Journal & Issues

Volume 41 (2020): Issue 184-185 (November 2020)

Volume 40 (2019): Issue 182-183 (December 2019)

Volume 40 (2019): Issue 180-181 (November 2019)

Volume 39 (2018): Issue 178-179 (December 2018)

Volume 39 (2018): Issue 176-177 (November 2018)

Volume 38 (2017): Issue 174-175 (December 2017)

Volume 38 (2017): Issue 172-173 (November 2017)

Volume 37 (2016): Issue 170-171 (December 2016)

Volume 37 (2016): Issue 168-169 (November 2016)

Volume 36 (2015): Issue 166-167 (December 2015)

Volume 36 (2015): Issue 164-165 (November 2015)

Volume 35 (2014): Issue 162-163 (December 2014)

Volume 35 (2014): Issue 160-161 (November 2014)

Volume 34 (2013): Issue 158-159 (December 2013)

Volume 34 (2013): Issue 156-157 (June 2013)

Volume 33 (2012): Issue 154-155 (December 2012)

Volume 33 (2012): Issue 152-153 (March 2012)

Volume 32 (2011): Issue 150-151 (December 2011)

Volume 32 (2011): Issue 148-149 (June 2011)

Volume 31 (2010): Issue 147 (December 2010)

Volume 31 (2010): Issue 145-146 (September 2010)

Volume 31 (2010): Issue 144 (March 2010)

Volume 30 (2009): Issue 141-143 (December 2009)

Volume 30 (2009): Issue 140 (March 2009)

Journal Details
Format
Journal
eISSN
2199-6067
First Published
21 Oct 2009
Publication timeframe
4 times per year
Languages
English

Search

Volume 40 (2019): Issue 180-181 (November 2019)

Journal Details
Format
Journal
eISSN
2199-6067
First Published
21 Oct 2009
Publication timeframe
4 times per year
Languages
English

Search

8 Articles
Open Access

Breeding population dynamics of Common Tern Sterna hirundo and associated gull species with overview of conservation management in continental Slovenia

Published Online: 03 Apr 2020
Page range: 5 - 48

Abstract

Abstract

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 Sterna hirundo 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 Larus ridibundus 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 L. melanocephalus 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.

Keywords

  • Common Tern
  • breeding population
  • conservation management
  • continental Slovenia
Open Access

Dynamics of Common Sterna hirundo and Little Tern Sternula albifrons populations along the Sava River in North-western Croatia between 2002 and 2019

Published Online: 03 Apr 2020
Page range: 49 - 54

Abstract

Abstract

Between 2002 and 2019, monitoring of Common Tern Sterna hirundo and Little Tern Sternula albifrons 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.

Keywords

  • Common Tern
  • Little Tern
  • Sava River
  • monitoring
  • Natura 2000 site
  • threats
Open Access

Area use and important areas for Common Tern Sterna hirundo inland populations breeding in Slovenia and Croatia

Published Online: 03 Apr 2020
Page range: 55 - 67

Abstract

Abstract

During the breeding periods of 2018 and 2019 we investigated the extent of areas Common Terns Sterna hirundo 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.

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.

Keywords

  • Common Tern
  • foraging areas
  • GPS-UHF tags
  • home range
  • Drava
  • Sava
Open Access

Mitochondrial DNA control region diversity in Common Terns Sterna hirundo from Slovenia and Croatia

Published Online: 03 Apr 2020
Page range: 69 - 78

Abstract

Abstract

63 Common Tern Sterna hirundo 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.

Keywords

  • mtDNA
  • freshwater colonies
  • population genetics
  • Laridae
  • seabird
Open Access

Terns (Sterninae) in the collection of the Slovenian Museum of Natural History

Published Online: 03 Apr 2020
Page range: 79 - 92

Abstract

Abstract

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 Chlidonias niger and Common Tern Sterna hirundo. Among the collected terns, the specimens found in Slovenia predominate. Five specimens originate from other countries, specifically Eritrea, Oman, Serbia and Croatia.

Keywords

  • museum collection
  • Laridae
  • inventory
  • catalogue
  • bird collectors
  • history
Open Access

Morphometry of inland Common Terns Sterna hirundo in Croatia and Slovenia

Published Online: 03 Apr 2020
Page range: 93 - 96

Abstract

Abstract

Morphometric data on Common Terns breeding in Croatia and Slovenia are presented herewith for the first time. 130 breeding adult Common Terns Sterna hirundo were measured between 2016 and 2019 along the Sava and Drava Rivers. Sex was determined for 53 birds: 22 males and 31 females. Significant sexual differences were found for head and bill length, length of bill to skull, and bill depth. Croatian and Slovenian terns had slightly shorter wings and tails compared to birds from the Netherlands, Germany and England and were lighter than birds from Germany and Italy. Head, bill and tarsus lengths were similar to those in north European populations. Contrary to results from Scotland, in our studied population, birds with head and bill lengths >79.0 mm could not be sexed as males reliably.

Keywords

  • sexual dimorphism
  • head and bill lengths
Open Access

First data on breeding success of Croatian inland colonies of Common Tern Sterna hirundo

Published Online: 03 Apr 2020
Page range: 97 - 103

Abstract

Abstract

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.

Keywords

  • phenology
  • clutch size
  • hatching success
  • fledging success
  • productivity
Open Access

37 years of Common Tern Sterna hirundo breeding at Sečovlje Salina

Published Online: 03 Apr 2020
Page range: 105 - 112

Abstract

Abstract

Years ago, the Common Tern Sterna hirundo 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.

Keywords

  • Common Tern
  • Sečovlje Saltpans
  • breeding
8 Articles
Open Access

Breeding population dynamics of Common Tern Sterna hirundo and associated gull species with overview of conservation management in continental Slovenia

Published Online: 03 Apr 2020
Page range: 5 - 48

Abstract

Abstract

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 Sterna hirundo 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 Larus ridibundus 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 L. melanocephalus 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.

Keywords

  • Common Tern
  • breeding population
  • conservation management
  • continental Slovenia
Open Access

Dynamics of Common Sterna hirundo and Little Tern Sternula albifrons populations along the Sava River in North-western Croatia between 2002 and 2019

Published Online: 03 Apr 2020
Page range: 49 - 54

Abstract

Abstract

Between 2002 and 2019, monitoring of Common Tern Sterna hirundo and Little Tern Sternula albifrons 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.

Keywords

  • Common Tern
  • Little Tern
  • Sava River
  • monitoring
  • Natura 2000 site
  • threats
Open Access

Area use and important areas for Common Tern Sterna hirundo inland populations breeding in Slovenia and Croatia

Published Online: 03 Apr 2020
Page range: 55 - 67

Abstract

Abstract

During the breeding periods of 2018 and 2019 we investigated the extent of areas Common Terns Sterna hirundo 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.

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.

Keywords

  • Common Tern
  • foraging areas
  • GPS-UHF tags
  • home range
  • Drava
  • Sava
Open Access

Mitochondrial DNA control region diversity in Common Terns Sterna hirundo from Slovenia and Croatia

Published Online: 03 Apr 2020
Page range: 69 - 78

Abstract

Abstract

63 Common Tern Sterna hirundo 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.

Keywords

  • mtDNA
  • freshwater colonies
  • population genetics
  • Laridae
  • seabird
Open Access

Terns (Sterninae) in the collection of the Slovenian Museum of Natural History

Published Online: 03 Apr 2020
Page range: 79 - 92

Abstract

Abstract

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 Chlidonias niger and Common Tern Sterna hirundo. Among the collected terns, the specimens found in Slovenia predominate. Five specimens originate from other countries, specifically Eritrea, Oman, Serbia and Croatia.

Keywords

  • museum collection
  • Laridae
  • inventory
  • catalogue
  • bird collectors
  • history
Open Access

Morphometry of inland Common Terns Sterna hirundo in Croatia and Slovenia

Published Online: 03 Apr 2020
Page range: 93 - 96

Abstract

Abstract

Morphometric data on Common Terns breeding in Croatia and Slovenia are presented herewith for the first time. 130 breeding adult Common Terns Sterna hirundo were measured between 2016 and 2019 along the Sava and Drava Rivers. Sex was determined for 53 birds: 22 males and 31 females. Significant sexual differences were found for head and bill length, length of bill to skull, and bill depth. Croatian and Slovenian terns had slightly shorter wings and tails compared to birds from the Netherlands, Germany and England and were lighter than birds from Germany and Italy. Head, bill and tarsus lengths were similar to those in north European populations. Contrary to results from Scotland, in our studied population, birds with head and bill lengths >79.0 mm could not be sexed as males reliably.

Keywords

  • sexual dimorphism
  • head and bill lengths
Open Access

First data on breeding success of Croatian inland colonies of Common Tern Sterna hirundo

Published Online: 03 Apr 2020
Page range: 97 - 103

Abstract

Abstract

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.

Keywords

  • phenology
  • clutch size
  • hatching success
  • fledging success
  • productivity
Open Access

37 years of Common Tern Sterna hirundo breeding at Sečovlje Salina

Published Online: 03 Apr 2020
Page range: 105 - 112

Abstract

Abstract

Years ago, the Common Tern Sterna hirundo 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.

Keywords

  • Common Tern
  • Sečovlje Saltpans
  • breeding

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