Oak wood in the snow. (Increase the size in a new window)

There are two types of oak groves: in depth soil areas in the valley depths, grow the eutrophic oak groves. Characterised by its enormous diversity, together with the oak (Quercus robur), appear other trees, such as the ash-tree (Fraxinus excelsior), lime-tree (Tilia platyphyllos), elm tree (Ulmus glabra), maple tree (Acer campestre). Various types of bushes form the hawthorn underwoods: (Crataegus monogyna), balckthorn (Prunus spinosa), etc. In the lower bedding stand out the crowns of the Polysticchum setiferum and other type of ferns like the lady fern (Athyrium filix-femina), together with a number of perennial plants such as the tuberous comfrey (Symphytum tuberosum) the Pulmonaria (Pulmonaria longifolia). In the limy substratum areas the forest becomes poor, and the oak trees take a more prominent role in the tree stratum, where only once in a while the whitish bark of a birch tree (Betula celtiberica) or the lustruous leaves of the European Holly (Ilex aquifolium) appear

Climbing in altitude, with the increase of rainfalls, the Beech Forests, the type of forest in a temperate European antonomasia, where in its shady areas the moss develops in wide areas of the European mythology, for many a symbol of these lands. Nevertheless, the European beech tree (Fagus sylvatica) is a recent acquisition. Only 8.000 years ago it remained cornered out in the Balkans, secluded behind the glacial episodes, and only spread out when climatic conditions improved, advancing towards the west together with other trees (Fir-tree, red-Fir or Douglas-Fir,...), being amongst all these the one that travelled further. A little less than three thousand years ago it managed to cross the Pyrenees. There are some writers that state that in the North of Europe its expansion still continues. The recent arrival of this species in the Iberian Peninsula puts a question mark on the theory of the immobility of plants.

European beech tree gives and intense shade, resulting in an intense competition for light in its Underwood, as can be seen in areas where a lot of young trees start to sprout, with slender growth reaching the highest without really thickening its steam. Surprisingly in some areas on the other hand appear trees with a thick trunk, that at a very small height show an intense ramification: these are the pollarded Beech Forests with great historical value, as they are the result of a custom now nearly forgotten, whereby wood was obtained by cutting off its branches.

This Beech forest situated in the vicinities of the Sanctuary, is a clear example of the traditional exploitation of our forests.

Wood anemone in flower. (Increase the size in a new window)

The wood anemone (Anemone nemorosa), is of early flowering and shows a very clear preference for low fertility soils.

Parasitic fungus known as Honey Fungus (Increase the size in a new window)Parasitic fungus known as Honey Fungus(Armillaria mellea)

The Armillaria mellea is a parasite mushroom that feeds on the wood of living trees, known to cause extensive damage to Beech trees forests and pinewoods


Although very demanding as far as rainfall is concerned, the European beech tree is practically indifferent as to the type of substratum, occupying equally sandstone and limestone areas. Directly related to the type of soil where these are found, different species appear in its company. When the substratum is acid and poor, as is the case of sandstone areas, the interior of the forest shows a very poor floristic growth. Between the few species that survive these conditions stands out the hair grass (of the graminae family) with thin leaves Deschampsia flexuosa, the dwarf bilberry (Vaccinium myrtillus) and the wood anemone (Anemone nemorosa). Sometimes, in the interior of these forests, appears some or other European Holly (Ilex aquifolium) or birch tree (Betula celtiberica), these forests are mainly found in the Mendiola, Sakonandi and Condebaso areas, where they appear in contact with formations of black oak (Quercus pyrenaica).

When settling over limestone, the flora is enriched, even though the Underwood covering continues to be scarce. The geophytes are frequent here; as a result of own resources they develop rapidly, before the European beech tree closes its bark. The lovely squill flowers (Scilla lillio-hyacinthus), the bear paw garlic (Allium ursinum) or the dogs tooth (Erytbronium dens-canis), indicate the beginning of spring, other species are not such early rises and develop when the forest is already shady, such is the case of the wood melick (Melica uniflora) or a cousin of the false-brome family, Brachypodium sylvaticum. Lastly some bushes such as the spurge-laurel (Daphne laureola) show evergreen foliage with which it takes advantage of the spring and autumn periods, during which the European beech tree leafless. These forests can be enjoyed in the mountain ranges of Aramotz, Anboto and Arangio.

Bear paw garlic (Increase the size in a new window)

Of the common garlic family, the bear paw garlic (Allium ursinum), it sprouts forming large populations in the more humid Beech Fores

In this vast 20 % surface of the Park, covered with Beech Forest, the presence of other "plants" stands out. Moss and fungus supposedly are an important element in the growth and survival of the Beech Forest. In more humid conditions, the moss will cover up any rock or any tree trunk that protrudes in between the leaf litter. Even though in these habitats its importance as a species and spreading ability is superior to phanerogames, they are rarely known. The fungus, is the group that carries out more tasks inside the Beech Forest; apart from its role as decomposers, shutting off the cycle of nourishment, digesting wood and leaf litter, with a second symbiotic function in terms of the tree roots, allowing these to gather nourishment with great easiness. In the autumn and rainy springs, these species, surviving between the animal and vegetable world, leave their hideouts and show their reproductive bodies, these are mushrooms, amongst whom the following are worth being mentioned: the King bolete (Boletus edulis), the wood hedgehog toadstool (Hydnum repandum), (Laccaría ametbystina) or the Common Yellow Russula (Russula ochroleuca).

The black oak (Quercus pyrenaica) is a tree that adapts well to high draught conditions, and can be seen more and more in Mediterranean areas. The adapting feature is well manifested in its morphology, with leaves profoundly lobulated, that do not detach themselves from the branches when dry, and remain on the tree, until the end of spring when the new leaves sprout. They can be found in places with siliceous substratum, as is the case of the Condebaso area, and in general on the whole southern area of the Park. Many times interlaced within the Beech forest, the black oaks occupy the drier soils. The species that form its Underwood are a mixture between the acidophilus oak groves and the healthland.

In Urkiola, other forests of great importance can also be found. The birch tree forests located at Txakurzulo, and on the SE slopes of Saibi, form pioneer vegetation, implemented prior to the development of other forests. In places of steep slopes and higher acidic soils, the birch tree (Betula celtiberica), makes up forests that are very rich in ferns and Dwarf bilberry (Vaccinium myrtillus). In similar situations, but on lime soils, where the rocks take over the scenery, forests at the foot of the cliffs can be found, these are places where the soil movements do not allow for the implementation of mature Beech Forests, but are abundant in hazelnut bushes (Corylus avellana), whitebeam (Sorbus aria) and English yew (Taxus baccata). In some places, in between the acidophilus Beech Forest, groves of sessile oak (Quercus petraea) appear, sometimes accompanied by the Norway maple (Acer platanoides), or the great maple (Acer pseudoplatanus).

Wood with yellow ochre coloured leaves with the Urkiola mountains. (Increase the size in a new window)

Before the falling leaf, chlorophyll and nutrients are reabsorbidos, acquiring the forests the usual ocher tone.

Lone beech tree in Zabalaundi (Increase the size in a new window)

The pastures, located in the territory of the forest, conserve some vestiges of the same one like this solitary beech forest of Zabalaundi.

Ecosystem in the Urkiola Park. Birch tree, european beech tree, hazelnut bushes, liverleaf, english yew, woodpecker, wild boar, salamander, squirrel, mouse trap and owl. (Increase the size in a new window)


The epigraph, under which this type of vegetation formation is introduced, is somewhat ambiguous, seeing that, in reality it refers to two types of forests: the Beech Forest and the oak grove. The first one, as mentioned, is well implemented in Urkiola, and presently the situation of the second one is barely traceable. Therefore when we refer to the duciduous forest, we basically refer to the Beech Forest.

One of the most accountable characteristics, of this forest, is the relatively poor fauna it holds. This is self-explanatory, in the scarce trophic from which the higher vertebra species benefit. The physical absence of the bush stratum -motivated by the extensive covered, created by the crowns of the European beech trees with the result that the source of food supply required by the forest birds, great consumers of berries and other fruit, is totally eliminated. This basic lack, of the Beech Forest, has repercussions on other groups of vertebra. As a result, the carnivorous mammals have a less extensive source of food supply; therefore the number of species that can live in the forest under these circumstances is less than otherwise found in other forests, where the level of potential pray is of a higher range. These circumstances are repeated in the oak groves, this is why the ones partially affected, are those faunlike groups that do not directly depend on the strong presence of bushy stratum, in the interior of the forest. In Urkiola and other Beech Forests of the area, such animals are, on one side, the micro mammals and on the other the amphibious; that is faunlike groups that basically live all their life on the ground stratum, that in the case of the Beech Forest has its own particularities.In many areas the soil surface of the Beech Forest shows a lack of any type of vegetation, mossy inclusive. In other areas, the soil is non-existent as the European beech trees grow directly on lime rock surfaces. Bare rock and soil without vegetation, mean no food resources at all. These signs of biological poverty are reduced, and in a certain way compensated by the presence of a potential extract of decomposing foliage, sometimes on a regular basis and other times no so much. This fact, apparently less transcendent, is of a basic importance, for a certain vertebra fauna to be able to occupy the Beech Forest (micro mammals and the herpetofauna previously mentioned). In between the decomposing leaves, of the European beech tree, interesting communities of artropodes and other invertebrates live, these leaves are its source of food supply; the humidity retention is very high, resulting in an ideal micro climate, that allows various amphibious species to live a good part of the year, away from water resources.

Tawny owl perched on a branch. (Increase the size in a new window)

The nocturnal bird of pray with a more prominent presence and a better distribution in the Park is the Tawny Owl (Strix aluco), and this due to the vast tree surface available in Urkiola. The species, shown in the photograph, is a young bird just out of its nest.

The fauna that lives in the Beech Forest is, in practice, similar to the one that lives in the Atlantic oak groves. The difference is, the density of the settled population in a forest so scarce of resources, as is the case of the Beech Forest. Reference has been made to the reduced amount of food supply that this forest can provide, to a great number of species above all the birds but nevertheless lets not loose sight of the difficulties, often with no alternatives, that many of the bird species and mammals of intermediate size (mainly mustelidae) are faced with, when establishing their nests and dens, respectively. This additional impediment in the end results in the conformance by a vertebra community, of relatively low diversity.

One of the forest bird species better distributed in the Parks area is the Tawny Owl (Strix aluco). It is strictly a forest owl that can be found in the extensive tree patch of Urkiola, an ideal place for it to live without major difficulties. It is a bird of an intermediate size having a light copper coloured plumage in its back, and crème colour on its breast and belly. More or less reddish, depending on which of the two colouring phases, existent in the species, it belongs to. The song is an audible howling during autumn and winter, its mating period, coming out through the tree formation, and sometimes forming an important part of the audible scenery, of a normally still, winter silent of the forest. Like the majority of the owls, it is unlikely to observe this species in flight during the day. In any case he could be seen moving if surprised by an observer. Most of the times, this could be due to another bird settling on the branch, where he rests during daylight, his normal resting period. The specialised trophic of this bird species consists in hunting micro mammals, that after being trapped in its thin claws, are eaten on the branch of any tree. Therefore it is not a species that concentrates the aegagropile, resultant form the digestion, as is the case with other owl species.

In the extensive European Forest´s Fauna, Woodpeckers are found amongst the species that characterise these tree environments. Two types are known to live in the Urkiola´s Nature Park, the Great Spotted Woodpecker Dendrocopos major, and the Green Woodpecker Picus viridis. The one mentioned first lives in the Park area, with very exiguous populations. The reason for this remains a mystery. This type of bird species, whose existence is developed in forest areas without forming groups, remains solitary throughout the major part of the year. The normal explanation presented, to justify such abnormal low population density, is usually the effects of synergetic activity, which lacks verisimilitude, as it is difficult to have direct generalised action over them. Even with this general situation, its presence in its southern area of the Park (Beech Forest of Condebaso), looks assured. As is the case for the majority of the forest avifauna it is easier to localise it audibly than to visualise it. The call is a strong quick, although it can also be detected by following the noise of its typical drum like sounds (rhythm beat produced by the bird when pecking on hollow wood). Its plumage stands out, and is a mixture of white, especially on the breast, belly and head; black on the dorsal part and head, and red on the lower belly section and back part of the nape, the last feature applicable only to the male. They are smaller that when observed during flight, 23 cm from beak to tail. Their diet is made up of insect worms found on rotten wood, but it is the trees´ seeds (Beech nuts, acorn, hazelnuts, etc.) that form the most important part of its food source, throughout the whole year. In order to ingest this type of feed, generally covered by a coarse shell, the morphology of the bark of the trees is used, embedding the seeds in them and pecking these until opening and eating same. These are known the well known "anvils"

Booted eagle (Increase the size in a new window)

In the big spot of hardwoods, south of the Park, has settled some or other couple of booted eagles (Hieraaetus pennatus). This small eagle only has a seasonal presence in Europe.

Like the woodpeckers are found amongst the bird species, that characterises the forest, the European or Red Squirrel, Sciurus vulgaris, is together with the edible dormouse, Glis glis, one of the most exclusive mammals of forest environments. The first one is an animal of small size, 23 cm in body length, apart from 15 or 20 cm of tail. Its tail is very furry, one of the main physically identifiable characteristics of this species. Its body presents some coloured areas; the neck and abdomen are always white, and the rest of the coat, tail included, are reddish, at least the ones observed in the Park. Nevertheless their corporal colour can vary from one individual to another, existing species with a very dark coat. The front paws, more developed then the back ones, aid the animal in its springing from branch to branch. For their winter coat they develop long tuffs in the ears. To breed, they frequently build their own nests, sometimes using tree holes, other times taking advantage of the tree crown they often use a bird nest as platform. Contrary to the majority of the mammals, the European or Red Squirrel develops its activities during the day. This circumstance makes it less complicated for observes to spot it, during their journeys through the Park, when compared with almost remote possibility with other mammals. Even though this is a common animal in Urkiola´s forest, it often goes by unnoticed by the observers, mainly due to two factors that characterise this species; it can be considered as a silent animal - emitting only squeaking sounds when threatened by some king of danger - and secondly it rarely leaves the foliage level, therefore being out of sight to the ground observer. Its basic food supply is, the plants found on the tree stratum, but when necessary, it does not hesitate to descend to the ground in search of food.

The most characteristic bird of pray of this type of forest environment, in humid and temperate areas of the northern hemisphere is the goshawk, Accipiter gentiles. Unfortunately at present it is confirmed that this bird is not settled in the Park or any of its surroundings. Another type of bird of pray, typical of forest environment, but with a type of life not so closely related to the forest as the previous genus is the buzzard (mouse trap-"ratonero", Buteo buteo, - being this species settled in the park, and with a higher level of presence. This bird of prey, without having substituted no other kind - in reality it does not cover the gap left on the biocenosis of Urkiola´s forest, by the goshawk - is, perhaps, the one that better represents the forest´s winged birds of prey type. Physically it does not have any outstanding characteristics, the dominant colour of his plumage being the colour brown. The breast and abdomen has a cream colour base with brown spots, having the same colour composition in the lower wings. It is a species with great individual variety with regards to colour, existing lighter coloured specimen and others with more prominent browns than the general patron described. It gives the impression of being a heavy bird, when watched in flight, with an excessively wide and short head, and a tail not excessively long. One of the most common tactics used by this bird, in catching its prey, is to remain motionless on a branch in the boundary strip of the forest, over a grass stack or on electric cables and electric posts in search of its prey. This is most common way of establishing contact with this species. It is also not difficult to detect and spot it when hearing its "mewing" call, a sound it emits with a certain frequency when in flight. It´s name in Spanish (common mouse trap) does this species justice as it is an animal that catches large number of rodents (water rats, moles, mouse, etc.) not forgetting the reptiles, such as lizards and snakes, as well as, occasionally, birds.

Mountain cat (Increase the size in a new window)

Of nocturnal habits, the wild cat (Felis silvestris), is an animal that specialises in capturing small prey, that it hunts from the ground.

The wild boar, Sus scrofa, is, together with the corzo, Capreolus capreolus, the largest mammal actually living in Urkiola´s Nature Park. It is an animal of robust and compact body covered by a thick dark coat. With short paws and ears, the males have well-developed canines (tusks), protruding through its mouth. The young ones ("jabatos"- young wild boar) have a horizontally stretched out coat, during their first months of live. As far as its feeding habits it is an omnivorous, whose diet consists mainly of plants. The numbers that inhabit the forest grounds of the Park are occasionally important, as to the population that lives in it, on a permanent basis, (located on the southwestern side of the park) are added on, the animals proceeding from the Alava area, in seek of shelter from the hunts these are exposed to on the outskirts of the Park. These animals, in general, usually enter from the northwestern side (Arrietabaso and Ezkubaratz), and after remaining here for a short while, return to their original hideouts. Therefore there are no fix populations in this part of Urkiola. Its habits are predominantly nocturnal, in this area, due to the high human transit. Their presence can, for example, be mainly detected on the mountain pastures at the base of Anboto, where uproots, caused by these animals, when in search of food, are constantly being repaired. Normally this is the doing of specimen coming from the Condebaso forest area.

Roe deer fawn (Increase the size in a new window)

Knowledge of its presence, in the Urkiola forest, dates back to the end of the last century. Its absence from the area during the last decades seems to have come to its end. In the summer of 1994 the sighting of a young Roe Deer calf was registered (Capreolus capreolus) in the Park.

The common salamander, Salamandra salamandra, is an amphibious with a very peculiar physical aspect, as it presents a colour unusually seen amongst the Iberian species. The colour of its skin is divided between a yellow and black combination, which stands out wherever they might be. The reason for its presence here, leaving behind all myths, is due to the defence tactics it uses when confronted by a potential predator. Its skin is covered by a secretion that is toxic for its predators´ bucal mucosa, the result of this being irritations suffered by these when trying to capture them. So its colour serves as a reminder to those that previously attempted to base their feeding habits on a salamander meal. It is a robust animal that leads a nocturnal life, appearing momentaneously during the day after rainfall. It occupies the shadier, humid places, spending most of the day under rocks amongst the leaf litter. Feeds on insects and molluscs that it catches with very slow movements.

Luis Viera (Geología).
José Miguel Olano, Francisco Solván y Josetxo Riofrío (Vegetación y fauna).
José Ramón Aihartza (Murciélagos).
Elena Barrena y Miren Ayerbe (La huella humana).
Servicio Central de Publicaciones del Gobierno Vasco.
Year edited
Page extracts
64-73 (both inclusive).

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