Sunday, January 5, 2014

Looking for the European otter

What does a nature guide when not working?
 Learning and improving skills (among other things ..)
some weeks ago I went to an outlet to identify fingerprints and traces of mammals within the project territory mink for European mink conservation .The guide was Benjamin Sanz  expert in mammals, and had been very enjoyable and interesting.

Otter (Lutra lutra) deep and marked with little nails.

We went by the shore of a river  of Navarra and  we found traces of European mink, hedgehog, otter, genet(Genetta genetta), marten, fox, wild boar, domestic cat, rat and vole, heron, badger,... and some more I do not remember.
Also saw (and we smelled) otter and fox droppings and traces of activity of the European beaver
The European beaver (Castor fiver) disappeared from Navarra in the seventeenth century, but a group of Belgian environmentalists illegally reintroduced by 2003 in Navarra, Aragón at the mouth of the Ebro.It seem that they like the land of their ancestors and flourishes extending along the Ebro and its tributaries, although people hunting  their  in many areas because has not been introduce by the administration with a plan for the wild species. The strange (and dramatic) is that while it is a protected species in Europe, here is hunting.
We saw their tracks, but yes their works on the bark to feed or directly on the trunks of trees.

Damage caused by Goat willow (Salix caprea) to more than 1 meter from the normal course.
This is a recent damage in the last flood when the river rose, and the beaver was high above.

Comparing  the coin, with the Beaver upper incisors
Trunk  barking trail for food
Unlike their American relatives (curiously we will have seen on tv many documentaries of the American beaver but certainly not the European ..) makes large dams in rivers, but makes its burrows in accumulations of branches and / or bushes along the banks.
Observe the size of the teeth, cleaning and cutting: wood is not torn except in the far right, to fall. The bites are clean as freshly made ​​with sharp gouges.

Felling trees or stripped of its bark is not more than ten meters from the bed of the river, so that damage to poplar refers I think that these poplars are planted in an area that should be of  nature vegetation and not manipulated by a human being:

There is also talk about possible harm to other wildlife such as the European mink and otter, by shooting down of the vegetation. I sincerely believe that if these species coexisted in balance until humans decided to exterminate the beaver, and leave almost extinct to others, is necesary a lot of hypocrisy to place blame now the beaver of a possible decline of other species, keeping in mind the fact that it is a protected species other European countries.
I'm not in favor at all of reintroductions without control, but I think if it is already done, and the species grows, you have to find a way to come back to find the niche that, in addition to the debt concerns that as humanity we for this specie.

I will recommend this blog about the European beaver(spanish)

Here we have a truly invasive species that should never get here, and we found in the river.
This is the Asian clam (Corbicula fluminea) that first appeared in Navarra in 2004.
Almeja asiática(Corbícula flumínea)
This would be an edible species (not encourage anyone to eat) and looks like it was introduced in the U.S. by the Chinese for this purpose, but outside their place of origin, can affect in an unpredictable way ecosystems, to be able to move to other species, changing your diet, etc. ..

As for the tracks themselves, here is the European mink (not very good)

European mink (Mustela lutreola)

Genet (Genetta Genetta) small footprints, pad and fingers together without nails.
The Marten
Marten (Martes foina) Larger than the genet, with fingers separated from the pads.

The field rat:
Field rat (R. rattus) is similar to the hedgehog (Erinaceus europaeus) but rat nails are thin and short, stuck to the fingers, while the hedgehog are long and thick.

The field mouse:
Field Mouse (Apodemus sylvaticus). Quite tiny compared to the rat.

Galápago Europeo:
Galápago Europeo(Emys orbicularis)

We also found a hole, like this badger sett, or these old woodpecker nests (Dendrocopos major)
Badger sett. Sometimes form colonies of several individuals.
Nests of woodpeckers (Dendrocopos major) in a poplar, not far from the ground.

And this is the web of Benjamín Sanz

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