Mark Howery, senior wildlife biologist for the Wildlife Department, documents all the birds he sees or hears during a Breeding Bird Survey on and around Pushmataha Wildlife Management Area in southeastern Oklahoma.
For biologist Mark Howery, getting up early is for the birds.
“I’m not in the habit of going to bed early to get up early. It’s hard to break a decades old habit of staying up late,” Howery said.
But each June, during the annual North American Breeding Bird Survey window, the self-proclaimed night owl shifts his sleep schedule and is at his designated routes well before dawn.
“I can be motivated to wake up early for birds.”
As the assigned observer for two Oklahoma Breeding Bird Survey routes located near Holdenville and Clayton, Howery navigates to the respective areas in the dark and is at the starting points, ready to tally every bird he sees or hears in a three-minute period at each of the route’s 50 stops, before the sun breaks over the horizon.
Sixty-two Breeding Bird Survey routes have been created in Oklahoma. On average, 39 routes are surveyed each year.
Originally developed by the U.S. Fish and Wildlife Service and now coordinated by the U.S. Geological Survey and Environment Canada, the Breeding Bird Survey is a long-term, large scale, international monitoring program that began in 1967. More than 4,100 routes have since been established across North America, with 62 routes located in Oklahoma. Once the route is surveyed, observers submit the data to their state’s volunteer coordinator and the analysis begins. The resulting index of bird abundance has been used to estimate trends for more than 420 bird species and their relative abundances at various scales, which can help biologists better manage the populations.
Consistency is Key
To be able to track the status and trends of North America’s bird populations, the Breeding Bird Survey relies on standardization. The same routes are run in the same month every year, according to the same procedures, regardless of which observer runs the route. The observer’s goal is “to expend the same effort in the same way each year to ensure the count numbers reflect real changes in birdlife and not changes in the methods.” Observers must be able to identify all the breeding birds in the area by sight and sound, and new observers must also successfully complete a training program before their data will be used in the survey’s analysis.
Breeding Bird Survey Specifics
Where to Survey: Each survey route is approximately 24.5 miles long with 50 stops located at half-mile intervals along the route. Stop descriptions were collected at the creation of the route and the assigned observer leans on both written landmarks and their odometer to locate each stop.
When to Survey: Breeding Bird Surveys are conducted in June, during the height of avian breeding season for most of the United States, with some exceptions. Start times are route-specific but are generally 30 minutes before official sunrise. The route must be completed within five hours of the start time.
How to Survey: At each survey stop, the assigned observer tallies all birds seen within one-quarter mile of the location and all birds heard during a three-minute window. Once the three minutes are completed, the observer quickly moves to the next stop.
In many cases, the survey’s consistency also extends to its observers. Howery has been the assigned observer for the Pushmataha Breeding Bird Survey route since 2005 but joined then state coordinator Bill Carter and experienced birder Mike Dugan on a test run when they first established the route in 1993. And since 37 of the route’s 50 stops are located on the Wildlife Department’s Pushmataha Wildlife Management Area, Howery is also familiar with the extensive habitat management efforts that have taken place since 1982, when the area became a research site studying the effects of prescribed fire on an oak-pine forest.
The Pushmataha Breeding Bird Survey route’s 50 stops have been surveyed in the same way almost every year since 1994. A majority of the stops are located along Pine Tree Circle on the Wildlife Department’s Pushmataha Wildlife Management Area, near Clayton.
“When the route first started, the habitat was so dense, it was difficult to hear or see birds. So, the number of individual birds documented was lower than it is today. Now that many of the roads have been daylighted and a lot of the area has been thinned, its much easier to hear and detect the birds.
“The habitat changes have also altered the bird community somewhat by increasing edge habitat that has expanded the populations of species like indigo bunting, blue grosbeak, orchard oriole, yellow-breasted chat, common yellowthroat, and prairie warbler. It has also resulted in a decrease in the population of red-eyed vireos, but other forest birds such as the summer tanager and pine warbler haven’t been substantially affected.”
Because so many survey variables are consistent, biologists are able to assess changes in the bird community. During the Pushmataha route’s first three years, an average of 50 species and 521 individuals were detected. In the three most recent years of available data, an average of 59 species and 758 individuals were detected. (The Pushmataha route was not surveyed in 1999, 2000, and 2004 because of weather conditions. No routes were surveyed in 2020 due to COVID-19 protocols.)
The Challenge of Bird Identification
As Howery starts the stopwatch to begin the three-minute countdown at his first stop, he is greeted with a cacophony of sound. It’s his job to transcribe the sounds he hears into data, logging which species is present, and how many individuals of each species he can detect.
Birding by Ear…or by App
If your ears aren’t as cued into the species-specific bird songs as Howery’s, you can still bird by ear with the help of Merlin, an app from the Cornell Lab of Ornithology. The app’s “Sound ID” feature listens for birds, records the spectrogram, and then offers real-time suggestions for which bird is singing. This can help train your ear for future birding trips, or simply give you confidence in knowing which birds are visiting your backyard. Once you’ve identified the bird by its song, you can then learn more from All About Birds.
“It will slow down in a few hours, but at these first few stops, I’m mainly listening for bird songs. I’ll be visually looking for birds more as the day grows lighter,” Howery said.
“Learning the birds that are likely to be detected on the route is probably one of the biggest challenges of this survey. That and keeping birds and their songs straight. There are a few confusing pairings, like the summer tanager, scarlet tanager, and the red-eyed vireo, that can sound very similar. And the pine warbler and chipping sparrow pairing is even more challenging.”
Despite Howery’s experience as a birder, those challenges are especially real for the Pushmataha Breeding Bird Survey route.
Since its creation in the mid-1990s, 94 bird species have been detected along the Pushmataha route, more than one-third of the 276 total species detected statewide since Oklahoma’s first Breeding Bird Surveys in the late 1960s. And the sound-alike summer tanager and vireo are the second and third most encountered species on the Pushmataha route. The indigo bunting, a small, brilliant blue songbird, is the most encountered species.
After hours of listening to the bunting’s two-note song, deciphering the sound-alike species, and tallying hundreds of other birds along the route, Howery is still tempted to stay longer and add a few more birds to the list.
“Staying on time is another real challenge of the survey,” Howery said. “It’s easy to want to stay at a stop longer than the allotted three minutes. To add a few more birds.”
Howery’s survey efforts are supported by the Wildlife Department and State Wildlife Grant F22AF02644.