rss_2.0Sciendo RSS Feed for Acrocephalushttps://sciendo.com/journal/ACROhttps://www.sciendo.comhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/647077a071e4585e08a9dd13/cover-image.jpghttps://sciendo.com/journal/ACRO140216https://sciendo.com/article/10.2478/acro-2020-0006<abstract> <title style='display:none'>Abstract</title> <p>Although the Mallard is one of the most numerous and best-studied waterbirds in the world, it received almost no attention in Slovenia. It is one of the most frequently observed waterbirds in our country, with frequency often reaching 100%. Sites with lower frequency either freeze in winter or have a low number of individuals to start with. The Mallard is also the most dominant species (17.5% and 89.0%) with higher dominance at sites less suitable for waterbirds due to the lack of available shoals. Mallards reach their maximum numbers during fall migration and winter. Spring migration has no discernible peak and has been significant only for Lake Cerknica. On shallow waters, the maximum is reached in August and September, a month before fall migration begins, indicating local movement to food-rich sites. Females make up only 36.7% of the observed Mallards and reach the maximum proportion (41.5%) in winter and the lowest in April and May (14.7%), when they nest. The breeding season in Slovenia lasts from mid-January to early December, with the majority of females rearing broods from April to July. Average brood size is 6.2 ± 2.66 and declines with season, age of young and altitude. It varies between habitat types and is highest on Treatment and Coastal Wetlands (7.3) and lowest on deep waters such as Reservoirs (5.7) and Lakes (5.6). No really high breeding densities were found in Slovenia and were similar to those in other countries. Breeding densities are higher on smaller Ponds (&lt; 8 ha), on sites with isolated islands and breeding colonies of gulls and terns (e.g. Lake Ptuj). Breeding density also decreases with elevation. Slovenian breeding population is estimated at 1,473–3,763 bp and wintering population averages 22,237 (10,376–32,010) individuals. Data suggest a decline in the wintering population most likely due to warmer winters. The majority of Mallards winter in NE Slovenia, where eight of eleven sites have a maximum of more than 1,000 Mallards. Most Mallards winter on the Drava river with Ptuj and Ormož lakes, where the highest numbers of Mallards were also recorded (Lake Ptuj: 8,330 ind., Lake Ormož: 5,400 ind.). The highest number of individuals during spring migration was recorded on Lake Cerknica (4,581) and during autumn migration on Medvedce reservoir (3,379). Apart from standing waters, the highest density of wintering Mallards is found in urban sections of slow-flowing rivers, probably due to higher safety and food availability.72,731 Mallards were hunted between 2001 and 2018, mainly in NE Slovenia (28% in the Pomursko hunting management district). The number of Mallards hunted is declining in all hunting areas and has declined by 64% since 2001 and even more since the 1990s. According to hunt data, hunting is by far the most important cause of the Mallard mortality in Slovenia (97.4%), followed by predation (1.1%). The Mallard mortality in Slovenia is largely unstudied and natural mortality is most likely underestimated, not only because it does not include mortality in the pre-fledging period, a period with the lowest survival, but also because the detectability of natural mortality is considerably lower. In contrast to the hunted numbers, there have been only nine recoveries of ringed individuals from abroad in the last 100 years, suggesting that hunters may not be reporting recoveries to the ringing centre. Apart from the 1972–1975 period, when 87% of Mallards were ringed, the intensity of ringing of Mallards in Slovenia is low, resulting in only seven Mallards recovered abroad. The longest distance of a Mallard ringed in Slovenia comes from Ukraine (1,290 km), while the longest distance between ringing and recovery sites is 2,075 km from an individual ringed in Finland. The only colour morphs documented in Slovenia are Mallards with paler feathers, attributed to one of the colour aberrations resulting from lower melanin productivity. Only few hybrids and mixed pairings with other wild duck species were observed.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00062023-10-08T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0008ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00082023-10-08T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0007ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00072023-10-08T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0009ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00092023-10-08T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0003ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00032021-12-14T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0002<abstract> <title style='display:none'>Abstract</title> <p>The Goosander <italic>Mergus merganser</italic> was not recorded breeding in Bulgaria till recently. We present herewith the very first record of the species breeding in the country and estimate the size of its breeding population in Bulgaria. Thus, we propose a change in its status in the country with more effort to be invested in the survey of this small, isolated population.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00022021-12-14T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0004<abstract> <title style='display:none'>Abstract</title> <p>Grassland birds were surveyed in two mountain pastures (Zaprikraj and Zapleč) in the southern part of the Julian Alps, Slovenia. The survey was carried out during the mornings between 26 and 30 June 2005. Due to the incomplete survey (only one visit, no nocturnal or targeted surveys and late season survey), the surveyed birds’ breeding density is only a rough estimate. 167 pairs belonging to 12 species were counted, with Tree (average density of 1.64 p/10 ha) and Water Pipit (average density of 1.60 p / 10 ha) being the most abundant. Both were observed in all altitudinal belts. The highest density in individual altitudinal belt was calculated for Red-backed Shrike <italic>Lanius collurio</italic> (3.78 p/10 ha) and Water Pipit (3.61 p/10 ha). In well preserved grasslands in the study area, most species reached high breeding densities compared to other parts of Slovenia and all were recorded higher than during the 1992 survey, although still mostly within limits of the elevations elsewhere in Slovenia. Breeding density of Skylark <italic>Alauda arvensis</italic> decreased with the elevation. Whinchat <italic>Saxicola rubetra</italic>, Skylark and Red-backed Shrike used significantly gentler slopes, while Pipits showed no preference for particular slopes.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00042021-12-14T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0005ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00052021-12-14T00:00:00.000+00:00https://sciendo.com/article/10.2478/acro-2020-0001<abstract> <title style='display:none'>Abstract</title> <p>Barn Owl <italic>Tyto alba</italic> pellets and loose bones on a cave floor from Amorgos (Cyclades, Greece) were examined and the birds found to have caught at least 39 species of bird, mostly identified from humeri, plus shrews <italic>Crocidura suaveolens</italic>, a few lizards and dung beetles, in addition to their principal diet of rodents (rats <italic>Rattus rattus</italic>, mice <italic>Apodemus</italic> spp. &amp; <italic>Mus musculus</italic>). Amongst the birds, migrants appeared most vulnerable to owl predation, with some notable exceptions, while resident species were under-represented. The range of bird species found appears to be the largest recorded for any Barn Owl study of a single site. Considerable differences were found in species proportions of taxa in fresh pellets and in loose bones, probably due to differential rates of degradation. Photographs of all humeri are included to aid identification in other studies.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/acro-2020-00012021-12-14T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0010ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00102021-01-29T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0009<abstract><title style='display:none'>Abstract</title><p>The Northern Lapwing numbers across Europe are declining owing to its insufficient breeding success. To determine the size, dynamics and habitat use of the lapwing population at Dravsko and Ptujsko polje, a survey was carried out between 2016 and 2018. In 2016, 2017 and 2018, we recorded 148, 130, and 117 pairs, respectively. The population declined during the study and the population trend is uncertain. Approximately 12 to 21% of the national lapwing population was recorded at Dravsko and Ptujsko polje, making them one of the most important breeding areas in Slovenia. The majority of lapwings were found in bare tilled fields and fields with young spring crops that enable unbroken all-round views. Crop data analysis showed a significant preference for maize fields which are mostly bare tillage at the start of the incubation period and therefore act as an ecological trap for lapwings due to the time coincidence of the nesting period and farming operations. For the protection of the lapwing in Slovenia, we recommend a time limit of farming operations or avoiding individual nests while working in the field. Both measures are recommended to be implemented in combination with the provision of suitable foraging habitat for chicks. For greater effectiveness, we propose priority implementation of conser vation measures on traditiona l breeding sites.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00092021-01-29T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0012ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00122021-01-29T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0011ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00112021-01-29T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0008<abstract><title style='display:none'>Abstract</title><p>Years ago, the Common Tern S<italic>terna</italic> h<italic>irundo</italic> was known to nest in Slovenia along larger watercourses. Today it only breeds locally in artificially built nesting areas. On the seashore, its nesting was confirmed for the first time in 1983, when 9 pairs bred in the Sečovlje Saltpans. In the same year, we started mapping the breeders in the Sečovlje Saltpans, which has continued till this very day. Since 2010, we have been systematically collecting data on the number of fledged birds. In 1991, the number of breeding pairs increased, which coincides with the increase in other parts of the Mediterranean. Since 1991, the size of the breeding population has been quite stable, ranging from 30 to 70 pairs. The Common Tern’s breeding success in the Sečovlje Saltpans is poor, mainly due to precipitation (40% of all unsuccessful nests) and predation (35%). Long, dry periods without rainfall have a positive effect on the hatching and fledging success. Appropriate water management, artificial islands and access to nesting sites control can prevent the disturbance caused by visitors and, in part, predators such as foxes and martens. At the Sečovlje Saltpans, the Common Tern’s survival depends entirely on the active management. The expected climate change, with increasing sea level rise and consequently more frequent flooding of low-lying areas, further aggravates its existence and survival in the Sečovlje Saltpans.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00082020-04-03T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0005<abstract><title style='display:none'>Abstract</title><p>The catalogue presents the data on all specimens of terns (Sterninae) that have been inventoried into the ornithological collection of the Slovenian Museum of Natural History (PMS). The catalogue includes data on preserved as well as lost specimens. The data have been collected from all inventory books at hand in the Slovenian Museum of Natural History. By the end of 2019, 66 different specimens of eight tern species have been recorded in the ornithological collection, of which 56 specimens are still preserved. Most specimens were collected in the 1940–1970 period. The largest number of specimens concerns the Black Tern <italic>Chlidonias niger</italic> and Common Tern <italic>Sterna hirundo</italic>. Among the collected terns, the specimens found in Slovenia predominate. Five specimens originate from other countries, specifically Eritrea, Oman, Serbia and Croatia.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00052020-04-03T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0007<abstract><title style='display:none'>Abstract</title><p>In 2018 and 2019, the breeding success of two Common Tern colonies on artificial lakes near the River Sava in Zagreb, Croatia, was studied. The colonies were visited weekly from May to July and we collected data on phenology, number of breeding pairs, clutch size as well as egg and chick survival. We also conducted a comparison between early and late breeders. Hatching and fledging success was within previously observed ranges, apart from a low hatching success on Siromaja in 2019. The smaller colony on Siromaja had a higher productivity in both years than the colony on Rakitje, although in 2018 an avian pox virus killed much of the late chicks on Rakitje. Early breeders seem to have had higher hatching success and average clutch size. Furthermore, a greater proportion of them managed to hatch all their eggs compared to late breeders, but the differences were not statistically significant. Our study provided baseline data for future monitoring of phenology and breeding success with regard to the management of breeding colonies.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00072020-04-03T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0002<abstract><title style='display:none'>Abstract</title><p>Between 2002 and 2019, monitoring of Common Tern <italic>Sterna hirundo</italic> and Little Tern <italic>Sternula albifrons</italic> along the Sava River near Zagreb, Croatia was conducted. Natura 2000 site “Sava kod Hrušćice” was designated to protect colony at river islands, with estimated population sizes of 100–150 pairs of Common and 20 pairs of the Little Tern. Flooding of the colony caused breeding failure in several years. Common Terns moved to breed on islands in gravel pits with a total population around 150 pairs, while Little Tern did not breed after 2010. In the last few years, terns have not bred at Hrušćica and the only colony inside the Natura 2000 site is situated on a breeding platform at Siromaja gravel pit. Channelling of rivers and hydropower plants are the main threats, changing natural dynamics of water level and causing reduction of gravel sediment in rivers.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00022020-04-03T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0001<abstract><title style='display:none'>Abstract</title><p>An overview of the long-term (1980–2019) population development of colonial Laridae species in continental part of Slovenia, their nest sites at anthropogenic water bodies, and various conservation measures with special focus on Common Tern <italic>Sterna hirundo</italic> along the Slovenian/border part of the Drava River is given. Breeding of these species occurs only on the westernmost fringes of the Pannonian plain, on lowland floodplains of the main rivers of the Danube Basin. Altogether, breeding of Common Tern and Black-headed Gull <italic>Larus ridibundus</italic> was recorded at 11 and 10 sites, respectively. Lake Ptuj is the single site with mixed-species colony residing there in all years of the study period, while at Ormož (two sites) it was established during the early 1990s in the Slovenian territory but moved completely to the Croatian side by the second half of the 2010s. At all other sites, a suitable breeding habitat became available or was provided by management in just a few years, or created only recently. The percentage of Common Tern national population breeding in continental Slovenia was usually well above 50% throughout the 1980s and 1990s (52–136 pairs), while in the last 16 years (77–258 pairs) it ranged between 40.8% and 69.0%. Breeding of Black-headed Gull remains largely limited to continental Slovenia. Overall, continental populations of both species in the last few years have been substantially higher compared to the most of the study period. Long-term trends were estimated as a moderate increase for Common Tern and a strong increase for Black-headed Gull. Since 2006, the Mediterranean Gull <italic>L. melanocephalus</italic> has been a regular breeder at Lake Ptuj (up to 28 pairs), the only such site in Slovenia. Three general types of conservation measures implemented at different nesting locations are described in detail: (1) measures to create/increase the total surface of breeding habitat – the construction of new breeding structures, such as artificial islands and nesting rafts, (2) measures to maintain and enhance breeding habitat through recurring management activities, and (3) measures aimed to increase chick/nest survival and improve breeding success.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00012020-04-03T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0004<abstract><title style='display:none'>Abstract</title><p>63 Common Tern <italic>Sterna hirundo</italic> samples from Croatia and Slovenia were analysed with respect to their genetic diversity and differentiation. Samples originated from two freshwater populations (areas of the rivers Sava and Drava) and one coastal population (Sečovlje Salina). The molecular marker of choice was 709 bp long fragment of the mitochondrial control region, the fastest-evolving part of the mitochondrial genome. 21 haplotypes with 12 polymorphic sites were identified. Overall haplotype diversity was substantial and estimated at 0.8599, while the overall nucleotide diversity was low and estimated at 0.0025. Diversity indices were highest for the Drava population, followed by the Sava and the lowest for the Sečovlje population. Overall genetic structure was significantly low (Fst=0.0377) and attributed to the differences in haplotype frequencies between the populations. The high level of genetic diversity found in continental populations illustrates the importance of their habitats as reservoirs of genetic diversity and calls for their further protection and management.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00042020-04-03T00:00:00.000+00:00https://sciendo.com/article/10.1515/acro-2019-0003<abstract><title style='display:none'>Abstract</title><p>During the breeding periods of 2018 and 2019 we investigated the extent of areas Common Terns <italic>Sterna hirundo</italic> use while searching for food. We used GPS-UHF tags to follow the movements of 23 terns from Slovenia (7 individuals) and Croatia (16 individuals). We investigated the movements of birds from three breeding sites, i.e. Lakes Ptuj, Siromaja 2 and Rakitje. Conclusions are based on 43,105 locations which were collected with a frequency of one reading per 20 minutes during the day and one reading per 4 hours during the night.</p><p>In Slovenia, terns used a 60 km long and narrow area over Stara struga Drave (former river-bed of the Drava River) between Ormož and Maribor as well as eleven fishponds / lakes in its surroundings, most of them in the Pesnica valley. The most distant location was 30 km of straight line from breeding islands, but it was visited only once by a single tern. The areas with the most locations, hence important areas, were Lake Ptuj, Drava at Ptuj, Stara struga Drave between Ptuj and Rošnja and about 20 km distant Lakes Radehova and Gradiško. These were probably the most important feeding areas for Common Terns breeding on Lake Ptuj. In Croatia, terns were found along the Sava almost exclusively, with only a few visits more than 2 km from the river. The most distant locations were over 60 km away from the breeding grounds, but terns visited them only rarely. Most locations of terns nesting on Siromaja were within a 5 km radius, while terns from Rakitje were making regular flights to waters up to 23 km from their colony. The area with the most locations visited by terns from both colonies was the Sava at Hrušćica. Besides, birds from the Rakitje colony were frequently recorded on the Sava near Savica and waterbodies within 5 km of the colony. These were probably the most important feeding areas for Common Terns breeding around Zagreb.</p></abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/acro-2019-00032020-04-03T00:00:00.000+00:00en-us-1