Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of s... more Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the AfricanEurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation
Detecting extremely rare and elusive species from vast wilderness areas is highly challenging. Th... more Detecting extremely rare and elusive species from vast wilderness areas is highly challenging. The Fennoscandian population of lesser white-fronted goose (LWfG; Anser erythropus) is the most endangered bird in Europe, with only 25-30 breeding pairs remaining in Northern Norway. Its former breeding range, however, covered mountainous parts of the entire Fennoscandia. Targeted conservation efforts during the 21st century has enabled the LWfG to recolonise some of its former breeding areas in Norway and possibly also in Finland. To locate individuals of this elusive species during the breeding season, we used environmental DNA (eDNA) extracted from ltered lake water from selected lakes in the former breeding habitat in northern Finland. We ampli ed and sequenced a short region of the mitochondrial control region to identify Anser-goose species in the lake water. In addition, we sampled eDNA from the water of a spring staging site of the Fennoscandian LWfG and from a known Norwegian breeding site, from which eDNA of the LWfG was positively found. eDNA of the LWfG was not detected within the former Finnish breeding range. Based on this, the LWfG has not recolonised its former breeding habitats in Finland or alternatively, we may not have sampled the exactly right lakes, or the eDNA concentration was below detection limits. Due to genus-speci c primers, we discovered taiga (A. fabalis fabalis) and tundra bean goose (A. fabalis rossicus) eDNA from several lakes in Northern Finland, proving the usefulness of the method.
Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of s... more Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation.
ABSTRACT Investigating space use of wild birds provides important knowledge of bird behavior and ... more ABSTRACT Investigating space use of wild birds provides important knowledge of bird behavior and ecology, which is crucial in the management and conservation of threatened species. In the present study, we used GPS satellite telemetry to investigate space use and movements of seven adult Eurasian Eagle-Owls (Bubo bubo) in Norway during breeding and post-breeding seasons. Breeding adults had a mean home range size of 42.9 km2 (SD ± 35.1 km2; 95% kernel density estimation Had hoc), and five individuals performed long (>20 km) excursive movements away from their breeding territories during autumn. Such wide-ranging behavior has not previously been reported for adults of the nominate subspecies B. b. bubo. The study demonstrates the need to investigate seasonal movements of species, populations, and age groups even if they are considered residents, and provides valuable information for management and conservation of the Eurasian Eagle-Owl.
Homage to Hersteinsson and Macdonald: climate warming and resource subsidies cause red fox range ... more Homage to Hersteinsson and Macdonald: climate warming and resource subsidies cause red fox range expansion and Arctic fox decline. Polar Research, 36(sup1).
Snøugleprosjektet er et samarbeid mellom Norsk institutt for naturforskning (NINA), Naturmuseum o... more Snøugleprosjektet er et samarbeid mellom Norsk institutt for naturforskning (NINA), Naturmuseum og Botanisk hage, Universitetet i Agder (NMB-UIA) og Norsk Ornitologisk Forening (NOF). Den forventede hekkesesongen i 2019 ble spolert da lemenbestanden kollapset på grunn av kraftig regn med påfølgende ising vinteren 2018/2019. Lemen har en 3-5 års syklus, så neste lementopp er forventet først i 2022/2023. Det ble derfor som forventet ikke rapportert noen hekkinger av snøugle i Norge i 2020. Et fåtalls snøugler forekom, med 20 kvalitetssikrede observasjoner fra Troms og Finnmark. Det ble i tillegg observert en snøugle på Hardangervidda (Vestland) ved to tilfeller i juli. Vi har fått inn opplysninger om 18 observasjoner i Finland, og 2 i Sverige, hvorav de fleste er fra grensetraktene mot Norge. Det ble heller ikke rapportert noen hekkinger i disse to nabolandene. Vi hadde ingen snøugler med aktive satellittsendere i Europa i 2020.
Snøugleprosjektet ble startet i 2005, og er et samarbeid mellom Norsk institutt for naturforsknin... more Snøugleprosjektet ble startet i 2005, og er et samarbeid mellom Norsk institutt for naturforskning (NINA), Naturmuseum og Botanisk hage, Universitetet i Agder (NMB-UIA) og Norsk Ornitologisk Forening (NOF). Det ble ikke rapportert noen hekkinger av snøugle i Norge i 2017, men vi fikk opplysninger om en ny dokumentert hekking fra 2015 i Troms. Det foreligger fire vinterobservasjoner fra Finnmark, og i tillegg ble en snøugle observert på Røst i perioden fra mai til september 2017. I 2017 hadde vi fire snøugler med aktive satelittsendere, og i slutten av februar 2018 var dette redusert til én ugle med fungerende sender av de syv som ble fanget i 2015. Det ble gjennomført kontroll av status for flere gamle hekkelokaliteter på Hardangervidda.
The Snowy Owl project, initiated in 2005, is a cooperation between the Norwegian Institute for Na... more The Snowy Owl project, initiated in 2005, is a cooperation between the Norwegian Institute for Nature Research, Agder Museum of Natural History and the Norwegian Ornithological Society. 2011 was the best breeding season for Snowy Owls in Fennoscandia since 1978. In Norway, 43 nests were confirmed. Twelve breeding Snowy Owls were captured in the counties of Finnmark and Troms, Northern Norway, and satellite transmitters were mounted. We had still six birds left in the beginning of 2013, but one of them was found dead in the middle of Norway in Mid-January. Four of them stayed at Novaja Semlja during summmer 2013, were three probably bred. The last one migrated north to Severnaja Semlja, where it's transmitter finally stopped sending signals in July 2013. There were no breeding records of snowy owls in Norway in 2013, but there have been some observations. By the end of February 2014, we have two owls alive with battery-transmitters that still send signals every 8 day. Both of them are at the Kola Peninsula. Two more owls with solar cell transmitters will hopefully start to send signals again in March-April.
European Journal of Wildlife Research, Jan 11, 2016
Genetic analysis has shown to be an important and efficient method for monitoring species, but th... more Genetic analysis has shown to be an important and efficient method for monitoring species, but the lack of genetic markers constrains such monitoring for many species. Here, we cross-amplified microsatellite loci in the snowy owl (Bubo scandiacus) using primers previously characterized in other species. Among polymorphic loci, we selected 12 loci that amplified relatively short fragments (<250 base pairs) to facilitate genotyping of moulted feathers and other non-invasively collected samples. These 12 loci, and a sex-typing marker, were amplified in two multiplex PCR sets and used to screen 49 snowy owls from a northern European population. The number of alleles observed at single loci was 2 to 17. Expected and observed heterozygosity ranged from 0.12 to 0.91 and from 0.12 to 0.96, respectively. The combined probability of identity for the 12 loci was 5.7 × 10−11. Our multiplex PCR assays are expected to be useful for genetic monitoring, parentage analysis, and population genetic studies of the snowy owl.
T he Lesser White-fronted Goose (Anser erythropus, subsequently referred to as LWfG) is the most ... more T he Lesser White-fronted Goose (Anser erythropus, subsequently referred to as LWfG) is the most threatened arctic goose species of the Palearctic region, and the populations throughout the range from Fennoscandia to easternmost Siberia are still declining (Lorentsen et al. 1999). At the Valdak Marshes (Finnmark, Norway), the most important staging area in the Nordic countries, the spring staging population has decreased by approximately one third since 1990 (Aarvak & Øien 2004, pp 19-24 in this report). The other traditionally important spring staging area of the Fennoscandian population, the Bothnian Bay coast in Finland, has experienced a decrease by more than 85% since 1990 and this site hosted less than 10 individuals in spring 2003 (Markkola & Luukkonen 2004, pp. 14-18 in this report). Part of the decrease at the Bothnian Bay coast may be due to the changing migration pattern of the LWfG: it seems that more individuals than earlier simply pass the Bothnian Bay coast and continue straight to Lapland after a staging period in western Estonia. A possible explanation for this could be that springs have become earlier and enabled an earlier arrival of the LWfG in the staging and breeding areas in Lapland. The current estimate for the Fennoscandian population (excluding the Russian Kola Peninsula) is 20-30 breeding pairs. This estimate is updated and based on a statistically significant negative population trend in Fennoscandia since the year 1990. At the time of the previous corresponding estimate (see Aarvak et al. 2001, Aarvak & Øien 2001), the population trend in the 1990's was not statistically significant. The population has had the same negative trend during the whole period, but after adding the years 2001-2003 to the matrix, the population decline is now significant. The most important threat for all LWfG populations is the high mortality due to hunting and poaching. Also, loss of habitats on the staging and wintering grounds and disturbance are serious threats for the species all over the distribution range. The present report documents the results of the work conducted by the Fennoscandian Lesser White-fronted Goose conservation project, jointly run by the Norwegian Ornithological Society and WWF Finland, during the last three years (2001-2003). The report also presents important data and news from other parts of the LWfG breeding, migration and wintering range, and an overview of the situation of the Swedish reintroduced LWfG population.
Migratory species display a range of migration patterns between irruptive (facultative) to regula... more Migratory species display a range of migration patterns between irruptive (facultative) to regular (obligate), as a response to different predictability of resources. In the Arctic, snow directly influences resource availability. The causes and consequences of different migration patterns of migratory species as a response to the snow conditions remains however unexplored. Birds migrating to the Arctic are expected to follow the spring snowmelt to optimise their arrival time and select for snow-free areas to maximise prey encounter en-route. Based on large-scale movement data, we compared the migration patterns of three top predator species of the tundra in relation to the spatio-temporal dynamics of snow cover. The snowy owl, an irruptive migrant, the rough-legged buzzard, with an intermediary migration pattern, and the peregrine falcon as a regular migrant, all followed, as expected, the spring snowmelt during their migrations. However, the owl stayed ahead, the buzzard stayed on, and the falcon stayed behind the spatio-temporal peak in snowmelt. Although none of the species avoided snow-covered areas, they presumably used snow presence as a cue to time their arrival at their breeding grounds. We show the importance of environmental cues for species with different migration patterns. Animals are expected to alter their behaviour as a response to ongoing climate change 1. Animal movement is a behaviour that can be strongly influenced by external, biotic and abiotic environmental factors 2. Several studies suggested that avian species adjust their movements in response to environmental conditions 3-5 and consequently, optimise their reproduction and survival 6,7. However, more evidence is necessary to fully understand
Blackflies (Simuliidae) have been shown to influence birds negatively in several ways. In 2011, d... more Blackflies (Simuliidae) have been shown to influence birds negatively in several ways. In 2011, during a peak lemming year, we found that two of 28 nests of Snowy Owls Bubo scandiacus in Northern Norway and Finland failed due to blackfly attacks on the incubating female. The observations also suggest that adult survival may be influenced by these insects. The owls' choice of breeding habitat can be decisive in their vulnerability to blackflies.
In this study we demonstrate that non-breeding adult Lesser White-fronted Geese Anser erythropus ... more In this study we demonstrate that non-breeding adult Lesser White-fronted Geese Anser erythropus from the Fennoscandian breeding population may undertake long-distance moult migration eastwards. Of three individuals equipped with satellite transmitters at a spring staging site in northern Norway, two migrated to moulting sites in the area of Kolgujev Island and Kanin Peninsula, while the third headed towards the Taimyr Peninsula, all in northern Russia. The first leg of the moult migration route for non-breeders was between Finnmark, Norway and the Kanin Peninsula area in northwestern Russia, a similar route to that taken on autumn migration by Fennoscandian Lesser White-fronted Geese that had bred successfully. After the moulting period, one of the individuals followed a southwestern route to Poland and Germany, where it spent the first part of the winter. The satellite signals from the other two geese ceased abruptly in early autumn, indicating that the birds may have been illegally shot in Russia. Locating new moulting and migration stopover sites is of crucial importance for the conservation of the critically endangered Fennoscandian subpopulation of this species.
Arctic warming and decreasing sea-ice cover along the Siberian coast in the Arctic Ocean leads to... more Arctic warming and decreasing sea-ice cover along the Siberian coast in the Arctic Ocean leads to greater accessibility for operations such as oil drilling and traffic of tankers. This implies increasing risks for Steller's Eider Polysticta stelleri wintering, moulting and staging along the coasts of the Varanger Peninsula, Norway. Steller's Eiders were surveyed by monthly counts during winter and early spring 2016/2017 to investigate numbers and distribution throughout the winter. The highest number of wintering Steller's Eiders was found in January, representing ~7 % of the European population. In February-April numbers were lower, but at a rather stable level. We found relatively little variation in distribution between months, although the birds were more evenly distributed along the coast later in winter. Mean flock size was significantly larger in January than in March and April. Feeding behaviour was exclusively observed in shallow water, generally at depths of up to 6 m. Areas of focus for an oil pollution emergency plan are pointed out and discussed.
In the face of global change, conservation actions are implemented worldwide to reduce the risk o... more In the face of global change, conservation actions are implemented worldwide to reduce the risk of extinction of declining populations. Population dynamics can be, however, the result of complex biotic and abiotic interactions. Therefore, it is often unsure to what extent management contributes to the recovery of a population if a proper scientific assessment is lacking. If conservation is the goal, it is crucial to quantify the impact of management actions. The Fennoscandian population of the Lesser White-Fronted Goose Anser erythropus (henceforth LWFG) experienced a dramatic decline in the last decades, to the point that conservation actions were deemed necessary. Among several conservation initiatives, culling of invasive red fox has become relevant, as red fox is perceived to be the main factor affecting reproductive success through predation on chicks and eggs. The LWFG population trend has reversed from negative to positive since the onset of the fox control program, suggesting an overall positive effect of management. However, in Arctic ecosystems, factors such cyclic small rodent populations and fluctuations in ungulate carrion availability can determine strong variation in annual predation pressure and in turn affect geese recruitment and survival. Using 19 years of data, we investigated to what extent red fox culling contributed to the recovery of the population. Specifically, we evaluated whether fox removal had the expected positive effect on LWFG reproductive success, while taking into account those factors outlined above that may confound the effect of the management action. We predicted LWFG breeding success to fluctuate synchronously with the rodent cycle due to an apparent facilitation mechanism. We also expect that increased availability of reindeer carcasses sustain foxes during the harsh arctic winter and enhance their survival, especially in years with deep snow that makes small rodents less accessible. Thus, we predicted lower reproductive success in years with high carcass abundance, due to an apparent competition mechanism. Moreover, we used these relationships to assess the relative impact of fox culling program. We found a strong positive effect of rodent density on geese breeding success, as well as a negative effect of the yearly amount of reindeer carcasses. However, there was no evidence in the data for any positive effect of fox culling. These results are relevant for the conservation of the LWFG population. Overall, this study emphasize the importance of scientifically evaluating the effectiveness of management actions by taking into account all the potential confounding factors.peerReviewe
The use of tracking devices to monitor birds is extensive, but the effects of such instruments on... more The use of tracking devices to monitor birds is extensive, but the effects of such instruments on equipped individuals are still insufficiently taken into account. Here we evaluate potential effects of backpack-mounted satellite transmitters (platform terminal transmitters; PTTs) on survival of 28 Snowy Owls Bubo scandiacus. Six confirmed deaths were all probably related to natural and human-induced causes. Although PTT operational time was significantly shorter than expected lifetime of Snowy Owls, five owls were observed alive after transmissions ceased. Additionally four PTTs stopped due to low battery levels, indicating end of transmitter life and not owl mortality. We found no evidence of mortality caused by PTTs, but sample sizes are relatively low and detrimental effects on equipped Snowy Owls cannot be excluded. We recommend caution when instrumenting large owls.
Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of s... more Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the AfricanEurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation
Detecting extremely rare and elusive species from vast wilderness areas is highly challenging. Th... more Detecting extremely rare and elusive species from vast wilderness areas is highly challenging. The Fennoscandian population of lesser white-fronted goose (LWfG; Anser erythropus) is the most endangered bird in Europe, with only 25-30 breeding pairs remaining in Northern Norway. Its former breeding range, however, covered mountainous parts of the entire Fennoscandia. Targeted conservation efforts during the 21st century has enabled the LWfG to recolonise some of its former breeding areas in Norway and possibly also in Finland. To locate individuals of this elusive species during the breeding season, we used environmental DNA (eDNA) extracted from ltered lake water from selected lakes in the former breeding habitat in northern Finland. We ampli ed and sequenced a short region of the mitochondrial control region to identify Anser-goose species in the lake water. In addition, we sampled eDNA from the water of a spring staging site of the Fennoscandian LWfG and from a known Norwegian breeding site, from which eDNA of the LWfG was positively found. eDNA of the LWfG was not detected within the former Finnish breeding range. Based on this, the LWfG has not recolonised its former breeding habitats in Finland or alternatively, we may not have sampled the exactly right lakes, or the eDNA concentration was below detection limits. Due to genus-speci c primers, we discovered taiga (A. fabalis fabalis) and tundra bean goose (A. fabalis rossicus) eDNA from several lakes in Northern Finland, proving the usefulness of the method.
Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of s... more Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation.
ABSTRACT Investigating space use of wild birds provides important knowledge of bird behavior and ... more ABSTRACT Investigating space use of wild birds provides important knowledge of bird behavior and ecology, which is crucial in the management and conservation of threatened species. In the present study, we used GPS satellite telemetry to investigate space use and movements of seven adult Eurasian Eagle-Owls (Bubo bubo) in Norway during breeding and post-breeding seasons. Breeding adults had a mean home range size of 42.9 km2 (SD ± 35.1 km2; 95% kernel density estimation Had hoc), and five individuals performed long (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;20 km) excursive movements away from their breeding territories during autumn. Such wide-ranging behavior has not previously been reported for adults of the nominate subspecies B. b. bubo. The study demonstrates the need to investigate seasonal movements of species, populations, and age groups even if they are considered residents, and provides valuable information for management and conservation of the Eurasian Eagle-Owl.
Homage to Hersteinsson and Macdonald: climate warming and resource subsidies cause red fox range ... more Homage to Hersteinsson and Macdonald: climate warming and resource subsidies cause red fox range expansion and Arctic fox decline. Polar Research, 36(sup1).
Snøugleprosjektet er et samarbeid mellom Norsk institutt for naturforskning (NINA), Naturmuseum o... more Snøugleprosjektet er et samarbeid mellom Norsk institutt for naturforskning (NINA), Naturmuseum og Botanisk hage, Universitetet i Agder (NMB-UIA) og Norsk Ornitologisk Forening (NOF). Den forventede hekkesesongen i 2019 ble spolert da lemenbestanden kollapset på grunn av kraftig regn med påfølgende ising vinteren 2018/2019. Lemen har en 3-5 års syklus, så neste lementopp er forventet først i 2022/2023. Det ble derfor som forventet ikke rapportert noen hekkinger av snøugle i Norge i 2020. Et fåtalls snøugler forekom, med 20 kvalitetssikrede observasjoner fra Troms og Finnmark. Det ble i tillegg observert en snøugle på Hardangervidda (Vestland) ved to tilfeller i juli. Vi har fått inn opplysninger om 18 observasjoner i Finland, og 2 i Sverige, hvorav de fleste er fra grensetraktene mot Norge. Det ble heller ikke rapportert noen hekkinger i disse to nabolandene. Vi hadde ingen snøugler med aktive satellittsendere i Europa i 2020.
Snøugleprosjektet ble startet i 2005, og er et samarbeid mellom Norsk institutt for naturforsknin... more Snøugleprosjektet ble startet i 2005, og er et samarbeid mellom Norsk institutt for naturforskning (NINA), Naturmuseum og Botanisk hage, Universitetet i Agder (NMB-UIA) og Norsk Ornitologisk Forening (NOF). Det ble ikke rapportert noen hekkinger av snøugle i Norge i 2017, men vi fikk opplysninger om en ny dokumentert hekking fra 2015 i Troms. Det foreligger fire vinterobservasjoner fra Finnmark, og i tillegg ble en snøugle observert på Røst i perioden fra mai til september 2017. I 2017 hadde vi fire snøugler med aktive satelittsendere, og i slutten av februar 2018 var dette redusert til én ugle med fungerende sender av de syv som ble fanget i 2015. Det ble gjennomført kontroll av status for flere gamle hekkelokaliteter på Hardangervidda.
The Snowy Owl project, initiated in 2005, is a cooperation between the Norwegian Institute for Na... more The Snowy Owl project, initiated in 2005, is a cooperation between the Norwegian Institute for Nature Research, Agder Museum of Natural History and the Norwegian Ornithological Society. 2011 was the best breeding season for Snowy Owls in Fennoscandia since 1978. In Norway, 43 nests were confirmed. Twelve breeding Snowy Owls were captured in the counties of Finnmark and Troms, Northern Norway, and satellite transmitters were mounted. We had still six birds left in the beginning of 2013, but one of them was found dead in the middle of Norway in Mid-January. Four of them stayed at Novaja Semlja during summmer 2013, were three probably bred. The last one migrated north to Severnaja Semlja, where it's transmitter finally stopped sending signals in July 2013. There were no breeding records of snowy owls in Norway in 2013, but there have been some observations. By the end of February 2014, we have two owls alive with battery-transmitters that still send signals every 8 day. Both of them are at the Kola Peninsula. Two more owls with solar cell transmitters will hopefully start to send signals again in March-April.
European Journal of Wildlife Research, Jan 11, 2016
Genetic analysis has shown to be an important and efficient method for monitoring species, but th... more Genetic analysis has shown to be an important and efficient method for monitoring species, but the lack of genetic markers constrains such monitoring for many species. Here, we cross-amplified microsatellite loci in the snowy owl (Bubo scandiacus) using primers previously characterized in other species. Among polymorphic loci, we selected 12 loci that amplified relatively short fragments (<250 base pairs) to facilitate genotyping of moulted feathers and other non-invasively collected samples. These 12 loci, and a sex-typing marker, were amplified in two multiplex PCR sets and used to screen 49 snowy owls from a northern European population. The number of alleles observed at single loci was 2 to 17. Expected and observed heterozygosity ranged from 0.12 to 0.91 and from 0.12 to 0.96, respectively. The combined probability of identity for the 12 loci was 5.7 × 10−11. Our multiplex PCR assays are expected to be useful for genetic monitoring, parentage analysis, and population genetic studies of the snowy owl.
T he Lesser White-fronted Goose (Anser erythropus, subsequently referred to as LWfG) is the most ... more T he Lesser White-fronted Goose (Anser erythropus, subsequently referred to as LWfG) is the most threatened arctic goose species of the Palearctic region, and the populations throughout the range from Fennoscandia to easternmost Siberia are still declining (Lorentsen et al. 1999). At the Valdak Marshes (Finnmark, Norway), the most important staging area in the Nordic countries, the spring staging population has decreased by approximately one third since 1990 (Aarvak & Øien 2004, pp 19-24 in this report). The other traditionally important spring staging area of the Fennoscandian population, the Bothnian Bay coast in Finland, has experienced a decrease by more than 85% since 1990 and this site hosted less than 10 individuals in spring 2003 (Markkola & Luukkonen 2004, pp. 14-18 in this report). Part of the decrease at the Bothnian Bay coast may be due to the changing migration pattern of the LWfG: it seems that more individuals than earlier simply pass the Bothnian Bay coast and continue straight to Lapland after a staging period in western Estonia. A possible explanation for this could be that springs have become earlier and enabled an earlier arrival of the LWfG in the staging and breeding areas in Lapland. The current estimate for the Fennoscandian population (excluding the Russian Kola Peninsula) is 20-30 breeding pairs. This estimate is updated and based on a statistically significant negative population trend in Fennoscandia since the year 1990. At the time of the previous corresponding estimate (see Aarvak et al. 2001, Aarvak & Øien 2001), the population trend in the 1990's was not statistically significant. The population has had the same negative trend during the whole period, but after adding the years 2001-2003 to the matrix, the population decline is now significant. The most important threat for all LWfG populations is the high mortality due to hunting and poaching. Also, loss of habitats on the staging and wintering grounds and disturbance are serious threats for the species all over the distribution range. The present report documents the results of the work conducted by the Fennoscandian Lesser White-fronted Goose conservation project, jointly run by the Norwegian Ornithological Society and WWF Finland, during the last three years (2001-2003). The report also presents important data and news from other parts of the LWfG breeding, migration and wintering range, and an overview of the situation of the Swedish reintroduced LWfG population.
Migratory species display a range of migration patterns between irruptive (facultative) to regula... more Migratory species display a range of migration patterns between irruptive (facultative) to regular (obligate), as a response to different predictability of resources. In the Arctic, snow directly influences resource availability. The causes and consequences of different migration patterns of migratory species as a response to the snow conditions remains however unexplored. Birds migrating to the Arctic are expected to follow the spring snowmelt to optimise their arrival time and select for snow-free areas to maximise prey encounter en-route. Based on large-scale movement data, we compared the migration patterns of three top predator species of the tundra in relation to the spatio-temporal dynamics of snow cover. The snowy owl, an irruptive migrant, the rough-legged buzzard, with an intermediary migration pattern, and the peregrine falcon as a regular migrant, all followed, as expected, the spring snowmelt during their migrations. However, the owl stayed ahead, the buzzard stayed on, and the falcon stayed behind the spatio-temporal peak in snowmelt. Although none of the species avoided snow-covered areas, they presumably used snow presence as a cue to time their arrival at their breeding grounds. We show the importance of environmental cues for species with different migration patterns. Animals are expected to alter their behaviour as a response to ongoing climate change 1. Animal movement is a behaviour that can be strongly influenced by external, biotic and abiotic environmental factors 2. Several studies suggested that avian species adjust their movements in response to environmental conditions 3-5 and consequently, optimise their reproduction and survival 6,7. However, more evidence is necessary to fully understand
Blackflies (Simuliidae) have been shown to influence birds negatively in several ways. In 2011, d... more Blackflies (Simuliidae) have been shown to influence birds negatively in several ways. In 2011, during a peak lemming year, we found that two of 28 nests of Snowy Owls Bubo scandiacus in Northern Norway and Finland failed due to blackfly attacks on the incubating female. The observations also suggest that adult survival may be influenced by these insects. The owls' choice of breeding habitat can be decisive in their vulnerability to blackflies.
In this study we demonstrate that non-breeding adult Lesser White-fronted Geese Anser erythropus ... more In this study we demonstrate that non-breeding adult Lesser White-fronted Geese Anser erythropus from the Fennoscandian breeding population may undertake long-distance moult migration eastwards. Of three individuals equipped with satellite transmitters at a spring staging site in northern Norway, two migrated to moulting sites in the area of Kolgujev Island and Kanin Peninsula, while the third headed towards the Taimyr Peninsula, all in northern Russia. The first leg of the moult migration route for non-breeders was between Finnmark, Norway and the Kanin Peninsula area in northwestern Russia, a similar route to that taken on autumn migration by Fennoscandian Lesser White-fronted Geese that had bred successfully. After the moulting period, one of the individuals followed a southwestern route to Poland and Germany, where it spent the first part of the winter. The satellite signals from the other two geese ceased abruptly in early autumn, indicating that the birds may have been illegally shot in Russia. Locating new moulting and migration stopover sites is of crucial importance for the conservation of the critically endangered Fennoscandian subpopulation of this species.
Arctic warming and decreasing sea-ice cover along the Siberian coast in the Arctic Ocean leads to... more Arctic warming and decreasing sea-ice cover along the Siberian coast in the Arctic Ocean leads to greater accessibility for operations such as oil drilling and traffic of tankers. This implies increasing risks for Steller's Eider Polysticta stelleri wintering, moulting and staging along the coasts of the Varanger Peninsula, Norway. Steller's Eiders were surveyed by monthly counts during winter and early spring 2016/2017 to investigate numbers and distribution throughout the winter. The highest number of wintering Steller's Eiders was found in January, representing ~7 % of the European population. In February-April numbers were lower, but at a rather stable level. We found relatively little variation in distribution between months, although the birds were more evenly distributed along the coast later in winter. Mean flock size was significantly larger in January than in March and April. Feeding behaviour was exclusively observed in shallow water, generally at depths of up to 6 m. Areas of focus for an oil pollution emergency plan are pointed out and discussed.
In the face of global change, conservation actions are implemented worldwide to reduce the risk o... more In the face of global change, conservation actions are implemented worldwide to reduce the risk of extinction of declining populations. Population dynamics can be, however, the result of complex biotic and abiotic interactions. Therefore, it is often unsure to what extent management contributes to the recovery of a population if a proper scientific assessment is lacking. If conservation is the goal, it is crucial to quantify the impact of management actions. The Fennoscandian population of the Lesser White-Fronted Goose Anser erythropus (henceforth LWFG) experienced a dramatic decline in the last decades, to the point that conservation actions were deemed necessary. Among several conservation initiatives, culling of invasive red fox has become relevant, as red fox is perceived to be the main factor affecting reproductive success through predation on chicks and eggs. The LWFG population trend has reversed from negative to positive since the onset of the fox control program, suggesting an overall positive effect of management. However, in Arctic ecosystems, factors such cyclic small rodent populations and fluctuations in ungulate carrion availability can determine strong variation in annual predation pressure and in turn affect geese recruitment and survival. Using 19 years of data, we investigated to what extent red fox culling contributed to the recovery of the population. Specifically, we evaluated whether fox removal had the expected positive effect on LWFG reproductive success, while taking into account those factors outlined above that may confound the effect of the management action. We predicted LWFG breeding success to fluctuate synchronously with the rodent cycle due to an apparent facilitation mechanism. We also expect that increased availability of reindeer carcasses sustain foxes during the harsh arctic winter and enhance their survival, especially in years with deep snow that makes small rodents less accessible. Thus, we predicted lower reproductive success in years with high carcass abundance, due to an apparent competition mechanism. Moreover, we used these relationships to assess the relative impact of fox culling program. We found a strong positive effect of rodent density on geese breeding success, as well as a negative effect of the yearly amount of reindeer carcasses. However, there was no evidence in the data for any positive effect of fox culling. These results are relevant for the conservation of the LWFG population. Overall, this study emphasize the importance of scientifically evaluating the effectiveness of management actions by taking into account all the potential confounding factors.peerReviewe
The use of tracking devices to monitor birds is extensive, but the effects of such instruments on... more The use of tracking devices to monitor birds is extensive, but the effects of such instruments on equipped individuals are still insufficiently taken into account. Here we evaluate potential effects of backpack-mounted satellite transmitters (platform terminal transmitters; PTTs) on survival of 28 Snowy Owls Bubo scandiacus. Six confirmed deaths were all probably related to natural and human-induced causes. Although PTT operational time was significantly shorter than expected lifetime of Snowy Owls, five owls were observed alive after transmissions ceased. Additionally four PTTs stopped due to low battery levels, indicating end of transmitter life and not owl mortality. We found no evidence of mortality caused by PTTs, but sample sizes are relatively low and detrimental effects on equipped Snowy Owls cannot be excluded. We recommend caution when instrumenting large owls.
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Papers by Tomas Aarvak