Wednesday 11 August 2021

Breeding season at the coastal wetlands

Spring goes by so fast that we don't even have the time to keep you posted on all the work & censuses we carry at the nature reserves where we work: Škocjanski zatok Nature Reserve and Strunjan Landscape Park. As the breeding season is now coming to an end, it's time for a short photo review of the wildlife we worked with on a daily basis. Beginning with Škocjanski zatok we can say that the breeding season in the brackish lagoon was overall quite successfull, mostly because of the numerous pairs of Common Terns Sterna hirundo (around 100 p), Little Terns Sternula albifrons (around 10 p) and Redshanks Tringa totanus (9-12 p) that have successfully fledged many juveniles. On the contrary the 20 or so pairs of Black-winged Stilts Himantopus himantopus seemed to have a weak nesting success, with only a few pairs fledging their chicks. Avocets Recurvirostra avosetta didn't breed in the lagoon this year (after two consecutive nestings), however we were again glad to have a few breeding pairs of Kentish Plovers Charadrius alexandrinus and two pairs of Great Crested Grebes Podiceps cristatus. The freshwater marsh produced yet again a brood of Purple Herons Ardea purpurea (5th consecutive year), one of Greylag Geese Anser anser and several pairs of Little Bittern Ixobrychus minutus & Water Rail Rallus aquaticus, as well as other commoner waterbirds and passerines. Like every year, we carried out regular weekly censuses, bird mappings and several escursions with kayak to the most inaccessible parts of the reserve, to map breeding birds. Photos of nests & chicks were taken during bird mapping censuses & bird ringing sessions in the lagoon and serve to give the idea about the nesting habitat of each presented species.

As the autumn migration is upon us, recently there were also some interesting migrant sightings at the reserve. The now-famous Grey-headed Lapwing Vanellus cinereus is a story by itself (last seen Monday 9 August), but among other goodies we also recorded: Black Stork Ciconia nigra (4), Caspian Tern Hydroprogne caspia (1-2), Glossy Ibis Plegadis falcinellus (2-4), Whiskered Tern Chlidonias hybrida (2), Little Crake Zapornia parva (1) and others. As usual, for more detailed & regular bird sightings info, check the reserve's official website & FB page.

Common Tern Sterna hirundo ringed as a chick in 2017 at Škocjanski zatok and now breeding in the same place.
Common Terns like to nest in the central part of the muddy islands, on the "higher ground".
Common Tern's nest with newly-hatched chicks.

Little Tern Sternula albifrons
Little Tern's nest, typically on the flatter part of an island, close to the water.
Little Tern Sternula albifrons - small and big chick.
Black-winged Stilt Himantopus himantopus
Black-winged Stilt's nest - a larger "woody" construction, containing 4 large pointed eggs.
Black-winged Stilt Himantopus himantopus - 3 juvenile sizes.
Common Redshank Tringa totanus & Little Tern Sternula albifrons
Common Redshank's nest - difficult to find as it's usually well hidden in the halophyte bushes.
Common Redshank's chick.
Little Ringed Plover Charadrius dubius
Little Ringed Plover's nest.
Little Ringed Plover Charadrius dubius - juvenile.
Puccinellia palustris - a salt-loving grass, growing on muddy islets in the brackish lagoon.
Kayaking the brackish lagoon during a census, with the town of Koper in the background.
Pygmy Cormorant Microcarbo pygmaeus - good numbers in summer, up to 45 individuals.
Common Sandpiper Actitis hypoleucos - July/August is the peak migration time of this species at the reserve.
Wood Sandpiper Tringa glareola - another common migrant from July onwards.
Little Bittern Ixobrychus minutus - female
Little Bittern Ixobrychus minutus - juvenile
Purple Heron Ardea purpurea - adult above & juvenile below.
Greylag Goose Anser anser - adult with juveniles.
Summer roost: Little Egrets Egretta garzetta & Pygmy Cormorants Microcarbo pygmaeus.
Cattle Egret Bubulcus ibis - small numbers are present throughout summer.
Young Fox Vulpes vulpes - big trouble for breeding birds when these are around.
Turtle Dove Streptopelia turtur - juvenile (increasingly rare breeding bird).
Green Woodpecker Picus viridis - juvenile in the nest (1st breeding for the reserve).
Rose-coloured Starling Pastor roseus - small numbers were present in Starling's roosting flocks throughout June, following the usual late May/early June "invasion".
Black Stork Ciconia nigra - group of 4 juveniles.
Grey-headed Lapwing Vanellus cinereus - see here.
"Southern Bladderwort" Utricularia australis - a rare species of water carnivorous plant.
European Tree Frog Hyla arborea hiding in Wild Teasel Dipsacus fullonum
Breeding bird's surveys in the wildest parts of Škocjanski zatok.

Meanwhile at Strunjan Landscape Park, despite the summer invasion by hordes of people and the encroaching pressure by parking lots and tourist attractions, wildlife still survives. Bee-eaters Merops apiaster are the main protagonists of the summer, with at least 4 pairs breeding again this year (see post from 2020) in the olive groves. By now most of the chicks are already out of the nests, but last week there was still some young-feeding action, with adults bringing large cicadas to their offsprings. The saltpans on the other hand this season hosted 3 pairs of Kentish Plovers Charadrius alexandrinus (but sadly with no fledgling success) and 4-5 pairs of Black-winged Stilts Himantopus himantopus. Large numbers of Mediterranean Gulls Ichthyaetus melanocephalus gather in the saltpans in summer for pre-roost and flocks of up to 500 individuals can be counted, while the sea hosts good numbers of Mediterranean Shags Phalacrocorax aristotelis ssp. desmarestii. Autumn migration in the last days was visible here too with a nice summer-plumaged Dunlin Calidris alpina, showing extremely well and close on a muddy bank by the visitor centre.

Kentish Plover Charadrius alexandrinus incubating
Kentish Plover's nest.
Black-winged Stilt Himantopus himantopus - smaller & larger juveniles.
Bee-eater Merops apiaster carrying cicadas to the nest.
Bee-eater's nest-hole and a prey leftover - Surreptitious Palm-borer Paysandisia archon
Bee-eater Merops apiaster - chick at the nest-hole & after leaving the nest.
Typical Beer-eater nesting site at Strunjan.
Mediterranean Gulls Ichthyaetus melanocephalus (different ages).
Dunlin Calidris alpina

There's also other interesting wildlife to be found in Strunjan, including a whole variety of truly Mediterranean species that are otherwise rare in Slovenia. One of them is the impressive Mammoth Wasp Megascolia maculata, a parasite wasp whose larva feeds on the larva of the European Rhinoceros Beetle Oryctes nasicornis (another Mediterranean species). Sara has managed to photograph this wasp back in June, feeding on Wild Privet Ligustrum vulgare blossoms. Also interesting was the find of a "Beach Tiger Beetle" Calomera littoralis on a muddy bank in the saltpans, representing another rare & specialised species of the Slovenian fauna.

Mammoth Wasp Megascolia maculata (compare size with the bee).
"Beach Tiger Beetle" Calomera littoralis
Strunjan's flysch cliffs - the largest remnant of untouched natural coast in Slovenia.