Research Spotlight: Tracking Longspurs in the Wichita Mountains
Photos and story by Josh Kouri
It’s a cold, overcast day when a mud-and-ice covered truck pulls up to the edge of a mile-wide grassy plain nestled in the rugged hills of the Wichita Mountains National Wildlife Refuge. John Muller, a PhD student at the University of Oklahoma, steps out of the truck, pulls on a pair of binoculars and a radio receiver, and sets off through the field for his day’s work. John is studying the Chestnut-collared Longspur, a small grassland bird with drastically declining populations across Oklahoma. Today he’s using radio telemetry technology to search for a handful of birds that have gone missing from his study area.
John is part of a larger project to inform the best management practices for maintaining healthy populations of longspurs in Oklahoma. Longspur numbers have dropped precipitously in recent years (perhaps a 90% decline from historical numbers) largely due to habitat loss caused by agriculture and energy development. John uses radio transmitters attached to the birds to track their seasonal movement patterns as they overwinter in the Wichitas. Nu Perera, another graduate student at OU, tracks the birds at a finer scale to get a glimpse into their social interactions. A shared goal of these projects is to determine if local management efforts actually benefit migrating longspurs. The current view is that longspurs are “vagrant” birds, constantly moving between locations as resources are depleted. “But if they’re staying here throughout the winter,” John says, “you can actually manage for them.”
Although the results of the study are still preliminary, at least half of the birds appear to be doing just that. Birds Four and Five were captured, banded, and outfitted with radio transponders shortly after the initiation of the study at the start of this [winter. They were captured in a small grassland in the Wildlife Refuge near the road to the famous Meers restaurant, and they remained nearby throughout most of the winter. Then there was Bird Six, nicknamed Beyoncé for her independent attitude (although John jokes “we banded her, so technically we did put a ring on it.”). Whereas most longspurs spend the majority of their time in flocks with other birds, Beyoncé preferred to be by herself, spending her winter alone near the visitor center.
Besides the important conservation implications of his work, John has other reasons for studying longspurs. “They’re cool little unsuspectingly-charismatic birds” he says, “they’re little brown things that live in brown grass but they’ve got some cool behaviors.” Longspurs are experts at disappearing into their surroundings. They’re so good, in fact, that the researchers used to joke that they must be hiding underground. As it turns out this wasn’t so far from the truth. Several longspurs were observed hiding out in bison footprints, and a few were even sheltering in prairie dog burrows!
Longspurs are also unusual among migratory songbirds in that they only molt once a year. They start the winter in drab coloration that helps them blend in with the dormant grasses of their habitat, but as the winter progresses fringing on their feathers slowly wears away to reveal their breeding plumage. By the time they fly north in the spring, the males have distinct black feathers on their breast and a reddish brown ring around their necks that gives them the name “Chestnut-collared” Longspur. Most migratory songbirds, on the other hand, molt twice, once into their drab winter coat and once into their showy breeding feathers.
While the primary goal of this project is to understand the movement of longspurs throughout the winter, John and Nu also want to better understand the unique molting strategy of longspurs by tracking the degradation of the outer fringing over the winter. Additionally, they take blood samples to determine the amount of genetic diversity in the Oklahoma population and to learn what diseases the birds are exposed to. The only way to gather this information is to capture the birds, but doing so during the day is extremely difficult. That’s where the “Reign of Fire” technique comes in.
Photos by John Muller
John smirks a little as he starts to explain. “‘Reign of Fire’ comes from that crappy Matthew McConaughey movie with the dragons, where they can kill the dragons only at dusk because they see in both day and at night but they can’t see in between. In the twilight the longspurs don’t tend to flush very far and they don’t seem to see the net, so we’re calling it the ‘Reign of Fire’ technique.”
Towards sunset we met up with John, Nu, and their research technicians, Mary and Daniel, to put this plan into action. As dusk began to settle in we split up and spread out over the grassland. The temperature hovered around freezing but a brisk wind made it feel much colder, numbing our hands and faces. Fighting off the cold, we each took our post at a vantage point that provided a clear view of the birds as they flew in to find a warm place to sleep.
Although the goal was to follow a large flock of longspurs until they settled down for the night, we had no such luck this evening. Instead we resorted to an imprecise method of unguided sweeping through the field, targeting promising habitat in the hope of startling a few sleeping longspurs into our net. A pair of researchers held taut a large net parallel to the ground and marched it over the grass as the rest of the team followed behind to flush the birds.
Nu set up her radio receiver to try to locate a tagged bird and follow it to a flock. The receiver began to chirp quietly as it picked up the signals of Bird Five and Bird Thirty-One. Like a submarine stalking its quarry we set off quietly through the frigid darkness, guided only by the faint beeping of our tracking equipment. Unfortunately even the tagged birds managed to escape our search, changing directions on us several times without settling down long enough to guide us to a flock.
We continued making unguided sweeps, but after several hours in the cold and dark without any success we were ready to call it a night. We made one final sweep on our way back to the truck, and in a perfect confluence of events a flock of longspurs flushed at our feet just as a distant car rounded a bend and swept its light across the fluttering wings of our elusive targets. As their feathers illuminated in the headlights, the spectral forms of the longspurs seemed to hang motionless in the inky blackness before scattering into the night.
We managed to capture two longspurs in the net, a male and female, which John and Nu tenderly disentangled before placing in canvas bags for transport back to the truck. The bed of the truck served as a mobile field station containing all the equipment needed to record detailed measurements of the birds. The tailgate served as a makeshift lab bench for the researchers to carefully examine the longspurs. Despite frozen fingers, they gingerly banded each bird, recorded its weight, beak length, and approximate age, sampled feathers to track the emergence of their breeding plumage, photographed their feathers, and drew blood samples for genetic analysis and disease screening.
After all the measurements were taken we brought the birds back into the grassland and found a suitable hollow in a patch of grass where they could shelter, then released them. The information we collected tonight on the movement and health of these birds will help John and his team assess the large-scale patterns of movement and health within Oklahoma’s population of longspurs. Ultimately this work could help ensure longspurs are around for generations of Oklahoma birders and outdoor enthusiasts to appreciate and enjoy. But for now we returned to out trucks, satisfied with the night’s work, and thanked whoever it was who had the foresight to include seat warmers in the research vehicles!
This project was funded in part by ODWC’s State Wildlife Grants Program Grant F18AF00623, the USFWS Wildlife & Sport Fish Restoration Program, and the University of Oklahoma