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Tag Archive: birds

  1. Fracking tied to reduced songbird nesting success

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    February 14, 2018 American Ornithological Society Publications Office Read full ScienceDaily coverage here

    The central Appalachian region is experiencing the country’s most rapid growth in shale gas development, or ‘fracking,’ but we’ve known almost nothing about how this is affecting the region’s songbird populations — until now. A new study demonstrates that the nesting success of the Louisiana waterthrush — a habitat specialist that nests along forested streams, where the potential for habitat degradation is high — is declining at sites impacted by shale gas development in northwestern West Virginia…

    Mack W. Frantz, Petra B. . Wood, James Sheehan, Gregory George. Demographic response of Louisiana Waterthrush, a stream obligate songbird of conservation concern, to shale gas development. The Condor, 2018; 120 (2): 265 DOI: 10.1650/CONDOR-17-130.1

  2. Wildfire management of CA’s chaparral ecosystem can devastate wild bird populations and fire-risk reduction is only temporary- new study

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    • Although bird species diversity and abundances rebounded after one-time use of prescribed fires, most birds never returned to masticated sites. Mastication reduced the number of bird species by about 50 percent and reduced total numbers of birds by about 60 percent.
    • “The best available science tells us that managing chaparral imperils wildlife and increases fire risk…Our study continues to build the case that we should live densely and away from chaparral.”

    February 14, 2018 University of Arizona read full ScienceDaily article here

    On the tail of California’s most destructive and expensive year of firefighting ever, it might seem obvious that vegetation removal would reduce the risk of such a year happening again. But scientists are showing that in chaparral, California’s iconic shrubland ecosystem, management can devastate wild bird populations and that fire-risk reduction is only temporary.

    …Chaparral is a fire-prone ecosystem in North America that is widespread throughout California. Although it makes up only 6 percent of California by area, it contains one-quarter of the species found in the California Floristic Province, a global biodiversity hotspot. To date, no other studies have compared the effects of different fire management types on California chaparral wildlife….

    …Although bird species diversity and abundances rebounded after one-time use of prescribed fires, most birds never returned to masticated sites. Mastication reduced the number of bird species by about 50 percent and reduced total numbers of birds by about 60 percent….

    …Much of California’s chaparral is burning too frequently to replace itself because of human-caused ignitions and longer wildfire seasons due to climate change. According to Scott Stephens, the principal investigator of the experiment at UC Berkeley, too-frequent fire can cause chaparral to be replaced by invasive grasses, which can increase fire risk.

    This leads to other problems. Grasses don’t hold soils in place, so deadly mudslides may follow wildfires, such as those in Santa Barbara, California….

    …”The best available science tells us that managing chaparral imperils wildlife and increases fire risk,” she said. “Our study continues to build the case that we should live densely and away from chaparral.”

    Erica A. Newman, Jennifer B. Potts, Morgan W. Tingley, Charles Vaughn, Scott L. Stephens. Chaparral bird community responses to prescribed fire and shrub removal in three management seasons. Journal of Applied Ecology, 2018; DOI: 10.1111/1365-2664.13099

  3. Researchers discover specific protein and location in bird retina responsible for magnetic compass

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    • A protein in the birds’ eye helps them take information from light and process it to a travel course: an inner magnetic compass
    • Researchers discovered that the Cry4 protein – unique to birds- expression level in European robin retinae is significantly higher during the migratory season compared to the non-migratory seasons
    • They found these long sought proteins in migratory birds are situated at the outer segment of the double cone photoreceptor cells in the retina per studies on the European Robin.

    February 7, 2018 University of Southern Denmark

    Migratory birds use a magnetic compass in their eye for navigation. Its basic sensory mechanisms have long remained elusive, but now researchers reveal exactly where in the eye, the birds’ control center for navigation is situated.

    …In 2000 researchers suggested that a protein in the birds’ eye helps them take information from light and process it to a travel course: an inner magnetic compass. Since then the basic sensory mechanisms underlying this magnetoreception has remained elusive….

    The magnetic compass sense in migratory birds is light dependent, and we wanted to find out which protein is at play. Theories have been circling around the so-called cryptochromes — but these cryptic proteins come in very different variations — so which one?

    …To date, four different cryptochromes have been found in the retina of several bird species. Three of them show no relevance for magnetoreception, the researchers conclude.

    But the fourth, Cry4, seems to be significantly different from its family members,” Ilia Solov’yov said.

    When light hits cryptochromes in the eye of a migrating bird, they undergo chemical reactions that are influenced by the direction of Earth’s magnetic field, providing a signal of the bird’s orientation.

    …They discovered that the Cry4 expression level in European robin retinae is significantly higher during the migratory season compared to the non-migratory seasons. “This is a strong indicator that the responsible protein is indeed cryptochrome 4.”…

    …Inner compasses are not only found in migratory birds, but also in other animals such as bees.

    “Understanding these inner compasses in animals can give us a fundamental knowledge of nature and maybe we can use it to protect wildlife. Many birds are killed in windmills, because they get disturbed by the turbulence around the mills. If we knew what magnetic fields exist around the mills, we maybe could construct some kind of protection zone around the mills,” said Ilia Solov’yov….

    Anja Günther, Angelika Einwich, Emil Sjulstok, Regina Feederle, Petra Bolte, Karl-Wilhelm Koch, Ilia A. Solov’yov, Henrik Mouritsen. Double-Cone Localization and Seasonal Expression Pattern Suggest a Role in Magnetoreception for European Robin Cryptochrome 4. Current Biology, 2018; 28 (2): 211 DOI: 10.1016/j.cub.2017.12.003

  4. Urban Bird Feeders Are Changing the Course of Evolution

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    • More than 50 million Americans are conducting an unwitting experiment on a vast scale.

    Emily Voigt

    ….According to experts, feeding birds is probably the most common way in which people interact with wild animals today. More than 50 million Americans engage in the practice, collectively undertaking an unwitting experiment on a vast scale. Is what we’re doing good or bad for birds? Recently, researchers at the Cornell Lab of Ornithology sought to answer this question, analyzing nearly three decades’ worth of data from a winter-long survey called Project FeederWatch. Preliminary results suggest the species visiting our feeders the most are faring exceptionally well in an age when one-third of the continent’s birds need urgent conservation. Still, what are the consequences of skewing the odds in favor of the small subset of species inclined to eat at feeders? What about when the bird we’re aiding is invasive, like our house finch?…

    …..Traditional wisdom dictates that birds don’t become dependent on a free lunch. The idea traces to the mid-1980s when the wildlife ecologist Stanley Temple and his then-student Margaret Brittingham color-banded several hundred black-capped chickadees in the Wisconsin woods, mounted two specially designed feeders, then laboriously counted the sunflower seeds each bird ate. To the scientists’ astonishment, the chickadees obtained only 21 percent of their daily energy requirements from the feeders. The findings suggest that birds haven’t evolved to rely on a single ephemeral food source; rather, they’re constantly sampling the environment, forever scanning for backup options in a changeable world.

    When Temple and Brittingham removed a feeder that had been stocked for more than 25 years from one of their study sites—a nature center at Devil’s Lake State Park—the chickadees there fared as well through the winter as those in the remote reaches of the reserve, where birds had never even seen a feeder. In other words, birds don’t forget how to forage just because they’re receiving handouts. Only in especially severe weather did feeders appear to undoubtedly help: chickadees with access to one had nearly double the chance of surviving the harsh Wisconsin winter—the difference coming down to a few frigid days….

    ….If the classic studies on rural chickadees found they didn’t become dependent on feeders, how much did that tell us about birds eking out an existence on the mean streets of Greenwich Village? The question is more relevant today than ever before, in an age when half the human population now resides in cities for the first time in history, a proportion that’s rapidly on the rise. Over the coming decades, the future of many wild animals will depend on their ability to adapt to an increasingly urbanized world. At the library, I searched out a book called Avian Urban Ecology, which said that little is known about the impact of feeding most birds in cities. There is, however, one stunning exception….

    ….If Darwin saw his theory of natural selection illuminated in the finches of the Galapagos, Badyaev is looking deep into the house finch to resolve a question he feels Darwin never answered: How does life maintain evolvability, the facility to change and adapt to the future?

    ….In the Southwest, for example, where Badyaev is a professor at the University of Arizona, house finches live on their native turf and nest on the cholla cactus, females shielding eggs against temperatures hot enough to hard-boil them. Meanwhile, some thousand miles to the north, where Badyaev earned his doctorate at the University of Montana, the same species hatches its young under snow cover, having undergone a transformation involving everything from hormonal signaling to eggshell architecture. To understand such radical metamorphoses, executed over a few short decades, his team has been measuring nearly every conceivable metric in hundreds of thousands of banded finches across dozens of populations, yielding one of the largest studies of wild birds in the world.

    ….Comparing the beak sizes, bite forces, and diets of the two populations, the researchers showed that the urban finches rely so heavily on feeders that their beaks have adapted: they’ve become longer and deeper to accommodate the sunflower seeds typically on offer, which are much larger and harder than the small cactus and grass seeds that rural finches eat. This adaptation has altered not only how urban males sing, but also what urban females prefer in a mate. It’s a pattern that Badyaev has since found in other places where finches live in the shadow of humans, the same large beaks arising from a surprisingly diverse array of developmental pathways. Such varied routes to an identical end—a beak strong enough to crack sunflower seeds—may be one way that nature hides variability from the swinging axe of natural selection….

    ….so should we feed birds? By doing so, we’re almost certainly changing them. A recent study in Science found that the beaks of great tits have evolved to be longer in the United Kingdom than in continental Europe, possibly due to the popularity of feeders in England. What’s more, species from hummingbirds to northern cardinals are wintering farther north than they have in the past, though whether as a consequence of feeders, the warming climate, or both remains a largely open question. (To say nothing of the garbage and waste grain from agriculture that we feed many birds without intending to.) Precisely because we’re altering nature so radically and in so many ways, bird feeders are bound to seem comparatively innocuous. Meanwhile, proponents argue that they connect us to wildlife, opening our eyes to the world beyond our backyards, including those species most in need of our help, such as seabirds and tropical birds….

  5. Warming temperatures may cause birds to shrink

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    • Clinal variation in avian body size is better explained by summer maximum temperatures during development than by cold winter temperatures

    January 24, 2018 American Ornithological Society Publications Office read full ScienceDaily article here

    Biologists have known for a long time that animals living in colder climates tend to have larger bodies, supposedly as an adaptation to reduce heat loss. However, a new study shows that this trend in birds might actually be due to the effects of high temperatures during development — raising new alarms about how populations might be affected by global warming...

    ….”If variation in body size is linked directly or indirectly to adapting to different climates, then body size could be useful for monitoring the extent to which bird populations are capable of adapting rapidly to changing climates,” says Andrew. “Our work on this common species helps us to understand the adaptive responses of birds to a changing climate and their constraints, and this fundamental knowledge will help future workers and managers focus their work on other species and potentially identify those species most at risk from climate change.“…

    Samuel C. Andrew, Monica Awasthy, Amanda D. Griffith, Shinichi Nakagawa, Simon C. Griffith. Clinal variation in avian body size is better explained by summer maximum temperatures during development than by cold winter temperatures. The Auk, 2018; 135 (2): 206 DOI: 10.1642/AUK-17-129.1

  6. Protecting piping plovers: Evaluating population viability and efficacy of conservation management using integrated population models

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    • The results show that by integrating many data sources — long-term population survey, nest monitoring and mark-resight data (banding birds and recording their presence during subsequent annual surveys) — our understanding of past and future population changes can be improved.

    Posted: 23 Jan 2018 08:25 AM PST read full ScienceDaily article here

    Visitors to Sleeping Bear Dunes National Lakeshore are often treated to tiny scurrying beachcombers — piping plovers. Future visitors, however, could see fewer of these celebrated shorebirds. A new study reveals that the endangered shorebird population could decline over the next 10 years and changes in management strategies are needed. The authors demonstrate that current counting methods may not accurately predict future plover populations without considering a growing predator population…

    Sarah P. Saunders, Francesca J. Cuthbert, Elise F. Zipkin. Evaluating population viability and efficacy of conservation management using integrated population models. Journal of Applied Ecology, 2018; DOI: 10.1111/1365-2664.13080

  7. When birds collide with high-speed rail

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    January 24, 2018  read full phys.org article here
     …The development of high-speed rail poses new ecological challenges. The thousands of kilometers of railways with trains operating at speeds of more than 155 mph can generate unwanted effects, such as the mortality of , a fact that until now had not been analyzed or quantified.

    A study published in the journal Frontiers in Ecology and Evolution, has developed a new methodology to study the impact of high-speed trains on birds. For this purpose, a video system was installed in the cabins of locomotives during more than 8,700 miles of circulation at speeds of 155-185 mph….

    …The video record also confirms that the birds generally react at a distance of 200 to 445 feet of the train, so the train´s speed leaves them little time to escape. “As a result, a small fraction of the birds that can be seen from the front of a train end up dying,” he adds.

    To reduce collisions with birds, the research team will seek methods to repel birds from infrastructure elements, and develop systems that decrease the frequency with which animals fly through the risk areas. The latter is a specific objective of the LIFE + Zero Impact project.

    Read more at: https://phys.org/news/2018-01-birds-collide-high-speed-rail.html#jCp

    Read more at: https://phys.org/news/2018-01-birds-collide-high-speed-rail.html#jCp

    More information: Eladio L. García de la Morena et al. On-Board Video Recording Unravels Bird Behavior and Mortality Produced by High-Speed Trains, Frontiers in Ecology and Evolution (2017). DOI: 10.3389/fevo.2017.00117

  8. City lights setting traps for migrating birds

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    • Researchers found an increasing density of migratory birds as they get closer to cities due to light pollution, which is increasing with more LED use;

    • They also found that suburban areas, such as people’s backyards and city parks, ….harbor some of the highest densities of birds in the northeast, potentially increasing their risk of mortality due to domestic cat predation.

    19 Jan 2018 University of Delaware read full ScienceDaily article here

    A new study has examined how light pollution lures birds into urban areas during fall migration, a trend that poses risk for the fowl that often fly into buildings and has increased with the addition of brighter LED lights. The researchers were interested in seeing what factors shape the birds’ distributions and why they occur in certain areas.

    We found an increasing density of birds the closer you get to these cities. The effect goes out about 200 kilometers [about 125 miles]. We estimate that these flying birds can see a city on the horizon up to several hundred kilometers away. Essentially, there is no place in the northeastern United States where they can’t see the sky glow of a city.”

    …The researchers also found that suburban areas, such as people’s backyards and city parks, such as Fairmount Park in Philadelphia, harbor some of the highest densities of birds in the northeast.

    …”Domestic cats could be the largest anthropogenic source of mortality for birds. If birds are being drawn into these heavily developed areas, it may be increasing their risk of mortality from anthropogenic sources and it may also be that the resources in those habitats are going to be depleted much faster because of competition with other birds.”

    Another concern: light pollution created in these cities has been increasing in recent years with the advent of LED lights, which are much brighter than the incandescent lights they replaced. “The transition of street lighting from incandescent to LED continues to increase the amount of light pollution”….

    James D. McLaren, Jeffrey J. Buler, Tim Schreckengost, Jaclyn A. Smolinsky, Matthew Boone, E. Emiel van Loon, Deanna K. Dawson, Eric L. Walters. Artificial light at night confounds broad-scale habitat use by migrating birds. Ecology Letters, 2018; DOI: 10.1111/ele.12902

  9. As climate is warming up, timing of nesting & harvesting changing, more bird nests are destroyed in Finnish farmland

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    • ….Finnish farmers are adapting to the warming climate by anticipating the time when they sow their fields in the spring. At the same time, birds have also advanced the time of breeding as the spring temperatures are becoming milder in response to climate change.

    January 11, 2018 University of Helsinki read full ScienceDaily article here

    A new study shows that birds have shifted the time of their breeding much faster than the farmers are anticipating their sowing times in Finnish farmland. This means that more birds are nowadays laying their eggs on fields that are still to be sown, a mismatch in timing that is most likely fatal for the bird nests…….Mechanical sowing of large arable areas in spring causes the destruction of many lapwing and curlew nests and traditionally, the majority of the birds started breeding later and thus avoided nest destruction. The new study found that this issue has grown much bigger under climate change. The long-term ringing data of breeding curlew and lapwings since 1970s suggest that as a result of shifts in timing of breeding, the incoming mechanical sowing destroys most of the nests that are laid on arable land….Andrea Santangeli, Aleksi Lehikoinen, Anna Bock, Pirjo Peltonen-Sainio, Lauri Jauhiainen, Marco Girardello, Jari Valkama. Stronger response of farmland birds than farmers to climate change leads to the emergence of an ecological trap. Biological Conservation, 2018; 217: 166 DOI: 10.1016/j.biocon.2017.11.002

  10. Why did the passenger pigeon die out? Humans really did cause the extinction of this species

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    • Unlike a previous study which suggested that the passenger pigeon was already in decline when Europeans arrived in North America, a new study in Science concludes that the passenger pigeon died out because of people and that the passenger pigeon wasn’t in trouble prior to Europeans arrival in North America.
    • The story of the passenger pigeon has contributed to a greater understanding that even prolific species can become extinct.
    • Scientists previously believed that the larger the population of a species is, the more genetically diverse it will be. But this theory has turned out to be wrong, as the recent passenger pigeon research has shown.

    January 11, 2018 Norwegian University of Science and Technology

    The passenger pigeon was once among the most numerous species on Earth. The last passenger pigeon died in the Cinncinati Zoo just over 100 years ago. How did it all go so wrong?

    ….In 2014, a study in published in the scientific journal PNAS strongly suggested that humans were simply the final straw in destroying a species that was already vulnerable and headed to oblivion…..The researchers asserted that…the population of the species varied greatly, similar to lemmings, but over a longer period of time.

    [They used] the PSMC method [that] can use the information in the genes of a single individual of a species to map the history of the species….The problem is that the PSMC method can’t be used on passenger pigeons. The new research in Science provides completely different results.

    …In passenger pigeons, most of the genetic diversity was found at the ends of the chromosome. The middle of the chromosome showed little variation from one generation to the next as a result of the selection on these genes….The researchers behind the [new] article in Science didn’t use the PSMC method. Instead, they used mitochondrial DNA from 41 passenger pigeons as their starting point. …

    …Scientists previously believed that the larger the population of a species is, the more genetically diverse it will be. But this theory has turned out to be wrong, as the recent passenger pigeon research has shown…..[in this new Science study] the large population size appears to have enabled passenger pigeons to adapt and evolve more quickly and thus remove harmful mutations. In species with fewer individuals, chance can cause a less beneficial mutation to persist, but chance plays less of a role in species with greater numbers of individuals….

    ….”The passenger pigeon died out because of people,” is Gilbert’s short version. The passenger pigeon wasn’t in trouble prior to Europeans arrival in North America. Nothing suggests that the species was struggling in any way….

    In the 19th century passenger pigeons were so numerous that there were contests to shoot as many of them as possible during a certain period of time. In one competition, the winner had shot 30 000 birds.

    …the story of the passenger pigeon has contributed to a greater understanding that even prolific species can become extinct…

    …People ate passenger pigeons in huge amounts, but they were also killed because they were perceived as a threat to agriculture. As Europeans migrated across North America, they thinned out and eliminated the large forests that the pigeons depended on. The pigeons lived primarily on acorns.

    As the species was already dying out, 250,000 birds – the last big flock – were shot on a single day in 1896. That same year, the last passenger pigeon was observed in Louisiana. It was also shot.

    The pigeons were probably dependent on a large flock size to reproduce. Their instincts didn’t work when only a few individuals remained here and there. The last passenger pigeon died in the Cincinnati Zoo in 1914.

    Gemma G. R. Murray, André E. R. Soares, Ben J. Novak, Nathan K. Schaefer, James A. Cahill, Allan J. Baker, John R. Demboski, Andrew Doll, Rute R. Da Fonseca, Tara L. Fulton, M. Thomas P. Gilbert, Peter D. Heintzman, Brandon Letts, George McIntosh, Brendan L. O’Connell, Mark Peck, Marie-Lorraine Pipes, Edward S. Rice, Kathryn M. Santos, A. Gregory Sohrweide, Samuel H. Vohr, Russell B. Corbett-Detig, Richard E. Green, Beth Shapiro. Natural selection shaped the rise and fall of passenger pigeon genomic diversity. Science, 2017; 358 (6365): 951 DOI: 10.1126/science.aao0960