Friday, 22 March 2019

Forests & wetlands in early spring

In recent weeks we've been quite busy with our traditional census of Middle Spotted Woodpecker Dendrocopos medius in western Slovenia, particularly in the Karst. Since 2016 we've been carrying out the census with the standardised playback method, usually with the help of other DOPPS-BirdLife Slovenia's volunteers (who we sincerely thank!). This year we decided to repeat the census in some areas we first investigated in 2016, as well as try to discover new territories, especially in the Karst. Currently we still need to carry out some of the census transects, but we already covered most of the areas of interest during the past week. So far the census has been a major success, with at least one Middle Spot recorded on every transects, but higher numbers were usually the norm. We are particularly happy with the results from the Brkini hills, where two transects (with approx. 8 census points each) held 13-14 individuals, while a trasect in a large area of oak woodland in the western part of the Karst held 7 individuals. Therefore this year we discovered several new territories on previously unknown locations for the species. All in all it looks like the species is fairly common in the right habitat, but is probably also expanding its range westwards, year after year. For more about the species in western Slovenia see here.
Middle Spotted Woodpecker Dendrocopos medius

During the first day of the census and even before recording the first Middle Spot, we were taken by surprise by a large raptor that we flushed in the oak-beech forest. It was a beautiful Ural Owl Strix uralensis - probably one of the 3 individuals we've been observing in recent years as wintering and erratic birds in the wider area of this observation. As we had a census to carry on, we didn't have much time to follow the owl's movements, but when it disappeared in the trees, it even delivered us a few spontaneous notes of its song.
Ural Owl Strix uralensis

Other forest wildlife was also to be enjoyed during the censuses. On one point we found a Black Woodpecker Dryocopus martius excavating a nest hole, while the usual 4 other woodpecker species were also commonly heard/seen. Interesting was the presence of some singing Treecreepers Certhia familiaris, sharing their territories with the commoner Short-toed Treecreepers Certhia brachydactyla. There aren't many areas in Slovenia where the two species live in the same habitat. 
The forest flora was (and still is) on good show and the plants we enjoyed most were certainly Dog's-tooth Violets Erythronium dens-canis, covering the woodland floor in some areas. It was also nice to see year's first Hacquetias Hacquetia epipactis, one of Slovenia's most typical spring wildflowers.
Black Woodpecker Dryocopus martius excavating a nest-hole.
Treecreeper Certhia familiaris
Dog's-tooth Violet Erythronium dens-canis
Hacquetia Hacquetia epipactis
Mezereon Daphne mezereum
Alpine Squill Scilla bifolia
Spring Crocus Crocus vernus
Spring Heath Erica carnea

In an area of open meadows in the Brkini hills we also observed probably winter's last Great Grey Shrike Lanius excubitor and the year's first copper - a Small Copper Lycaena phlaeas
Last weekend we also attended DOPPS' yearly Eagle Owl census in the Karst and checked our traditional site, where male and female Eagle Owl Bubo bubo were singing at dusk. We even saw the male perched on top of a black pine, similar to last year's encounter. After nightfall a Tawny Owl Strix aluco began to call and then an unexpected group of 3-4 Golden Jackals Canis aureus started howling at the moon!
Great Grey Shrike Lanius excubitor
Small Copper Lycaena phlaeas

In the Karst, during one of the censuses we also stopped at a large pond, where quite a lot of amphibian activity was going on. Common Toads Bufo bufo were everywhere (about 15 specimen) and in full reproductive frenzy. Also a few Agile Frogs Rana dalmatina were around, although even commoner were their eggs in the pond.
Common Toad Bufo bufo during copulation.
Common Toad's eggs.
Agile Frog Rana dalmatina
Agile Frog's eggs.

Meanwhile spring has also arrived to Škocjanski zatok Nature Reserve and in the last few days, we greeted the return of several migrants. The year's first Swallows Hirundo rustica and House Martins Delichon urbicum arrived a few days ago and are now an almost daily sight, especially during spells of bad weather. Of course we were also super-excited by the appearence of two Hoopoes Upupa epops, chasing each other in the freshwater marsh.
Many of the wintering ducks have left, but Garganeys Anas querquedula have returned instead. Perhaps the most interesting sight at the reserve was a flock of Spoonbills Platalea leucorodia. Four of them descended in the freshwater marsh a few days ago, while another 8 appeared a few days later and finally a flock of 13 was observed today. These birds are not common in Slovenia and are only seen a few times a year during migration. A ridiculously-confiding male Little Crake Porzana parva, walking along the reserve's main path was also one of the highlights of the last days. It didn't show any signs of fear as we approached it down to 1,5 meters (see video). Two Spotted Crakes Porzana porzana were also feeding at the side of a reedbed, while 3 rather late Common Cranes Grus grus were migrating overhead. Other interesting birds observed recently at the reserve included: 4 Marsh Harriers Circus aeruginosus, 4 Black-winged Stilts Himantopus himantopus, 1 Black-tailed Godwit Limosa limosa, 1 Little Ringed Plover Charadrius dubius, 3-4 Lapwings Vanellus vanellus, 1 Ferruginous Duck Aythya nyroca, 1 Bittern Botaurus stellaris, 1 Stonechat Saxicola torquatus.
A nice European Tree Frog Hyla arborea was also seen in a small pond by the visitor's center, while among flowers the first Early Spider Orchids Ophrys sphegodes in bloom have officially opened the orchid season.
For more up-to-date information on the latest bird observations at Škocjanski zatok, follow the Reserve's official Facebook page.
Little Crake Porzana parva (male)
Spotted Crake Porzana porzana
Common Crane Grus grus
Spoonbill Platalea leucorodia
Hoopoe Upupa epops
Garganey Anas querquedula
Black-winged Stilt Himantopus himantopus
Bittern Botaurus stellaris
Ferruginous Duck Aythya nyroca
Common Snipe Gallinago gallinago
Water Pipit Anthus spinoletta (breeding plumage)
European Tree Frog Hyla arborea
Marsh Frog Pelophylax ridibundus
Speckled Wood Pararge aegeria
Mahaleb Cherry Prunus mahaleb
Early Spider Orchid Ophrys sphegodes

Monday, 18 March 2019

Magical blue frogs


Among European frogs, certainly the greatest spring spectacle is performed by Moor Frogs Rana arvalis. The males, usually brown-coloured like many other frogs, turn bright blue during the courting season each spring. This spectacle is not very easy to witness as the blue colouring lasts for only a few days a year. Yesterday, with the help of two friends, one of our long-lasting dreams finally came true. We visited one of the known spawning sites at Ljubljansko barje (Ljubljana moor), just at the outskirts of Slovenia's capital and enjoyed in up to 150-200 colourful Moor Frogs. The frogs were gathering in pools of water in a beautiful floodplain forest of alder Alnus glutinosa and English oak Quercus robur. As a backdrop there were Middle Spotted Dendrocopos medius and Black Woodpeckers Drycopus martius calling in the trees overhead. As Moor Frogs are rare and endangered in Slovenia and moreover also very shy, we payed attention not to disturb them and kept a safe distance, viewing them with the telescope. For this reason, the photos are purely for documentation - watch the video in HD instead. The spawning sites at Ljubljansko barje are potentially vulnerable as they are isolated from other sites where the species occurs - that is: locally in eastern and northeastern Slovenia. Like many other "lekking" animals, also Moor Frogs are rather intolerant to any disturbance at their breeding sites, so great care should be taken when watching, but especially photographing these animals.
A special thank to Kaja and Leon for the precious help and for the good company in the field.

Wednesday, 6 March 2019

Marching into spring

It's prime time for woodpecker activity at the moment. Since the end of February we've been following our local woodpeckers in two patches of woodland in the Karst. Up to 6 species can be seen during a short afternoon birding session in a relatively small area of a few hectares. This is, all European species except White-backed, Three-toed, Syrian Woodpecker and Wryneck (the latter hasn't returned from Africa yet). The best time for observing them is late afternoon when they prepare for roosting. A pair of Black Woodpeckers Dryocopus martius is using its two traditional (old) nest-holes for roosting and is thus easy to observe. The male arrives early at the roosting site and announces its presence to other males, as well as "calls in" the female. Then several noisy pair rituals follow and sometimes a third woodpecker intrudes and causes a bit of mess. Here's a video of the male drumming and entering the roost hole in the evening (raise the volume):

Black Woodpecker Dryocopus martius

Middle Spotted Woodpeckers Dendrocopos medius on the other hand are more difficult to track down and we still didn't manage to find their roosting holes yet. However they can be frequently heard "mewing" at this time of year (like this). In a few days we'll begin with our traditional census of the species in the Karst and hopefully we'll discover some new breeding territories of this rather rare, but increasingly widespread woodpecker in western Slovenia.
Other woodpecker species are also making themselves prominent, including the common Great Spotted Dendrocopos major & Green Picus viridis, as well as the less common Lesser Spotted Dendrocopos minor & Grey-headed Woodpecker Picus canus. Trying to tell their territorial drummings apart is our popular pastime at the moment, especially now that we discovered that our local pair of Green Woodpeckers regularly drum as well (an otherwise uncommon and rarely-heard habit in most Green Woodpeckers).
Lesser Spotted Woodpecker Dendrocopos minor
Green Woodpecker Picus viridis

Spring flora is also emerging on the woodland floor, although slightly slower and later than in other parts of continental Slovenia (see previous post). This is mainly due to the well-drained limestone soil of the Karst which makes growth rather tough for the plants that inhabit it. Several butterflies are also frequently seen these days and among the very common ones like Brimstone Gonepteryx rhamni (infesting our Forsythia), Large Tortoiseshell Nypmphalis polychloros, Peacock Aglais io ect, we've also seen several Nettle-tree Butterflies Libythea celtis. This south-European species is common in the Primorska region of western Slovenia and scarce or very rare elsewhere. As the name suggests, its life cycle is linked to the nettle tree Celtis australis, which in turn grows mainly along the coast and in more sub-Mediterranean areas.
Nettle-tree Butterfly Libythea celtis
Large Tortoiseshell Nymphalis polychloros
Comma Polygonia c-album
Wood Mouse Apodemus sylvaticus
Spring Heath Erica carnea
"Reticulated Crocus" Crocus reticulatus
Cornelian Cherry Cornus mas
White Violet Viola alba

In the past two weeks there has been a massive migration of Common Cranes Grus grus over our skies. Birds wintering in Spain and the Mediterranean are now making their return journey to northern Europe and the first days of March represent the peak migration time for the species in our area. Large flocks have become increasingly common in recent years. Flocks of hundreds of birds have been observed almost on a daily basis since the end of February. Most flocks enter Slovenia thorough northeastern Italy and the Gulf of Trieste. We've been lucky to see or hear several flocks, including 44 over Škocjanski zatok (pics below), 107 over Sežana and about 50 over mount Nanos. A few days ago, we were even waken up in the middle of the night by the loud trumpeting calls of a flock of Cranes, migrating low over our house!
Common Cranes Grus grus over Škocjanski zatok.

Apart from the occasional migrating Cranes, the situation at Škocjanski zatok Nature Reserve is rather quiet at the moment. Many wintering birds have already left, while others haven't arrived yet. The reedbeds are still hosting small numbers of wintering Bearded Tits Panurus biarmicus, although seeing them proves quite difficult. Making them company are flocks of Reed Buntings Emberiza schoeniclus and Penduline Tits Remiz pendulinus, while a recent playback census of Water Rail Rallus aquaticus yielded at least 12 singing birds in the small wetland. Among the most interesting birds we've observed recently are Ferruginous Duck Aythya nyroca, White-fronted Goose Anser albifrons and the first Lapwings Vanellus vanellus, while someone has already observed two returning Purple Herons Ardea purpurea (maybe the pair that bred here last year).
Ferruginous Duck Aythya nyroca
Pochard Aythya ferina
Wigeon Anas penelope
White-fronted Goose Anser albifrons
Bearded Tit Panurus biarmicus - a typical view.
Lapwing Vanellus vanellus
Cetti's Warbler Cettia cetti - exploding around every corner!

Meanwhile we also visited lake Cerknica where we finally observed the two wintering Smews Mergellus albellus, together with the usual flock of +20 Goldeneyes Bucephala clangula. Other wildfolwl was also well represented on the lake, including a large flock of 235 Pintails Anas acuta, hundreds of Teals Anas crecca and the first two Garganeys Anas querquedula of the season. By the shores of the lake was even a nice female Merlin Falco columbarius, hunting small passerines in an orchard, as well as a male Hen Harrier Circus cyaneus.
Smew Mergellus albellus (with Wigeon Anas penelope).
Pintail Anas acuta
Merlin Falco columbarius