Tag Archives: habitat

How Wildfires Affect Birds

(By Andy McGlashen, 11 Oct 2017; Photo:Robert Royse)

Big burns are natural, but climate change could make especially destructive fire seasons the new normal.

Devastating and deadly wildfires in California’s wine country this week made it clear that this summer’s brutal fire season in the West isn’t over yet. Nationwide, 38 fires are still burning, 17 of them large and uncontained, according to a daily report from the National Interagency Fire Center. Fires have scorched more than 8.5 million acres in 2017 so far, compared to a 10-year average of about 6 million acres. Multiple firefighters and citizens have died in blazes this season, and thousands of homes and businesses have been destroyed. Smoke has made the air dangerous to breathe in many parts of the West.

Like melting glaciers and rising seas, larger fires and longer fire seasons are among the predicted effects of climate change that are now coming to pass. With that in mind, it’s worth exploring how wildfires affect birds. It’s hard to definitively say how avian communities will be affected in the long term, but generally speaking—for now, anyway—wildfires don’t pose a major threat for most birds.

What do birds do when wildfires break out? No surprise here: They fly away. A fire might kill weak birds or, depending on the time of year, claim nestlings. But at least in the Western forests that U.S. Forest Service research biologist Vicki Saab studies, birds evolved alongside fire and flee in the face of conflagrations. “Direct mortality is not a big concern,” Saab says.

How do wildfires physically affect birds? Assuming birds escape a fire, smoke might still affect their health in ways that aren’t very well understood. “We do know that exposure to particulate matter, which of course is of great concern for human health, can affect birds as well,” says Olivia Sanderfoot, a National Science Foundation Graduate Research Fellow at the University of Washington Seattle who studies how air pollution affects birds. For example, veterinarians and poultry scientists who study captive birds have found that smoke can damage lung tissue and leave the animals susceptible to potentially lethal respiratory infections.

How that plays out in the wild is largely unknown, Sanderfoot says. Her current research aims to track changes in bird populations and diversity after exposure to smoke from large wildfires. In some cases, smoke inhalation might make it harder for birds to flee onrushing flames. Thick smoke, for instance, may have contributed to the deaths of 50 adult White Ibises during a 1999 fire in the Everglades, Sanderfoot reported in a recent paper. And some low-flying species might succumb to smoke inhalation or exhaustion before they can escape forest fires, according to the Alberta Institute for Wildlife Conservation.

How do wildfires affect habitat, and do any birds benefit from blazes? A little disturbance is a good thing for many species. In the dry, mixed-conifer forests Saab studies, most wildfires—even intense ones—burn unevenly, leaving behind a mosaic of habitat patches. “Fire definitely benefits a lot of bird species,” Saab says. “It’s not all doom and gloom.”

For a Black-backed Woodpecker, for example, a newly burned forest provides a smorgasbord. Bark- and wood-boring beetles arrive in droves and lay eggs in charred trees; woodpeckers feast when they reach the larval stage. There’s often an influx of other bugs, too, which draws aerial insectivores like Dusky Flycatchers and Mountain Bluebirds that hunt for midair meals in the new forest openings created by fire, Saab says. The patchwork of post-fire habitats also suits White-headed Woodpeckers and other species that nest in open areas but forage in unburned surrounding forests.

Other birds benefit from fires over the longer term. Kirtland’s Warbler, for instance, nests only in the fire-dependent jack pine forests of Michigan, Wisconsin, and Ontario. Jack pine cones are sealed tight with resin until fire opens them up, releasing the seeds and generating new warbler habitat. Red-headed Woodpeckers, which nest in the high limbs of dead trees, can see a local population boom after a fire devastates a patch of forest.

Blazes aren’t a boon for all avian species. Wildfire forces those that dwell in old-growth forests—including Pileated Woodpeckers, Townsend’s Warblers, and Golden-crowned Kinglets—to go in search of new places to nest and forage. It also poses a serious risk to a bird that faces plenty of other threats: the Greater Sage-Grouse. Fire in the sagebrush ecosystem—upon which this iconic species depends—often gives invasive plants such as cheatgrass and juniper a leg up on slower-growing sage, and they provide fuel for future fires.

Do birds ever start wildfires? When combined with electricity, yes. We’ve all seen birds perched harmlessly on power lines. But if they manage to touch two transmission lines at once, they form a circuit and get zapped. In two recent fires started by birds, hawks were carrying snakes. Chances are, those writhing meals-to-be touched the second power line, electrocuting dinner and diner both, and sparking the blaze below.

There are credible claims that birds intentionally spread fires, too. Audubon and other publications have covered anecdotal reports of northern Australia raptors picking up burning sticks and dropping them elsewhere on the arid landscape to flush out prey like lizards and snakes. Mark Bonta, the Penn State geographer behind those reports, says that he and colleagues have a forthcoming peer-reviewed paper with further evidence that Black Kites, Brown Falcons, and Whistling Kites all spread fires intentionally. The researchers haven’t yet captured video or photographic evidence of the phenomenon, but Bonta says they’ve confirmed it by interviewing local experts and reviewing publications of aboriginal knowledge.

How big of a role does climate change play? Researchers detect a changing climate’s fingerprints on this year’s ferocious fires, which may be just a glimpse of things to come. In northern California, for example, heavy winter rains fueled a riot of new plant growth in the spring, but the summer’s record heat parched that vegetation, turning it to tinder. That’s part of a broader trend; Columbia University scientists last year showed that climate change has doubled the area of the western U.S. affected by forest fires over the past three decades. “Climate is really running the show in terms of what burns,” one of that study’s authors said. “We should be getting ready for bigger fire years than those familiar to previous generations.”

What climate-charged fires will mean for birds is hard to say. “More and more, the past is becoming irrelevant as we advance to the no-analog future climate,” one researcher told Audubon in 2015. Saab, from the Forest Service, says she expects future fires to rearrange habitat types and the distribution of bird species. For now, the patchwork of habitat left behind by blazes helps maintain bird diversity in Western forests. “In the future?” she says, “I don’t know.”

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Native trees, shrubs provide more food for birds

(University of Delaware 31 Oct 2017; Photo;Desiree Narango and Doug Tallamy)

University of Delaware doctoral student Desiree Narango is researching trees and shrubs planted in the lawns of homeowners throughout the Washington, D.C., Maryland and northern Virginia areas to assess how those choices are impacting food webs.

Narango, who is working with Doug Tallamy, professor of entomology in UD’s Department of Entomology and Wildlife Ecology, is also associated with the Smithsonian Migratory Bird Center and works through a citizen-science program called “Neighborhood Nest Watch.” Narango is co-advised by Pete Marra, director of the Smithsonian Migratory Bird Center.

Through her research, Narango looks at breeding birds and the food resources they need, such as insects and caterpillars.

Different trees vary in how much food they provide birds, and Narango said she has a network of homeowners in the D.C. metropolitan area who allowed her to use their yards for her study. Over the course of the four-year study, Narango has looked at 203 yards.

One thing that has stood out to her is the sheer number of different trees that are planted in these yards.

“We focus on woody plants — so trees and shrubs — and we’ve documented over 375 different species in these 203 yards. Which is crazy,” said Narango who added that it became apparent quickly that some trees are better than others with regard to sustaining food webs.

“We just had a paper come out in the journal of Biological Conservation where we show that native trees are better at providing caterpillars for birds, which is a really important food resource,” said Narango. “Native trees are better, hands down, but even among the native trees, there are some that are better than others so things like oaks and cherries and elms are highly productive for caterpillars, so they have lots of good food for the birds.”

Narango added that there are a lot of non-native plants — such as zelkova, ginkgo and lilac — that don’t provide any resources for breeding birds.

“Those species are true non-natives so they’re not related to anything here, and they provide almost nothing in terms of caterpillars for birds,” said Narango. “There are also species like Japanese cherry and Japanese maple that are non-native but are related to our native maples and cherries. We found that those species have an average of 40 percent fewer caterpillars than the native versions of that tree. If you had a choice between a black cherry and a Japanese cherry and if you’re interested in food for birds, then you should choose the native version.”

Narango said that a problem homeowners may face when trying to select native versions of plants is that a lot of the big box stores don’t carry them.

“There are a lot of really great small nurseries that have many native plants that are productive in terms of caterpillars and are also very beautiful,” said Narango. “You definitely don’t have to sacrifice beauty to get plants that are ecologically beneficial. There’s a lot to choose from so you can have beauty, you can have fruit and then also have food for birds, too. It’s all interconnected.”

As for the most eye-opening aspect of her research, Narango said that it has to be the tremendous amount of diversity in bugs and birds in people’s backyards.

“A lot of people think you need to go to the woods to see beautiful butterflies or beautiful birds, but they’re actually in people’s backyards, too,” said Narango.

In the group’s bird surveys, they documented 98 different bird species.

Narango focuses on the Carolina chickadee and said that she would follow individual birds around to see what trees they were choosing. One of the major findings in her paper is that the number of caterpillar species a plant supports predicts how strongly chickadees prefer it.

“When these birds would choose a tree, all the other birds in the neighborhood were choosing those trees, too. So we would see these amazing warblers that don’t breed in Delaware or in D.C. but are migrating through, and they’re using all these suburban habitats on their way north. In a way, our chickadees were telling us what all of the birds want during that period,” said Narango.

As a landscaper herself, Narango added that it was surprising to see how much life happened in her own backyard when she started planting the right species.

“I planted this flower called ironweed, and the first year it was there, I had the specialist bees that use that flower and then I have caterpillars in my shrubs, and it’s really cool how quickly you can see life be attracted to your yard when you plant the right species,” she said.

Vadare försvunna från vindkraftpark

(SOF 11 augusti 2017)
Det påtalas ofta att effekter sällan kan utläsas av kontrollprogram som upprättas efter etablering av vindkraft. Det kan bl.a. bero på naturliga variationer i de (fågel-)bestånd som undersöks samt att synbara förändringar ibland uppstår med avsevärd fördröjning – eller så klart att vindkraftverken inte utgör någon påverkan.
Nu finns emellertid ett intressant exempel från Stor-Rotlidens vindkraftpark i Åsele kommun, Västerbottens län. Granholmsmyran, en myr som tidigare hyste ett vadarsamhälle, saknar mindre än tio år efter etableringen helt häckande vadarfåglar.
Vid basinventeringen 2009 räknades 11 ljungpipare, 4 grönbenor, 6 gluttsnäppor, 2 skogssnäppor samt enstaka exemplar av rödbena och storspov. Ett halvt decennium senare, 2014, hade vadarsamhället minskat till 4 grönbenor, 2 ljungpipare, 1 skogssnäppa samt 1 småspov. Ytterligare två år senare stod alltså inte en enda vadare att finna vid inventeringen.
Detta är givetvis en dramatisk utveckling och även om det inte är vetenskapligt belagt att vindkraftparken är det som har orsakat vadarnas försvinnande så finns det ingen annan uppenbar förklaring.
Det kan i sammanhanget nämnas att det 2016 publicerades ännu en undersökning som påvisade vadares känslighet för vindkraftsetablering. I den brittiska studien minskade antalet häckande ljungpipare med 79 % i anslutning till en vindkraftpark och undanträngningseffekterna var tydliga upp till 400 meter från verken (Sansom et al. 2016. Negative impact of wind energy development on a breeding shorebird assessed with a BACI study design. IBIS 158: 541–555)

Isotope fingerprints in feathers reveal songbirds’ secret breeding grounds

Using isotope fingerprints in feathers, researchers have pinpointed the northern breeding grounds of a small, colourful songbird.

Myrtle warblers breed across much of Canada and the eastern United States, but winter in two distinct groups—one along the Atlantic and Gulf coasts, another along the US Pacific Coast. They are also one of the few breeds of eastern warbler that have been able to extend their range into the far northwest of the continent.

“The Pacific Coast warblers migrate through the Vancouver area, but it’s been a bit of a mystery exactly where they breed over the summer,” says David Toews, who began the research while a graduate student at the University of British Columbia (UBC).

So Toews, UBC undergraduate student Julian Heavyside, and UBC professor Darren Irwin used isotope signatures to pinpoint where the myrtle warblers breed.

‘We were able to match stable hydrogen isotopes in feathers collected in Vancouver to latitudinal isotope records in rainwater, to determine where the feathers were actually grown,” says Toews, who conducted the analysis as a postdoctoral researcher at Cornell University.

It turns out the warblers that summer on the Pacific Coast breed in Alaska and Yukon, suggesting this form of the eastern warbler spends its entire lifecycle—wintering, migrating and breeding—near the western edge of the continent.

The observatory was started in 2010 by WildResearch, a non-profit dedicated to conservation science and outreach. The observatory allows researchers to monitor how birds use Iona Beach Regional Park, estimate population trends, and create training and

These high latitude warblers also have longer wings and tails, likely adaptations for their longer migration. The evolution of the shorter migration route to wintering sites on the Pacific Coast may have facilitated the breeding expansion of myrtle warbles into northwestern North America.

“Migration has been shown to be genetically based in many species of songbirds such as warblers,” says Irwin. “An intriguing possibility is that the genes for the western migratory route were introduced to the myrtle warblers through interbreeding with a related western group, the Audubon’s warblers.”

The feathers were collected by Heavyside and volunteers at the Iona Island Bird Observatory in Iona Beach Regional Park, Vancouver, with permission from Metro Vancouver Regional Parks.

“UBC has fantastic research opportunities for undergraduate students, and I really enjoyed the chance to contribute to this project,” says Heavyside.

“I’ve volunteered at the IIBO station for several years and it was exciting to see a collaboration form between UBC and WildResearch. Holding a bird in the hand will never get old, and it’s amazing what we can learn from a single feather.”

Birds avoid crossing roads to prevent predation

(Science Daily 19 July 2017)

Roads can be dangerous to wildlife. Animals making the perilous journey against the traffic run the risk of meeting an untimely death. Until recently, it was widely believed, unlike other animals, birds were largely unaffected by the presence of roads and traffic, simply because they could fly.

A new study, published in the open-access journal, Frontiers in Ecology and Evolution, reveals this is not the case. Birds can find roads challenging too – they are less likely to be found next to roads and are hesitant to cross them.

“We observed fewer bird species and individuals of each species near to roads. In addition, they were less likely to cross wide roads,” says Christopher Johnson, who completed this research as part of his graduate studies at the Griffith University, Brisbane, Australia. “We found the smaller-bodied, forest-dependent species were the most affected, avoiding all but the narrowest of roads.

A keen bird-watcher, Mr. Johnson spent many hours carefully recording birds seen next to and crossing roads of different widths around the southern suburbs of Brisbane, Australia. He made sure that the vegetation on either side of the road of his recording sites were the same, as it was more likely that bird crossings occurred between similar habitats. These results were compared to the number of birds seen and heard in the vegetation 100m in from the roadside, to see if the species and numbers of individuals differed.

“For this study, we decided to try something new, by looking at the influence of different road widths (two, four and six-lanes) on bird crossings. In addition, we analyzed the road-crossing ability of birds of different body sizes and whether the type of bird, for example, small forest dependent, large forest dependent, honeyeater or urban tolerant species, had an effect,” explains Mr. Johnson.

The results were quite clear. The widest roads – six-lane carriageways – had fewer bird species and individuals of each species crossing them than the narrower two- and four-lane carriageways. When they looked at the different body sizes and bird types, it was the smaller forest-dependent species that showed the biggest difference.

The authors have suggested several reasons for these findings, such as birds choosing not to come out into the open for fear of predation and the creation of territorial boundaries, as breaks in vegetation can be used by birds to mark the edge of their territory. In addition, many highly aggressive, territorial bird species were seen to be taking advantage of the space near the roads, which would put off other birds crossing.

The findings of this study raises concerns, because bird species play an important role in the health of our natural environment.

Professor Darryl Jones, co-author of the study and Deputy Director of Environmental Futures Research Institute and the School of Environment at the Griffith University explains. “Birds perform a range of services that are of huge benefit to humans, from controlling pests such as mosquitoes and flies to the pollination and seed dispersal of many plants, including those of economic and medicinal value. By restricting bird movements through transportation networks, we are limiting their ability to perform these services and, ultimately, undermining the benefits we gain.”

The authors of the study strongly advise that measures are put in place to connect fragments of forest across roads, allowing wildlife to move freely.

“People use the road transport system to get from point a to b. Unfortunately, this has a negative impact on wildlife movement, particularly within urban environments,” says Daryl Evans, who also collaborated on this the research and is based at the Griffith University. “There are wildlife-friendly solutions to many of these issues, such as specially-designed overpasses, fauna underpasses and fencing so animals can avoid accessing the road, all of which need to be incorporated into the design of our road systems.”

“Further studies should look at the impacts of man-made breaks in vegetation, such as forest tracks and park walkways on bird movements,” adds Professor Jones. “We are currently using our data to identify the ‘at risk’ bird species within suburban areas, to assist with conservation management.”

Det tabte paradis: Europas sidste naturskov Bialowieza ødelægges (Lost paradise)

Före (before):

bialowieza forest

Efter (after):

bialowieza.jpg

(Toke F. Nyborg 26 June 2017)

Intens træfældning i Bialowieza-skoven i Polen er ved at tilintetgøre Europas bedst bevarede og sidste stykke urskov

Under trækronernes beskyttende baldakin i Bialowieza-skoven i Polen finder man det bedst bevarede skov-økosystem og sidste stykke løvfældende urskov i hele Europa.

Skoven er udpeget som UNESCO verdensarv og Natura 2000 område.

Nu er intens afskovning ved at tilintetgøre Europas ‘Yellowstone’. Det beretter Jaroslaw Krogulec, leder af BirdLife Polens naturfaglige afdeling:

”Så langt øjet rækker har træfældning efterladt et spor af ødelæggelse. Bialowieza-skoven er et paradis for biodiversitet uden sidestykke på dette kontinent, som byder på et rigt dyre- og planteliv blandt andet Europas største bestand af bisoner”.

Intet undslipper skovarbejdernes motorsave
Godt en tredjedel af Bialowieza-skoven er under officiel beskyttelse som nationalpark, mens de resterende to tredjedele er underlagt skovforvaltning og i stigende grad dårlig forvaltning. I store områder er det kun stubbene efter 150 år gamle træer, som vidner om skovens majestætisk fortid.

Statsstøttet hærværk
BirdLife Polen gør hvad de kan, for at stoppe, hvad de kalder ”statsstøttet hærværk”:

”I løbet af de seneste uger vi (red. BirdLife Polen) sammen med andre miljøorganisationer holdt UNESCO underrettet om ødelæggelserne, og opfordrer indtrængende EU-Kommissionen til at skride ind overfor den polske regerings overtrædelse af habitatdirektiverne,” forklarer Jaroslaw Krogulec.

DOF til Polens premierminister
Sammen med andre BidLife-organisationer støtter DOF de polske organisationers kamp for bevarelse af Europas sidste urskov, og har blandt skrevet direkte til den polske premierminister, Beata Szydlo, med en kraftig opfordring til at stoppe den ødelæggende skovhugst og respektere EU’s naturbeskyttelsesdirektiver.

Læs DOF brev til Polens premierminister

Den store britiske avis The Guardian har også fokus på sagen

Read more about Bialowieza in The Guardian

War-torn Kabul becomes a protected site for migratory birds

(Anne Chaon 13 June 2017)

A rare Afghan marsh that was once a royal hunting ground is set to come under the official protection of the UN environment agency, with the aim of saving hundreds of migratory bird species.

On the long, arid journey to the Caucasus and Siberia, across the Hindu Kush massif, the Kol-e-Hashmat Khan wetlands outside Kabul provide sanctuary for the thousands of storks, egrets, pelicans and flamingos that head north every spring from southern India.

But after 40 years of conflict and neglect, their habitat is being threatened by the growth in new homes, irrigation systems, rubbish and global warming which is gradually changing the local environment.

Now the UN has designated the wetlands a conservation site, the Afghan government said on Sunday, as it also looks to help preserve the water supply of the capital.

“There are probably more than 300 or 400 species that pass through, though without an accurate count it is hard to be sure,” says Andrew Scanlon, head of the United Nations Environment Programme (UNEP) in Afghanistan.

They are migratory birds and “tourists” who stay for a very short period of time to find food, he adds.

At daybreak, the marsh comes alive with the morning chatter of the birds hungry for breakfast.

Binoculars in hand, Scanlon stands atop a tower that dominates the landscape.

In the distance is the silhouette of Bala Hissar, an ancient fortress that defended the city for centuries. Opposite, mud houses and sturdier dwellings made from bricks seem to spring up at random, hurrily erected during wars for tides of refugees and displaced people.

It was once a favoured place for royals to go hunting, though Scanlon stresses any activity would have been carried out “in a sustainable way”.

But with the invasion of the Soviet army in 1979 and the succession of conflicts afterwards, including the civil war in the early 1990s, Afghans were preoccupied by their own survival and the environment suffered.

War saw the marshes more or less abandoned until 2005, Scanlon explains.

Read more