Coelenterates are not considered important food items for waders such as Grey Plovers (Pluvialis squatarola), although this has rarely been investigated in detail. During three days of fieldwork on the Bulgarian Black Sea coast in October 2020 Grey Plovers were documented deliberately choosing and swallowing barrel jellyfish Rhizostoma pulmo (Scyphozoa: Rhizostomatidae) while foraging on sand seashore where Scyphozoan jellyfish are often stranded. According to peer-reviewed literature, there is to-date no evidence of Grey Plovers consuming scyphozoan medusae, particularly as a specific choice for their food components. As a result of the present study, it is concluded that barrel jellyfish is part of the diet of Grey Plovers on the Black Sea coast and is purposely chosen by them. So far, this is the first video-recorded observation and published record of such an event in Europe and Western Palearctic. It suggests that coelenterates may be more important food items for waders than previousely believed and shows the potential of medusae to become an important food alternative for them.
{"title":"Are Grey Plovers true Jelly Bon lovers? First record of Grey Plovers (Pluvialis squatarola) deliberately feeding on barrel jellyfish (Rhizostoma pulmo) in the Western Palearctic","authors":"Liliana V. Vassileva","doi":"10.51812/of.121247","DOIUrl":"https://doi.org/10.51812/of.121247","url":null,"abstract":"Coelenterates are not considered important food items for waders such as Grey Plovers (Pluvialis squatarola), although this has rarely been investigated in detail. During three days of fieldwork on the Bulgarian Black Sea coast in October 2020 Grey Plovers were documented deliberately choosing and swallowing barrel jellyfish Rhizostoma pulmo (Scyphozoa: Rhizostomatidae) while foraging on sand seashore where Scyphozoan jellyfish are often stranded. According to peer-reviewed literature, there is to-date no evidence of Grey Plovers consuming scyphozoan medusae, particularly as a specific choice for their food components. As a result of the present study, it is concluded that barrel jellyfish is part of the diet of Grey Plovers on the Black Sea coast and is purposely chosen by them. So far, this is the first video-recorded observation and published record of such an event in Europe and Western Palearctic. It suggests that coelenterates may be more important food items for waders than previousely believed and shows the potential of medusae to become an important food alternative for them.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":"57 8","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138995535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In altricial birds, the length of the nestling period, i.e. time from hatching until fledging (young leaving the nest) varies within and between species. In general, however, variation in the time of fledging and factors mediating such variation remain largely unexplored. To assess the time of nestlings leaving the nest, daily observer visits to the nest are usually done in the predicted fledging period. However, this might initiate premature fledging of young and/or increase the predation risk. The application of iButtons – coin-sized temperature data loggers, which are increasingly used in ornithological studies – may help to overcome these obstacles. We tested whether nest temperatures recorded with iButtons might be used to identify the date and hour of young fledging, i.e. when the last nestling in the brood left the nest, in a small cavity-nesting passerine – the Great Tit (Parus major). We installed iButtons in 38 nests when nestlings were 14–15 days old (hatching day = day 0) and verified the presence of nestlings during daily inspections starting on day 17 post-hatching or later. We found that the day of fledging could be accurately determined based on the difference between the temperature of the nest cup and the outside. The age of nestlings ranged between 17 and 22 days at fledging, with nearly 58% of broods fledging at the age of 20 and 21 days. The majority (81.6%) of broods fledged within 6 h after sunrise. We discuss the advantages and disadvantages of using iButtons to identify fledging time in altricial birds.
{"title":"Assessing timing of fledging in a cavity-nesting passerine using temperature data loggers","authors":"Anna Dubiec, Tomasz Mazgajski","doi":"10.51812/of.126936","DOIUrl":"https://doi.org/10.51812/of.126936","url":null,"abstract":"In altricial birds, the length of the nestling period, i.e. time from hatching until fledging (young leaving the nest) varies within and between species. In general, however, variation in the time of fledging and factors mediating such variation remain largely unexplored. To assess the time of nestlings leaving the nest, daily observer visits to the nest are usually done in the predicted fledging period. However, this might initiate premature fledging of young and/or increase the predation risk. The application of iButtons – coin-sized temperature data loggers, which are increasingly used in ornithological studies – may help to overcome these obstacles. We tested whether nest temperatures recorded with iButtons might be used to identify the date and hour of young fledging, i.e. when the last nestling in the brood left the nest, in a small cavity-nesting passerine – the Great Tit (Parus major). We installed iButtons in 38 nests when nestlings were 14–15 days old (hatching day = day 0) and verified the presence of nestlings during daily inspections starting on day 17 post-hatching or later. We found that the day of fledging could be accurately determined based on the difference between the temperature of the nest cup and the outside. The age of nestlings ranged between 17 and 22 days at fledging, with nearly 58% of broods fledging at the age of 20 and 21 days. The majority (81.6%) of broods fledged within 6 h after sunrise. We discuss the advantages and disadvantages of using iButtons to identify fledging time in altricial birds.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":"91 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135365321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wetland birds such as waders are in decline across Europe. Information on demography is vital for assessing the causes of population declines, but estimates are needed from multiple populations and time periods. We used capture-recapture data from 2013–2022 including 134 individuals to estimate sex-specific apparent adult survival of Eurasian Curlews from a population breeding on agricultural fields in Finland, a stronghold region for this species in Europe. Using the Cormack–Jolly–Seber-model that considers the recapture probability of individuals, we estimated apparent survival of adults to be 0.89 (SE 0.03) for males and 0.92 (SE 0.03) for females. Our estimates of adult survival are slightly higher than those previously estimated from Fennoscandian breeding grounds in 1980s–1990s (0.82–0.88). Thus, our results suggest that adult survival of populations breeding in northern Europe has not declined during the last decades. Our study supports the view that changes in reproductive success is the main cause of decline in the Eurasian Curlew populations.
{"title":"High adult survival in a northern Eurasian Curlew (Numenius arquata) population","authors":"Veli-Matti Pakanen, Reijo Kylmänen","doi":"10.51812/of.126810","DOIUrl":"https://doi.org/10.51812/of.126810","url":null,"abstract":"Wetland birds such as waders are in decline across Europe. Information on demography is vital for assessing the causes of population declines, but estimates are needed from multiple populations and time periods. We used capture-recapture data from 2013–2022 including 134 individuals to estimate sex-specific apparent adult survival of Eurasian Curlews from a population breeding on agricultural fields in Finland, a stronghold region for this species in Europe. Using the Cormack–Jolly–Seber-model that considers the recapture probability of individuals, we estimated apparent survival of adults to be 0.89 (SE 0.03) for males and 0.92 (SE 0.03) for females. Our estimates of adult survival are slightly higher than those previously estimated from Fennoscandian breeding grounds in 1980s–1990s (0.82–0.88). Thus, our results suggest that adult survival of populations breeding in northern Europe has not declined during the last decades. Our study supports the view that changes in reproductive success is the main cause of decline in the Eurasian Curlew populations.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":"1980 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135366652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A dense island population of Eagle-Owls (Bubo bubo) close to the Arctic circle had suffered considerable mortality due to powerlines (electrocution and collision) throughout many decades. A study using GPS transmitter technology was carried out between 2009 and 2014. We studied home-range sizes, dispersal distances, mortality, and proposed mitigation techniques to prevent accidents. We found as expected that juvenile Eagle-Owls had larger home-ranges and moved farther than adults, but both age-groups moved much less than shown elsewhere in Europe. The probable reason for this was thought to be that this population was isolated by the surrounding sea, which might act as a barrier. The GPS data indicated that the poles of the grid were used as perching posts more than expected from a random distribution. This was explained by the lack of high trees and other elevated landscape features on these low islands. As a mitigation effort, we contributed to designing a perching-device for fitting on the poles that would prevent electrocution of the owls. This is now used by several grid-owners in coastal areas with high electrocution risk and is followed up by the National action plan for Eagle-Owl in Norway.
{"title":"Home-range, movements and use of powerline poles of Eagle-Owls (Bubo bubo) at an island population in northern Norway","authors":"T. Nygård, Karl-Otto Jacobsen, J. O. Gjershaug","doi":"10.51812/of.116340","DOIUrl":"https://doi.org/10.51812/of.116340","url":null,"abstract":"A dense island population of Eagle-Owls (Bubo bubo) close to the Arctic circle had suffered considerable mortality due to powerlines (electrocution and collision) throughout many decades. A study using GPS transmitter technology was carried out between 2009 and 2014. We studied home-range sizes, dispersal distances, mortality, and proposed mitigation techniques to prevent accidents. We found as expected that juvenile Eagle-Owls had larger home-ranges and moved farther than adults, but both age-groups moved much less than shown elsewhere in Europe. The probable reason for this was thought to be that this population was isolated by the surrounding sea, which might act as a barrier. The GPS data indicated that the poles of the grid were used as perching posts more than expected from a random distribution. This was explained by the lack of high trees and other elevated landscape features on these low islands. As a mitigation effort, we contributed to designing a perching-device for fitting on the poles that would prevent electrocution of the owls. This is now used by several grid-owners in coastal areas with high electrocution risk and is followed up by the National action plan for Eagle-Owl in Norway.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48105542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Artificial feeding is a widely used management tool, but it often attracts nontarget species, including birds, to permanent feeding sites. This study used camera traps to monitor the presence of birds at selected sites used for bear management in Dinaric forest. A large number of bird species (35) were recorded, representing roughly half of all species breeding in the surrounding area. These species were grouped based on monthly and hourly presence, and corresponded to food groups, with most belonging to granivores or scavengers. Some species, such as Pigeons (Columba sp.), Raven (Corvus corax) and Buzzard (Buteo buteo), adapted their presence to the availability of food at the feeding sites, while others were not affected by this. Both Chaffinches (Fringilla coelebs) and Jays (Garrulus glandarius) frequented the feeding sites, but their temporal presence was influenced by their biology rather than by food availability. The Sparrowhawk (Accipiter nisus) also adapted its presence to food availability, and its presence was closely associated with that of the Jay. This study confirms the temporal differences in the use of feeding sites by birds and mammals, which is likely due to their different biology and past management. This can be used to make wildlife management more efficient and reduce the undesirable effects of artificial feeding.
{"title":"Temporal occurrence and species composition of birds on artificial feeding sites maintained for game mammals in the Dinaric Mountains, Slovenia","authors":"Dejan Bordjan, A. Soultan, K. Jerina","doi":"10.51812/of.121820","DOIUrl":"https://doi.org/10.51812/of.121820","url":null,"abstract":"Artificial feeding is a widely used management tool, but it often attracts nontarget species, including birds, to permanent feeding sites. This study used camera traps to monitor the presence of birds at selected sites used for bear management in Dinaric forest. A large number of bird species (35) were recorded, representing roughly half of all species breeding in the surrounding area. These species were grouped based on monthly and hourly presence, and corresponded to food groups, with most belonging to granivores or scavengers. Some species, such as Pigeons (Columba sp.), Raven (Corvus corax) and Buzzard (Buteo buteo), adapted their presence to the availability of food at the feeding sites, while others were not affected by this. Both Chaffinches (Fringilla coelebs) and Jays (Garrulus glandarius) frequented the feeding sites, but their temporal presence was influenced by their biology rather than by food availability. The Sparrowhawk (Accipiter nisus) also adapted its presence to food availability, and its presence was closely associated with that of the Jay. This study confirms the temporal differences in the use of feeding sites by birds and mammals, which is likely due to their different biology and past management. This can be used to make wildlife management more efficient and reduce the undesirable effects of artificial feeding.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49438207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel A. F. Bloche, K. Thorup, K. Olsen, P. Ekberg, Peter Ellegaard Larsen, Knud-Erik Strange, A. P. Tøttrup
Agricultural intensification and habitat degradation across Europe have caused declines since the 20th century in populations of birds adapted to open landscapes, such as the Red-backed Shrike (Lanius collurio). Effective conservation strategies require knowledge on species’ breeding biology. To understand the status of the Danish breeding population better, we investigate which factors affect their breeding parameter (i.e. distribution, performance, post-fledging survival and behaviour). Our focus on the post-fledging period addresses present knowledge gaps due to the importance of this, yet under-studied, phase of passerines’ breeding cycle. We studied breeding pairs on different habitat types with Denmark-wide Citizen Science data, complemented by data of local projects in Northern Zealand and Northern Jutland (Denmark). Significantly fewer pairs were found in agricultural habitats and more in forests, semi-natural open habitats and synanthropic habitats. Pairs in forests had a significantly higher breeding productivity compared to agricultural or semi-natural open habitats for data from the years 2000 to 2021. Some project sites showed significantly higher number of fledglings compared to others, indicating that these sites are potential core areas for breeding productivity. Over the last two decades, the mean breeding productivity across Denmark was stable with 2.3 fledglings per successful pair. The survival rate of ringed fledglings increased during the post-fledging period, likely due to their increase in more active and independent behaviour. The relatively low breeding productivity found in this study calls for further studies including detailed data from potentially secondary habitats like agricultural areas to understand the effects of habitat on population fluctuations.
{"title":"Breeding biology of Red-backed Shrikes (Lanius collurio): distribution, performance and post-fledging survival in Denmark","authors":"Daniel A. F. Bloche, K. Thorup, K. Olsen, P. Ekberg, Peter Ellegaard Larsen, Knud-Erik Strange, A. P. Tøttrup","doi":"10.51812/of.124729","DOIUrl":"https://doi.org/10.51812/of.124729","url":null,"abstract":"Agricultural intensification and habitat degradation across Europe have caused declines since the 20th century in populations of birds adapted to open landscapes, such as the Red-backed Shrike (Lanius collurio). Effective conservation strategies require knowledge on species’ breeding biology. To understand the status of the Danish breeding population better, we investigate which factors affect their breeding parameter (i.e. distribution, performance, post-fledging survival and behaviour). Our focus on the post-fledging period addresses present knowledge gaps due to the importance of this, yet under-studied, phase of passerines’ breeding cycle. We studied breeding pairs on different habitat types with Denmark-wide Citizen Science data, complemented by data of local projects in Northern Zealand and Northern Jutland (Denmark). Significantly fewer pairs were found in agricultural habitats and more in forests, semi-natural open habitats and synanthropic habitats. Pairs in forests had a significantly higher breeding productivity compared to agricultural or semi-natural open habitats for data from the years 2000 to 2021. Some project sites showed significantly higher number of fledglings compared to others, indicating that these sites are potential core areas for breeding productivity. Over the last two decades, the mean breeding productivity across Denmark was stable with 2.3 fledglings per successful pair. The survival rate of ringed fledglings increased during the post-fledging period, likely due to their increase in more active and independent behaviour. The relatively low breeding productivity found in this study calls for further studies including detailed data from potentially secondary habitats like agricultural areas to understand the effects of habitat on population fluctuations.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42683087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pihla Kortesalmi, Salli Pääkkönen, J. Valkonen, Ossi Nokelainen
Climate change can challenge the inherited or learned behavioural patterns that were useful in the past. In particular, it may change the spatio-temporal dynamics of migratory behaviour in birds. Here, we explored a 40-year-long time series of Bean Goose (Anser fabalis) observations using a citizen science database (tiira.fi – BirdLife Finland) to link the timing of the migration across last forty years and with the large-scale temporal weather fluctuation described by an index of North Atlantic Oscillation (NAO). During 1978–2018, the peak of spring migration of the Bean Goose has advanced approximately a month, whereas the timing of autumn migration has remained more similar across the years. The NAO index was associated only with spring migration. Strong temporal changes of the Bean Goose migration are evident as they adjust their migratory behaviour to changing spring conditions.
{"title":"Bean goose migration shows a long-term temporal shift to earlier spring, but not to later autumn migration in Finland","authors":"Pihla Kortesalmi, Salli Pääkkönen, J. Valkonen, Ossi Nokelainen","doi":"10.51812/of.119806","DOIUrl":"https://doi.org/10.51812/of.119806","url":null,"abstract":"Climate change can challenge the inherited or learned behavioural patterns that were useful in the past. In particular, it may change the spatio-temporal dynamics of migratory behaviour in birds. Here, we explored a 40-year-long time series of Bean Goose (Anser fabalis) observations using a citizen science database (tiira.fi – BirdLife Finland) to link the timing of the migration across last forty years and with the large-scale temporal weather fluctuation described by an index of North Atlantic Oscillation (NAO). During 1978–2018, the peak of spring migration of the Bean Goose has advanced approximately a month, whereas the timing of autumn migration has remained more similar across the years. The NAO index was associated only with spring migration. Strong temporal changes of the Bean Goose migration are evident as they adjust their migratory behaviour to changing spring conditions.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42825417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In Northern Europe, the Mistle Thrush (Turdus viscivorus) is a relatively poorly studied species inhabiting forested landscapes where it has historically experienced population declines. Those declines have been attributed to the spread of intensive forest management; yet, the populations have stabilized or increased in recent decades. To distinguish the main forestry impacts on its breeding numbers and distribution, a multiple-visit territory-mapping study was carried out over 15 km2 of production forest landscape in Estonia. At the landscape scale, the breeding distribution was concentrated to conifer forests on bog peat where the densities were five times higher than in other conifer forests and (at least) ten times higher than in non-conifer forests. This reveals a broad distribution pattern where high-density (core) habitats only host a small fraction of the total population; their relative contribution to the recruitment remains unknown. At the breeding territory scale (within 150 m from a nest), Mistle Thrushes avoided recent clear-cuts and preferred larger areas of old stands more than expected from the distribution of suitable stands for nesting. This indicated that, in a short term, clear-cutting reduces nesting habitats of this species disproportionately more than expected from the cut area alone; this is in accordance with the documented 20th century declines of the species in Fennoscandia. The relationship with forestry drainage is more complicated, however, due to delayed effects and covariation with the main breeding habitat. The basic ecology of the species in conifer forest-wetland landscapes, which are subjected to management pressures, warrants future studies and might provide general insights into the dynamics and functioning of these ecosystems.
{"title":"The Mistle Thrush (Turdus viscivorus) in a production forestry context: A territory mapping study","authors":"A. Lõhmus","doi":"10.51812/of.120604","DOIUrl":"https://doi.org/10.51812/of.120604","url":null,"abstract":"In Northern Europe, the Mistle Thrush (Turdus viscivorus) is a relatively poorly studied species inhabiting forested landscapes where it has historically experienced population declines. Those declines have been attributed to the spread of intensive forest management; yet, the populations have stabilized or increased in recent decades. To distinguish the main forestry impacts on its breeding numbers and distribution, a multiple-visit territory-mapping study was carried out over 15 km2 of production forest landscape in Estonia. At the landscape scale, the breeding distribution was concentrated to conifer forests on bog peat where the densities were five times higher than in other conifer forests and (at least) ten times higher than in non-conifer forests. This reveals a broad distribution pattern where high-density (core) habitats only host a small fraction of the total population; their relative contribution to the recruitment remains unknown. At the breeding territory scale (within 150 m from a nest), Mistle Thrushes avoided recent clear-cuts and preferred larger areas of old stands more than expected from the distribution of suitable stands for nesting. This indicated that, in a short term, clear-cutting reduces nesting habitats of this species disproportionately more than expected from the cut area alone; this is in accordance with the documented 20th century declines of the species in Fennoscandia. The relationship with forestry drainage is more complicated, however, due to delayed effects and covariation with the main breeding habitat. The basic ecology of the species in conifer forest-wetland landscapes, which are subjected to management pressures, warrants future studies and might provide general insights into the dynamics and functioning of these ecosystems.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47490804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although the Great Spotted Woodpecker (Dendrocopos major) is the most common of the European woodpecker species, there are no studies detailing its foraging behaviour in the breeding and non-breeding seasons. Our research, conducted in the primeval oak-lime-hornbeam forest of the Białowieża National Park in 1999–2011, compared foraging sites and foraging techniques used by this species in these two seasons. Great Spotted Woodpecker predominantly foraged on standing trees, while lying trees and the ground were occasionally used as foraging sites, but almost exclusively in the breeding season. European hornbeam (Carpinus betulus) and small-leaved lime (Tilia cordata) were the most frequently used for foraging in the breeding season, whereas Norway spruce (Picea abies) and pedunculate oak (Quercus robur) were used in the non-breeding season. Great Spotted Woodpecker foraged more frequently on dead and large trees in the non-breeding season. In the breeding season, Great Spotted Woodpecker collected food mainly from living substrates, predominantly sites on large diameter trunks and at low height, while in the non-breeding season it collected food from thin, dead and upper branches. Searching for food and gleaning it from the tree surface was the most common foraging technique used in the breeding season, whereas seed extraction from cones dominated in the non-breeding season. The percentage of foraging time spent on this type of food was positively correlated with the index of Norway spruce seed production. Our study showed that the foraging behaviour of the Great Spotted Woodpecker in the two seasons differs significantly due to changes in food resources.
{"title":"Foraging behaviour of the Great Spotted Woodpecker (Dendrocopos major) in the Białowieża National Park","authors":"T. Stański, M. Stańska, D. Czeszczewik","doi":"10.51812/of.126163","DOIUrl":"https://doi.org/10.51812/of.126163","url":null,"abstract":"Although the Great Spotted Woodpecker (Dendrocopos major) is the most common of the European woodpecker species, there are no studies detailing its foraging behaviour in the breeding and non-breeding seasons. Our research, conducted in the primeval oak-lime-hornbeam forest of the Białowieża National Park in 1999–2011, compared foraging sites and foraging techniques used by this species in these two seasons. Great Spotted Woodpecker predominantly foraged on standing trees, while lying trees and the ground were occasionally used as foraging sites, but almost exclusively in the breeding season. European hornbeam (Carpinus betulus) and small-leaved lime (Tilia cordata) were the most frequently used for foraging in the breeding season, whereas Norway spruce (Picea abies) and pedunculate oak (Quercus robur) were used in the non-breeding season. Great Spotted Woodpecker foraged more frequently on dead and large trees in the non-breeding season. In the breeding season, Great Spotted Woodpecker collected food mainly from living substrates, predominantly sites on large diameter trunks and at low height, while in the non-breeding season it collected food from thin, dead and upper branches. Searching for food and gleaning it from the tree surface was the most common foraging technique used in the breeding season, whereas seed extraction from cones dominated in the non-breeding season. The percentage of foraging time spent on this type of food was positively correlated with the index of Norway spruce seed production. Our study showed that the foraging behaviour of the Great Spotted Woodpecker in the two seasons differs significantly due to changes in food resources.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41408718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We estimated the onset of natal dispersal for a large diurnal raptor with high propensity towards large-scaled exploratory movements during the post-fledging period, the White-tailed Sea Eagle (Haliaeetus albicilla). We analysed GPS tracking data of 21 juveniles with respect to the onset of natal dispersal comparing six methods available from the recent literature. While none of the methods significantly differed from the visual method, the Distance Threshold method underestimated the dispersal onset for some individuals. Likewise, coefficient of variation methods overestimated the dispersal onset in few cases, presumably because the temporal scale of available GPS fixes did not correspond to the scale of discrete dispersal movements. We conclude that all tested methods are generally suitable to estimate the dispersal onset, specifically if the research question does not depend on an exact but rather a rough estimate. A visual determination might increase flexibility to account for individual behavior and yields consistent results across individuals, but highly reduces the comparability across observers and studies. For research questions relying on exact estimates, we propose using a combination of an automated method and a visual determination as a back-up method for single individuals with clear under- or overestimation. An exploratory comparison showed that the temporal resolution of the GPS may further affect the accuracy of natal dispersal estimates. For individuals with clear movement patterns, high-resolution movement data could increase the accuracy of Coefficient of Variation methods. We underline the necessity for further investigation on the effects of temporal resolution on dispersal onset estimates.
{"title":"Estimating the onset of natal dispersal for a large diurnal raptor: A methodological comparison","authors":"M. Engler, O. Krone","doi":"10.51812/of.115528","DOIUrl":"https://doi.org/10.51812/of.115528","url":null,"abstract":"We estimated the onset of natal dispersal for a large diurnal raptor with high propensity towards large-scaled exploratory movements during the post-fledging period, the White-tailed Sea Eagle (Haliaeetus albicilla). We analysed GPS tracking data of 21 juveniles with respect to the onset of natal dispersal comparing six methods available from the recent literature. While none of the methods significantly differed from the visual method, the Distance Threshold method underestimated the dispersal onset for some individuals. Likewise, coefficient of variation methods overestimated the dispersal onset in few cases, presumably because the temporal scale of available GPS fixes did not correspond to the scale of discrete dispersal movements. We conclude that all tested methods are generally suitable to estimate the dispersal onset, specifically if the research question does not depend on an exact but rather a rough estimate. A visual determination might increase flexibility to account for individual behavior and yields consistent results across individuals, but highly reduces the comparability across observers and studies. For research questions relying on exact estimates, we propose using a combination of an automated method and a visual determination as a back-up method for single individuals with clear under- or overestimation.\u0000An exploratory comparison showed that the temporal resolution of the GPS may further affect the accuracy of natal dispersal estimates. For individuals with clear movement patterns, high-resolution movement data could increase the accuracy of Coefficient of Variation methods. We underline the necessity for further investigation on the effects of temporal resolution on dispersal onset estimates.","PeriodicalId":49718,"journal":{"name":"Ornis Fennica","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43640941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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