Grasshopper sparrow, one of the study birds in our survey
Notice the yellow on the wings and head. Also the breast is not streaked.
While it may be hard to believe living here in West Texas, grasslands are one of America’s most quickly disappearing ecosystems. Over-grazing of sheep, cattle and goats combined with changing weather patterns and recent droughts in the west, plus erosion and the crowding out of native grasses by invasive species are a big part of the problem. Commercial development of grasslands also takes a toll. And then there is the booming oilfield.
|Setting up the nets|
The Borderlands Research Institute (BRI) and graduate students at Sul Ross State University have been monitoring the decline of migratory bird populations of the Chihuahuan Desert and the Big Bend Region. At least two of these birds, Baird’s and grasshopper sparrows, are considered to be keystone species as their numbers are declining and they depend on healthy grasslands to thrive.
Baird's sparrow, another bird in the study
Notice the streaked breast.
|Untangling the birds from the nets can sometimes be a delicate process.|
Two Sul Ross graduate students, working on thesis projects, are monitoring avian biodiversity and these two keystone sparrows. David and I plus many of our classmates in Ornithology, have been assisting the graduate students.
Not a study bird, many savannah sparrows were caught in the nets.
This one is none too happy about it either -- getting a nip is just one of the hazards.
Part of the research has been taking place on the Mimm’s Ranch in Marfa. The ranch is an ideal place for this study as the owners are committed to a long-term project of shrub clearing and seeding in order to reestablish native grasses and the grassland habitat. Presently it is not known exactly how or even if the invasive exotic grasses are used in the diets of Baird’s or grasshopper sparrows. The study on Mimm’s Ranch may someday answer many questions and help improve the survival of these birds.
|Setting up nets in the wind is a challenge|
Much of the project has consisted of banding these two sparrows. But transmitters were placed on some captured birds to follow their movements in order to learn about their winter survival and habitat use. David and I helped with setting up nets to capture the birds and then helped flush the birds into the nets so they could be banded. The graduate students did the banding, but we got to see the birds up close, help record data and then release the birds.
|Graduate student, Fabby, hands a bird off to David for release.|
A typical research day started at 7:30 at the ranch headquarters, meaning an early rise for us as we had about a 30 minute drive. After a quick briefing at the headquarters we would help gather the equipment, load the trucks then head out to the study areas. Nets were untangled, moved across the fields and set up. Then a large horseshoe was formed, and we would all wave our sticks both high and low to drive the birds into the nets.
|Forming the horseshoe|
Usually there was at least one bird in the net and several of us would help the graduate students with the bird by recording banding information while others would move the net to the next spot. This process went on for several hours with a break for lunch.
|Measuring beak length|
Measuring wing length
Birds were also weighed, checked for fat reserves, and feathers examined
Other researchers worked with us tracking some of the birds that had been fitted with transmitters. As it is migration time, a lot of effort has been made in the last several weeks to recapture these birds and remove the transmitters. The birds are having a hard enough time surviving as it is and migration is quite an extraordinary feat without having to carry extra 'luggage.'
|Grasshopper sparrow - examining wings|
Since this is a winter survival and habitat use study of grassland birds, the research just wound down before spring break. One of the graduate students is finishing her research this year, but another one will continue his study for another year. Probably others will follow as it may take many years to get answers for these young researchers. Science is a slow process and it is always ongoing. We learned a lot and it feels good to have assisted in this research in some small way.