Tuesday, 6 July 2021

A touch of Alps & Lepidoptera

An early summer excursion to the meadows on the southern edge of Trnovski gozd (Trnovo forest) is a soul-healing experience. In terms of (some of the) wildlife it's like visiting the Alps, without actually going to the Alps. As we have already written many times in this blog (we probably do about once a year!), the mountain meadows of Trnovski gozd are extremely biodiverse due to the mix of Alpine, Balkan, continental and Mediterranean elements. The area is a botanical and also a butterfly hot-spot. The end of June & beginning of July represent the peak of butterfly (and insect) activity. Needless to say during our recent visit a few days ago, the main focus were butterflies, but we actually also enjoyed in some of the rare plants present in the area. Birds were few (July is not a good time for birding), but some nevertheless proved quite cooperative and showy, especially those typical inhabitants of rocky mountain meadows like Rock Bunting Emberiza cia, Tree Pipit Anthus trivialis and Lesser Whitethroat Sylvia curruca. The major bird highlight however was an occupied nest of Golden Eagles Aquila chrysaetos in an inaccessible (and rather distant) cliff face. Only with the telescope we were able to see a large chick inside the nest and take some photos with digiscoping. The adults were nowhere to be seen (as typical with this species, which is rather elusive, even in its breeding area), despite us working the wider area of their hunting territory for most of the day. This nest has been known for several years, but as far as we know it hasn't been occupied in the last few years. It was therefore a pleasant surprise to see a young eagle inside! Among other raptors of note was a female Honey Buzzard Pernis apivorus, certainly a breeder in the area, as we regularly observe the species there in summer.

Golden Eagle Aquila chrysaetos - chick in the nest (digiscoping).
Rock Bunting Emberiza cia - male.
Lesser Whitethroat Sylvia curruca
Tree Pipit Anthus trivialis
Honey Buzzard Pernis apivorus - female.
Dry mountain meadows on the southern edge of Trnovski gozd.
View to the Vipava valley and mount Nanos in the distance.
Species-rich dry meadows.

 

Perhaps even more exciting than birds (and all the butterflies) was an encounter with two Horn-nosed Vipers Vipera ammodytes, in the driest and rockiest parts of the meadows. We almost trod on the one depicted below (a nice mid-sized individual), while the second one was found by specifically checking a good area of limestone scree. The second individual was quite small, but too quick and didn't allow any photographs. These vipers are otherwise very calm animals and usually slide away from you only when you come too close. If you spot them from a distance you are even able to watch and photograph them in all tranquility. But with their typical limestone-colour pattern is not always easy to spot them, especially the less-marked individuals (those with only a faint zig-zag on the back). This year, as also told by experts, has seen a boom in snake numbers, probably also due to the great abundance of small rodents in the Dinaric mountains. So far this year we have seen 3 Horn-nosed Vipers and 2 Adders Vipera berus already, while in some years it can actually happen we see none.

Horn-nosed Viper Vipera ammodytes
Typical Horn-nosed Viper habitat.

 

If we turn to butterflies, the indisputable highlight was the Apollo Parnassius apollo, one of our rarest and most endangered Lepidoptera. Although the species' stronghold is in the Julian Alps, a small isolated population exists on the edge of Trnovski gozd. In previous years we checked the location in mid summer and found several individuals, while this year we were perhaps a bit early. We saw only two Apollos and both quite briefly. Hopefully more will emerge in the next weeks. The Apollo was just one of the 32 butterfly species we saw that day and some of them are depicted in the photos below. There were also lots of Burnets Zygaena sp., as well as other Lepidoptera (including hawk-moths) and especially bumblebees and all sorts of Dipteras, all attracted to the amazing variety of blooming flowers, including the huge umbellifers like Laserpitium siler and Ligusticum seguieri.

Apollo Parnassius apollo
Woodland Ringlet Erebia medusa & Broad-bordered Bee Hawk-moth Hemaris fuciformis
Hummingbird Hawk-moth Macroglossum stellatarum on Cirsium erisithales
Chestnut Heath Coenonympha glycerion
Queen of Spain Fritillary Issoria lathonia
Heath Fritillary Melitaea athalia
Blue-spot Hairstreak Satyrium spini on Ruta divaricata
Scarce Swallowtail Iphiclides podalirius
Dark Green Fritillary Argynnis aglaja
Large Wall Brown Lasiommata maera
Burnet Zygaena sp.
Essex/Small Skipper Thymelicus lineola/sylvestris
Common Blue Polyommatus icarus
Small Tortoiseshell Aglais urticae
Painted Lady Vanessa cardui & Brimstone Gonepteryx rhamni
Anastrangalia sanguinolenta (Longhorn beetle-Cerambycidae)
Beech Longhorn Beetle Morimus funereus

 

On the botanical front it was very interesting (as usual in Trnovski gozd) due to the amazing mixture of Alpine and Balkan species of plants (not unlike the mix on mount Sne┼żnik). The dry meadows have mostly a sub-Mediterranean character and contain many of the plants seen in the warmer Karst & the Adriatic region, but at the same time, the elevation (1100-1200 m a.s.l.) opens the way to some Alpine "intrusions". Plants such as Hairy Alpenrose Rhododendron hirsutum, Edelweiss Leontopodium alpinum, Bear's Ear Primula auricula, Trumpet Gentian Gentiana clusii, Encrusted Saxifrage Saxifraga crustata, Narrow-leaved Wormwood Artemisia nitida and Shaggy Hawkweed Hieracium villosum are all alpine elements. On the other hand, some truly Balkanic species such as Genista holopetala, Scabiosa graminifolia, Euphorbia triflora and several others occur here. 

Species rich meadows with Alpine & Balkan elements.
Carniolan Lily Lilium carniolicum
Orange Lily Lilium bulbiferum
Horned Rampion Phyteuma scheuchzeri
Carniolan Vetch Astragalus carniolicus & Horned Rampion Phyteuma scheuchzeri
Rock Knapweed Centaurea rupestris
Hairy Alpenrose Rhododendron hirsutum
Spiked Bellflower Campanula spicata
Genista holopetala - a rare Balkan endemic.
Grass-leaved Scabious Scabiosa graminifolia
Edelweiss Leontopodium alpinum
Encrusted Saxifrage Saxifraga crustata
Shaggy Hawkweed Hieracium villosum
Triumfetti's (Perennial) Cornflower Centaurea triumfettii
Sainfoin sp. Onobrychis alba - very rare species in Slovenia, only found at Trnovski gozd's edge.
Southern Globethistle Echinops ritro ssp. ruthenicus

 

Down in the valley, a stop along the river Vipava was very productive (again in terms of butterflies), as we came across two Lesser Purple Emperors Apatura ilia, a species we're not used to see often, mostly because we don't visit the proper habitat in the proper season. This butterfly is a strictly lowland species, occurrying along rivers with willow Salix and poplar Populus trees. Apparently it is fairly common in the Vipava valley. Nearby we also saw a juvenile Cuckoo Cuculus canorus, while we failed to connect with the last breeding pair of Lesser Grey Shrikes Lanius minor in the Vipava valley (probably because of the inappropriate time).

Lesser Purple Emperor Apatura ilia
Juvenile Cuckoo Cuculus canorus

 

During the previous week (and in the end of June) we've been also around, mostly looking for butterflies in the dry Karstic grasslands near home, but also in some wetter areas of the Brkini hills for rarer species. The dry grasslands produced the usual early summer variety of species, although a Tufted Marbled Skipper Carcharodus floccifera was quite a find (a rare species inhabiting both traditional wet and dry meadows). Instead, along a small forest stream in the Brkini hills we found several Hungarian Gliders Neptis rivularis, another localised species in western Slovenia, with few localities so close to the Karst. 

Dry karstic meadows with Ferulago campestris, a typical summer umbellifer.
Spotted Fritillary Melitaea didyma
Great Banded Grayling Brintesia circe

Tufted Marbled Skipper Carcharodus floccifera
Black-veined White Aporia crataegi
High Brown Fritillary Argynnis adippe
Large Skipper Ochlodes sylvanus
Marbled Fritillary Brenthis daphne
Large Chequered Skipper Heteropterus morpheus
Meadow Brown Maniola jurtina
Hungarian Glider Neptis rivularis
Goat's Beard Aruncus dioicus - Hungarian Glider's larval foodplant.
Hungarian Glider's habitat.