Chihuahuan Desert Grasslands
Grasslands birds have declined more than any other group of North American birds. The causes for most of the declines are poorly understood but likely stem from changes in the quantity and quality of grasslands across their migratory range.
Two-thirds of the Chihuahuan Desert lies in Mexico. Less than 15 percent is grassland and less than half of that is suitable for species that require ample grass cover and little or no shrub cover. Many Chihuahuan Desert grasslands have been destroyed or radically altered through conversion to cropland, inappropriate grazing, urbanization and invasive species. The ongoing loss of wintering habitat is likely a principal factor in population declines among species wintering here.
Of 34 grassland-obligate species breeding in the western Great Plains, 85 percent over-winter in the Chihuahuan Desert. Only the three prairie grouse species do not depend on the Chihuahuan Desert grasslands for at least part of their life cycle. Because so many of North America’s grassland bird species concentrate in the limited grasslands of Chihuahuan Desert, suitable habitat in this region is critical to their conservation. However, conservation efforts on the wintering grounds have lagged far behind those to the North.
Unfortunately, the loss of desert grasslands is accelerating, especially in Mexico where more than 1 million acres have been lost in Chihuahua alone since 2005. This recent surge in land conversion is threatening to extirpate the last remaining, native desert-dwelling Aplomado Falcons and the Mexican Pronghorn, while severely impacting other grassland species.
 RMBO is working with partners in Mexico and the U.S. to conserve Chihuahuan Desert grasslands and the birds that depend on them. One factor hindering conservation efforts is that little is known about how grassland birds are distributed among the grasslands of the region and what affects their abundance and survival. RMBO is leading the way to fill these critical information gaps, while developing a platform for broader conservation. We are producing the scientific knowledge and tools needed to advance strategic habitat conservation, while building international partnerships, local capacity and public support for grassland conservation throughout the region. (Photo by G. Levandoski)
Wintering Grassland Bird Survey
Since 2007 RMBO has been leading a bi-national effort to inventory and monitor wintering grassland bird populations in the most important grasslands in the Chihuahuan Desert. This project has produced, for the first time, rigorous information on the distribution, density and habitat use of nearly 30 grassland species throughout most of the desert. We have used this information to redraw the map of priority conservation sites and develop conservation tools for this region.
We have also developed a bi-national network and partnership of organizations with increased capacity to address grassland bird conservation in their programs. To learn more about this project, see our latest reports on the right side of the page.
Winter Grassland Bird Survival
 RMBO began a pilot project in 2009 to research the winter survival and daily movements of grassland birds to better understand if populations are limited during the winter and what factors affect their survival.
We have focused our initial efforts on Vesper Sparrows, using radio-telemetry and in the winter of 2012 - 2013 extened this research to Grasshopper and Baird's Sparrow (pictured left). Early indications from the Vesper Sparrow study suggest grass height has a strong effect on survival, with at least 20cm of standing cover needed to provide effective protection from predators. (See the reports on this project in the right sidebar). Data from the 2012 - 2013 study is currently being analyzed and results will be posted here when completed. Read these recent blog posts from our telemetry crew leader for more information.
Education and Outreach
RMBO has developed education and outreach tools for people living and working in grasslands. Our Chihuahuan Desert Grassland Pocket Guide to Birds has successfully engaged landowners and increased their awareness about birds. In March 2010, we published 'Compartiendo Sus Agostaderos con Las Aves de Pastizal' (Sharing Your Rangelands with Grassland Birds), a best management practices manual to help landowners and range managers understand bird conservation needs and incorporate bird-friendly practices into their management and extension services (see our Available Reports for link to the pdf version).
Next Steps
Using the data we collect, along with other data on climate and land-cover change, we aim to better understand processes driving spatio-temporal and other ecological patterns of wintering grassland birds in the Chihuahuan Desert and predict impacts from climate change and other anthropogenic sources. This knowledge will help us identify where the most suitable and climate-resilient grasslands are most likely to persist in the future and adapt conservation strategies appropriately. We also aim to increase on-the-ground conservation efforts in key grasslands through engaging land managers and the public in protecting and improving habitat for birds and people.
Some of the 2013 telemetry crew in Janos, MX (Photo by Denis Perez)
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For More Information:
International@rmbo.org
230 Cherry Street
Fort Collins, CO 80521
Arvind Panjabi
International Program Director
(970) 482-1707 ext. 20
Greg Levandoski
Chihuahuan Desert Grasslands
Project Manager
(970) 482-1707 ext. 15
1997 Wintering Grassland Birds in Mexico (Report).pdf
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