Monday 20 January 2020

A day with Dippers

As we didn't see any Dippers Cinclus cinclus during our recent IWC winter count, this weekend we were happy to join a colleague who was counting them on the river Bača in the Julian Prealps. The narrow alpine valleys in northern Slovenia, with their fast-flowing mountain streams hold large populations of these water specialists. Every winter, volunteers from DOPPS-BirdLife Slovenia work all the main mountain rivers in detail, counting Dippers as well as other waterbirds. On Sunday we gave a little contribution to this count, walking the Bača river valley between Hudajužna and Grahovo ob Bači, on a distance of about 9 kilometers and counting 27 Dippers. However this year's total count for the river Bača (measuring 22 kilometers), was 47 Dippers! The Bača ranks among rivers with the highest density of this species in Slovenia.
We had thus plenty of opportunities to enjoy this amazing bird we are never tired of watching. Dippers start breeding very early and therefore some birds were already singing and defending their territories. We also managed to find two old nests on natural cliffs by the river.
Dipper Cinclus cinclus
Old Dipper's nest.

In one of the small pools created by the river we glimpsed two trouts that could have been Marbled Trouts Salmo marmoratus, an endemic and highly endangered species of the Adriatic basin, found mostly in western Slovenia and northeast Italy. Later we came upon a dead fish which we confirmed as a Marbled Trout. Unfortunately we also came across several small hydropower plants built on some beautiful stretches of almost natural river. These plants are a great problem for migrating fish as well as other river organisms. Marbled Trouts, being so rare and vulnerable can be seriously affected by such interventions.
Marbled Trout Salmo marmoratus
River Bača.
Girls counting Dippers.
One of the several waterfalls joining the Bača in its canyon.

Walking along the Bača there weren't many other birds to keep us company, apart from the occasional Grey Wagtail Motacilla cinerea, another typical inhabitant of the river ecosystem. However in the riparian trees, our attention was caught by a small flock of 4-5 Long-tailed Tits Aegithalos caudatus. The interesting fact was that all had a pure white head - a sign that usually points out to a northern origin of such birds (ssp. caudatus perhaps?). Regardless of the birds' origin, white-headed Long-tailed Tits are uncommon in Slovenia and homogeneous flocks like the one we observed are very rare. Two male Bullfinches Pyrrhula pyrrhula drinking water from the river were also nice to see.
Possible caudatus Long-tailed Tit Aegithalos caudatus ssp. caudatus
Bullfinch Pyrrhula pyrrhula

On this trip we finally managed to write down in the notebook the first (short) plant list of the year! On the fertile woodland floor along the river Bača we were greeted by the first flowers this winter. First we saw the "usual suspects" - Primrose Primula vulgaris and Snowdrop Galanthus nivalis, followed by single flowers of Spring Crocus Crocus vernus, Christmas Rose Helleborus niger and Spring Heath Erica carnea. An interesting addition was the bizzarre fungus Elf Cap Sarcoscypha austriaca
Walking down the valley we also enjoyed in the views of the beautiful "Lower Bohinj mountains" - the southern chain of the Julian Alps, rising above the Bača river valley.
Snowdrop Galanthus nivalis
Spring Crocus Crocus vernus
Elf Cup Sarcoscypha austriaca
One of the several small tributaries of the river Bača and a traditional barn.
Mt. Črna Prst (1844 m) towering above the Bača valley.
Mt. Rodica (1964 m) is the highest peak above the Bača valley.
Mt. Raskovec (1956 m).