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Do Power Lines Help Birds?

Debbie Blicher is Senior Producer of Ray Brown's Talkin' Birds.

A team of researchers in New Hampshire and Maine are investigating whether birds move into land that has been cleared along the route of a power line or has recently been logged. “Our goal is to get a better understanding for how these habitats function in our landscape,” says wildlife specialist Matt Tarr of the University of New Hampshire Cooperative Extension.

The study is being funded by the federal Natural Resources Conservation Service. A more controversial source is the National Fish and Wildlife Foundation’s New England Forests and Rivers Fund, to which the utility Eversource is a contributor. The controversy is that Eversource has proposed the Northern Pass energy transmission project, which entails building a 192-mile electricity transmission line from Pittsburg to Deerfield, New Hampshire. Property owners and tourism officials, among others, have criticized the project. 

Tarr explains that the study isn’t intended to find benefits in building a transmission line. Rather, it's to help determine how birds use the forests that emerge after such a project is built. Tarr's research could help inform policymakers as they work to create more young forests for birds and other species. It will focus on 24 transmission line rights-of-way and 12 logged areas in southeastern New Hampshire and southern Maine. “We might find these rights of way aren’t used as we think they are for mature forest birds," explains Tarr. "That would be important for us to know.”

Starting in late May, Tarr and his colleagues will catch songbirds and band them, then track them over the next two years. Tarr says as many as 40 songbird species nest in young forests, and another group nests in mature forests. Additional evidence suggests young birds that have just left the nest will often live in young forests while their development finishes. In some parts of the country, these younger forests have been found to provide food sources and protection for birds. 

We here at Talkin' Birds are all for the peaceful coexistence of humans with birds and other creatures. We appreciate careful research that leads to wise decisions. We wish Matt Tarr and his team good luck and clear results. 

 

A Lesson in Careful Tree-Cutting

When Canadian biologist Chris Fisher drove through Banff, Jasper, Mount Revelstoke and Glacier national parks in May, he noticed that many trees were being cut down along the highways for various park projects. May is prime nesting season, so he wondered how the park service was managing not to disturb birds. After all, the Migratory Birds Convention Act prohibits killing, capturing, taking and disturbing of migratory birds or their nests from late April until mid-August. Wouldn't you be curious too?

Michael den Otter, an environmental assessment specialist with Banff, Yoho and Kootenay, confirms that safety upgrades, fence maintenance, and other infrastructure improvements are indeed requiring the cutting of trees along the highways, but he says that all the national parks are following the standards. “Most of the trees you see beside the highway were actually cut before the end of April. We try whenever possible to schedule our work so we’re not going into that bird breeding season.”

Sometimes it isn’t possible to schedule work so it doesn't interfere with nesting season, for instance in places where snow doesn't melt until quite late. In those places, there's a set of rules to follow that includes extensive nest sweeps. Biologists search for nests for three days during the week before cutting is scheduled. den Otter says, “If we find any sign of nesting birds, then that project will have to either mitigate that or it will have to be put on hold until whatever happens to be nesting there moves on.”

For example, a recent sweep found a dark-eyed junco along the Trans-Canada Highway during some tree removal in Yoho National Park. den Otter says, “We put a 100-meter buffer around that nest area and we’ll have to wait to complete that work in the fall when the bird fledges." A 100-meter buffer is higher than the standard, so it sounds like these folks are serious.

den Otter says the crews haven’t encountered many nesting birds in the areas along the highways where the work is being done. After all, it's a pretty noisy and disturbed area, not the deep, dense, old-growth forest that many birds really like. Still, dark-eyed juncos and white-crowned sparrows do prefer these edge habitats, and they are plentiful—and being allowed to do their thing while the projects wait. 

Fisher, the biologist, states that Environment Canada suggests not performing any nest sweeps in forested environments. “It’s their position that the likelihood of finding every single nest or the complexity of the habitat really makes it difficult to find all of the nests." He'd prefer that the national parks not even try to remove trees until after nesting season. 

Now Starring: No American Birds

When we birders watch films and TV shows made in America, we often say, "Wha-?" We notice that the birds onscreen in a show supposed to take place here are actually foreign birds. No, it's not because of Hollywood sloppiness. It's because of the law. 

The Washington Post explains: The federal Migratory Bird Treaty Act (MBTA) of 1918 prohibits the possession of migratory birds for commercial purposes. This means it's illegal to keep domestic bird species as animal actors. Why? Steve Holmer, a senior policy advisor at the American Bird Conservancy, says that, before the MBTA, populations of some birds were severely harmed because they were used so often commercially. Snowy egrets, for example were decimated in the early 1900s because their plumes were used to decorate hats.

Are you surprised that native birds can't be used as actors? So were we, and so are many producers. Benay Karp, owner of Benay’s Bird and Animal Rentals in Woodland Hills, California, says producers often come to her looking to rent a native bird and leave with one that looks similar but actually isn't the genuine article. 

The good news is that egret numbers have rebounded, along with those of many other species. The Migratory Bird Treaty Act has been a success, and Hollywood is still abiding by it. 

The bad news is that birds are being used in film and television that aren't native to the United States. Not only is it expensive to import a non-native bird, but it also can't be pleasant for the bird. We here at Talkin' Birds are rather conservation-minded; we don't want birds from anywhere to be harmed. 

Now, how about when we hear the wrong bird in a film or TV show? Is that also because of the MBTA?

No. That really is because of Hollywood sloppiness. 

 

A Scandinavian Christmas Tradition for the Birds

Birds don't celebrate Christmas, but they appreciate a feast at any time of year. Begun perhaps to distract birds from grain stores, the Swedish tradition of sharing the final harvest is a charming way to end the old year and welcome the new. 

The Julkarve, or Christmas sheaf, is customarily a farmer's last sheaf of harvested grain. The household bundles it together and places it high on a pole or rooftop on Christmas Eve, inviting local wild birds to dine. Legend says that a good crop next year is foretold if many birds gather. 

Want to try this? Check this article for an easy how-to. 

Don't have a pole or rooftop? Try spreading seed on the ground, a doorstep, or the top of a fence. Just make sure to tell the birds to stay clear of any reindeer. 

OMG! Birding Abbreviations

Go into the field with a flock of birders and you may hear abbreviations you've never heard before. "FOS"? First of season. "BOP"?  Bird of prey. Odd as they might sound, abbreviations are useful for jotting notes in a field journal with minimal time lost. Here are a few others that might be new to you. For example:

LBJ = Little brown job. (We have also heard this as "LBB" = little brown bird.)

UFR = Unidentified flying raptor. 

BVD = Better view desired. (No, not the long underwear).

Besides these general field abbreviations, there are also species abbreviations, such as:

TUVU or TV = Turkey Vulture.

MODO = Mourning Dove.

RWBL = Red-Winged Blackbird. 

We wonder whether birds have abbreviations for us. We imagine ones like these:

MTN = Much too noisy.

SGB = Squinty guy with binoculars. 

SYC = Shivering, yawning, and complaining.

For more species abbreviations, check out the Birding Species list at the American Ornithological Union. As for general field abbreviations, well, you might just have to PTUOYO (= pick them up on your own).

 

Few Answers (So Far) Concerning West Nile Virus in Bird Populations

 A new study in Proceedings of the National Academy of Sciences indicates that West Nile virus (WNV) is killing millions of birds every year in North America, but few clear patterns are yet visible. 

West Nile Virus (WNW), which arrived on this continent about 16 years ago from Africa, is carried by mosquitoes. It can infect and kill people, but birds are its preferred host. Because North American bird populations had not previously encountered WNV, they had not developed any resistance to it. Therefore, the virus spread across the entire continent in only five years, leaving millions of birds dead. Earlier studies had shown that other factors, such as climate and habitat, influenced the virus's effect on various bird species. For instance, it was found that birds in urban environments seemed more likely to contract it, for reasons that are still unknown.

A team of scientists analyzed 16 years of data collected from 1992 to 2007 at more than 500 Monitoring Avian Productivity and Survivorship (MAPS) stations across the United States. (MAPS data after 2007 weren't included because they have not yet been processed.) Using this information, the scientists were able to determine whether and how the virus first affected various bird populations and whether their numbers have recovered or are still declining. They studied a quarter-million birds from 49 species, focusing on adults.

Twenty-three of the species studied were negatively affected. Some initially suffered huge declines. For example, Red-Eyed Vireo (Vireo olivaceus) populations dropped about 29% in the year they first encountered the disease. As expected by disease ecologists, their numbers subsequently recovered. Ryan Harrigan, an infectious disease biologist at the University of California, Los Angeles (one of the study's authors) explains, “Everyone builds up immunity, and the impact tends to wane.” Eleven of the 23 affected species in the study experienced this type of recovery. 

 

But the other twelve species were not so lucky: their populations are still declining for unknown reasons. For example, populations of Warbling Vireos (Vireo gilvus) dropped only 8.7% when they contracted WNV. But instead of recovering, they've continued to drop every year by roughly the same percentage.

To try to understand why some species overcome the disease better than others, the researchers compared their habitats. Here, too, results were mixed. Ten species, including the Spotted Towhee (Pipilo maculatus) and Song Sparrow (Melospiza melodia), did not show significant losses among adults, but eleven other species in these same urban areas did. The scientists also studied whether closely related species were affected similarly by WNV. Again, the pattern was mixed. Researchers are now looking more closely at regions where certain species are still dying to see whether they can spot the reason. And they have no idea why WNV did not affect at least three species, the black-capped chickadee (Parus atricapillus), American robin (Turdus migratorius), and house wren (Troglodytes aedon). Meanwhile, Staffan Bensch, an animal ecologist at Lund University in Sweden, wonders whether the virus might even be benefitting some songbird species by killing off jays and crows, which prey on them.

One further area of concern is that the virus may be causing particular harm to birds with smaller populations and ranges--that is, endangered birds. No answers are presenting themselves at this time. The researchers say that finding them will require more long-term data of the type collected at the MAPS stations. Ultimately, they hope that understanding the behavior of WNV in bird populations will help us understand its behavior in human populations.

For further reading, check out the study: http://www.pnas.org/content/early/2015/10/27/1507747112

 

How Do Owls Turn Their Heads?

An interesting fact about owls: they cannot move their eyes! In order to follow the movements of their prey, they have to turn their heads. Owls can turn their heads up to 270 degrees, or three-quarters of the way around. If we did that we'd rupture blood vessels and cut off the blood supply to our brains. So how do owls do it?

Researchers at Johns Hopkins University, led by medical illustrator Fabian de Kok-Mercado, M.A., found major biological adaptations in owls' bones and arteries that prevent injury when they rotate their heads. 

The team studied the heads and necks of Snowy, Barred and Great Horned Owls after they'd died from natural causes. They discovered that one of the major arteries nourishing the brain passes through bony holes in the vertebrae (neck bones). The hollow cavities are about 10 times larger across than the artery traveling through them. The researchers say that this extra space allows the artery to move when it's twisted. Twelve of the 14 vertebrae in the owl's neck were found to have this adaptation.

Among the team's other findings: small vessel connections between the carotid and vertebral arteries that allow blood to be exchanged between them. We humans don't have these connections. The researchers say they allow for uninterrupted blood flow to the brain even if one route is blocked when the neck rotates.

No word on whether your high school math teacher had any of these adaptations. Better to assume she simply had eyes in the back of her head.

Want to hear more about owls and their amazing necks? We did a Science Corner piece about it on the radio show of December 8, 2013. Click here to listen! 

 

 

Around the Web

This week, we see how birds are adapting to climate change—or not; why vehicles and birds collide so often (and so tragically); and how you can get involved in a little bit of citizen science, right from your laptop!