2012/12/20
Can Birds Make Us Happy?
Iturria: Science Daily
There has been an increasing amount of research on the health
benefits of green spaces such as parks and nature reserves, but we know
far less about how the wildlife within these habitats contributes
towards well-being benefits.
Take wild birds for example says PhD student Natalie Clark from the University of Reading, who is leading the study: "Most of us say we enjoy seeing wild birds in our local environments every day, be that the friendly robin visiting our garden each Christmas or ducks swimming in the local pond. But we have little idea of how much we value their presence and how they're contributing to our overall well-being."
Given the declining numbers of many bird species the study -- which also involves the University of East Anglia, the RSPB and the University of Chicago -- is timely. "Any well-being benefit we may be receiving could soon be in jeopardy as numbers of many wild bird species have declined across the UK since the 1970s," says Clark.
"We know that wild birds are very important to a significant proportion of people living in the UK, with more than 60% of people with a garden providing supplementary food to birds. What we need to understand next is how and to what degree wild birds are benefiting people in the UK, so that we can work to conserve these birds and the well-being benefits they provide for future generations. This is particularly important at a time when many of us are feeling the 'economic pinch' and will appreciate benefits from increased well-being to an even greater degree."
Participants from across the UK have been filling in questionnaires designed to find out how often they visit green spaces and why, and to measure how differing levels of bird activity near people's homes may be affecting their well-being.
According to Clark: "We're really interested in the reasons why people visit green spaces and how important different aspects of wildlife, particularly birds, are to their outdoor experiences. That friendly robin hopping across your lawn might be more important than you could imagine."
Results from the study are expected in the spring, and the three and a half year project is funded by the Natural Environment Research Council, with additional support from the RSPB.
Natalie Clark will outline the study on Tuesday 18 December 2012 to the British Ecological Society's Annual Meeting at the University of Birmingham.
Story Source:
The above story is reprinted from materials provided by British Ecological Society (BES), via AlphaGalileo.
Dec. 17, 2012 — As millions
of us post our Christmas cards -- many of which star a robin red breast
-- ecologists are investigating whether birds make us happy. Speaking at
this week's British Ecological Society Annual Meeting, researchers will
reveal how they are investigating the links between birds and our
well-being, and explain how their results -- due out next year -- could
have a major impact on UK bird conservation.
Take wild birds for example says PhD student Natalie Clark from the University of Reading, who is leading the study: "Most of us say we enjoy seeing wild birds in our local environments every day, be that the friendly robin visiting our garden each Christmas or ducks swimming in the local pond. But we have little idea of how much we value their presence and how they're contributing to our overall well-being."
Given the declining numbers of many bird species the study -- which also involves the University of East Anglia, the RSPB and the University of Chicago -- is timely. "Any well-being benefit we may be receiving could soon be in jeopardy as numbers of many wild bird species have declined across the UK since the 1970s," says Clark.
"We know that wild birds are very important to a significant proportion of people living in the UK, with more than 60% of people with a garden providing supplementary food to birds. What we need to understand next is how and to what degree wild birds are benefiting people in the UK, so that we can work to conserve these birds and the well-being benefits they provide for future generations. This is particularly important at a time when many of us are feeling the 'economic pinch' and will appreciate benefits from increased well-being to an even greater degree."
Participants from across the UK have been filling in questionnaires designed to find out how often they visit green spaces and why, and to measure how differing levels of bird activity near people's homes may be affecting their well-being.
According to Clark: "We're really interested in the reasons why people visit green spaces and how important different aspects of wildlife, particularly birds, are to their outdoor experiences. That friendly robin hopping across your lawn might be more important than you could imagine."
Results from the study are expected in the spring, and the three and a half year project is funded by the Natural Environment Research Council, with additional support from the RSPB.
Natalie Clark will outline the study on Tuesday 18 December 2012 to the British Ecological Society's Annual Meeting at the University of Birmingham.
Story Source:
The above story is reprinted from materials provided by British Ecological Society (BES), via AlphaGalileo.
Birdsong Bluster May Dupe Strange Females, but It Won't Fool Partners
Iturria: Science Daily
Just as some men try to cast themselves in a better light when they
approach would-be dates, so male birds in poor condition seek to portray
that they are fitter than they really are. But males do not even try to
deceive their long-term partners, who are able to establish the true
condition of the male by their song.
Researchers at the University of Exeter studied zebra finches to establish how trustworthy birdsong was in providing honest signals about the male's value as a mate. Singing is a test of the condition of birds because it uses a lot of energy. Fit and healthy birds are thought to be able to sustain a high song rate for longer, making them more attractive to females.
The research team, which included scientists from the Université de Bourgogne in France, looked at short and longer encounters with unknown females, as well as patterns of song around females who were familiar to them.
The team discovered that males in poor condition could "cheat" and vary their song to give a false impression to stranger females. But they did not even try to fool those who knew them, who used song as a reliable test of their underlying qualities. The research is published on December 19 in the journal Proceedings of the Royal Society B.
Dr Sasha Dall, of the University of Exeter, was involved in the research. He said: "Every man wants to cast himself in a favourable light when he meets an attractive female, and we have shown that birds are no different. But just like many humans, it seems zebra finch males are unable to dupe females who know them well enough. When the birds were in an established relationship, the female could tell the true condition of a male by his song, and judge whether he would make a good father for her next brood."
Zebra finches are Australia's most popular finch. They make common pets and are widely used in scientific research. They are particularly easy to keep, and adapt extremely well to their surroundings. For zebra finches, both colour and birdsong are important factors in choosing a mate.
The research was funded through a young researcher prize of the Bettencourt-Schueller Foundation for life sciences and a PhD grant, as well as two honorific master grants provided by the Conseil Régional de Bourgogne in France.
The team studied 91 male and 91 female birds from a colony at the Université de Bourgogne and 12 of each gender from a colony at the University of Exeter. The body condition of each of the birds was measured. Scientists then videoed both brief and longer encounters between birds of each gender who were unknown to each other, and patterns of behaviour when they were with their mate, with whom they pair for life. They were also monitored to see if they showed signs of mutual attraction and going on to breed.
In the study, there was no difference in the singing of male single birds in either short or long encounters with unknown females. But, when in front of their partners, paired birds who were in good condition sang at a higher rate than those in poor condition.
Dr Morgan David, who led the research, said: "This is the first study to find evidence that the link between male body condition and birdsong differs depending on the context of the encounter with the opposite sex. It could have significant implications for learning more about the evolution of courtship patterns such as birdsong."
Story Source:
The above story is reprinted from materials provided by University of Exeter, via EurekAlert!, a service of AAAS.
Dec. 18, 2012 — Male birds use their song to dupe females they have just met by pretending they are in excellent physical condition.
Researchers at the University of Exeter studied zebra finches to establish how trustworthy birdsong was in providing honest signals about the male's value as a mate. Singing is a test of the condition of birds because it uses a lot of energy. Fit and healthy birds are thought to be able to sustain a high song rate for longer, making them more attractive to females.
The research team, which included scientists from the Université de Bourgogne in France, looked at short and longer encounters with unknown females, as well as patterns of song around females who were familiar to them.
The team discovered that males in poor condition could "cheat" and vary their song to give a false impression to stranger females. But they did not even try to fool those who knew them, who used song as a reliable test of their underlying qualities. The research is published on December 19 in the journal Proceedings of the Royal Society B.
Dr Sasha Dall, of the University of Exeter, was involved in the research. He said: "Every man wants to cast himself in a favourable light when he meets an attractive female, and we have shown that birds are no different. But just like many humans, it seems zebra finch males are unable to dupe females who know them well enough. When the birds were in an established relationship, the female could tell the true condition of a male by his song, and judge whether he would make a good father for her next brood."
Zebra finches are Australia's most popular finch. They make common pets and are widely used in scientific research. They are particularly easy to keep, and adapt extremely well to their surroundings. For zebra finches, both colour and birdsong are important factors in choosing a mate.
The research was funded through a young researcher prize of the Bettencourt-Schueller Foundation for life sciences and a PhD grant, as well as two honorific master grants provided by the Conseil Régional de Bourgogne in France.
The team studied 91 male and 91 female birds from a colony at the Université de Bourgogne and 12 of each gender from a colony at the University of Exeter. The body condition of each of the birds was measured. Scientists then videoed both brief and longer encounters between birds of each gender who were unknown to each other, and patterns of behaviour when they were with their mate, with whom they pair for life. They were also monitored to see if they showed signs of mutual attraction and going on to breed.
In the study, there was no difference in the singing of male single birds in either short or long encounters with unknown females. But, when in front of their partners, paired birds who were in good condition sang at a higher rate than those in poor condition.
Dr Morgan David, who led the research, said: "This is the first study to find evidence that the link between male body condition and birdsong differs depending on the context of the encounter with the opposite sex. It could have significant implications for learning more about the evolution of courtship patterns such as birdsong."
Story Source:
The above story is reprinted from materials provided by University of Exeter, via EurekAlert!, a service of AAAS.
Boreal Bird Species of Conservation Concern Affected by Climate Change
Iturria: Science Daily
Population changes of different bird species groups according to
their habitat preferences in boreal protected areas in Finland were
studied on the basis of large-scale bird censuses carried out in 1981
and in 2000. Mean temperatures rose clearly between the two time slices
in Finland, for example, mean April-June temperature by 0.7 °C.
The study "Preserving species populations in the boreal zone in a changing climate: contrasting trends of bird species groups in a protected area network" by Raimo Virkkala from the Finnish Environment Institute and Ari Rajasärkkä from Metsähallitus was published in the open access journal Nature Conservation. Bird censuses were compiled and organized by Metsähallitus, which governs the stated-owned protected areas in Finland. Tens of competent ornithologists carried out the censuses, which included altogether over 11,600 km of line transects.
According to the study, population densities of common forest habitat generalists remained the same between the two periods, while densities of species of conservation concern showed contrasting trends: species preferring old-growth or mature forests increased, but those living on mires and wetlands, and species of Arctic mountains decreased.
"These trends are most probably connected with climate change, but successional changes in protected areas and regional habitat alteration should also be taken into account," says Dr Virkkala, the leading author of the study. Of species preferring old-growth or mature forests, a larger proportion are southern than among species of mires and wetlands, or of Arctic mountains, most or all of which, respectively, had a northerly distribution.
In general, northern species have decreased and southern species increased. It is suggested that climate change effects on species in natural boreal and Arctic habitats most probably are habitat-specific with large differences in response times and susceptibility. Open mires and mountain heaths change more rapidly in consequence of climate warming than old-growth forests, for which reason populations on mires and mountain heaths may also be more affected by climate change.
Story Source:
Journal Reference:
Dec. 17, 2012 — A protected area
network should ensure the maintenance of biodiversity, but climate is
changing rapidly, thereby creating further demand for the protected area
network to be efficient in preserving biota. Due to climate change
species ranges are expected to move polewards, which poses challenges to
the protected area network.
The study "Preserving species populations in the boreal zone in a changing climate: contrasting trends of bird species groups in a protected area network" by Raimo Virkkala from the Finnish Environment Institute and Ari Rajasärkkä from Metsähallitus was published in the open access journal Nature Conservation. Bird censuses were compiled and organized by Metsähallitus, which governs the stated-owned protected areas in Finland. Tens of competent ornithologists carried out the censuses, which included altogether over 11,600 km of line transects.
According to the study, population densities of common forest habitat generalists remained the same between the two periods, while densities of species of conservation concern showed contrasting trends: species preferring old-growth or mature forests increased, but those living on mires and wetlands, and species of Arctic mountains decreased.
"These trends are most probably connected with climate change, but successional changes in protected areas and regional habitat alteration should also be taken into account," says Dr Virkkala, the leading author of the study. Of species preferring old-growth or mature forests, a larger proportion are southern than among species of mires and wetlands, or of Arctic mountains, most or all of which, respectively, had a northerly distribution.
In general, northern species have decreased and southern species increased. It is suggested that climate change effects on species in natural boreal and Arctic habitats most probably are habitat-specific with large differences in response times and susceptibility. Open mires and mountain heaths change more rapidly in consequence of climate warming than old-growth forests, for which reason populations on mires and mountain heaths may also be more affected by climate change.
Story Source:
The above story is reprinted from materials provided by Pensoft Publishers, via EurekAlert!, a service of AAAS.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Virkkala R, Rajasärkkä A. Preserving species populations in the boreal zone in a changing climate: contrasting trends of bird species groups in a protected area network. Nature Conservation, 2012; 3: 1 DOI: 10.3897/natureconservation.3.3635
2012/12/15
Bird Beaks Show Why 'Sister' Species Don't Live Together
ScienceDaily:
Oxford University scientists examined 'sister' species -- species that are each other's closest relatives -- of the 'ovenbird' family from South America. They compared data on when these species diverged and where they live today and found that those that have been separated for longest and have evolved very different beaks were able to coexist more rapidly after they became two separate species.
The findings suggest that species displaced due to climate change may not be able to survive in what appears to be a suitable new habitat because a related species already living there will out-compete them for resources.
A report of the research appears this week in Ecology Letters.
'Competitive exclusion between species is generally thought to be limited to relatively small spatial scales, such as between individual birds or across local patches of habitat,' said Dr Alex Pigot of Oxford University's Department of Zoology, lead author of the report. 'In our work we are able to show that competition is a major factor responsible for excluding closely-related species from entire regions. The key was being able to rule out other explanations like geographical barriers, such as rivers, or unsuitable habitats from being the main barriers to 'sister' species co-existing.'
'Ovenbirds' (Furnariidae), so called because in some species their domed nests resemble a traditional Dutch oven, are found throughout South America; there are hundreds of species inhabiting a range of environments from deserts and grasslands to tropical forests. The Oxford team chose to study them because their very diverse beaks give useful information on how related species have evolved to fill particular ecological niches.
'The beak is the main tool used by birds for capturing and consuming food items and so has been moulded by natural selection to fit this purpose,' said Dr Pigot. 'In ovenbirds some species have evolved bizarrely long curved bills in order to prise insects from bamboo stems or beneath the bark of trees, but only one such species tends to live in any given place. Our results suggest that it can take a long time to evolve a foraging niche different enough to allow coexistence amongst related species.'
As environments become hotter or drier, for instance due to climate change, it has been generally assumed that species will track suitable conditions and move to new locations. This new research shows that the area of suitable habitats could be much smaller than current estimates suggest, as many regions will already be occupied by related species that will out-compete any newcomers. This implies that the full impact of environmental change cannot be understood without considering competitive interactions between species.
Story Source:
The above story is reprinted from materials provided by University of Oxford.
Dec. 14, 2012 — A study of closely-related bird species has found that they do not coexist in the same region because they remain too ecologically similar and will out-compete each other, not because of geographical barriers or unsuitable habitats.
Campylorhamphus trochilirostris. (Credit: Joseph Tobias)
The findings suggest that species displaced due to climate change may not be able to survive in what appears to be a suitable new habitat because a related species already living there will out-compete them for resources.
A report of the research appears this week in Ecology Letters.
'Competitive exclusion between species is generally thought to be limited to relatively small spatial scales, such as between individual birds or across local patches of habitat,' said Dr Alex Pigot of Oxford University's Department of Zoology, lead author of the report. 'In our work we are able to show that competition is a major factor responsible for excluding closely-related species from entire regions. The key was being able to rule out other explanations like geographical barriers, such as rivers, or unsuitable habitats from being the main barriers to 'sister' species co-existing.'
'Ovenbirds' (Furnariidae), so called because in some species their domed nests resemble a traditional Dutch oven, are found throughout South America; there are hundreds of species inhabiting a range of environments from deserts and grasslands to tropical forests. The Oxford team chose to study them because their very diverse beaks give useful information on how related species have evolved to fill particular ecological niches.
'The beak is the main tool used by birds for capturing and consuming food items and so has been moulded by natural selection to fit this purpose,' said Dr Pigot. 'In ovenbirds some species have evolved bizarrely long curved bills in order to prise insects from bamboo stems or beneath the bark of trees, but only one such species tends to live in any given place. Our results suggest that it can take a long time to evolve a foraging niche different enough to allow coexistence amongst related species.'
As environments become hotter or drier, for instance due to climate change, it has been generally assumed that species will track suitable conditions and move to new locations. This new research shows that the area of suitable habitats could be much smaller than current estimates suggest, as many regions will already be occupied by related species that will out-compete any newcomers. This implies that the full impact of environmental change cannot be understood without considering competitive interactions between species.
Story Source:
The above story is reprinted from materials provided by University of Oxford.
If You Cut Down a Tree in the Forest, Can Wildlife Hear It?
ScienceDaily:
The tool, SPreAD-GIS, uses spatial data layers to predict how sound spreads from a source through the surrounding landscape and how it is affected by such factors as vegetation, terrain, weather conditions, and background sound levels. By determining how sound propagates, potential impacts to wildlife can be forecasted. Such impacts can include reducing habitat quality, altering the geographic distribution of species, disrupting animal communication, and causing stress.
In an example discussed in the paper, the sensitivities of humans and owls to motor vehicle sound levels were compared. The results of the SPreAD-GIS analysis showed that in the same location, motor vehicle noise would affect owls in an area 45 percent larger than the area affected for humans. Exposure to noise may affect an owl's livelihood as the animal relies on its acute sense of hearing to detect even the slightest movement of its prey.
WCS Scientist Sarah Reed said, "Exposure to human-caused noise can change the game for many species. Those species that are less tolerant of noise can be put at a disadvantage and ultimately, this may result in a loss in biodiversity. By predicting what the effects of sound will be on a bird or mammal species in advance, we can more adequately balance our land-use planning decisions with conservation considerations."
Reed and colleagues are currently using SPreAD-GIS and field measurements of motor vehicle noise to forecast the area affected for bird and mammal communities in the Sierra National Forest in California. In addition, the model has been downloaded by hundreds of users in more than 25 countries and used for diverse education, research, and management applications. This includes modeling potential noise propagation from roads, recreational activity, heavy equipment, residential development, and natural resource extraction.
Reed added, "Most existing tools are used to understand noise in human-dominated environments and don't incorporate factors affecting noise propagation in natural systems. This tool is free and relatively user-friendly for the average desktop GIS user, and comes at a time when ecologists are just beginning to understand the critical role that sound disturbances play in affecting wildlife."
Reed started the SPreAD-GIS project as a scientist with The Wilderness Society (TWS) and completed it as a Smith Conservation Research Fellow and WCS employee. The model is available for download from TWS's Landscape Collaborative (www.landscapecollaborative.org) website.
The tool is described in the November print edition of the journal Environmental Modeling & Software. Authors include Sarah E. Reed of the Wildlife Conservation Society and Colorado State University, Jennifer L. Boggs, formerly of The Wilderness Society, and Jacob P. Mann.
Story Source:
Dec. 14, 2012 — A new tool developed by the Wildlife Conservation Society (WCS) and its partners is being used by scientists and land managers to model how noise travels through landscapes and affects species and ecosystems -- a major factor in land and wildlife management decisions such as where to locate new roads or recreational trails.
“A new tool is being used by scientists and land managers to model how noise travels through landscapes and affects wildlife.” (Credit: Julie Larsen Maher, copyright WCS)
In an example discussed in the paper, the sensitivities of humans and owls to motor vehicle sound levels were compared. The results of the SPreAD-GIS analysis showed that in the same location, motor vehicle noise would affect owls in an area 45 percent larger than the area affected for humans. Exposure to noise may affect an owl's livelihood as the animal relies on its acute sense of hearing to detect even the slightest movement of its prey.
WCS Scientist Sarah Reed said, "Exposure to human-caused noise can change the game for many species. Those species that are less tolerant of noise can be put at a disadvantage and ultimately, this may result in a loss in biodiversity. By predicting what the effects of sound will be on a bird or mammal species in advance, we can more adequately balance our land-use planning decisions with conservation considerations."
Reed and colleagues are currently using SPreAD-GIS and field measurements of motor vehicle noise to forecast the area affected for bird and mammal communities in the Sierra National Forest in California. In addition, the model has been downloaded by hundreds of users in more than 25 countries and used for diverse education, research, and management applications. This includes modeling potential noise propagation from roads, recreational activity, heavy equipment, residential development, and natural resource extraction.
Reed added, "Most existing tools are used to understand noise in human-dominated environments and don't incorporate factors affecting noise propagation in natural systems. This tool is free and relatively user-friendly for the average desktop GIS user, and comes at a time when ecologists are just beginning to understand the critical role that sound disturbances play in affecting wildlife."
Reed started the SPreAD-GIS project as a scientist with The Wilderness Society (TWS) and completed it as a Smith Conservation Research Fellow and WCS employee. The model is available for download from TWS's Landscape Collaborative (www.landscapecollaborative.org) website.
The tool is described in the November print edition of the journal Environmental Modeling & Software. Authors include Sarah E. Reed of the Wildlife Conservation Society and Colorado State University, Jennifer L. Boggs, formerly of The Wilderness Society, and Jacob P. Mann.
Story Source:
The above story is reprinted from materials provided by Wildlife Conservation Society.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Scientists Develop Novel Method to Study Parasite Numbers in Wild Seabirds
Iturria: ScienceDaily
The research is published today (Dec. 13, 2012) in the scientific journal Methods in Ecology and Evolution.
The research team trialled the use of endoscopy, often used in human and veterinary medicine but rarely in field situations, to measure natural parasite loads, or burdens, of European shags, a member of the cormorant family. The new study is part of ongoing work into how different factors such as gut parasites might affect the breeding success or survival of seabirds.
Shags have nematode worms (Contracaecum rudolphii) in their stomachs, obtained from their fish diet. These worms feed directly on food obtained by the birds, reducing for the food available to both parent and chicks.
The team behind today's study was led by Dr Sarah Burthe from the NERC Centre for Ecology & Hydrology (CEH) in the UK. Dr Burthe and colleagues from CEH collaborated with scientists from the University of Edinburgh (UK), Biomathematics and Statistics Scotland (UK), Aarhus University, (Denmark) and the Natural History Museum, London (UK). The study was carried out on the Isle of May NNR, an important seabird colony off the east coast of Scotland which has been intensively studied since the 1970s.
Dr Burthe said, "Endoscopy is used routinely in veterinary and human medicine but to our knowledge has not been used to measure parasites in wild animals. Our new method using an endoscope is a rapid, reliable and repeatable way of looking at gut parasites in European shags which has no obvious adverse effects."
The study found that all birds had parasitesranging from low burdens of several worms through to high burdens of more than 40 worms. Burdens were significantly higher in males and in late breeders. There was a slight seasonal decline in worm counts within individuals.
One way to get an understanding of the impact of parasites on breeding success and survival is to treat birds with an anti-parasite drug to reduce or remove worm burdens and then compare to untreated birds. However, until now the lack of a method to measure parasite numbers effectively has made it difficult to know whether such treatments have worked. The use of the endoscope enabled the researchers to conclude that, at a suitable dose, the anti-parasite drug completely removed nematode worms from the stomach of treated shags.
Study co-author Dr Francis Daunt, a population ecologist at the NERC Centre for Ecology & Hydrology said, "Being able to monitor individual parasite burdens is a major step forward in this field of research. We are hopeful this new technique could be applied to other wild animal systems, possibly including reptile, mammal and other bird hosts."
Dr Burthe added, "Endoscopy opens up some interesting research questions, enabling us to more fully explore the role parasites play in impacting the breeding success and survival of seabirds, particularly how impacts may vary with changes in prey availability."
Why use endoscopy to study parasites in wild seabirds?
Parasites are an important part of ecosystems, occurring in all wild animal species and playing an important part in the evolutionary process. Relatively few studies have focussed on gut parasites in wild animals, in part because it is very difficult to measure parasite levels in hosts without resorting to examining animal carcasses or counting eggs in faeces, both of which can be unreliable measures. Some previous ways of studying parasites in wild populations have involved killing birds.
The endoscopy method is rapid and well suited to species that routinely swallow large prey items and/or where chicks feed by inserting their heads into the parent's throat. Observations from this study confirmed that Shags went straight back to their broods and their breeding success was as high as pairs that were not endoscoped.
Endoscopy is a licensed procedure and was undertaken under a Home Office Project Licence and conducted by trained personnel. The work had full ethical approval from the University of Edinburgh and CEH's Ethics Committees and the Home Office. As this was a novel technique that is usually undertaken in a clinical setting, the work was initially carried out under full independent veterinary supervision.
Story Source:
Journal Reference:
Dec. 13, 2012 — Scientists have developed a new method for studying parasite numbers in the stomachs of individual seabirds in the wild. The technique enables the recording of video footage of worms inside seabird stomachs and is an important step forward in understanding the impact of parasites on seabird populations.
Shag on the Isle of May. (Credit: Mark Newell / Centre for Ecology & Hydrology)
The research team trialled the use of endoscopy, often used in human and veterinary medicine but rarely in field situations, to measure natural parasite loads, or burdens, of European shags, a member of the cormorant family. The new study is part of ongoing work into how different factors such as gut parasites might affect the breeding success or survival of seabirds.
Shags have nematode worms (Contracaecum rudolphii) in their stomachs, obtained from their fish diet. These worms feed directly on food obtained by the birds, reducing for the food available to both parent and chicks.
The team behind today's study was led by Dr Sarah Burthe from the NERC Centre for Ecology & Hydrology (CEH) in the UK. Dr Burthe and colleagues from CEH collaborated with scientists from the University of Edinburgh (UK), Biomathematics and Statistics Scotland (UK), Aarhus University, (Denmark) and the Natural History Museum, London (UK). The study was carried out on the Isle of May NNR, an important seabird colony off the east coast of Scotland which has been intensively studied since the 1970s.
Dr Burthe said, "Endoscopy is used routinely in veterinary and human medicine but to our knowledge has not been used to measure parasites in wild animals. Our new method using an endoscope is a rapid, reliable and repeatable way of looking at gut parasites in European shags which has no obvious adverse effects."
The study found that all birds had parasitesranging from low burdens of several worms through to high burdens of more than 40 worms. Burdens were significantly higher in males and in late breeders. There was a slight seasonal decline in worm counts within individuals.
One way to get an understanding of the impact of parasites on breeding success and survival is to treat birds with an anti-parasite drug to reduce or remove worm burdens and then compare to untreated birds. However, until now the lack of a method to measure parasite numbers effectively has made it difficult to know whether such treatments have worked. The use of the endoscope enabled the researchers to conclude that, at a suitable dose, the anti-parasite drug completely removed nematode worms from the stomach of treated shags.
Study co-author Dr Francis Daunt, a population ecologist at the NERC Centre for Ecology & Hydrology said, "Being able to monitor individual parasite burdens is a major step forward in this field of research. We are hopeful this new technique could be applied to other wild animal systems, possibly including reptile, mammal and other bird hosts."
Dr Burthe added, "Endoscopy opens up some interesting research questions, enabling us to more fully explore the role parasites play in impacting the breeding success and survival of seabirds, particularly how impacts may vary with changes in prey availability."
Why use endoscopy to study parasites in wild seabirds?
Parasites are an important part of ecosystems, occurring in all wild animal species and playing an important part in the evolutionary process. Relatively few studies have focussed on gut parasites in wild animals, in part because it is very difficult to measure parasite levels in hosts without resorting to examining animal carcasses or counting eggs in faeces, both of which can be unreliable measures. Some previous ways of studying parasites in wild populations have involved killing birds.
The endoscopy method is rapid and well suited to species that routinely swallow large prey items and/or where chicks feed by inserting their heads into the parent's throat. Observations from this study confirmed that Shags went straight back to their broods and their breeding success was as high as pairs that were not endoscoped.
Endoscopy is a licensed procedure and was undertaken under a Home Office Project Licence and conducted by trained personnel. The work had full ethical approval from the University of Edinburgh and CEH's Ethics Committees and the Home Office. As this was a novel technique that is usually undertaken in a clinical setting, the work was initially carried out under full independent veterinary supervision.
Story Source:
The above story is reprinted from materials provided by Centre for Ecology and Hydrology.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Sarah Burthe, Mark A. Newell, Gidona Goodman, Adam Butler, Thomas Bregnballe, Eileen Harris, Sarah Wanless, Emma J.A. Cunningham, Francis Daunt. Endoscopy as a novel method for assessing endoparasite burdens in free-ranging European shags (Phalacrocorax aristotelis). Methods in Ecology and Evolution, 2012; DOI: 10.1111/2041-210x.12015
2012/12/11
Turbera de Saldropo, su registro palinológico y el haya
Interesnatísimos daots, tomados del blog de JA Pérez de Ana.
Iturria: Blog MACIZO DEL GORBEA
Iturria: Blog MACIZO DEL GORBEA
Turbera de Saldropo, su registro palinológico y el haya
En las páginas 169-172 del libro "Paleoflora y paleovegetación de la Península Ibérica e Islas Balaeares" (130 MB) o solo del capítulo dedicado al País Vasco, publicado en 2012, se resumen los resultados de dos estudios palinológicos de la turbera de Saldropo, municipio de Zeanuri (Bizkaia). Mientras existía, se tomaron muestras de turba que analizaron en sendos estudios Mercedes García-Antón y María Cristina Peñalba Garmendia. En las turberas, debido a la acidez y la falta de oxígeno, se conserva en buen estado el polen producido por las plantas del entorno, en capas sucesivas que siguen, como es lógico, el orden cronológico, siendo más antiguas las profundas y más recientes las superficiales.
Gracias al estudio del polen conservado en la turbera de Saldropo y la datación mediante C14 se conoce qué especies de la flora y en qué abundancia vivían en el Macizo del Gorbea desde hace 6.420 años. Para el primer estudio, de Mercedes García-Antón, publicado en 1989 en el artículo "Análisis geomorfológico y palinológico de la turbera de Saldropo (Barazar. Zeanuri/Bizkaia)" en el número 12 de la revista Lurralde, se tomaron muestras de 260 cm de profundidad directamente sobre el corte durante la explotación de la turbera. En el estudio de María Cristina Peñalba Garmendia, publicado en 1994, se tomaron muestras de 350 cm de profundidad.
El análisis del polen depositado en la desaparecida turbera de Saldropo ha permitido conocer que el haya (Fagus sylvatica) estaba ausente hace 6.420 años en el Macizo del Gorbea. Apareció hace 5.170 años, pero su expansión se produjo desde hace 3.900 años y se volvió la vegetación dominante hace 2.540 años y así permaneció hasta hace 850 años, cuando comenzó su declive por la desforestación provocada por el ser humano para generar pastizales para el ganado. Tomé estas fotografías el 9 de diciembre de 2012 en el Humedal de Saldropo, municipio de Zeanuri (Bizkaia).
En esta fotografía se muestran en color rojo las 5,6 hectáreas del Humedal de Saldropo, donde se encontraba la turbera de Saldropo, explotada hasta su total agotamiento.
IMPORTANTE PRESENCIA DE COLIMBOS Y CORMORANES MOÑUDOS EN LA DESEMBOCADURA DEL NERVIÓN
Gorka, como siempre, aportando información abundante y de calidad, y además actual.
Iturria: El Blog de Gorka Ocio
Iturria: El Blog de Gorka Ocio
martes, 11 de diciembre de 2012
IMPORTANTE PRESENCIA DE COLIMBOS Y CORMORANES MOÑUDOS EN LA DESEMBOCADURA DEL NERVIÓN
Este invierno hemos realizado la V temporada de avistamientos de aves por el Abra y la ría del Nervión, organizados por el Área de Turismo del Ayuntamiento de Santurtzi (Bizkaia). Para ello hemos tenido varias jornadas de visitas tanto a pie como con embarcación a motor.
Los fuertes temporales sufridos a primeros de diciembre hacían presagiar una importante entrada de aves en busca de refugio y con la posibilidad de asentarse en nuestras aguas. Sin embargo y a pesar de contabilizarse un importante paso de álcidos por los cabos cercanos como Getaria (Gipuzkoa) y Ajo (Cantabria) gracias a los censos de Asier Aldalur y Jesús Menéndez respectivamente, este año apenas han entrado álcidos en las aguas interiores. Algo que ha contrastado mucho con la invernada de cientos de alcas (Alca torda) y decenas de Araos comunes (Uria aalge) del año pasado.
Y es que llama mucho la atención las diferencias de un año a otro. El año pasado apenas hubo colimbos en la desembocadura del Nervión. Sin embargo este año hemos avistado casi una decena de Colimbos chicos (Gavia stellata) entre la Playa de Ereaga y la Playa de La Bola en Getxo. De hecho, se ha podido disfrutar mucho de ellos desde la costa gracias a la costumbre que tienen de pescar muy cerca de la orilla.
Lo mismo nos ha pasado con los amenazados Cormoranes moñudos (Pharacrocorax aristotelis). Las voces de alerta de nuestros compañeros David Álvarez y Jon Hidalgo sobre las graves amenazas que se ciernen sobre las poblaciones asturianas y vascas que estudian, con la utilización de tresmallos por parte de pescadores “artesanales”... redes de fondo y nada selectivas que se arrian muy cerca de la costa. Este último domingo 9 de diciembre nos vimos sorprendidos con dos pesqueros cántabros arriando sus redes muy cerca de la orilla y en la playa de Ereaga. Lugar habitual de pesca de nuestros amenazados cormoranes y otras aves buceadoras.
Estas aguas las utiliza entre otros, un cormorán moñudo jóven y anillado por Jon Hidalgo en la Isla de Billano (Bizkaia). La anilla verde con los dígitos AX nos permite conocer un poco más sobre su zona de invernada y costumbres pesqueras.
Estas aguas abiertas también están siendo utilizadas por unos pocos Somormujos lavancos (Podiceps cristatus), una solitaria hembra tuerta de Serreta mediana (Mergus serrator)
así como un par de Negrones comunes... hembra adulta (Melanitta nigra)...
hembra jóven...
Con las nieblas matinales hemos sorprendido a otras aves menos habituales y que en algunos casos han preferido hacer un alto en el camino esperando una mejoría para continuar su migración. Esto ha hecho un grupito de Ánades frisos (Anas strepera)
Cercetas comunes (Anas crecca), Ánades reales (Anas platyrhynchos)
e incluso media docena de Grullas comunes (Grus grus), aunque estas no llegaron a posarse.
En sus orillas y alimentándos en pequeñas charcas y en las rocas encontramos a la Garceta común (Egretta garzetta)
a los inquietos Correlimos oscuros (Calidris maritima)
un solitario Correlimos tridáctilo (Calidris alba)
Andarrios chico (Actitis hypoleucos)
y prácticamnete por todas sus orillas incluso andando entre la gente a los cada vez más abundantes y confiados Vuelvepiedras (Arenaria interpres).
Enfrente del Marítimo de Las Arenas hay un velero con un inmovil habittante. Un buho real mantiene firme su guardia para evitar que las gaviotas y cormoranes grandes (Pharacrocorax carbo) manchen con sus deyecciones la embarcación. Se trata de un pájaro de plástico y sí ha cumplido su cometido... la embarcación no presenta manchas de pájaros... sin embargo no podemos decir lo mismo de él. Está literalmente cagado por las aves. Ya no muestra peligro y éstas parecen “vengarse” ante tanta osadia. La verdad es que nos provocó una buena sonrisa.
Si bien este señuelo es ninguneado por los cormoranes, la persecución al que están siendo sometidos por la presión de los pescadores “deportivos” los han vuelto excesivamente desconfiados. Es una gran pena. Ya no dejan ni pasar a más de cien metros de distancia de ellos mientras remontamos la ría. A la mínima levantan el vuelo. Aunque quienes se acerquen a ellos sean deportistas desde sus embarcaciones a remo.
Menos esquivos tenemos a los pequeños Zampullines cuellinegros (Podiceps nigricollis)
En cuanto a gaviotas. No tiene nada que ver con otros años y más tras el cierre del vertedero de getxotarra de Fadura. Sólo podemos disfrutar de abundantes gaviotas medianas y pequeñas coincidiendo con temporales. Así podemos disfrutar de buenos números de Gaviotas enanas (Larus minutus)
y de Gaviotas cabecinegras (Larus melanocephalus).
Otras gaviotas... las patiamarillas (Larus michaellis)
Gaviotas reidoras (Larus ridibundus)
Gaviotas sombrías (Larus fuscus graellsii)
Un saludete
Gorka Ocio
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