Saturday 27 March 2021

March censuses with rare birds

The season of intense fieldwork has begun and the time to put together regular blogs is becoming increasingly limited. Nevertheless here's a quick review of our recent sightings and findings from the last couple of weeks around various sites in Slovenia.

First we'll start with Krakovski gozd, the last large remnant of oak lowland forest in Slovenia (close to Krško), where together with a small team of colleagues, a few days ago we carried out a group census of Middle Spotted Woodpecker Leiopicus medius. Unsurprisingly, this is a prime site for the species, supporting the highest population densities in Slovenia. Indeed, we recorded no less than 55 territorial Middle Spots in a single morning! The forest also supports good numbers of Ural Owls Strix uralensis - 5 birds were "flushed" while walking the transetcs, including one that posed really well (see pics). Two of our colleagues also observed a pair of White-tailed Eagles Haliaeetus albicilla close to its nest (the only known pair in Krakovski gozd), while common birds recorded by all included Black Dryocopus martius, Grey-headed Picus canus & Lesser Spotted Woodpeckers Dryobates minor. The forest floor was coming to life with all sorts of common wildflowers, but also rare species such as the omnipresent Dacian Lungwort Pulmonaria dacica, while the attractive Snake's-head Fritillaries Fritillaria meleagris were already looking a bit "poor" - they bloomed early this year, while at Ljubljansko barje they seem to be still in fine flower. For more similar posts about Krakovski gozd see here & here.

Oak-hornbeam lowland riparian forest, Krakovski gozd.
Primeval forest reserve, Krakovski gozd.
Fresh signs of recent logging in Krakovski gozd.
Middle Spotted Woodpecker Leiopicus medius, Krakovski gozd. One of 55 recorder!
Ural Owl Strix uralensis, Krakovski gozd.
Snake's-head Fritillary Fritillaria meleagris, Krakovski gozd (old photo).
Surely the most amazing news of the spring season so far is our recent find of the only known nest of Black Stork Ciconia nigra in western Slovenia! After we've been following the species for years at two different sites, this year we began to follow our local pairs a bit earlier, as soon as they returned from Africa around mid March and managed to find their nest rather quickly and unexpectedly. As one of the adults was on the nest when we found it, we kept a safety distance and left the site immediately to avoid disturbance, hence we only managed to take one single pic documenting the find. In the photo you can just make out the bill and part of the body sticking out behind the tree. Black Storks are extremely shy birds, especially at their nesting sites, therefore great caution must be taken when observing them breeding. Nevertheless, finding the nest of such a charismatic and rare bird in western Slovenia, was absolutely thrilling! Hopefully later in the season we'll be able to confirm the fledging of the juveniles, as we did a couple of years ago, when we observed a family circling above their home valley in summer. Good luck to them!
Black Stork Ciconia nigra on the nest, Western Slovenia.
Black Stork Ciconia nigra surprised by a snowstorm, Western Slovenia.
Black Stork Ciconia nigra, Western Slovenia.
On the nest-finding front another big success and satisfaction was discovering the nest of our local pair of Eagle Owls Bubo bubo not far from our home. Scanning with the scope from a distance of around 350 metres, Sara was able to locate a strange-looking clump of grass on a cliff face. A quick 60x zoom (pics below) and we were able to lay eyes on the female incubating the eggs! After a few minutes of watching the owl a shadow appeared in the sky above us: the season's first Short-toed Eagle Circaetus gallicus, flying in tandem with a Peregrine Falco peregrinus. A few very intense minutes of local patch highlight!
Find the owl...
Eagle Owl Bubo bubo on the nest, Karst.
Short-toed Eagle Circaetus gallicus, Karst.

On the limestone cliffs of the Karst edge wintering Wallcreepers Tichodroma muraria are still around, although shortly they will be on the move to their summer breeding quarters in the Alps. During a recent visit we spotted a nice male with black throat hopping around the mossy clumps of the endemic Tommasini's Sandwort Moehringia tommasinii (sadly not in flower yet). While observing the Wallcreeper, an Eagle Owl Bubo bubo surprised us with its hoots coming from the cliffs in the middle of the day! Nearby was also the local pair of Peregrines Falco peregrinus that exchanged prey in mid-air and entered a small ledge, where it already bred last year. Circling in the sky were also a few Crag Ptyonoprogne rupestris & House Martins Delichon urbicum, although we'll still need to wait a bit to see more hirundines returning in large numbers. 
On the migration front, surely the best find so far was a Red Kite Milvus milvus flying low above our house (garden tick) in the Karst on the 27th - a rare (although regular) migrant through most of Slovenia.
Wallcreeper Tichodroma muraria (male), Karst edge.
Peregrine Falco peregrinus, Karst edge.
Goshawk Accipiter gentilis, Karst.
Red Kite Milvus milvus, Karst.
A breathtaking sunset over the Karst (village of Avber) with a freshly snow-covered Trnovo plateau in the background.
The coastal marshes are also becoming particularly lively at this time of year as the advancing spring brings new migrants on a daily basis, while wintering birds leave for the north. Škocjanski zatok Nature Reserve recently saw a small and late passage of Cranes Grus grus that included around 200 birds flying by, as well as some stopping at the wetland to roost. Some days later (March 26th) we were lucky to see two birds descend into the freshwater marsh to rest and feed. As in most such cases, the birds were juveniles. Another good find was a Jack Snipe Lymnocryptes minimus feeding amongst +20 Common Snipes Gallinago gallinago, while certainly as much exciting was seeing returning the real harbingers of spring like Garganeys Spatula querquedula, Black-winged Stilts Himantopus himantopus, Little Ringed Plovers Charadrius dubius, Ruffs Calidris pugnax and the like - read more about the reserve's regular sighitgs here & here
Sara also found a Whimbrel Numenius phaeopus in the saltpans at Landscape Park Strunjan, where Kentish Plovers Charadrius alexandrinus have also returned.
Common Crane Grus grus, Škocjanski zatok NR.
Snipe Gallinago gallinago, Škocjanski zatok NR.
Jack Snipe Lymnocryptes minimus, Škocjanski zatok NR. Note the distinctive "bobbing".
Little Grebe Tachybaptus ruficollis, Škocjanski zatok NR.
Whimbrel Numenius phaeopus & Common Sandpiper Actitis hypoleucos, Landscape Park Strunjan.
Whimbrel Numenius phaeopus, Landscape Park Strunjan.
Shelduck Tadorna tadorna, Landscape Park Strunjan.

Sunday 14 March 2021

An exciting beginning

Early March is the time when the season of spring censuses begins and the traditional collective Eagle Owl monitoring represents the main opening event. Every year volunteers all around Slovenia gather to count singing Eagle OwlsBubo bubo (Europe's largest owl) simultaneously in one evening. The census is rather simple as it only involves waiting for dusk at defined spots, listening for spontaneous-calling Eagle Owls. Males sing intensively at this time of year, making them quite easy to hear and therefore confirm an occupied territory. This year we had a record of registered owls as 19 territories were confirmed in one evening (mostly in western Slovenia), among which 13 were in the Karst (the species' stronghold). 

Another exciting news is that two live cameras on the nests of Eagle Owls are now streaming on this website and the entire breeding cycle can be followed on the internet! So far only the second webcam shows an occupied nest, where the female is already incubating two eggs. The first webcam, showing the nest of our local pair we've been following for the past years is also active, but the owls visit it only occasionally. For those who speak and read Slovene, we recommend checking not only the webcams, but also the other pages within the highly informative website, treating the Eagle Owl's status, biology and conservation in Slovenia:


In the past few weeks we've spent several evenings listening to Eagle Owls in the Karst around our home. On one occasion we also made a fantastic daytime encounter with an owl, roosting at its favoured little cave in a cliff face. The distance from the bird was considerable and although the bird had initially seen us, it acted pretty relaxed and soon carried on with its daytime napping.

Eagle Owl Bubo bubo, Karst.

In the Karst and other parts of western Slovenia we are currently carrying out the census of Middle Spotted Woodpecker Leiopicus medius. Some transects were pretty productive with up to 11 Middle Spots counted, while others had disappointingly few individuals. Some areas we censused back in 2018 and 2019 have been completely transformed by logging and don't support woodpeckers anymore. Actually in recent times, wherever we visit Slovenian forests (be in the Karst or the Dinaric mountains) we find ourselves deeply saddened by the sight of heavy logging and the omnipresent sound of chainsaws...

Middle Spotted Woodpecker Leiopicus medius, Karst.
Middle Spotted Woodpecker's habitat in the Brkini hills.
An increasingly common sight across Slovenian forests.

Fortunately there's still some forest wildlife cheering us up during every census including countless Grey-headed Picus canus, Black Dryocopus martius and Lesser Spotted Woodpeckers Dryobates minor, Short-toed Certhia brachydactyla & Common Treecreepers Certhia familiaris, Hawfinches Coccothraustes coccothraustes and a dawn chorus of Song Turdus philomelos & Mistle Thrushes Turdus viscivorus. Although Wild Boars Sus scrofa are considered a big nuisance because of the damage they do on crops (but also on meadow & forest wildflowers), it's still nice to sometimes encounter these animals while walking in the forest. Yesterday we came across a large group of around 20 animals that included at least 10 newly born piglets.

Grey-headed Woodpecker Picus canus, Karst.
Raven Corvus corax, Karst.
Wild Boar Sus scrofa, Brkini hills.

Early March is also the time when amphibians emerge and head to water bodies to mate and deposit their eggs. Even the smaller ponds in the forest attract a great number of frogs and recently we came across several frogspawns. Most were the single and spherical clusters of the common Agile Frog Rana dalmatina, a widespread species in the warmer parts of Slovenia, while apparently Common Toads Bufo bufo haven't started to breed yet. On the other hand yesterday, in the Brkini hills we witnessed an incredible assembly of Common Frogs Rana temporaria, whose spawns are not laid singly like those of the Agile Frog, but in large clusters floating on the water. We counted around 20 adults in amplexus, floating among the freshly-laid eggs. A truly beautiful spring spectacle.

At this time of year, in the flysch hills bordering the Karst, which are rich in surface water (unlike the karstic limestone) is is not difficult to encounter Fire Salamanders Salamandra salamandra, especially in proximity of small water bodies in the forest. Wildflowers are also in full bloom on the wet soils of the cooler wooded hills or karstic dolinas and among them the Dog's-tooth Violet Erythronium dens-canis certainly steals the show.

A fantastic little pond in the middle of the forest in the Brkini hills.
Common Frog Rana temporaria, Brkini hills.
Fire Salamander Salamandra salamandra, Karst.
Spring Heath Erica carnea, Karst.
Liverwort Hepatica nobilis, Karst.
Dog's-tooth Violet Erythronium dens-canis, Karst.


Concerning the spring bird migration, occasional flocks of Common Cranes Grus grus are still passing overhead through western Slovenia and on the 7th we were again lucky to spot a distant flock above our house. Meanwhile in Škocjanski zatok even the first true summer migrants have appeared: on the 12th we observed a lone House Martin Delichon urbicum, 4 Alpine Swifts Apus melba and 4 Black-winged Stilts Himantopus himantopus. More to come in the following weeks...

Common Crane Grus grus, Karst.