All About Birds Blog

Home Page

By Hugh Powell


A hundred years after they went extinct, Passenger Pigeons are suddenly everywhere you look on the Internet. Scientists and historians, newspapers and blogs alike are revisiting what is likely the starkest conservation lesson we’ve ever learned. That’s because Monday, September 1, 2014, marks the centennial of the death of Martha, the very last member of what was once the most abundant bird on the planet.

In an op-ed for the New York Times today, Cornell Lab director John Fitzpatrick remembers the extinction of the Passenger Pigeon and then looks ahead, wondering, “What can we tell Martha we’ve learned since her passing?”

We learned the main lesson quickly, Fitzpatrick argues: that extinction is forever, unless we do something about it. The Migratory Bird Treaty Act was passed just four years after Martha vanished; and eventually, in the 1970s, the United States passed the Endangered Species Act—a powerful piece of legislation that likely would have saved the Passenger Pigeon had it existed during the bird’s decline.

But there are other lessons that we’ve been slower to learn. The epic scale of the Passenger Pigeon at its height—those sun-darkening flocks; the boughs that broke under the combined weight of all those perching feet; the barrels upon barrels of salted pigeon meat—seem to put the bird in a class by itself. To many people it is a mysterious disaster, but a unique one that surely could never be repeated.

To which Fitzpatrick says: this disaster has already been repeated, in the commercial cod fishery in the Atlantic. And it is being repeated again right now, with Atlantic bluefin tuna. With the seabirds of the open ocean. With what few native birds of Hawaii still remain. With the aridlands of the West.

These are all issues addressed by the 2014 State of the Birds report, due to be released in just over a week. Written by bird conservation experts from the Cornell Lab and other nonprofits, government agencies, and academia, the State of the Birds has functioned since 2009 as an early warning system as well as a chronicle of conservation successes. This year’s report takes the lessons of the Passenger Pigeon to heart and, with the help of massive datasets that have only recently become available, identifies the conservation challenges of the future so that we can work at averting them.

It does this by spotlighting key habitats, like the ones mentioned above, as well as by creating two types of lists: a Watch List of species with serious population concerns, and a list of Common Birds in Steep Decline—the ones that, like the Passenger Pigeon, have long been numerous but seem to be quietly disappearing. (Check back for links to these lists after the report’s Sept. 9 launch date.)

Extinction is forever, unless we do something about it. The second half of that lesson is what keeps conservationists going. It’s not just wishful thinking—we’ve proven it with decisive victories that brought species like the Bald Eagle, Brown Pelican, and Peregrine Falcon back from the brink. As the 2014 State of the Birds report shows, we still have many bird species on a Passenger Pigeon-like trajectory. But with all of us pulling together, it’s a fate that does not have to be repeated.

More about the Passenger Pigeon:

(Top image: Passenger Pigeons by Louis Agassiz Fuertes.)

Posted in conservation | Tagged , , , , , , | Leave a comment


By Pat Leonard

It was just over a year ago, on the same day, that two young Red-tailed Hawks were injured in separate accidents on the Cornell campus. One was found dead; the other was euthanized because of the severity of its injuries. Many people feared the young birds were the offspring of Big Red and Ezra, the beloved hawk pair that have nested on campus for years and have been featured on our live Bird Cams since 2012. But there was no way to tell for sure.

It was the not-knowing that bothered Cornell University employees Christine and Steve Bogdanowicz. But unlike most Bird Cams fans, they were in a position to investigate. Steve is an evolutionary biologist who turned his expertise with DNA analyses to determine the hawks’ familial relationships. He directs the Evolutionary Genetics Core Facility at Cornell University. Christine is the Assistant Director for Academic Programs for the Shoals Marine Lab and a Birder on the Ground. These “BOGs” are a dedicated group of local, volunteer hawk enthusiasts, most of whom work on campus. They follow the birds in their spare time and report to the wider Bird Cams community.

So, were the two dead birds the offspring of Big Red and Ezra? It took hard work (all by volunteers), plus feathers, tissue samples, and another injured hawk to clear up the uncertainty. And when the answers emerged they were surprising: one yes and one no.


DNA testing confirmed that the fledgling found injured in 2013 was the offspring of Big Red and Ezra and a female. She was most likely D1, the eldest of the 2013 brood. Photo by Christine Bogdanowicz.

Steve learned that the bird found severely injured does appear to be one of the young hawks from Big Red’s and Ezra’s 2013 “D” brood. This bird, a female, was known as “D1″ to the hawk cam community. The other young bird, the one that had been found dead, had been assumed to be “D3.” This bird, a male, turned out not to be related to Big Red or Ezra and must have come from another hawk nest in the area.

In October 2013 Steve began the necessary DNA work using tissue samples from the two dead juvenile hawks sent over from Cornell’s Animal Health and Diagnostic Center. His goal was to create a library of specific genetic “markers” for Red-tailed Hawks—something that did not exist at the time. During the fall of 2013, Steve developed 15 microsatellite DNA (msat) loci (locations) from the samples.

“Msats are simple, relatively short, repetitive sequences interspersed throughout otherwise complex genomes,” Steve explains. “Humans, Red-tailed Hawks, plants, and other animals typically have tens of thousands of distinct msat loci.” Finding a set of specific markers that can be used as a basis for comparison is the same technique used to identify human crime suspects or establish paternity.

To establish relatedness, Steve also needed to get DNA from Big Red and Ezra and one of their known offspring for comparison. That didn’t happen until 2014. Another dedicated BOG and Cornell staffer, Karel Sedlacek, collected feathers he witnessed drop from Big Red and Ezra and passed them to Steve. (Note: Sedlacek was issued a special permit to take these feathers. It is otherwise illegal to do so.)


E3, a fledgling from Big Red and Ezra’s 2014 nest, was also injured and is recovering at the Janet L. Swanson Wildlife Health Center. E3′s DNA sample was a crucial part of determining the identities of the 2013 hawks. Photo by Dr. Noha Abou-Madi.

Then E3, a bird hatched by Big Red and Ezra this year, was injured after fledging. The Janet L. Swanson Wildlife Health Center is caring for him and was able to provide a blood sample.

“E3 was key,” says Christine. “His sample solidified what an offspring of Big Red and Ezra would look like genetically.”

“DNA extracted from an individual hawk can be amplified through a process called polymerase chain reaction (PCR) at each of these microsatellite loci,” says Steve. Amplification means the PCR process increases the amount of DNA available, creating enough genetic material to visualize and measure. A separate test to determine gender was made possible by Laura Stenzler at the Cornell Lab’s Fuller Evolutionary Biology lab.

Steve’s work established that E3 had DNA markers showing he inherited one PCR fragment (allele) from Big Red and another from Ezra at each microsatellite locus—just as humans inherit one copy of each parent’s DNA. Any offspring of Big Red and Ezra would inherit one PCR fragment from each parent for all 15 of the loci—all 15 loci have to match, as they did for E3. (The figure below shows 1 of the 15 loci.) If there is even one mismatch, that’s enough to rule out that bird as being related. And that’s what happened with the mystery juvenile originally thought to be D3.


Sample results from 1 of the 15 microsatellite loci used in the DNA analysis. Like humans, birds receive one copy of their DNA from each of their parents. By lining up the peaks in the graphs, it’s clear that E3 received one copy of this locus from Big Red and another from Ezra. By comparison, the mystery hawk has two copies of the same allele (and thus shows only one peak). That peak does not match either Big Red or Ezra, indicating he is not related to either of them, and therefore cannot be D3. Photos: Big Red and Ezra by Christine Bogdanowicz, E3 from the Janet L. Swanson Wildlife Health Center.

There are many other Red-tailed Hawks in and around the Cornell campus. Some hang out near the horse paddock, others live along nearby cliffs, and still others frequent a nearby cemetery. Perhaps the mystery juvenile came from one of those groups. Steve has gotten tissue bank information for about 40 red-tails that the Wildlife Health Center has taken in since 2011. With that and any future samples gathered, he could start building up a profile of what the local Red-tailed Hawk population looks like and determine relationships from a tangle of overlapping territories.


DNA testing established that the fledgling found dead in 2013 was not related to Big Red or Ezra. D3 (above) may still be out in the wild somewhere. Photo by Christine Bogdanowicz.

“Now we’ll be able to focus on these 15 established markers to determine if birds come from an isolated population or if there’s gene flow between two or more populations,” says Steve. “We can learn family-level relationships and individual identity. Big Red and Ezra have produced maybe 20–25 offspring over the last decade. Are any of them back in the area as adults? I’m doing this work because I’m curious, primarily, and because of the mystery of the two dead birds last year.”

“Maybe it’s a little bit of closure,” says Christine. “There was so much hurt and angst, anxiety and sorrow. But these birds will not have died in vain if we learn from them. They’re helping us understand the family of Red-tailed Hawks that live in this area and maybe beyond.”

Find out more about the Cornell Bird Cams Hawks:

(Top image: Cornell Lab Bird Cams.)

Posted in Bird Cams | Tagged , , , , , , , , , | 21 Comments


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.)

Posted in citizen science | Tagged , , , , , , , , , | 12 Comments

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:

Posted in Uncategorized | 3 Comments
Older Entries |