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By Pat Leonard

“The results were shocking,” says André Dhondt, director of Bird Population Studies at the Cornell Lab of Ornithology. “More than half the bird species we tested have been exposed to the bacteria responsible for House Finch eye disease.” A paper recently published in the online scientific journal PLOS ONE shows that a bacterial parasite previously thought to infect only a few species of feeder birds actually can infect a wide range of species, though most do not show signs of illness.

“This organism, Mycoplasma gallisepticum, is much more widespread than anyone thought,” Dhondt explains, “although in most species there are no signs of conjunctivitis.”


Black-capped Chickadees, though exposed to the mycoplasma bacterium, do not show symptoms of eye disease. Photo by Shirley Gallant.

Species testing positive for exposure to the bacteria include feeder favorites such as Black-capped Chickadees, Tufted Titmice, and American Goldfinches. But exposure was also detected in forest species, such as the Wood Thrush.

“That was another surprise,” says Dhondt. “How on earth do Wood Thrushes get infected with mycoplasma? They’re not a feeder bird at all. Everyone has always assumed that feeders play a major role in the transmission of the disease and this study shows that’s not necessarily so.”

Dhondt’s team caught and tested nearly 2,000 individual birds from 53 species, looking for evidence of current infections (bacterial DNA) or past infections (antibodies) by Mycoplasma gallisepticum. The birds were studied in and around Ithaca, New York, between January 2007 and June 2010. The diagnostic tests revealed that 27 species of birds were infected by this bacterium. The actual number of species exposed to the bacteria could be even higher than suggested by this study because the test for antibodies is known to produce false negatives.

House Finch eye disease first appeared in North America in 1994 when people watching backyard feeders started seeing birds with swollen, runny eyes. Dhondt says that a strain of the bacteria, usually found in poultry, was able to grow successfully in House Finches (see Jumping the Species Barrier). The House Finch lineage of the bacteria has been mutating since it was first detected.

“The organism could mutate into a form that is much more virulent among other bird species and create a new epidemic,” noted Dhondt, who added that while we know that many species of songbirds are exposed to Mycoplasma gallisepticum, we still do not know whether the bacteria in other species of songbirds are identical to that living in House Finches in the same area.


This male House Finch shows obvious signs of eye disease. Photo by Errol Taskin.

While many species of songbirds can be infected by this bacterium, only House Finches regularly exhibit swollen eyes as a result of infections, and citizen-science participants in the Cornell Lab’s Project FeederWatch are still tracking the occurrence of disease in these finches. The take-home message for people who feed backyard birds remains the same: keep the feeders clean. If you see sick birds, leave them alone, take down the feeders and clean them, and be sure to wash your hands thoroughly afterward.

The paper, Diverse wild bird host range of Mycoplasma gallisepticum in eastern North America, is coauthored by André Dhondt, Jonathan C. DeCoste, and Wesley M. Hochachka from the Cornell Lab of Ornithology, and David H. Ley, North Carolina State University.

The work described in this paper is part of a larger collaborative research project that has received funding from both the NSF and NIH through their Ecology and Evolution of Infectious Diseases Initiative.

For more information about House Finch Eye Disease:

(Top image: male House Finch by Maria Corcacas/PFW.)

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By Kathryn Grabenstein

Red-backed Fairywren by Dale Curtis

Red-backed Fairywren—photo by Dale Curtis via Creative Commons.

As the crimson sun heaves itself over the horizon, smearing red across the Australian sky, I raise my binoculars and advance through the dew-laden, waist-high grass. My mission: to catch a Red-backed Fairywren.

Red-backed Fairywrens are small, grass-dwelling birds that occur throughout Australia’s tropical savannah but are sometimes hard to see in the dense grass they inhabit. Yet, each morning, as sunlight brushes the treetops, their songs fill the air as they proudly proclaim their existence amidst the scrubby landscape.

My six companions and I—all undergraduates getting our first taste of field research via a program called International Research Experiences for Students (IRES)—have risen early to ensure we hear these songs and have the best chances of catching the fairywrens.

Each of us has come up with an independent research project for our 2-month stay in the hot, tropical savannah of Australia’s Northern Territory. Our projects cover a broad range of topics, but they all deal with Red-backed Fairywren ecology and they all require identifying individual fairywrens from a distance. This is why we spend so much time banding the fairywrens.

Our primary tool is the mist net, a fine mesh net strung up between two poles that blends into the background. Birds, unable to see the fine weave of the net, will unknowingly fly into it, become caught, and then we’ll carefully untangle them.

As light tinges the sky, the warbled reel of fairywrens fills the air (listen to their songs here). Acting quickly, my companions and I set up a mist net nearby. We arc wide around the net, moving as quietly as possible in the swishing savannah grass, and fan out to encircle the tittering fairywrens. Then, with the fairywrens between us and the net, we push forward, herding them towards the net.

This was the start of a typical morning for the seven of us and our three advisors during our 2013 summer Down Under. Fairywrens made great study subjects because our advisors—Mike Webster, Jordan Karubian, and John Swaddle—collectively have four decades of experience studying these fascinating birds. They’ve worked out a lot of details of the system, and yet there are still many facets waiting to be explored. We had spent the previous academic year reading scientific papers and discussing research ideas with our advisors. They guided our inquiries and helped us design interesting but also feasible projects. After we returned from Australia, we analyzed our data, tested our ideas, and began work on scientific papers. (We later presented our results at the 125th Annual Meeting of the Wilson Ornithological Society.)

Here’s a little more about each of our fairywren projects, in video form:

As I reach the net, I see we’ve caught our target and begin carefully untangling a patchy young male molting from dull brown to the resplendent black and red garb of an adult male. While female Red-backed Fairywrens maintain light-brown plumage year-round, males molt from brown female-like plumage to red and black feathers before each breeding season.

With the spotty male in hand I am reminded of how tiny fairywrens are—most weigh less than a house key! Our first task is placing a metal band around the male’s leg. The Australian government issues metal bands (just as the U.S. Fish and Wildlife Service does back home), each with its own unique number. We are required by law to put one on fairywrens we catch so birds with these permanent bands can be identified if they are caught in the future. The tiny identification numbers etched on this band are hard to see without having the bird in hand, so next we give the male three plastic color bands, two on the right leg and one on the left above the metal band. These bands sit like bracelets and create a unique color combination based on their order, such as green-yellow-pink. Only one bird receives each combination, so we know that whenever we see green-yellow-pink bands on a bird, we are seeing the patchy male we caught this morning.

One thing that makes working with Red-backed Fairywrens so exciting is that they are highly social and constantly chitchatting with each other. During the nonbreeding season they are also highly mobile, meaning that on any given day a single bird could interact with upwards of a dozen individuals. All this moving around makes it hard to keep track of individual birds, and it’s another reason why banding the birds on our study area is a basic necessity for our research projects.

Once we’ve banded the male, we take a small blood sample that we will use later to see who this bird is related to, confirm if it’s male or female, and what its hormone levels are, all useful information for constructing a picture of how these birds interact with their social and physical environments. Next, we take a series of body measurements such as wing length and how much fat the bird is carrying. Finally, we take photos to assess molt patterns and parasites. The whole process takes around 5 minutes and then we release the bird to fly on his merry way.

Banding is a fundamental skill for nearly any field ornithologist because it allows researchers to collect data on individual birds.  Through the IRES project, students such as myself not only get a chance to conceptualize their own project, but learn hands-on skills that help us succeed in the behavioral ecology field.

As the hot Australian sun climbs higher in the impossibly blue sky, we take down our nets and set off in search of other fairywrens to band. By the time our 3 months here are over, we will have caught nearly every fairywren at our study site (roughly 100 birds in all) at least once and watched the daily activities of these fairywrens extensively.  But for now, it’s one bird at a time.

Kathryn Grabenstein

Kathryn Grabenstein is from Oak Ridge, Tennessee. She graduated from Cornell University in 2014, where she studied Biology, concentrating in Neurobiology and Behavior. As an undergraduate she worked at the Cornell Lab with Mike Webster and Irby Lovette. She’s spending 2014–2015 as a researcher on a variety of bird research projects. In the video above, Kathryn is the student researching sound propagation.

More about fairywren research:

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Guest post by Amy E. Layton


“Birder on the Ground” Christine Bogdanowicz’s lovely photos chronicle the lives of the Cornell hawks when they’re off the nest.

When I sidled up to Christine Bogdanowicz on the Cornell University campus in the spring of 2013, I felt like a stalker. I had been admiring her camera gear from afar, watching as she feverishly snapped pictures of Big Red and Ezra—the two adult Red-tailed Hawks of the Cornell Lab’s Bird Cams project—like paparazzi hot on the trail of a celebrity. Ignorant of the world of photography I shyly asked what kind of camera she had. She smiled and tipped her equipment toward me. “My husband just bought me this,” she said proudly and quickly demonstrated how her Canon EOS 7D worked. Then she was off and running after a hawk—camera gear jostling behind her—her long, wavy, ponytail blowing in the wind like a tail feather.

I met her again in 2014, just as the hawks’ nesting season got underway, to talk about her hobby and how two hawks have unknowingly changed her life.

Students at Cornell’s Shoals Marine Laboratory know Bogdanowicz as the Assistant Director for Academic Programs, but in the world of Bird Cams watchers, she has a strong following as unofficial photographer of the hawk family and one of the main BOGs, or “Birders on the Ground.” The BOGs are a dedicated group of local, volunteer hawk enthusiasts, most of whom work on the Cornell campus. They follow the birds in their spare time and report back to the wider Bird Cams community. Viewers wait in anticipation for the next round of Bogdanowicz’s breathtaking snapshots of Big Red, Ezra and their brood taken outside the eye of the nest cam. She captures intimate moments off the nest with incredible detail—like Ezra flying back to the chicks, a snake twisted in his talons, and a small pink flower intertwined with the prey.

EZ brings home food and a flower

Ezra carries prey and flowers, 2014. Photo courtesy of Christine Bogdanowicz.

For BOGs, the real action begins after the young hawks fledge and the Bird Cams chat closes. Without a daily dose of live hawk viewing, the audience longs to see how the fledglings grow and learn to hunt. What’s it like to be in such demand? “Fun,” she laughs. “I enjoy it immensely…. It’s a way to educate people in so many different walks of life in so many different stages of life… and give back what I have learned in my experiences.

Following the real-life adventures of a wild bird family isn’t always easy. In 2013, two young hawks, apparently from Big Red’s and Ezra’s nest, died shortly after fledging in separate mishaps. The news devastated the Bird Cams community. Viewers had faithfully watched the nestlings’ lives from the beginning, sparking a debate about whether the hawk family was being anthropomorphized too much. Bogdanowicz thinks not. “Whether you are connecting with the hawks or a stray dog I don’t think humanizing is a bad thing. I think that any way people can connect with the natural world is a good thing.” She admits the fledglings’ demise affected her, too. “I was a mess. It really hit me hard because we develop such an attachment. We see them every day, we hear them every day. But I think that it is all part of life and it is an experience I will keep in my heart and take with me and remember and learn from.”


A recently fledged and still scruffy E2 perched in one of Cornell’s campus gardens in June 2014. Photo courtesy of Christine Bogdanowicz.

In 2014 those feelings resurfaced when “E3,” the youngest of the year’s fledglings, injured its wing just one day after leaving the nest. The young hawk had perched on a motorized greenhouse vent which caught the bird’s wing as it closed—one of the many unnatural hazards urban hawks encounter. Fortunately, BOGs were nearby to sound the alarm and take E3 to Cornell’s Janet L. Swanson Wildlife Health Center, where he received surgery and is still recovering. (You can find updates on E3 at our Bird Cams Facebook page.)

A massive outpouring of support and donations from viewers for E3’s rehabilitation demonstrated the community’s dedication to the hawk family. “I was broken-hearted along with the entire hawk community the day E3 was injured,” says Bogdanowicz. “None of us know how this story will end—will he be set free—will he become an educational bird? Either way, my heart is now very, very happy that he’s alive and being cared for by the best of the best here at Cornell.”

She credits two mentors, Anne Gilbert and Art Borror, for her love of photography and birds. Gilbert, a teacher and friend, bought Bogdanowicz her first “real” camera in high school and fostered her love of the outdoors and photography. Borror, a favorite professor Bogdanowicz studied under at University of New Hampshire and Shoals, helped her develop as a naturalist, which she credits with helping her photos. “Studying your subject without the camera is really key,” she says. “I think having knowledge of bird behavior is actually critical in being able to take any kind of picture of birds.”


D2 shortly after leaving the nest, 2013. Photo courtesy of Christine Bogdanowicz.

Free-spirited and compassionate, Bogdanowicz has always felt a strong connection to the natural world. Supported by family and her husband, Steve (a research biologist at Cornell) on her journey, she often gains life lessons from the creatures that cross her path. “It helps put a lot of perspective on life in general—getting out and enjoying every day, trying not to worry about stuff people worry about,” she says.

So what kind of bird does she liken herself to? “An albatross,” she declares (besides watching the hawks, she spent some time this year watching the Cornell Lab’s Laysan Albatross cam). “They are eternally devoted to their mate and family, long-lived and world travelers. Goofy on land, but that’s sort of the way I am too.” To see her dash across campus, camera and tripod in hand, toward that next great shot, you never would have guessed.

AmyLaytonAmy Layton is a New Jersey native who has lived in Cayuga County, New York, for the past 6 years. She works for Weill Hall Facilities at Cornell University. An amateur photographer, she is a BOG herself. She spends her free time snapping pictures of the Cornell hawk family and is known as “Trtldove” to the Cornell Lab’s hawk cam community.

Find out more about Christine Bogdanowicz and the Cornell Lab’s Bird Cams program:


Ezra stretches his wings. Photo courtesy of Christine Bogdanowicz.


Big Red takes off from the nest in 2014. Photo courtesy of Christine Bogdanowicz.


Two of the “D’s,” Big Red and Ezra’s offspring in 2013. Photo courtesy of Christine Bogdanowicz.

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Ruby-throated Hummingbird

Hummingbird Occurence map

Four species of hummers cover most of the continental U.S. What about the rest of the species? Click the image to explore the ranges of 10 North American species at our Citizen Science blog.

Hummingbirds are special—brilliant, tiny, precision-flying creatures that glitter like jewels in the sun and dazzle with their aerial acrobatics, flying fast then stopping instantly, hovering, and zipping up, down, or backwards with exquisite control.

They’re strictly a New World animal, and they fascinated the first Europeans who arrived in North America. Christopher Columbus wrote about them. Many naturalists at the time wondered if they were a cross between a bird and an insect (at one point being called “flybirds”).

More than a dozen species of hummingbirds regularly summer in the United States, including these four that are most commonly seen at backyard feeders:

Ruby-throated Hummingbirds depart for Central America in early fall, with many crossing the Gulf of Mexico in a single flight. To accomplish this incredible migratory feat, they feast on nectar and insects and double their body mass, from 3 grams to 6 grams (or from the weight of a penny to the weight of a nickel). Ruby-throated Hummingbirds have the largest breeding range of any North American hummer.

Ruby-throated Hummingbird &, Black-chinned Hummingbird

Ruby-throated Hummingbird (left) by Laura Erickson, Black-chinned Hummingbird (right) by Brian Sullivan.

Black-chinned Hummingbirds are the most adaptable of all North American hummingbirds, found from deserts to mountain forests and from urban areas to pristine natural areas. The Black-chinned Hummingbird’s tongue has two grooves that suck up nectar like a sponge. Then the bird retracts the tongue and squeezes the nectar into its mouth.

Anna’s Hummingbirds are dazzling with iridescent emerald feathers and sparkling rose-pink throats. Nineteenth-century French naturalist René Primevère Lesson was mesmerized by “the bright sparkle of a red cap of the richest amethyst” on the male’s head and named it after the French duchess of Rivoli, Anna de Belle Masséna. These hummingbirds live along the Pacific Coast and in many areas are present year-round.

Anna’s Hummingbird & Rufous Hummingbird

Anna’s Hummingbird (left) by Nancy Starczyk, Rufous Hummingbird (right) by Chris Wood.

Rufous Hummingbirds are small but feisty. They chase off larger hummingbirds at flowers and feeders, and they’ve even been seen chasing away chipmunks. Rufous Hummingbirds have the northernmost breeding range of any hummingbird, yet in fall they migrate about 4,000 miles south to Mexico—in what is possibly the longest migration relative to body size of any bird.

More about hummingbirds:


(Image at top: Ruby-throated Hummingbird by Kevin Click via Birdshare)

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