Sl. 1. Three-toed Woodpecker (Picoides tridactylus), foto: Andrej Radalj

AN INTRIGUING SPECIES OF WOODPECKER DISCOVERED IN THE PAKLENO REGION ON OBRUČ MOUNTAIN

Old-growth forests with overmature trees, standing dead
trees and downed trees are becoming increasingly difficult to come across
in the Primorsko-Goranska County. As a rule, trees that are old, damaged
or dead are removed from managed forests. The cavities and hollows of
such trees, however, are filled with insect larva and provide shelter
to birds and mammals, in addition to being a rich “pantry”.
Hence, old trees and standing dead trees represent microhabitats that
are of vital importance to conserving a forest’s wildlife. Many rare and
endangered species of plants, animals, fungi and lichen depend on such
trees. These microhabitats can be found in sufficient numbers only within
the protected old-growth forests of national parks, strict reserves and
forest reserves (Risnjak, Bijele i Samarske Stijene, Debela Lipa – Velika
Rebar), as well as in certain areas in which a lower category of protection
is provided (Golubinjak). Unfortunately, in other areas, there is mounting
pressure on their survival. This loss of biodiversity due to a decline
in the number of dead trees in forests has been observed throughout Europe,
and efforts are being made to increase the number of old and dry trees
per surface unit and so avoid the looming threat of biodiversity erosion.

A few days ago (on 31 October 2009), in one of the almost
pristine communities in the Pakleno region of the Obruč Mountain Cluster,
Andrej Radalj, external associate of the Public Institution “Priroda”
and excellent ornithologist, bird-ringer and collaborator of the Institute
of Ornithology of HAZU, made an extraordinary discovery. While conducting
field research needed for a study concerning the protection of Obruč Mountain,
he observed and photographed probably one of the least known birds of
the Primorsko-Goranska County – the Three-toed Woodpecker (Picoides tridactylus).
This bird is a typical boreal (northern) species, tied to dark coniferous
taiga forests in the far north of Eurasia. Towards the south of Europe,
the Three-toed Woodpecker is increasingly difficult to find, with it populations
becoming less numerous and more scattered. This is because there are fewer
coniferous forests, in particular dark spruce forests, most of which are
located on high mountain massives such as the Alps and the Carpathian
Mountains. That is why the sighting of this boreal species within reach
of the Mediterranean and on a fairly low mountain such as Obruč is exceptionally
important, all the more so because sightings of the Three-toed Woodpecker
are rare in all of Croatia. This is probably the first sighting in Obruč
Mountain and the most northwestern sighting in Croatia. The largest number
of sightings to date has been made in Gorski Kotar. Due to the rolling
karst relief, the forests of Obruč Mountain are unusually diverse and
possess a wide variety of ecological conditions ranging from typical Mediterranean-mountain
forests to boreal spruce forests surviving in special conditions provided
by deep dolines and frost pockets in which the Pakleno region abounds.

The Three-toed Woodpecker primarily feeds on wood-boring
insects and the larvae of the Long-horned Beetle found in dry spruce trees.
This makes the forest in Pakleno all the more important for the survival
of species tied to old, dying and dry trees. This unexpected ornithological
finding is yet another confirmation of the exceptional value of Obruč
Mountain and the need to conserve its well-preserved forest communities
consisting of many dry trees. Therefore, it is necessary to continue efforts
in researching Obruč Mountain that will definitely confirm the forewarnings
of the need to protect the valuable and almost primeval communities in
these extraordinary mountains on the Primorsko-Goranska County border.