Tuesday, 7 August 2018

The Golden Eagle's hunt

The past week or so has been quite slow in terms of trips and field activity. In the summer heat it can be quite hard to find something interesting, but during a few short trips to areas close to home, we at last gathered some observations worth of note. Yesterday we visited the grassy slopes of mount Nanos, where we witnessed an unbelievable hunting scene: an adult Golden Eagle Aquila chrysaetos caught a male Honey Buzzard Pernis apivorus in mid-air, then dropped it, while a second Golden Eagle collected the (now dead) prey, once again in mid-air! Both eagles then glided away to consume the prey. It all happened literally above our heads and we remained speechless!
Golden Eagle Aquila chrysaetos with a Honey Buzzard Pernis apivorus in the talons.

Nanos is a known breeding territory of Golden Eagles and we regularly observe these majestic birds, when we visit the plateau. However, witnessing a successful eagle's hunt is far from ordinary and even more so if we think about the chosen "victim" - another raptor! But the eagles on Nanos already amazed us last year in September, when up to 3 individuals (a family) "played" with a Chamois Rupicapra rupicapra - video here.
Nanos is in general an excellent raptor-watching location. In the warmest hours of the day we also observed 3 different Honey Buzzards Pernis apivorus (including the eagle's victim) patrolling the area, together with a Sparrowhawk Accipiter nisus, a Buzzard Buteo buteo and several Kestrels Falco tinnunculus. Around 1.00 pm also a short "train" of 4 Griffon Vultures Gyps fulvus headed north-west towards the Alps.
Honey Buzzard Pernis apivorus (male above, female below).

Griffon Vulture Gyps fulvus

Other interesting birds on Nanos included a juvenile Rock Thrush Monticola saxatilis on the steep southern slopes, a Black Woodpecker Dryocopus martius, a Hoopoe Upupa epops and the first Wood Warblers Phylloscopus sibilatrix of the autumn. Butterflies were quite thin on the ground due to the strong wind, but some species were nevertheless interesting, including the typical representatives of rocky grassland habitats. Of course we also enjoyed some late-summer plants.
Great Sooty Satyr Satyrus ferula (very worn).

Dryad Minois dryas

False Grayling Arethusana arethusa

Cross-leaved Gentian Gentiana cruciata with the eggs of the Alcon Blue Phengaris alcon f. rebeli
(those tiny white pearls in the lower pic).

Greater Yellow Gentian Gentiana lutea ssp. symphyandra

Southern Globethistle Echinops ritro ssp. ruthenicus

Stemless Carline Thistle Carlina acaulis

Rock Hare's-ear Bupleurum petraeum

Austrian Gentian Gentianella austriaca

Panicled Monk's-hood Aconitum paniculatum (A. degenii)

Yellow Bellflower Campanula thyrsoides

Jersey Tiger Euplagia quadripunctaria

Beech Longhorn Beetle Morimus funereus
Purple Hairstreak Quercusia (Neozephyrus) quercus

Thursday, 26 July 2018

Summer appointment with the Queen

Queen of the Alps - Alpine Eryngo Eryngium alpinum

Hairy Alpenrose Rhododendron hirsutum

White Adder's-mouth Malaxis monophyllos

Alpine Chamois Rupicapra rupicapra

Yellow-spotted Ringlet Erebia manto

Purple Emperor Apatura iris

Like every summer in recent years, also this time we made our traditional ascent to one of the very few mountains in Slovenia that is still home to the iconic Queen of the Alps or Alpine Eryngo Eryngium alpinum. This attractive plant was a once-widespread species on the mountain pastures of the Slovenian Alps (and elsewhere in the Alpine range), but was almost extirpated by intensive collecting. Nowadays the species is strictly protected, but it has become so rare that it can be only found on a few, quite inaccessible mountain slopes of the southern Julian Alps. Most of its strongholds (with the biggest stands containing up to 1000 plants) are found in the mountains south of Bohinj. Mount Črna prst (1844 m) is one of them and it has become a place we visit on a yearly basis, not only for its Queens, but also for the other alpine flora it hosts. A few days ago we visited the same place as last year (see this post) and found the Queens in an even better stage of bloom. However we noticed that there were far less specimen than the +800 we had last year and estimated no more than 200. But the season is still a bit early for the species as it is just starting to bloom and other specimen might be lurking in the shade of the tall undergrowth. For similar posts on the species, take a look at these posts from previous years: 2015, 2017, 2017.
Apart from a colourful multitude of alpine plants we also spotted a single White Adder's-mouth Malaxis monophyllos, a rare orchid found mostly in the wet mountainous regions of northern Slovenia. On the animal front we observed a juvenile Golden Eagle Aquila chrysaetos, an Alpine Chamois Rupicapra rupicapra, heard a Marmot Marmota marmota and almost trod on two adult Adders Vipera berus on the path! Among butterflies the most interesting finds included a single Purple Emperor Apatura iris and several Yellow-spotted Ringlets Erebia manto.

Saturday, 21 July 2018

The search for the Apollo

The Apollo Parnassius apollo is certainly one of the most beautiful butterflies in Europe, but sadly also a fast-declining one. Due to its beauty, it has always been a highly-prized species among collectors. However the main reason of the species' decline remains, as for many other species, habitat loss. Apollos live in warm and dry rocky grasslands, usually on mountain slopes. The habitat must contain a particular element - the presence of White Stonecrop Sedum album - the larval feeding plant. The abandonment of grazing in many areas throughout the Slovenian mountains has led to the overgrowing of grasslands and areas where the feeding plant grows. Thus, a once-widespread species all over the Slovenian Alps, the Apollo went extinct in many areas and today it can be found only in western Slovenia. Its main strongholds remain on the steep south-facing mountains above the Soča valley in NW Slovenia and on the southern edge of the Trnovo forest (Trnovski gozd). The latter is a disjuncted location from the rest of its Alpine range and is particularly vulnerable to habitat loss and consequently local extinction.
In the past years we had several encounters with the Apollo in the Julian Alps, but since then, we always wanted to see them closer to home, in the meadows of Trnovski gozd. A few days ago we set for a trip to the forest's southern edge, where rocky grasslands are alive with butterflies and colourful mountain flowers.
After a quite productive morning with lots of interesting butterflies, we finally stumbled into the first patch of White Stonecrop Sedum album. A few more steps along the limestone karstic edge and we were soon greeted by no less than three Apollos, dancing in the soft summer wind and occasionally perching to feed...
The adult's favourite feeding plants are different purple and pink-coloured Compositae, especially thistles Carduus sp. and plume thistles Cirsium sp., but also scabious Scabiosa sp. Our Apollos were most frequently feeding on Alpine Thistle Carduus defloratus. They were showing amazingly well and with a bit of patience we could have them feeding at a few centimeters away from our cameras. This also allowed to take the above short video. On their rocky slope, where the stonecrop abunded, we counted at least 7 specimen!
Making company to the Apollo (sometimes feeding on the same flower) were also a few Stirian Ringlets Erebia stirius. These interesting butterflies are widespread in the Slovenian Alps, but only found at a few sites outside of the alpine chain. One of these sites is the southern edge of Trnovski gozd and mount Nanos, where they inhabit rocky slopes, screes and limestone cliffs. The specimen in the lower picture above is feeding on this year's first flowering Liburnian Savory Satureja subspicata ssp. liburnica (an autumnal species).
The dry rocky grasslands at the edge of Trnovski gozd are extremely rich in plant & butterfly species. The meadows are completely covered in flowers from the end of April to the beginning of September and many species seem to be constantly in flower throughout the summer.
In the rockier places White Stonecrop Sedum album and other species of the same genus are accompanied by the succulent rosettes of Common Houseleek Sempervivum tectorum
Here and there, in the mountain meadows of Trnovski gozd one can still find some Edelweiss Leontopodium alpinum adorning the rocks. This species is one of the several alpine ones found in Trnovski gozd, outside their usual alpine distribution range (ice age relicts). Edelweiss was commoner in the past in Trnovski gozd, but due to uncontrolled collecting and habitat loss (overgrowing meadows), it has become quite rare and localised. It is thus, always a pleasure to find some nice bunches like the above, in hidden places, off the usual mountaineering tracks.
The meadows are also full of two species of pink, the more attractive being the fringed Montpellier's Pink Dianthus monspessulanus (or D. hyssopifolius), which resembles the high-altitude, alpine Sternberg's Pink Dianthus sternbergii (not found outside the Alps). The other abundant pink on dry karstic meadows is the Trieste's Pink Dianthus tergestinus (or D. sylvestris ssp. tergestinus) which sports a deep-pink colour of the petals.
Two beautiful bellflowers include the very common Clustered Bellflower Campanula glomerata (top pic) and the more attractive and rare Spiked Bellflower Campanula spicata (lower pic). The latter grows on steep rocky slopes and limestone cliffs. In Slovenia it is more of a mountain species.
In the Trnovo forest itself, butterflies are especially attracted to the flowers on forest glades or along roads. The above Peacock Aglais io was feeding on Heartleaf Oxeye Telekia speciosa, a common forest Compositae in the Dinaric mountains.
The above High Brown Fritillary Argynnis adippe was instead attracted to a Cabbage Thistle Cirsium oleraceum growing at the side of the forest road.
Perhaps the most surprising find of the day was the above Nettle-tree Butterfly Libythea celtis, that visited some puddles in a forest glade. This south European species is most at home in warm Mediterranean places, where its larval plant, Nettle Tree Celtis australis grows. In Slovenia it is common in the sub-Mediterranean west of the country and probably some individuals venture into the Trnovo forest from the warm Vipava valley.
Last but not least, while checking some wood piles at the side of the road, we found several Beech Longhorn Beetles Morimus funereus, including a very dark individual. In summer we regularly check all the fresh beech logs we see, in the hope of finding the rare Rosalia Longicorn Rosalia alpina. We really hope that we'll be able to show you this amazing species in one of the next posts!

Learn more about butterflies on our website:
Butterflies of Slovenia