Birding Bird searching in Slovenia
Birdwatching in Slovenia can be very satisfying. At other moments, it is a challenge. Imagine going to the largest lake in the country, only to find that there is no water? Or going to the largest forest in Central Europe, only to find that it is so vast that birds could be anywhere at all (except at the spot where you are)? Or standing in a barren, rocky place with flies buzzing and incredible butterflies all around, but the birds are silent and nowhere to be seen? This is the reality for me as a nature guide.
I know that the birds can be there, because they were, just a few weeks or days ago. I do not like to promise anything that I cannot deliver. This is why I rather offer nature tours in which we can also see birds. And then, magic can happen. With my guests, we did see griffon vultures, golden- and white-tailed eagles, black storks, nightjars, Ural owls and many other exiting bird species. I often say that nature in Slovenia offers a little surprise every day. Just, sometimes that surprise is a butterfly instead of a special bird.
Sedge warblers are common and can be approached relatively easily. However, they inhabit a vast habitat and can disappear behind plant stems anywhere.
Red-footed falcons often stay for weeks during spring muigration. At Lake Cerknica, they fatten up on maybeetles and mayflies before they move on to their breeding sites in Hungary.
Karst Lakes
The intermittent lakes in Notranjška present a highly dynamic and unpredictable habitat for water birds. The water level fluctuates along with regional rainfall and the entire lakes regularly dry up. As a consequence, the birds’ breeding success also fluctuates markedly. Some years they are highly succesful, while in other years their nests may get flooded or the water disappears before the young are fledged.
The 17 smaller karst lakes in the Pivka valley attract migratory waterbirds. Especially in autumn migration, mixed flocks of ducks gather that might include rare species like ferruginous duck. These flocks can be rather shy and without a telescope it may be hard to see them at all. In spring the lakes often dry quickly and waterbirds disappear. However, the surrounding scrubland forms an excellent habitat for red-backed shrikes and barred warblers while ravens and various birds of prey frequent the area.
Lake Cerknica is the local birding hotspot. At the highest water levels, it extends to a whopping 28 square kilometres of water, which makes it Slovenia’s largest lake. When it dries up, some water remains in the Obrh stream, which runs through the middle of the lakebed. Water also remains behind a dam which is constructed for the preservation of fish for sports fishing. The populations of the ten fish species in the lake go through boom-and-burst cycles. When the water recedes, millions of fish become stranded and die, many of which are scooped up by grey herons, lesser and great while egrets and black storks. Weeks or months later, when the water raises again, the fertile lakebed becomes a prime breeding site for fish, frogs and insects, which in turn attract a variety of ducks (ferruginous is breeding here) and grebes. This is the only breeding site for red-necked grebes in Slovenia and after an absence of several years, recent sightings give hope that the species has returned.
Lake Cerknica is also good for passerines including whinchat, sedge- reed and great reed warbler as well as the largest breeding population of western yellow wagtais in Slovenia (mainly cinereocapilla with some feldegg mixed in; other subspecies can be seen during migration). Along the edges you may hear common rosefinch singing and red-backed shrikes are hard to miss.
Some birds are naturally secretive and easier heard than seen: the lake boosts the largest Slovene population of corncrakes with up to 50 calling males as well as spotted and Baillon’s crakes. There are also a few bitterns whose booming calls can be heard across the valley.
Migration brings many species of waders and in springtime, a large flock of red-footed falcons can stay in the area for several weeks on the way to their Hungarian breeding colonies. An increasing number of Eurasian cranes has been wintering at the lake as well, with well over a thousand birds in some years. However, in the winter of 2025-2026 their numbers dropped dramatically and they might have fallen victim of the bird flu in Germany.
While this sounds promising for a great day of birding, seeing any birds at the lake can be challenging. The area is extensive and includes and reedbeds that are over four meters tall. Birds can be very close, but still hidden and out of view. The edges of the lake are easily accessible, but the vegetation towards the middle of the lake is hard to navigate with high tussocks of sedge and purple moor-grass. During my vegetation research, I often struggled for long distances only to disturb flocks of birds that I didn’t see until they flew up. Your best bet is to access Lake Cerknica from a variety of places along the edge and to return often, in different seasons. The birds are definitely there and one day, they will surprise you.
Dinaric Forest
Another challenge is the extensive Dinaric forest of the Snežnik-Javorniki mountain ridge. The area is well known for Ural- pygmy- and Tengmalms owl as well as a variety of woodpeckers. Then, when you are actually inside the forest, it can appear devoid of any birds. In part this absence is real: forestry practises favour straight trees without holes so nesting opportunities for hole-nesting birds are vanishing. Partly it is also a matter of seasons: the region has a continental climate and winter changes abruptly to summer. The spring breeding season is short and ends earlier in the year than most birdwatchers would expect. It pays to be here early in the season: March for owls and April-May for woodpeckers and songbirds. Sometimes it is a simple matter of chance: I regularly go to a prime spot for Ural owl, but I see them only about one in every five visits.
Throughout the year, tits are abundant and you likely encounter blue- , great- , coal- , crested- , willow- and long tailed tit. They form pairs in spring, and in summer you are likely to encounter family-groups. Later in the year they join mixed species flocks, often together with goldcrests, treecreepers and nuthatches. Most numerous are chaffinches, whose wintering numbers are strongly correlated with the availability of beech seeds.
Both ravens and jays are common as well, and often conspiciously present. Their relative, the nutcracker, is highly secretive for most of the year, but can be rather loud in September, when the hazelnuts ripen.
Even after I spend so many days in this forest, it still surprises me that there are common buzzards that hold territories so far from the forest edge, that they likely spend their entire lives inside the forest. Here, they hunt bank voles and even dormice!
The largest woodpecker species, the black woodpecker, is also among the most numerous in the Dinaric forest. It is highly vocal and its distinctive flight call can be heard from a large distance.
Wrynecks arrive in early spring, still before the apple trees have leaves. For a few weeks, they are very vocal as the males establish territories and try to attract mates. They are so well caumouflaged that you can look straight at them, without seeing any.
Farmland
Much of the farming in Notranjska is small-scale and extensive, with little use of pesticides or artificial fertilizers. This makes the area a true stronghold for farmland birds, especially those species that favour orchards and hedgerows. Red-backed shrike is common as is the elusive wryneck. Grey-headed woodpecker is as much an orchard-bird as a forest bird, and it is the most common woodpecker in the region.
Fieldfares nest patchily in the orchards. Pairs like to settle down close to each other because of their communal defence behaviour against predatory birds. You may encounter several pairs of fieldfares around one village and none around the next, even though the habitat appears similar. In the hay-meadows quail and corn bunting are surprisingly common. In some places, the meadows are extensive enough for skylarks, who like to stay clear of any trees or bushes.
A resident fieldfare in winter.
Dry Karst
The dry karst is a rocky and sometimes barren looking landscape. In the past shepherds intensively used it for sheep grazing. Nowadays, ownership is divided and largely private. Some owners raise beef cattle and here and there you see sheep, horses and donkeys which are permanently pastured behind electric fences. Because of this practise, the area is patchily overused, while most is abandoned by agriculture. For birds, the more extensively used places tend to be the best, as are the edges of pastures. Typical species for the karst include hoopoe and cirl bunting. Black-headed bunting was originally described from the Slovenian karst, but it is uncertain if it still breeds here.
When visiting the dry karst, it pays to linger until evening. Once it gets dark, nightjars can be seen hunting for moths. I find them so spectacular that I even planned special excursions to see them – even though they are a bit unpredictable and especially weather-dependent. Another highlight-of-the-evening are the persistently calling scops owls: a reminder that we are close to the Mediterranean.
The beautiful cirl bunting is one of my favourite Karst birds!
This rufous-tailed rock trush was the highlight of one of my trips. Next time, I want to photograph the splendid-coloured male of this species!
Inland Cliffs
With the »inland cliffs« I mean two steep ridges: one along the Vipava valley that is mostly known as »the edge of Trnovski gozd« and which includes mount Nanos and one roughly parallel to the coast: the »Karst edge«. In altitude they range from a few hundred meters to Čaven at 1.242 m and Kucelj at 1.237 m. However, it is not their altitude that makes these cliffs special, but the bare vertical rocks that cause an often-wind-swept climate with special living conditions for animals and plants. When you look up information on the local fauna, the first species that are mentioned are eagle owl and peregrine falcon. This has to do with the popular sport of rock climbing, which is strictly regulated in order to avoid the nesting sites of these birds!
Instead of the iconic peregrines, I usually see kestrels first, who also use the updrafts along the cliffs and who hunt for voles along the upper edges. Besides them, almost all birds of prey seem possible here, including golden eagles, short-toed eagles, honey buzzards and even griffon vultures! At such places, it pays off to just sit and stare at the sky for a while …
But, don’t forget to look at the rocks too: they are home to blue- and rufous-tailed rock thrushes and the lovely grey, black and brown rock buntings. There are also pigeons at these walls, which look like ordinary city pigeons. They are the same species, but their history is somewhat different. These are traditional nesting sites of rock pigeons: the wild ancestors of domestic pigeons. It gets complicated though, because the rock pigeons have crossbred with their domestic counterparts and some now have aberrant colour patterns. Because of this continuous interbreeding, we may slowly loose the rock pigeon as a wild species.
The Slovenian Coast
Slovenia has only 47 km of coastline, but the coast is very special to every Slovenian who I met. It is also a major tourist attraction with beautiful venetian style cities like Koper, Portorož and Piran. Land is at a premium and there is a huge pressure to use every meter to the maximum. Yet, somehow, nature areas are preserved even between the busy cities.
The best known is the Sečovlje Salt Pans Landscape Park, which are as much a cultural monument as it is a nature area. Here, the centuries-old tradition of manually obtaining sea-salt is still practised. The salt pans are habitat to a population of tiny brine-shrimp which are attracting increasing numbers of flamingos. Other important birds include Kentish plover, little tern and avocet. In order to protect both the birds and the fragile dams between the salt pans, only a main dam is open to visitors. This is one of the few Slovene nature areas where an entrance fee has to be paid.
Along the entire sea-shore you can expect to see Mediterranean shags. In winter time there are also numerous red-throated loons and black-necked grebes, which come surprisingly close to the shore at times. Kingfishers also winter along the sea, where they hunt for saltwater fish.
Perhaps the most important birding area at the coast is Škocjanski Zatok, a small nature reserve that is squeezed in between the motorway and the busy harbour of Koper. This reserve consists of a freshwater- and a brackish part and is only accessible from a circular walking path. Along the path there are bird-watching screens which offer amazing views to a wide variety of marshland birds. Locally breeding and easily seen are black-winged stilts, pygmy cormorants and common pochards. Little- and common terns are nesting on a shallow island in the brackish part and can be seen flying anywhere over the area. Both Cetti’s warblers and common nightingale are numerous. With some luck, you may be able to observe purple herons and least bitterns, both of which are breeding here as well. Al in all one of the best birding areas in Slovenia.
Several pairs of black-winged stilts nest close to the visitors’ path at Škocjanski Zatok and can be seen throughout the year.
Contact me for booking biologist.paul@gmail.com or tel ++386 41 902 110